A Phase 1/2 Trial Investigating the Safety and Efficacy of Autologous TAC T Cell Monotherapy, and TAC T Cells in Combination With Pembrolizumab, in Relapsed HER2-Positive Solid Tumors
Phase: PHASE1
Conditions: HER2 Positive Gastric Cancer, Metastatic HER2 Positive Gastroesophageal Junction Cancer
Sponsor: Triumvira Immunologics, Inc.

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A Phase 1/2 Trial Investigating the Safety and Efficacy of Autologous TAC 
T Cell Monotherapy, and TAC T Cells in Combination with Pembrolizumab, 
in Relapsed HER2-Positive Solid Tumors 
 
Protocol Number: 
TAC01-HER2-03 (TACTIC-2) 
 
Date: 
Version: 
 
25 October 2023 
6.0 
 
Regulatory Sponsor: 
Triumvira Immunologics, Inc.  
www.triumvira.com 
9433 Bee Cave Road  
Building 1 Suite 240 
Austin, TX 78733 
USA 
Phone: 512-790-0222 
 
and 
 
270 Longwood Road South 
Hamilton, ON L8P 0A6 
Canada 
Phone: 289-799-6463 
 
 
 
 
 
 
 
 
This study will be conducted in compliance with the protocol, International Council 
for Harmonisation Good Clinical Practice (ICH GCP), and applicable state, local, and 
federal regulatory requirements. 
 
 
 

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INVESTIGATOR PROTOCOL SIGNATURE PAGE  
A Phase 1/2 Trial Investigating the Safety and Efficacy of Autologous TAC T Cell 
Monotherapy, and TAC T Cells in Combination with Pembrolizumab, in Relapsed 
HER2-Positive Solid Tumors (TACTIC-2) 
I have read this protocol and agree to conduct the study as outlined herein, in accordance with 
the Declaration of Helsinki, the International Council for Harmonisation (ICH) E6 Guideline 
for Good Clinical Practice, US FDA regulations, IRB/IEC requirements, all national, state, and 
local laws and/or requirements of pertinent regulatory authorities. 
 
 
 
 
_______________________________________ 
Investigator Printed Name 
 
 
_______________________________________     __________________________ 
Investigator Signature  
                                   Date Signed 
 
 
 
 
 

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SPONSOR SIGNATURE PAGE 
A Phase 1/2 Trial Investigating the Safety and Efficacy of Autologous TAC T Cell 
Monotherapy, and TAC T Cells in Combination with Pembrolizumab, in Relapsed 
HER2-Positive Solid Tumors 
We, the undersigned, have read this protocol and agree that it contains all necessary 
information required to conduct the study. 
 
Signatures:                                                                      Date Signed: 
 
_________________________                                    __________________________ 
Deyaa Adib, MD 
Chief Medical Officer 
 
_________________________                                    __________________________ 
Peter Shabe 
Statistician 
 
 
_________________________                                    __________________________ 
Kara Moss 
Sr. Director of Clinical Operations 
 
 
 
 
 
 
 

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PROTOCOL SYNOPSIS 
Protocol Number: TAC01-HER2-03 (TACTIC-2) 
Product Name: TAC01-HER2 (TAC T Cells) 
Protocol Title: A Phase 1/2 Trial Investigating the Safety and Efficacy of Autologous TAC T Cell Monotherapy, and 
TAC T Cells in Combination with Pembrolizumab, in Relapsed HER2-Positive Solid Tumors 
Sponsor: Triumvira Immunologics, Inc. (Triumvira) 
Study Phase: 1/2 
Study Rationale:  
Despite recent therapeutic developments for patients with advanced, metastatic, unresectable human epidermal 
growth factor receptor 2 positive (HER2+) solid tumors, a significant unmet medical need still exists, especially in 
solid tumors where there are no approved HER2-targeted therapies and/or in tumors with low or intermediate 
HER2 expression. The T cell antigen-coupler (TAC) technology is a novel approach to modifying a patient’s own T 
cells, herein referred to as TAC T cells, and using them in the treatment of solid tumors. TAC T cells are produced 
through genetic engineering, incorporating TAC receptors into a patient’s own T cells. This redirects these 
enhanced T cells to specific cancer antigens, and upon recognition, activates them through the natural signaling 
pathways of the endogenous T cell receptor (TCR).  
In the TAC01-HER2 product, TAC T cells use the HER2 antigen, which is present on the surface of cancer cells, 
to recognize and eradicate tumor cells. Promising outcomes have been observed in mouse models, with TAC 
T cells accumulating within solid tumors, resulting in a robust antitumor efficacy profile paired with a favorable 
safety profile. TAC T cells can also persist for extended periods of time in mice and protect the host from tumor 
regrowth. Consequently, it is hypothesized TAC01-HER2 monotherapy will be safe and effective in treating 
patients with HER2+ solid tumors and can provide a significant therapeutic benefit in an area of high unmet 
medical need. 
Phase 1 will evaluate escalating single doses of TAC01-HER2 (on Day 1) as a monotherapy, and in combination 
with a fixed pembrolizumab approved prescription dose (200 mg every 3 weeks [Q3W]) beginning on either 
Day 21 or Day 14 to identify the recommended Phase 2 doses (RP2Ds) for TAC01-HER2 treatment in subjects 
with HER2+ solid tumors, who have progressed after 2 prior lines of  therapy.  
In vitro nonclinical studies conducted by Triumvira suggest that TAC T cells specifically engage with HER2+ 
cancer cells. As part of this T cell activation process, TAC T cells, similar to any other activated T cell, can induce 
the expression of programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1), which can 
consequently lead to reduced TAC T cell activity. Blocking PD-1 signaling via an anti-PD-1 checkpoint blockade, 
such as pembrolizumab, can counteract this inhibitory function. Therefore, these observations highlight the 
importance of evaluating the combination of TAC01-HER2 treatment with PD-1 blockade to potentially enhance 
the antitumor activity of administered TAC T cells. Attenuating the eventual exhaustion of TAC T cells may also 
facilitate the recruitment of endogenous polyclonal immune cells to overcome tumor heterogeneity and to prevent 
antigen escape (Grosser 2019). Mechanistically, this occurs through first treatment with TAC01-HER2, followed 
by pembrolizumab to block PD-L1 and PD-L2 ligands on cancer cells from binding to PD-1 receptors on resultant 
circulating TAC T cells.  
In addition to 3+ HER2 tumors, subjects with low-HER2 expressing solid tumors (i.e., 2+ and 1+) will also be 
allowed to participate in this trial. These subjects constitute an area of high unmet medical need, e.g., 60% of all 
breast cancer patients have low-HER2 expressing tumors (Modi 2022). Nonclinical studies have demonstrated that 
TAC T cells are equally effective in eliciting antitumor activity regardless of HER2 expression levels (Figure 7) 
and are active in killing tumor cells that are resistant to trastuzumab and pertuzumab. In addition, trastuzumab 
deruxtecan, a HER2-targeting antibody drug conjugate, has recently demonstrated significant success in treating 
low HER2-expressing tumors in breast cancer patients (i.e., with an objective response rate [ORR] of 37.0% in a 
Phase 1B trial [Modi 2020] and 52.3% in the Destiny Breast04 Phase 3 trial [Modi 2022]), with a median duration 
of response (DOR) of 10.7 versus 6.8 months (in the Phase 3 trial) for trastuzumab deruxtecan treatment vs the 
physician’s choice of chemotherapy (Modi 2022).  
In conclusion, HER2 overexpression and/or amplification is observed in breast, gastric, lung, pancreatic, 
salivary, vaginal, endometrial, gall bladder, colorectal, and cervical cancers. It activates numerous oncogenic 
signaling pathways (e.g., PI3K/AKT and Ras/Raf/ERK) resulting in improved malignant cell survival, proliferation, 

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migration, and resistance to immunotherapy (Vafaei 2022). HER2-targeted therapies continue to evolve in treating 
patients with varying levels of HER2 expression. However, continued advances using novel targeted therapies are 
still needed to treat patients more effectively and with fewer side effects. 
Study Objectives: 
Objectives 
Endpoints 
Primary 
Phase 1: To evaluate the safety of TAC01-HER2 
monotherapy and pembrolizumab combination 
therapy in subjects with HER2+ solid tumors 
Incidence of dose limiting toxicities (DLTs) 
Type, frequency, and severity of adverse events (AEs) 
(including clinically significant laboratory 
abnormalities). 
Phase 2: To evaluate the clinical activity of 
TAC01-HER2 monotherapy and pembrolizumab 
combination therapy in subjects with HER2+ solid 
tumors 
ORR 
DOR 
Overall survival (OS) 
Disease control rate (DCR) 
Progression-free survival (PFS) or 
Time to progression (TTP) 
 
Investigator-assessed imaging using Response 
Evaluation Criteria in Solid Tumors Version 1.1 
(RECIST 1.1) 
Secondary 
Phase 1: To determine the maximum tolerated dose 
(MTD) or RP2D for TAC01-HER2 monotherapy 
and pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
Incidence of DLTs 
Phase 2: To evaluate the safety of TAC01-HER2 
monotherapy and pembrolizumab combination 
therapy in subjects with HER2+ solid tumors 
Type, frequency, and severity of AEs (including 
clinically significant laboratory abnormalities). 
Phase 1 and Phase 2: To characterize the 
pharmacokinetic (PK) profile of TAC01-HER2 in 
subjects with HER2+ solid tumors 
Maximum concentration (Cmax), time to reach 
maximum concentration ( Tmax), and area under the 
concentration time curve (AUC) of TAC T cells 
Duration of persistence of TAC T cells 
Phase 1: To evaluate the clinical activity of 
TAC01-HER2 monotherapy and pembrolizumab 
combination therapy in subjects with HER2+ solid 
tumors 
ORR 
DOR 
OS 
DCR 
PFS or 
TTP 
 
Investigator-assessed imaging using RECIST 1.1 
Phase 1 and Phase 2: To evaluate the 
immunogenicity of TAC01-HER2 monotherapy and 
pembrolizumab combination therapy and to assess 
potential impacts on PK exposure and biological 
activity 
Immunogenicity of TAC T cells and pembrolizumab 

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Phase 1 and Phase 2: To investigate candidate 
efficacy biomarkers and anti-tumor activity of TAC 
T cells utilizing pre- and post-treatment tumor 
biopsies 
Cytokines and TAC copies/µg genomic DNA (gDNA) 
Exploratory 
Phase 1 and Phase 2: To explore biomarkers that 
may predict pharmacologic activity or response to 
TAC01-HER2 monotherapy and pembrolizumab 
combination therapy 
Characterize T cells and correlate with clinical 
outcomes 
Describe profile of soluble immune factors and 
relationship to cytokine release syndrome (CRS), 
neurotoxicity, and TAC T cell engraftment  
Study Design:  
This is a first-in-human study investigating TAC01-HER2 monotherapy and combination therapy with 
pembrolizumab to evaluate the safety, MTD or RP2D, PK parameters, and clinical activity in subjects with HER2+ 
solid tumors. During the Phase 1 portion of the study, increasing dose levels of TAC01-HER2 monotherapy will be 
evaluated first using the keyboard design method: 
Dose Level 
TAC T Cells/kg body weight 
(Single Dose on Day 1) 
-1 
6 – 8 x 104 
1 (starting dose) 
1 – 3 x 105 
2 
6 – 8 x 105 
3 
1 – 3 x 106 
4 
6 – 8 x 106 
Once monotherapy has been investigated, the safety data reviewed by the Data Safety Monitoring Committee 
(DSMC), and the RP2D is determined, combination therapy can begin in parallel with monotherapy dose expansion 
starting at a dose level that is 2 steps below the RP2D for TAC01-HER2. The RP2D has been determined by the 
DSMC to be Dose Level 4. Accordingly, the starting dose level will be Dose Level 2. The following TAC T cell 
dose levels will be investigated in the combination arm. 
Dose Level 
TAC T Cells/kg body weight 
(Single Dose on Day 1) 
Pembrolizumab 
 
1 
1 – 3 x 105 
200 mg Q3W 
2 (starting dose) 
6 – 8 x 105 
200 mg Q3W 
3 
1 – 3 x 106 
200 mg Q3W 
4  
6 – 8 x 106 
200 mg Q3W 
Subjects will be allocated to the group that allows the subject to start their treatment regimen in the shortest 
timeframe. Priority to enrollment will be for the combination dose escalation arm, with the following exceptions: 
within the safety gate interval, during DLT observation period, subject and Investigator preference, and if subject 
does not meet criteria to receive pembrolizumab. 
As an additional safety precaution, the first combination cohort will treat 3 subjects with TAC T cells and administer 
pembrolizumab on Day 21. After review of safety data by the DSMC and in the absence of DLTs, an additional 
3 subjects will be treated at this same initial combination dose level, with pembrolizumab administered on Day 14. 
Based on the results of these 6 subjects, the DSMC will either recommend Day 21 or Day 14 for the start of 
pembrolizumab administration in all subsequent combination cohorts, followed by administration of pembrolizumab 
200 mg Q3W for up to 2 years.  

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The overall study design is outlined below:  
 
Abbreviations: DSMC=Data Safety Monitoring Committee; HER2=human epidermal growth factor receptor 2; 
I/E=inclusion/exclusion; N=number of subjects; Pembro=pembrolizumab; PK=pharmacokinetics; RP2D=recommended Phase 2 
dose; TAC=T cell antigen coupler. 
Phase 1 will evaluate increasing dose levels of TAC01-HER2 as a monotherapy, and in combination with 
pembrolizumab, to identify RP2Ds in subjects with HER2+ solid tumors who have progressed after 2 prior lines of 
therapy.  
In Phase 2, dose expansion groups will further evaluate the safety, clinical activity, and PK of the RP2D for 
TAC01-HER2 in HER2+ gastric and esophageal adenocarcinoma who have progressed after 2 and no more than 4 
prior lines of therapy in 2 groups: Group A (TAC01-HER2 monotherapy) and Group B (TAC01-HER2 + 
pembrolizumab). Central laboratory confirmation of HER2+ by immunohistochemistry (IHC) and fluorescent in-
situ hybridization (FISH) will be conducted. 
In Phase 2, a second dose (monotherapy arm only) may be administered (see Section 3.4 for additional details 
and Section 4.3 for eligibility criteria of second dose).  
Upon enrollment, subjects will undergo leukapheresis to obtain T cells for TAC01-HER2 manufacture. Subjects 
may receive bridging anticancer therapy, after leukapheresis and before lymphodepleting chemotherapy (LDC) if 
deemed necessary by the Investigator. Bridging therapies must be discontinued at least 14 days prior to initiation of 
lymphodepletion, and subjects must continue to meet eligibility criteria pertaining to adequate organ function 
(except hematologic parameters), active infections, pregnancy, measurable disease confirmed by repeat imaging, 
and medication washout before initiation of lymphodepletion. If TAC01-HER2 cannot be manufactured from the 
first leukapheresis product, additional leukapheresis may be allowed after consultation with Triumvira. 
Upon the successful manufacturing of TAC01-HER2, subjects will enter the treatment phase. In the 
monotherapy arm, treatment will include LDC followed by a single dose of TAC01-HER2 administered 
intravenously (IV) on Day 1. In the combination arm, treatments will include LDC, a single dose of TAC01-HER2 
administered IV on Day 1, and pembrolizumab 200 mg administered IV Q3W starting on Day 21 or Day 14 based 
on recommendations from the DSMC.  
Subjects who receive 1 dose and subjects who receive combination therapy will follow procedures described in 
Appendix A1 and Appendix A2, respectively, for up to 24 months after the first dose, until the subject withdraws 
consent, or the subject is lost to follow-up. Radiographic disease assessments for progressive disease (PD) and other 
responses in single-dose subjects will occur at Day 29±2 days, then Q8W±2W for Year 1 and Q12W±2W for Year 

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2. If a subject who receives 1 dose has initial PD on the Day 29±2W scan, a confirmation scan should occur 28 days 
(± 7 days) later to confirm the initial PD was not a tumor flare.  
Subjects who receive 2 doses will follow procedures described in Appendix B for up to 24 months after the first 
dose, until the subject withdraws consent, or the subject is lost to follow-up. Assessments for PD will occur on Day 
29±2 days after the first dose on Day 1, then Q8W±2W until the second dose is administered. Once the second dose 
is administered (i.e., Day X), scans will be performed on Day X + 28±2 days, Q8W±2W after Day X for 1 year, and 
then Q12W±2W after Day X for up to 24 months after the first dose, until the subject withdraws consent, or the 
subject is lost to follow-up.  
If a subject has confirmed PD 3 months after the first dose, starts a new anticancer therapy, or is unwilling or 
unable to continue the respective procedures indicated in Appendix A1, Appendix A2, or Appendix B, then the 
subject will transition to the long-term follow-up (LTFU) protocol.  
The LTFU protocol has a reduced schedule of events that complies with regulatory requirements for follow-up 
and does not include radiographic disease assessments. After study completion, subjects will be followed for 
survival, long-term toxicity, and viral vector safety to be monitored for up to 15 years. 
Dose Limiting Toxicities: 
Toxicities will be evaluated and graded according to the National Cancer Institute (NCI) Common Terminology 
Criteria for Adverse Events (CTCAE) Version 5.0 (National Cancer Institute 2020), and CRS and neurotoxicity per 
American Society for Transplantation and Cellular Therapy (ASTCT; Lee 2019) Consensus Grading as in 
Appendix D.  
In the monotherapy arm, a DLT is defined as: 
• 
Any Grade 4 or 5 event determined by the Investigator to be related to the investigational product, and not 
attributable to the underlying disease or LDC, with the exception of Grade 4 laboratory abnormalities (such 
as electrolyte abnormalities) that may be at least possibly related to the investigational product but are 
rapidly reversible or correctable without substantial safety concerns. 
• 
Grade ≥3 TAC T cell-associated acute infusion reactions persisting for ≥24 hours 
• 
Grade ≥3 TAC T cell-associated CRS or neurotoxicity persisting for ≥72 hours 
• 
Grade ≥3 cardiovascular or pulmonary toxicity persisting for ≥72 hours 
• 
Grade ≥3 immune-related toxicities (i.e., colitis, nephritis, hepatitis, myocarditis, hypophysitis, salivary 
gland toxicity, etc.) 
• 
Grade ≥3 organ toxicities or non-hematologic toxicities that do not improve to Baseline within 7 days 
• 
Clinically consequential Grade ≥3 neutropenia or thrombocytopenia lasting ≥30 days from TAC01-HER2 
administration. Clinically consequential is defined as febrile neutropenia, serious infection, or bleeding 
events.  
In the combination arm, a DLT is defined as: 
Definitions from the monotherapy arm that also apply to the combination arm: 
• 
Any Grade 4 or 5 event determined by the Investigator to be related to the investigational product, and not 
attributable to the underlying disease or LDC, with the exception of Grade 4 laboratory abnormalities (such 
as electrolyte abnormalities) that may be at least possibly related to the investigational product but are 
rapidly reversible or correctable without substantial safety concerns. 
• 
Grade ≥3 TAC T cell-associated acute infusion reactions persisting for ≥24 hours 
• 
Grade ≥3 TAC T cell-associated CRS or neurotoxicity persisting for ≥72 hours 
• 
Grade ≥3 cardiovascular or pulmonary toxicity persisting for ≥72 hours 
• 
Grade ≥3 immune-related toxicities (i.e., colitis, nephritis, hepatitis, myocarditis, hypophysitis, salivary 
gland toxicity, etc.) 
• 
Grade ≥3 organ toxicities or non-hematologic toxicities that do not improve to Baseline within 7 days 
Additional definitions of DLTs applicable to the combination arm:  
• 
Any event that meets the definition of a DLT for the monotherapy arm that occurs before pembrolizumab 
administration, will prevent any pembrolizumab administration (subject will be discontinued from the 
combination arm and will follow the monotherapy schedule of events in Appendix A1).  
• 
Grade 4 nonhematologic toxicity (not laboratory) 
• 
Any new or worsening clinically significant Grade ≥3 neutropenia or thrombocytopenia lasting ≥7 days 

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that develops ≤3 days after pembrolizumab administration despite best institutional corrective treatment 
measures 
• 
Any Grade 4 hematological toxicity lasting ≥7 days after pembrolizumab administration despite best 
institutional corrective treatment measures 
• 
Any nonhematologic AE ≥Grade 3 in severity should be considered a DLT, with the following exceptions: 
Grade 3 fatigue lasting ≤3 days; Grade 3 diarrhea, nausea, or vomiting without use of anti-emetics or anti-
diarrheals per standard of care; Grade 3 rash without use of corticosteroids or anti-inflammatory agents per 
standard of care. 
• 
Any Grade 3 or Grade 4 non-hematologic laboratory value if: 
o 
Clinically significant medical intervention is required to treat the participant 
o 
The abnormality leads to hospitalization 
o 
The abnormality persists for >1 week 
o 
The abnormality results in a drug induced liver injury (DILI)  
o 
Exceptions: Clinically nonsignificant, treatable, or reversible laboratory abnormalities including 
liver function tests, uric acid, etc. 
• 
Febrile neutropenia Grade 3 or Grade 4: 
o 
Grade 3 is defined as absolute neutrophil count (ANC) <1000/mm3 with a single temperature of 
>38.3°C (101°F) or a sustained temperature of ≥38°C (100.4°F) for more than 1 hour. 
o 
Grade 4 is defined as ANC <1000/mm3 with a single temperature of >38.3°C (101°F) or a 
sustained temperature of ≥38°C (100.4°F) for more than 1 hour, with life-threatening 
consequences and urgent intervention indicated. 
o 
Prolonged delay (>2 weeks) in initiating Cycle 2 due to treatment-related toxicity 
• 
Any treatment-related toxicity that causes the participant to discontinue treatment during Cycle 1 
• 
Grade 5 toxicity 
DLT Evaluation Periods and Relatedness: 
In the monotherapy arm, DLTs will be assessed from the time of the TAC01-HER2 infusion on Day 1 through 
28 days post dose. The DLT evaluation period may be extended through 42 days post dose should clinically 
consequential (i.e., events associated with febrile neutropenia, serious infections, or bleeding) Grade ≥3 
neutropenia or thrombocytopenia occur.  
In the combination arm, DLTs will be assessed from the time of the TAC01-HER2 dose (Day 1) through Day 42 
for cohorts that dosed pembrolizumab on Day 21, and through Day 35 for cohorts that dosed pembrolizumab on 
Day 14. In both scenarios, DLTs will include assessments over 1 cycle of pembrolizumab treatment (or 21 days 
after the initial dose of pembrolizumab).  
DLTs that occur after TAC01-HER2 administration but before pembrolizumab treatment will be attributable to 
TAC01-HER2. DLTs that occur after pembrolizumab administration will be attributable to both study treatments. 
Since TAC01-HER2 is a single dose infusion, all DLTs or other adverse reactions observed after pembrolizumab 
administration will follow the guidelines for dose modification or discontinuation criteria listed in Appendix H and 
Appendix I. 
The dose elimination rule in the keyboard design will be used as a stopping boundary for toxicity. Specifically, 
enrollment will be stopped if data indicate more than a 95% chance that the DLT rate exceeds 30%, corresponding 
to a strong signal that the RP2D previously selected was in error. 
Inclusion Criteria: 
Subjects must meet all the following criteria to participate in this study: 
1. Signed, written informed consent obtained prior to any study specific procedures. 
2. Age ≥18 years at the time of informed consent. 
3. For Phase 1 and Phase 2:  
• 
Phase 1 monotherapy: HER2 1+, 2+, 3+ by IHC by central laboratory confirmation 
• 
Phase 1 combination: therapy: HER2 2+, 3+ by IHC and FISH by central laboratory confirmation  
• 
Phase 2 monotherapy (Group A): HER2 2+, 3+ by IHC and FISH by central laboratory confirmation  
• 
Phase 2 combination therapy (Group B): HER2 2+, 3+ by IHC and FISH by central laboratory 

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confirmation  
In both phases, subjects who are HER2+ via recent (preferably after last line of therapy or within 1 year) 
tissue biopsy local laboratory results using IHC, FISH, or next generation sequencing (NGS) assays may 
also be enrolled, as long as a recent (preferably fresh or archival within 1 year) tissue biopsy sample is 
available for central laboratory HER2+ confirmation after enrollment and/or after starting TAC01-HER2. 
In the instance of discordant results between central and local laboratories (i.e., central laboratory results 
are negative with regards to IHC or FISH), the subject will still be considered evaluable for safety and 
evaluation of DLTs. In the instance of discordant results between central and local laboratories, the subject 
may be replaced in Phase 2.  
Central laboratory confirmation of HER2+ tumor samples will occur by one of the following methods (in 
order of priority, also see Section 7.2.3.1):  
a. 
A fresh tumor tissue sample, if clinically feasible and safe 
b. An archival sample collected within 1 year prior to enrollment (samples may be collected >1 year 
prior to enrollment in Phase 1) 
c. 
A liquid biopsy to examine circulating tumor cells 
d. If a, b, or c are not obtainable, the most recent archival sample available regardless of when it was 
obtained during prior lines of therapy 
Fine needle aspirations, or brushing and scraping cytology samples, are not acceptable at Baseline or 
Screening. Since Phase 2 will be evaluating efficacy and since HER2 status often changes on progression 
after HER2-targeted therapies (e.g., trastuzumab), it is strongly recommended a fresh tumor tissue sample 
be obtained, if clinically feasible and safe, along with the corresponding pathology report for histological 
disease diagnosis confirming HER2-protein expression on the tumor cell surface.  
4. Histologically confirmed advanced, metastatic, unresectable solid tumors (regardless of PD-L1 expression 
levels; Phase 1) and histologically confirmed advanced, metastatic, unresectable gastric or esophageal 
adenocarcinoma (regardless of PD-L1 expression levels for Phase 1 combination therapy and Phase 2) after 
at least 2 prior lines of therapy (Phase 1) or after at least 2 and no more than 4 prior lines of therapy (Phase 
2). For the completed Phase 1 monotherapy subjects, HER2+ incurable malignancies for which no 
standard-of-care HER2 targeted therapy exists were enrolled regardless of the number of prior treatment 
lines, as long as in the opinion of the investigator the subject would be unlikely to tolerate or derive 
clinically meaningful benefit from other available treatment options. For breast cancer subjects, both prior 
lines of therapy must have included HER2-targeted agents per current standard-of-care. Subjects in the 
Phase 1 combination arm and Phase 2 can be enrolled if they have received less than 2 prior lines of 
therapy if, in the opinion of the investigator, the subject would not derive meaningful clinical benefit from 
an additional line of therapy. 
Subjects with solid tumors with genetic alterations and mutations (such as BRAF, BRCA, EGFR mutations, 
and ALK translocation) where approved targeted therapies were available to their specific cancers must 
have been previously treated with such approved therapies, or refused such approved targeted therapy for 
their cancers, prior to enrollment, or in the opinion of the investigator would be unlikely to tolerate or 
derive clinically meaningful benefit from these standard-of-care therapies. 
5. Measurable disease per RECIST 1.1 at time of enrollment. Lesions situated in a previously irradiated area 
are considered measurable if progression has been demonstrated in such lesions. 
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at Screening. 
7. Life expectancy of at least 12 weeks. 
8. Adequate organ and bone marrow reserve function prior to leukapheresis for monotherapy and combination 
arms can be found in Tables A and B, respectively. 
9. Recovery to Grade ≤1 or Baseline for any toxicities due to previous therapy. 
a. 
If a subject received major surgery, they must have recovered adequately from the procedure 
and/or complications from the procedure prior to starting TAC01-HER2 therapy. 
b. Toxicity that has not recovered to Grade ≤1 is allowed if it meets the inclusion requirements for 
laboratory parameters. 
c. 
For the combination arm only: Subjects with Grade ≤2 neuropathy may be eligible, as may 
subjects with endocrine-related Grade ≤2 AEs requiring treatment or hormone replacement. 
10. Adequate vascular access for leukapheresis as per institutional guidelines 
11. For women physiologically capable of becoming pregnant, agreement to use highly effective methods of 

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contraception starting 28 days prior to study treatment and for 1 year after the TAC01-HER2 dose. For men 
who have partners physiologically capable of becoming pregnant, agreement to use an effective barrier 
contraceptive method and refrain from donating sperm during study treatment and for 1 year after the 
TAC01-HER2 dose. 
12. Subjects who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received hepatitis B 
virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV viral load prior to 
enrollment. Note: Subjects should remain on anti-viral therapy throughout study intervention and follow 
local guidelines for HBV anti-viral therapy post completion of study intervention. 
13. Subjects with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable at 
Screening. Note: Subjects must have completed curative anti-viral therapy at least 4 weeks prior to 
enrollment.  
Table A: Adequate Organ Function Laboratory Values for the Monotherapy Arm 
System 
Laboratory Value 
Hematologic a 
Absolute neutrophil count (ANC) 
≥1,000.0/µL 
Absolute lymphocyte count (ALC) 
≥450.0/µL d 
Platelets a 
≥75,000.0/µL 
Hemoglobin a 
≥8.0 g/dL 
Renal 
Creatinine AND 
Estimated glomerular filtration rate (eGFR) b OR  
measured creatinine clearance c 
≤1.5 X upper limit of normal (ULN) AND 
≥60.0 mL/min/1.73 m2 OR 
≥40 mL/min 
Hepatic 
Total bilirubin 
≤1.5 X ULN OR 
Direct bilirubin ≤ULN for subjects with total 
bilirubin levels >1.5 X ULN OR 
≤3 x ULN in the presence of liver metastases OR 
In subjects with known Gilbert’s disease, serum 
total bilirubin <3 mg/dL 
Aspartate aminotransferase (AST) and alanine 
aminotransferase (ALT) 
≤2.5 X ULN or, 
If liver metastases present ≤5 X ULN 
Alkaline phosphatase (AP) 
≤2.5 X ULN or ≤5 x ULN for subjects with liver 
metastases or bone lesions. 
Coagulation 
International normalized ratio (INR) or prothrombin time 
(PT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or partial 
thromboplastin time (PTT) is within therapeutic 
range of intended use of anticoagulants 
Activated partial thromboplastin time (aPTT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or PTT is 
within therapeutic range of intended use of 
anticoagulants 
Respiratory 
Adequate respiratory reserve 
Grade 0 or 1 dyspnea and peripheral oxygen (O2) 
saturation of ≥92% on room air 
Cardiac 
Echocardiogram (ECHO) or multigated acquisition 
(MUGA) Scan 
Left ventricular ejection fraction (LVEF) ≥45% 

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a Hemoglobin and platelet requirements cannot be met by use of recent transfusion or growth factor support.  
b eGFR should be calculated per institutional standard. 
c Creatinine clearance should be calculated per institutional standard. 
d Subjects with an ALC below 450.0/µL should be discussed with Triumvira’s Medical Monitor for assessment of suitability 
for high volume leukapheresis based on the subject’s tolerance, underlying malignancy, and any latent effects from prior 
antineoplastic therapies. 
 
 
Table B: Adequate Organ Function Laboratory Values for the Combination Arm 
System 
Laboratory Value 
Hematologic a 
Absolute neutrophil count (ANC) 
≥1500/µL 
Absolute lymphocyte count (ALC) 
≥450.0/µL d 
Platelets  
≥100,000.0/µL 
Hemoglobin a 
≥9.0 g/dL or ≥5.6 mmol/L a 
Renal 
Creatinine AND 
Estimated glomerular filtration rate (eGFR) b OR  
measured creatinine clearance c 
≤1.5 X upper limit of normal (ULN) AND 
≥60.0 mL/min/1.73 m2 OR 
≥40 mL/min 
Hepatic 
Total bilirubin 
≤1.5 X ULN OR 
Direct bilirubin ≤ULN for subjects with total 
bilirubin levels >1.5 X ULN OR 
≤3 x ULN in the presence of liver metastases OR 
In subjects with known Gilbert’s disease, serum 
total bilirubin <3 mg/dL 
Aspartate aminotransferase (AST) and alanine 
aminotransferase (ALT) 
≤2.5 X ULN or, 
If liver metastases present ≤5 X ULN 
Alkaline phosphatase (AP) 
≤2.5 X ULN or ≤5 x ULN for subjects with liver 
metastases or bone lesions. 
Coagulation 
International normalized ratio (INR) or prothrombin time 
(PT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or partial 
thromboplastin time (PTT) is within therapeutic 
range of intended use of anticoagulants 
Activated partial thromboplastin time (aPTT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or PTT is 
within therapeutic range of intended use of 
anticoagulants 
Respiratory 
Adequate respiratory reserve 
Grade 0 or 1 dyspnea and peripheral oxygen (O2) 
saturation of ≥92% on room air 
Cardiac 
Echocardiogram (ECHO) or multigated acquisition 
(MUGA) Scan 
Left ventricular ejection fraction (LVEF) ≥45% 
a Criteria must be met without packed red blood cell (pRBC) transfusion within the prior 2 weeks. Participants can be on 
stable dose of erythropoietin (≥approximately 3 months). 
b eGFR should be calculated per institutional standard. 
c Creatinine clearance should be calculated per institutional standard. 
d Subjects with an ALC below 450.0/µL should be discussed with Triumvira’s Medical Monitor for assessment of suitability 
for high volume leukapheresis based on the subject’s tolerance, underlying malignancy, and any latent effects from prior 
antineoplastic therapies. 

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Exclusion Criteria: 
Subjects who meet any of the following criteria will be excluded from participation in this study: 
1. Intolerant to any component of TAC01-HER2. 
2. Prior treatment with any of the following: 
a. 
Adoptive cell transfer of any kind, including chimeric antigen receptor (CAR) T cells 
b. Gene therapy 
3. Investigational medicinal product within 5 half-lives or 21 days prior to leukapheresis, whichever is 
shorter. 
4. Has received a live or live-attenuated vaccine within 30 days prior to the first dose of study intervention. 
Note: Administration of killed vaccines are allowed. 
5. Monoclonal antibody (mAb), including PD-1 and PD-L1, therapies within 21 days prior to leukapheresis.  
6. Radiation within 28 days prior to leukapheresis. Palliative radiation is allowed up to 14 days prior to 
leukapheresis if additional non-irradiated lesions are present. 
7. Chemotherapy or targeted small molecule therapy within 14 days prior to leukapheresis, or within 7 days 
prior to leukapheresis for erlotinib, gefitinib, afatinib, crizotinib, or tucatinib. 
8. Colony stimulating factors, including granulocyte-colony stimulating factor (G-CSF), granulocyte-
macrophage colony-stimulating factor (GM-CSF), erythropoietin, and other hematopoietic cytokines, 
within 14 days prior to leukapheresis. 
9. Immunosuppressive medication within 14 days and corticosteroid treatment <72 hours prior to 
leukapheresis, except for physiological replacement doses (<12 mg/m2/24 hours) of hydrocortisone or 
equivalent and topical or inhaled steroids. 
10. History or presence of clinically relevant central nervous system (CNS) pathology such as epilepsy, 
seizure, paresis, aphasia, stroke, severe brain injury, dementia, Parkinson’s disease, cerebellar disease, 
organic brain syndrome, or psychosis. Has known active CNS metastases and/or carcinomatous meningitis. 
Participants with previously treated brain metastases may participate provided they are radiologically 
stable, i.e., without evidence of progression for at least 4 weeks by repeat imaging (note that the repeat 
imaging should be performed during study screening), clinically stable and without requirement of steroid 
treatment for at least 14 days prior to first dose of study treatment.  
11. Active inflammatory neurological disorders (e.g., Guillain-Barre Syndrome, amyotrophic lateral sclerosis, 
multiple sclerosis). 
12. Active autoimmune disease (e.g., lupus, rheumatoid arthritis, Sjogren’s syndrome) requiring systemic 
treatment (i.e., disease modifying agents, corticosteroids, or immunosuppressive drugs) in the past 2 years. 
Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal 
or pituitary insufficiency, etc.) is not considered a form of systemic treatment. 
13. Active or uncontrolled hepatitis B or C (HCV ribonucleic acid [RNA] positive) infection or any history of 
or active human immunodeficiency virus (HIV) infection. 
14. Uncontrolled, acute, or life-threatening bacteria, viral, or fungal infection. Subjects with ongoing use of 
prophylactic antibiotics, antifungals, or antivirals are eligible if no evidence of active infection, this 
includes COVID subjects. 
15. Class III or IV heart failure (as defined by the New York Heart Association [NYHA]), cardiac angioplasty 
or stenting, myocardial infarction, unstable angina, or other clinically significant cardiac disease within 6 
months prior to Screening. 
16. Cardiac arrhythmia not controlled by medical management. 
17. Clinically significant thrombotic events within 6 months prior to leukapheresis and/or inability to stop 
anticoagulation for at least 2 half-lives prior to TAC01-HER2 infusion without compromising a subject’s 
health. 
18. Known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell 
carcinoma of the skin, non-metastatic squamous cell carcinoma of the skin, or in situ cervical cancer that 
has undergone potentially curative therapy.  
19. Pregnant or nursing (lactating). Females physiologically capable of becoming pregnant must have a 
negative serum beta human chorionic gonadotropin (β-hCG) pregnancy test result at Screening and within 
48 hours prior to initiating LDC. 
20. As determined by the Investigator, any uncontrolled medical, psychological, familial, sociological, or 

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geographical condition(s) that do(es) not permit compliance with the protocol. 
21. Is currently participating in or has participated in a study using an investigational device within 4 weeks 
prior to the first dose of study treatment. 
22. Has a history or current evidence of any condition, therapy, or laboratory abnormality, or other 
circumstance that might confound the results of the study or interfere with the subject’s participation for the 
full duration of the study, such that it is not in the best interest of the subject to participate, in the opinion of 
the treating investigator. 
23. Has a known psychiatric or substance abuse disorder that would interfere with the participant’s ability to 
cooperate with the requirements of the study. 
Combination Arm Only Specific Exclusions: 
24. Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.  
25. Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to 
another stimulatory or co-inhibitory T-cell receptor (e.g., cytotoxic t-lymphocyte-associated protein 4 
[CTLA-4], OX-40, cluster of differentiation [CD]137), and was discontinued from that treatment due to a 
Grade 3 or higher immune-related AE (irAE). 
26. Removed; combined with exclusion #10 (protocol Version 6.0). 
27. Has received radiation therapy to the lung that is >30 Gy within 6 months of the first dose of trial 
treatment. 
28. Has a history of (non-infectious) pneumonitis/interstitial lung disease that required steroids or has current 
pneumonitis/interstitial lung disease.  
29. Has history of an allogeneic stem cell transplant or a solid organ transplant. 
30. Has a history of radiation pneumonitis. (Note: Cannot receive prior radiotherapy within 2 weeks of start of 
pembrolizumab. Note: Participants must have recovered from all radiation-related toxicities and not require 
corticosteroids. A 1-week washout is permitted for palliative radiation [≤2 weeks of radiotherapy] to non-
CNS disease; see Section 7.3.3). 
Investigational Product, Dosage, and Mode of Administration:  
Product Name and Description:  
TAC01-HER2 is an autologous T cell product comprising T cells expressing the TAC-HER2, a chimeric 
receptor that is genetically engineered into T cells via lentiviral transduction to furnish T cells with 2 main 
functions: (i) redirection to and specific recognition of HER2+ cells, and (ii) T cell activation via the endogenous 
TCR. 
Structure:  
The chimeric TAC-HER2 receptor consists of 3 main functional domains: (i) an extracellular HER2-binding 
domain provided by the H10-2-G3 designed ankyrin repeat protein (DARPin); (ii) an extracellular TCR/CD3ε-
binding domain (huUCHT1 scFv); and (iii) a membrane-anchoring domain that consists of the transmembrane and 
cytoplasmic domains of CD4. The HER2-binding domain is designed to bind to the HER2 surface antigen 
expressed on HER2+ cells, including HER2+ non-malignant cells. The TCR/CD3ε binding domain is designed to 
recruit the endogenous TCR complex. The cytoplasmic tail includes the lymphocyte-specific protein tyrosine 
kinase (Lck) binding site of CD4 which is expected to contribute to T cell activation upon recruitment of the TCR.  
Dosage Form:  
The TAC01-HER2 product is a suspension of genetically modified autologous T cells expressing TAC-HER2 for 
infusion (i.e., HER2-targeted TAC T cells) containing 10% dimethyl sulfoxide (DMSO) in approximately 20 mL. 
Administration:  
TAC01-HER2 will be administered as a single IV infusion approximately 72 hours after completion of LDC. 
LDC will preferentially consist of 3 consecutive days of fludarabine (30 mg/m2 IV) or clofarabine (52 mg/m2 IV) 
and cyclophosphamide (300 mg/m2 IV) with or without mesna IV. Central venous access is recommended for the 
infusion of TAC01-HER2.  
If fludarabine or clofarabine is unavailable (due to national shortages), subjects can be treated with 3 consecutive 
days of cyclophosphamide (300 mg/m2 IV) with or without mesna IV or with bendamustine 90 mg/m2 daily for 

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2 days for subjects who cannot tolerate cyclophosphamide. 
The dose intensity of either the primary (fludarabine or clofarabine + cyclophosphamide) or backup 
(cyclophosphamide or bendamustine) regimens can be modified based on a subject's complete blood count (CBC) 
and creatinine clearance, upon discussion with the Medical Monitor.  
Pembrolizumab: 
Pembrolizumab 200 mg IV will be administered Q3W starting on Day 21 or Day 14 from administration of the 
TAC T cells. The initial combination dose-escalation cohort will have pembrolizumab administered on Day 21. For 
all remaining cohorts, pembrolizumab will be administered on Day 14 if no DLTs or safety issues are identified (as 
approved by the DSMC). The Day 14 time point was chosen based on nonclinical in vivo data showing maximal 
TAC T cell expansion in the tumor around and after Day 7 post IV administration. The Day 21 time point for the 
initial pembrolizumab administration in the combination arm was chosen as an additional safety precaution to allow 
an extra week for any TAC T cell-related AEs to emerge and be managed as appropriate.  
Dose modifications and discontinuations will follow the guidelines described in Appendix H and Appendix I.  
Disease Response Assessments:  
Disease assessments should be performed using computed tomography (CT) (or magnetic resonance imaging 
[MRI] if indicated). Scans will be reviewed and assessed locally by the Investigator and radiology using RECIST 
1.1. The same imaging technique should be used for a subject throughout the study, and lesions detected at Baseline 
should be followed using the same imaging methodology and preferably the same imaging equipment at subsequent 
tumor evaluation visits. The Investigator may perform scans in addition to scheduled study scans if clinically 
indicated per the Investigator’s discretion. 
Safety Assessments:  
AEs will be assessed throughout the study according to CTCAE Version 5.0 (National Cancer Institute 2020), 
and CRS and neurotoxicity per ASTCT (Lee 2019) Consensus Criteria. AEs, serious adverse events (SAEs), and 
laboratory abnormalities (type, frequency, and severity) will be collected.  
Potential TAC01-HER2 cell related toxicities may include infusion reactions, CRS, neurotoxicity, macrophage 
activation syndrome, and tumor lysis syndrome (TLS); with the list of these risks being updated during the study 
based on any observed safety signals. Replication-competent lentivirus (RCL) and, if positive, follow-up viral 
vector sequence, testing will be performed at specified time points during the study using polymerase chain reaction 
(PCR)-based assays. 
Potential pembrolizumab related toxicities may include fatigue, musculoskeletal pain, rash, diarrhea, pyrexia, 
cough, decreased appetite, pruritus, dyspnea, constipation, pain, abdominal pain, nausea, and hypothyroidism. 
Immune-mediated and infusion-related adverse reactions, which may be severe or fatal, can occur in any organ 
system or tissue for which monitoring for early identification and management is required per Appendix H and 
Appendix I, respectively.  
In conclusion, there is no toxicity overlap to be expected between TAC01-HER2 cell therapy and 
pembrolizumab. 
Other Assessments: 
PK Assessments: Assessment of TAC T cell expansion and persistence in blood will be determined by quantitative 
polymerase chain reaction (qPCR) to detect the TAC-HER2 transgene and by flow cytometry to enumerate the 
number and immunophenotypic TAC T cells. 
Biomarker Assessments: Biomarker assessments will be performed to evaluate HER2+ tumor status, and immune 
system characteristics that may be associated with TAC T cell toxicity, clinical activity, and resistance mechanisms 
to TAC01-HER2 treatment. 
Statistical Methods: 
In Phase 1, the keyboard dose escalation design will govern the number of subjects to be enrolled. It is estimated 
27 to 54 subjects may be enrolled, i.e., ~3-6 subjects for each of the 4 dose levels across both arms (monotherapy 
and combination therapy). Based on the cumulative data from subjects treated in the dose finding phase, the MTD 
or RP2D will be selected for further evaluation in the dose expansion portion of the study. Once identified, an 

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additional 3-6 subjects may be treated at the RP2D to confirm safety before proceeding to Phase 2. 
In Phase 2, treatment with TAC01-HER2 will be evaluated both as a monotherapy (Group A), and in 
combination with pembrolizumab (Group B) in subjects with gastric and esophageal adenocarcinoma cancer using 
a Simon 3-stage design: 
In Phase 2, up to 36 subjects will be enrolled in monotherapy Group A using a Simon 3 stage design assessing 
futility to show a maximum- ineffective ORR of 6.0% and a minimum effective ORR of 20%. If 0 subjects have a 
response among the first 11 subjects in the cohort, the study will be stopped for a lack of efficacy. If >0 subjects 
have a response, then another 14 subjects will be enrolled, for a total of 25 monotherapy subjects. If ≤2 of the 
25 subjects have a response, the study will be stopped for lack of efficacy. If >2 subjects have a response, then 
another 11 subjects will be enrolled in the third stage, for a total of 36 monotherapy subjects. If ≤4 of the 
36 subjects have a response, then treatment with TAC01-HER2 as a monotherapy will not be considered as having 
adequate efficacy to continue investigation in HER2+ subjects. If >4 of the 36 subjects have a response, then 
treatment with TAC01-HER2 as a monotherapy will be considered efficacious and continued clinical study 
investigations will be warranted. The assumed ORR was selected based on the results of the TAGS study for 
Trifluridine/tipiracil, which enrolled gastric cancer and GEJ AC subjects after 2 prior lines of therapy. Since the 
ORR in that study was 4% (Shitara 2018), it was considered that the assumed 20% ORRs for Group A is clinically 
meaningful.  
In Phase 2, up to 34 subjects will be enrolled in combination therapy Group B using a Simon 3-stage design 
assessing futility to show a maximum ineffective ORR of 8.4% and a minimum effective ORR of 25%. If 
0 subjects have a response among the first 9 subjects in the cohort, the study will be stopped for a lack of efficacy. 
If >0 subjects have a response, then another 10 subjects will be enrolled, for a total of 19 combination therapy 
subjects. If ≤2 of the 19 subjects have a response, the study will be stopped for lack of efficacy. If >2 subjects have 
a response then another 15 subjects will be enrolled in the third stage, for a total of 34 combination therapy 
subjects. If ≤5 of the 34 subjects have a response, then treatment with TAC01-HER2 in combination with 
pembrolizumab will not be considered as having adequate efficacy to continue investigation in HER2+ subjects. If 
>5 of the 34 subjects have a response, then treatment with TAC01-HER2 in combination with pembrolizumab will 
be considered efficacious and continued clinical study investigations will be warranted. The assumed clinically 
meaningful ORR for group B was also selected based on the results of the TAGS study for Trifluridine/tipiracil. 
Since the ORR in that study was 4% (Shitara 2018) and given the anticipated add on benefit for the combination it 
was considered that the assumed 25% ORRs for group B is clinically meaningful. 
Simon Three-Stage Design Sample Size and Cutoff Requirements for Phase 2 (Dose Expansion) 
Parameter 
Group A 
Group B 
Maximum non-effective rate 
6.0% 
8.4% 
Minimum effective rate 
20.0% 
25.0% 
First stage total N 
11 
9 
First stage cutoff 
0 
0 
Second stage total N 
25 
19 
Second stage cutoff 
2 
2 
Final stage total N 
36 
34 
Final stage cutoff 
4 
5 
For the efficacy analysis, the ITT population is defined as any subject that received at least 1 course of 
TAC01-HER2. 
Subjects who are in DLT evaluation cohorts will be considered evaluable if they complete the defined DLT 
observation period. Estimates of ORR and other response proportions (e.g., DCR) will be presented together with 
95% confidence intervals calculated using the Clopper-Pearson method. Kaplan-Meier estimations will be used for 
the analysis of time-to-event endpoints, including DOR, OS, PFS, or TTP. 

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The cellular kinetics of TAC01-HER2 will be determined from individual concentration-time profiles of 
circulating TAC T cells and characterized in peripheral blood and summarized by treatment arm. 

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TABLE OF CONTENTS 
PROTOCOL SYNOPSIS ................................................................................................................4 
1. INTRODUCTION AND STUDY RATIONALE .....................................................................33 
1.1. HER2-positive Solid Tumors ........................................................................................33 
1.2. HER2 as a Therapeutic Target .......................................................................................33 
1.3. Adoptive T Cell Therapy ...............................................................................................34 
1.4. T Cell Antigen-Coupler Technology .............................................................................34 
1.5. TAC01-HER2 Investigational Product ..........................................................................36 
1.5.1. Product Name and Description .........................................................................36 
1.5.2. Structure ............................................................................................................36 
1.5.3. Dosage Form .....................................................................................................37 
1.5.4. Administration ..................................................................................................37 
1.6. Pembrolizumab ..............................................................................................................37 
1.6.1. Background .......................................................................................................37 
1.6.2. Pharmaceutical and Therapeutic Background ..................................................37 
1.6.3. Nonclinical and Clinical Studies ......................................................................38 
1.6.4. Justification for Dose ........................................................................................39 
1.6.5. Timing of Pembrolizumab Administration .......................................................40 
1.7. Study Rationale .............................................................................................................40 
1.8. TAC01-HER2 Monotherapy Rationale .........................................................................41 
1.9. Anti-PD-1 Combination Therapy Rationale ..................................................................43 
1.9.1. Background .......................................................................................................43 
1.9.2. Nonclinical Studies ...........................................................................................44 
1.9.3. Clinical Studies (Literature) .............................................................................50 
1.9.4. Protocol TAC01-HER2-03 (Status Update) .....................................................52 
1.10. Lymphodepleting Chemotherapy Rationale ................................................................53 
1.11. Second Dose Rationale ................................................................................................54 
1.12. Statistical Design Rationale ........................................................................................56 
2. STUDY OBJECTIVES AND ENDPOINTS .............................................................................57 
3. STUDY DESIGN AND INVESTIGATIONAL PLAN ............................................................58 
3.1. Overall Study Design ....................................................................................................58 

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3.2. Phase 1 Dose Escalation ................................................................................................62 
3.3. Phase 2 Dose Expansion ...............................................................................................68 
3.4. Administration of Second Dose (Phase 2 Monotherapy Group Only) ..........................69 
3.5. Duration of Subject Participation ..................................................................................69 
3.6. Subject Withdrawal from Study ....................................................................................70 
3.6.1. Subject Removal from Study ............................................................................70 
3.6.2. Study Subject Replacement ..............................................................................70 
3.6.3. Subject Discontinuation Prior to Lymphodepleting Chemotherapy or 
Prior to TAC01-HER2 Dose .........................................................................71 
3.7. Study Suspension or Termination ..................................................................................71 
3.7.1. Criteria for Study Interruption ..........................................................................72 
3.7.2. Criteria for Study Termination ..........................................................................72 
3.7.3. Continued Access to Pembrolizumab ...............................................................72 
4. STUDY POPULATION ............................................................................................................73 
4.1. Inclusion Criteria ...........................................................................................................73 
4.2. Exclusion Criteria ..........................................................................................................78 
4.3. Eligibility Criteria for Second Dose ..............................................................................80 
4.3.1. Inclusion Criteria ..............................................................................................80 
4.3.2. Exclusion Criteria .............................................................................................81 
4.4. Contraception Requirements .........................................................................................81 
4.5. Screen Failures ..............................................................................................................82 
5. STUDY THERAPIES ................................................................................................................83 
5.1. Therapy for Disease Control During TAC01-HER2 Manufacturing ............................83 
5.2. Lymphodepleting Chemotherapy ..................................................................................84 
5.3. TAC01-HER2 Infusion ..................................................................................................85 
5.3.1. Dosage Form .....................................................................................................85 
5.3.2. Administration ..................................................................................................85 
5.3.3. Premedication ...................................................................................................85 
5.3.4. Dosing Regimen ...............................................................................................85 
5.3.5. How Supplied ...................................................................................................86 
5.3.6. Non-Conforming Product .................................................................................86 
5.4. Pembrolizumab Infusion ...............................................................................................86 

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5.4.1. Dosage and Administration...............................................................................86 
5.4.2. Dose Modification and Toxicity Management for Immune-Related AEs 
Associated with Pembrolizumab ..................................................................86 
5.4.3. Dose Modification and Toxicity Management of Infusion-Reactions 
Related to Pembrolizumab ...........................................................................87 
5.4.4. Other Allowed Dose Interruptions for Pembrolizumab ....................................87 
5.4.5. Preparation and Storage ....................................................................................88 
5.4.6. How Supplied ...................................................................................................88 
5.5. Overdose ........................................................................................................................88 
5.6. Supportive Care, Additional Treatment, and Monitoring ..............................................89 
5.7. Concomitant Medications .............................................................................................89 
5.7.1. Reporting Periods .............................................................................................89 
5.7.2. Concomitant Medications During Hospitalizations ..........................................90 
5.8. Prohibited Medications .................................................................................................90 
6. POTENTIAL RISKS AND MANAGEMENT OF TREATMENT TOXICITIES ...................91 
6.1. Cytokine Release Syndrome .........................................................................................91 
6.2. Myelotoxicities ..............................................................................................................92 
6.3. Hypersensitivity Reactions ............................................................................................92 
6.4. Infusion Reactions .........................................................................................................92 
6.5. Immune-Mediated Reactions ........................................................................................93 
6.5.1. Pneumonitis ......................................................................................................93 
6.5.2. Fever .................................................................................................................93 
6.5.3. Neurologic Toxicities ........................................................................................93 
6.5.4. Macrophage Activation Syndrome ...................................................................94 
6.5.5. Tumor Lysis Syndrome .....................................................................................94 
6.5.6. Uncontrolled T cell Proliferation ......................................................................94 
6.5.7. Replication-Competent Lentivirus, Clonality, and Insertional 
Oncogenesis .................................................................................................94 
7. STUDY ASSESSMENTS AND PROCEDURES .....................................................................95 
7.1. Schedule of Events ........................................................................................................95 
7.2. Pre-Treatment ................................................................................................................97 
7.2.1. Screening ..........................................................................................................97 

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7.2.2. Leukapheresis ...................................................................................................98 
7.2.3. Pre-treatment Screening and Baseline Evaluations ..........................................98 
7.2.4. Pre-treatment Evaluations for Phase 2 TAC01-HER2 Second Dose ................99 
7.3. Study Treatments ...........................................................................................................99 
7.3.1. Lymphodepleting Chemotherapy......................................................................99 
7.3.2. TAC01-HER2 Treatment ................................................................................100 
7.3.3. Pembrolizumab (Starting Day 21 or Day 14 then Q3W; Combination 
Arm Only) ..................................................................................................100 
7.3.4. Confirmed Disease Progression and Treatment Beyond PD (PD Visit) .........101 
7.4. Post-treatment Evaluations ..........................................................................................101 
7.5. Unscheduled Evaluations ............................................................................................102 
7.6. Subject Death and Autopsy .........................................................................................102 
7.7. Early Withdrawal .........................................................................................................102 
7.8. Long-Term Follow-Up ................................................................................................102 
7.9. Study Procedures .........................................................................................................103 
7.9.1. Administrative Procedures ..............................................................................103 
7.9.2. Inclusion/Exclusion Criteria ...........................................................................103 
7.9.3. Subject Identification Card .............................................................................103 
7.10. Medical History .........................................................................................................104 
7.11. Prior and Concomitant Medications Review .............................................................104 
7.11.1. Prior Medications ..........................................................................................104 
7.11.2. Concomitant Medications .............................................................................104 
7.11.3. Prior Cancer Treatment Details .....................................................................104 
7.12. Assignment of Subject Identification Number ..........................................................104 
7.13. Clinical Procedures ...................................................................................................105 
7.13.1. Oncologic Disease Details ............................................................................105 
7.13.2. Full Physical Examination ............................................................................105 
7.13.3. Cardiac Evaluations ......................................................................................105 
7.13.4. Vital Signs .....................................................................................................105 
7.13.5. Eastern Cooperative Oncology Group Performance Status ..........................105 
7.13.6. Adverse Event Monitoring ............................................................................105 
7.13.7. Disease Assessments .....................................................................................106 

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7.13.8. Assessment of Disease and Tumor Response ...............................................106 
7.13.9. Laboratory Safety Evaluations .....................................................................109 
7.13.10. Blood Collection for Human Anti-Mouse Antibodies ................................ 111 
7.13.11. Future Biomedical Research ....................................................................... 111 
7.13.12. Other Procedures ........................................................................................ 111 
7.14. Withdrawal/Discontinuation ...................................................................................... 112 
7.14.1. Withdrawal from Future Biomedical Research ............................................ 112 
8. SAFETY MONITORING AND REPORTING.......................................................................113 
8.1. Overview ..................................................................................................................... 113 
8.2. Definitions ................................................................................................................... 113 
8.2.1. Adverse Event Definition ............................................................................... 113 
8.2.2. Serious Adverse Event Definition .................................................................. 114 
8.2.3. Pembrolizumab Events of Clinical Interest .................................................... 115 
8.3. Grading and Intensity of Adverse Events .................................................................... 116 
8.4. Relationship to Investigational Product ...................................................................... 116 
8.5. Recording and Reporting of Adverse Events .............................................................. 116 
8.5.1. Recording a Diagnosis versus Signs and Symptoms ...................................... 117 
8.5.2. Clinical Laboratory Abnormalities and Other Abnormal Assessments .......... 117 
8.5.3. Recording Serious Adverse Events ................................................................. 117 
8.5.4. Death Reports ................................................................................................. 118 
8.5.5. Pregnancy Reporting ...................................................................................... 118 
8.5.6. Use in Nursing Women ................................................................................... 119 
8.5.7. Adverse Event Reporting Periods ................................................................... 119 
8.5.8. Serious Adverse Event Reporting ................................................................... 119 
8.6. Data Safety Monitoring Committee ............................................................................122 
9. STATISTICAL METHODS ....................................................................................................123 
9.1. Overview and Sample Sizes ........................................................................................123 
9.2. General Considerations ...............................................................................................124 
9.3. Analysis Sets ...............................................................................................................125 
9.3.2. Analysis Sets for Subjects Treated at the RP2D .............................................126 
9.4. Planned Analyses .........................................................................................................127 

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9.4.1. Subject Disposition and Baseline Characteristics ...........................................127 
9.4.2. Primary Endpoints in Phase 1 Dose Escalation ..............................................127 
9.4.3. Secondary Endpoints in Phase 1 Dose Escalation ..........................................127 
9.4.4. Primary Endpoints in Phase 2 Expansion .......................................................128 
9.4.5. Secondary Endpoints in Phase 2 Expansion ...................................................129 
9.4.6. Safety Analyses ...............................................................................................129 
9.4.7. Concomitant Medications ...............................................................................131 
9.4.8. Pharmacokinetic Analyses ..............................................................................131 
9.4.9. Exploratory Endpoints ....................................................................................132 
9.5. Timing of Analyses ......................................................................................................132 
9.5.1. Interim Analysis ..............................................................................................132 
9.5.2. Final Analysis .................................................................................................133 
10. DATA MANAGEMENT.......................................................................................................133 
10.1. Data Collection System .............................................................................................133 
10.2. Data Quality ..............................................................................................................133 
11. STUDY ADMINISTRATION...............................................................................................134 
11.1. Regulatory and Ethical Compliance ..........................................................................134 
11.2. Regulatory Authority Review ....................................................................................134 
11.3. Institutional Review Board/Independent Ethics Committee Approval .....................134 
11.4. Subject Informed Consent .........................................................................................134 
11.5. Investigator Responsibilities .....................................................................................135 
11.6. Access to Information for Monitoring .......................................................................135 
11.7. Quality Assurance ......................................................................................................135 
11.8. Public Notification of Study Conduct .......................................................................136 
11.9. Study Termination .....................................................................................................136 
11.10. Investigative Site Termination .................................................................................136 
11.11. Records Retention ....................................................................................................136 
11.12. Confidentiality .........................................................................................................137 
11.13. Publication Plan .......................................................................................................137 
12. REFERENCES ......................................................................................................................138 
13. APPENDICES .......................................................................................................................145 

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APPENDIX A1.  
MONOTHERAPY SCHEDULE OF EVENTS (SUBJECTS WHO 
RECEIVE ONE DOSE) ...............................................................................................................145 
APPENDIX A2.  
COMBINATION THERAPY SCHEDULE OF EVENTS ........................149 
APPENDIX B.  
MONOTHERAPY SCHEDULE OF EVENTS (SUBJECTS WHO 
RECEIVE 2 DOSES [ON DAY 1 AND DAY X]) .....................................................................154 
APPENDIX C.  
DOSE ESCALATION & DE-ESCALATION GUIDELINE ....................158 
APPENDIX D.  
CYTOKINE RELEASE SYNDROME AND NEUROTOXICITY 
GRADING 
161 
APPENDIX E.  
ASSESSMENT AND MANAGEMENT CONSIDERATIONS CRS, 
NEUROTOXICITY AND MAS/HLH ........................................................................................163 
APPENDIX F.  
RESPONSE CRITERIA ............................................................................171 
APPENDIX G. ECOG SCALE (AND CONVERSION FROM KARNOFSKY SCALE) .........173 
APPENDIX H.  
DOSE MODIFICATION AND TOXICITY MANAGEMENT 
GUIDELINES FOR IMMUNE-RELATED AES ASSOCIATED WITH 
PEMBROLIZUMAB ...................................................................................................................174 
APPENDIX I.  
PEMBROLIZUMAB INFUSION REACTION DOSE 
MODIFICATION AND TREATMENT GUIDELINES.............................................................177 
 
 

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IN-TEXT TABLES 
Table 1: 
HER2 Surface Expressions in Various Cancer Cell Lines ..........................................48 
Table 2: 
Mesothelin Study: TEAEs in ≥15% of Patients Over First Month 
(Monotherapy; N=27) .................................................................................................51 
Table 3: 
Mesothelin Study: TEAEs Over First 6 Months (CAR T cell + Pembrolizumab; 
N=18) ..........................................................................................................................51 
Table 4: 
Study Objectives and Endpoints .................................................................................57 
Table 5: 
TAC01-HER2 Monotherapy Dose Escalation Schedule ............................................58 
Table 6: 
Combination Therapy Dose Escalation Schedule .......................................................59 
Table 7: 
DLT Evaluation Periods and Possible Extensions by Treatment Arm ........................68 
Table 8: 
Adequate Organ Function Laboratory Values for the Monotherapy Arm ..................76 
Table 9: 
Adequate Organ Function Laboratory Values for the Combination Arm ...................77 
Table 10: 
Reporting Periods for Concomitant Medications .......................................................90 
Table 11:  Tumor Tissue Assessments .......................................................................................108 
Table 12:  Monotherapy and Combination Therapy Blood Collection for Pharmacokinetic 
and Correlative Biomarkers Studies .........................................................................109 
Table 13:  Pharmacokinetic, Biomarker, Cytokine Blood Collection (After Second Dose) .....109 
Table 14:  Laboratory Tests ....................................................................................................... 110 
Table 15:  Definitions of SAEs .................................................................................................. 114 
Table 16:  Special Considerations for SAE Reporting .............................................................. 115 
Table 17:  Assessment of Relationship for Adverse Events ...................................................... 116 
Table 18:  Reporting Periods for AEs and SAEs in the Monotherapy Arm ..............................120 
Table 19:  Reporting Periods for AEs, ECIs, and SAEs in the Combination Arm ....................121 
Table 20: 
Operating Characteristics of the Keyboard Design ..................................................160 

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 IN-TEXT FIGURES 
Figure 1: 
Frequency of HER2 Alterations Across Tumor Types ................................................33 
Figure 2: 
TAC T Cell Receptor versus CARs and the Natural TCR Complex ..........................35 
Figure 3: 
Endo and Ectodomains of the TAC Receptor on the Surface of TAC T Cells ...........36 
Figure 4:  In Vivo Upregulation of PD-1 Levels in Activated TAC T Cells ...............................45 
Figure 5: 
In Vitro Upregulation of PD-L1 Levels in HER2+ Tumor Spheroids Upon 
Binding and Subsequent Eradication with TAC T Cells.............................................46 
Figure 6: 
Loss of TAC T Cell Activity Induced by high PD-L1 Levels on Tumor Cells 
Reversed by Pembrolizumab Addition .......................................................................47 
Figure 7: 
In Vitro Activation of TAC T Cells Across Various Levels of HER2-Expressing 
Cancer Cell Lines .......................................................................................................49 
Figure 8:  Response (RECIST 1.1) by CLDN18.2-Specific CAR T Cells Dose Level 
(Investigator Assessed) ...............................................................................................55 
Figure 9: 
Study Design ...............................................................................................................60 
Figure 10: Monotherapy Study Scheme .......................................................................................62 
Figure 11: Combination Therapy Study Scheme .........................................................................62 
 
 

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ABBREVIATIONS 
Abbreviation or Term 
Definition/Explanation 
ACT 
Adoptive T cell transfer 
AE 
Adverse event 
ALC 
Absolute lymphocyte count 
ALT 
Alanine aminotransferase 
ANC 
Absolute neutrophil count 
AP 
Alkaline phosphatase 
aPTT 
Activated partial thromboplastin time  
AST 
Aspartate aminotransferase 
ASTCT 
American Society for Transplantation and Cellular Therapy 
AUC 
Area under the concentration-time curve 
-hCG 
Beta human chorionic gonadotropin 
BSA 
Body surface area 
BTC 
Biliary tract cancer 
CAP 
College of American Pathologists 
CAR 
Chimeric antigen receptor 
CBC 
Complete blood count 
CD 
Cluster of differentiation 
CD3ζ 
CD3 zeta 
CFR 
Code of Federal Regulations 
CI 
Confidence interval 
c/kg 
Cells per kg 
Clast 
Last observed quantifiable level of transgene 
CLIA 
Clinical Laboratory Improvements Amendments 
Cmax 
Maximum concentration (or peak cell expansion) after infusion  
CNS 
Central nervous system 
CR 
Complete response 
CRC 
Colorectal cancer 
CRF 
Case report form 
CRP 
C-reactive protein 
CRS 
Cytokine release syndrome 
CSF 
Cerebrospinal fluid 
CT 
Computed tomography 
CTCAE 
Common Terminology Criteria for Adverse Events 
ctDNA 
Circulating tumor DNA 
CTLA 
Cytotoxic T-lymphocyte-associated protein 

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Abbreviation or Term 
Definition/Explanation 
CYC 
Cyclophosphamide 
D 
De-escalate 
DARPin 
Design ankyrin repeat protein 
DCR 
Disease control rate 
DIC 
Disseminated intravascular coagulation 
DILI 
Drug induced liver injury 
DLBCL 
Diffuse large B cell lymphoma 
DLT 
Dose-limiting toxicity 
DMSO 
Dimethyl sulfoxide 
DNA 
Deoxyribonucleic acid 
DOR 
Duration of response 
DRESS 
Drug Rash with Eosinophilia and Systemic Symptom 
DSMC 
Data Safety Monitoring Committee 
E 
Escalate 
ECG 
Electrocardiogram 
ECHO 
Echocardiogram 
ECI 
Events of clinical interest 
ECOG 
Eastern Cooperative Oncology Group 
EDC 
Electronic data capture 
EEG 
Electroencephalogram 
eGFR 
Estimated glomerular filtration rate 
EGFR 
Epidermal growth factor receptor 
EOS 
End of study 
ERBB2/erbB-2 
Erythroblastic oncogene B  
FBR 
Future biomedical research 
FDA 
Food and Drug Administration 
FISH 
Fluorescent in-situ hybridization 
FNA 
Fine needle aspiration 
FT3 
Free triiodothyronine 
FT4 
Free thyroxine 
G-CSF 
Granulocyte colony stimulating factor 
GCP 
Good Clinical Practice 
gDNA 
Genomic DNA 
GEJ 
Gastroesophageal junction 
GI 
Gastrointestinal 
GM-CSF 
Granulocyte-macrophage colony-stimulating factor 
HAMA 
Human anti-mouse antibodies 

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Abbreviation or Term 
Definition/Explanation 
HbsAg 
Hepatitis B surface antigen 
HBV 
Hepatitis B virus 
HCV 
Hepatitis C virus 
HER2 
Human epidermal growth factor receptor 2 
HIV 
Human immunodeficiency virus 
HLH 
Hemophagocytic lymphohistiocytosis 
HSCT 
Hematopoietic stem cell transplant 
IB 
Investigator’s Brochure 
ICANS 
Immune effector cell-associated neurotoxicity syndrome 
ICF 
Informed consent form 
ICH 
International Council for Harmonisation 
ICU 
Intensive Care Unit 
ID 
Identification 
IEC 
Independent Ethics Committee 
IFN-γ 
Interferon γ 
IgG/IgG4 
Immunoglobulin G/G4 
IgV 
Immunoglobulin variable 
IHC 
Immunohistochemistry 
IL 
interleukin 
IND 
Investigational New Drug 
INR 
International normalized ratio 
IO 
Immuno-oncology 
irAE 
Immune-related adverse event 
IRB 
Institutional Review Board 
IUD 
Intrauterine device 
IV 
Intravenous(ly) 
KM 
Kaplan-Meier 
Lck 
Lymphocyte-specific protein tyrosine kinase 
LDC 
Lymphodepletion chemotherapy 
LDH 
Lactate dehydrogenase 
LTFU 
Long-Term Follow-Up 
LVEF 
Left ventricular ejection fraction 
mAB 
Monoclonal antibody 
MAS 
Macrophage activation syndrome 
MedDRA 
Medical Dictionary for Regulatory Activities 
MFD 
Maximum feasible dose 
MFI 
Mean fluorescence intensity 

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Abbreviation or Term 
Definition/Explanation 
MHC 
Major histocompatibility complex 
MPM 
Malignant pleural mesothelioma 
MRI 
Magnetic resonance imaging 
MTD 
Maximum tolerated dose 
mTPI 
Modified toxicity probability interval 
MUGA 
Multigated acquisition (scan) 
NCI 
National Cancer Institute 
NCI-N87 
Human gastric epithelial cell line 
NE 
Non-evaluable 
NGS 
Next generation sequencing 
NRG 
NOD.Cg-Rag1tm1Mom Il2rgtm1Wjl/SzJ immuno-deficient mouse model 
NSCLC 
Non-small cell lung cancer 
NYHA 
New York Heart Association 
O2 
Oxygen 
OE19 
Oesophageal adenocarcinoma cell line 
ORR 
Objective response rate 
OS 
Overall survival 
OVCAR-3 
Human ovarian carcinoma cell line 
PBMC 
Peripheral blood mononuclear cell 
PBPK 
Physiologically based pharmacokinetic 
PCR 
Polymerase chain reaction 
PD 
Progressive disease 
PD-1 
Programmed cell death protein 1 
PD-L1 
Programmed cell death ligand 1 
Pembro 
Pembrolizumab 
PET 
Positron emission tomography 
PFS 
Progression free survival 
PK 
Pharmacokinetic 
PKCϴ 
Protein kinase C-theta 
PO 
By mouth 
PR 
Partial response 
pRBC 
Packed red blood cell 
PT 
Prothrombin time 
PTT 
Partial thromboplastin time 
ptarget 
Target toxicity probability 
Q 
Every 
qPCR 
Quantitative polymerase chain reaction 

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Abbreviation or Term 
Definition/Explanation 
r/r 
Relapsed/refractory  
RCL 
Replication-competent lentivirus 
RECIST 
Response Evaluation Criteria in Solid Tumors 
RNA 
Ribonucleic acid 
RP2D 
Recommended Phase 2 Dose 
S 
Stay 
SAE 
Serious adverse event 
SAP 
Statistical Analysis Plan 
SC 
Subcutaneous 
scFv 
Single-chain variable antibody fragment 
SCID 
Severe combined immunodeficiency 
SD 
Stable disease 
SDF-1 
Stromal cell-derived factor 1 
SJS 
Stevens-Johnson Syndrome 
SOC 
Standard-of-care 
SOE 
Schedule of events 
SUSAR 
Suspected Unexpected Serious Adverse Reaction 
T1DM 
Type 1 diabetes mellitus 
T3 
Triiodothyronine 
TAC 
T cell antigen-coupler 
TACΔ 
TAC lacking an antigen binding domain 
TCR 
T cell receptor 
TEAE 
Treatment-emergent adverse event 
TENS 
Toxic epidermal necrolysis 
Tlast 
Level of transgene at the last quantifiable time point 
TLS 
Tumor lysis syndrome 
Tmax 
Time to reach Cmax 
TMDD 
Target-mediated drug disposition 
Treg 
Regulatory T cell 
TSH 
Thyroid stimulating hormone 
TTP 
Time to progression 
ULN 
Upper limit of normal 
UPM 
Unit probability mass 
US 
United States 
W 
Week 
WHO-DD 
World Health Organization Drug Dictionary 
ZAP70 
Zeta-chain-associated protein kinase 

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Abbreviation or Term 
Definition/Explanation 
Λz 
Apparent terminal elimination rate constant 

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1. INTRODUCTION AND STUDY RATIONALE 
1.1. HER2-positive Solid Tumors  
The activation of human epidermal growth factor receptor 2 (HER2) signaling observed in 
approximately 20% of breast cancers is the result of overexpression, owing to erythroblastic 
oncogene B (ERBB2; Oh 2020), also known as cluster of differentiation (CD) 340, amplification 
or activating somatic mutations (Yarden 2001). HER2 overexpression has been described in a 
variety of other solid tumors, including gastric and gastroesophageal junction (GEJ) cancers, 
biliary tract cancer (BTC), colorectal cancer (CRC), non-small-cell lung cancer (NSCLC) and 
bladder cancer, with incidences varying from >50% of uterine cancers to around 2% of NSCLCs 
(Figure 1). Genomic profiling of human cancers has revealed recurrent somatic mutations in 
ERBB2, typically occurring in the absence of amplifications (Chmielecki 2015, Schram 2017, 
Zehir 2017). 
Figure 1: Frequency of HER2 Alterations Across Tumor Types 
 
ERBB2 amplifications or mutations and HER2 overexpression have been detected in a wide range of different tumor 
types. Nonetheless, as suggested by the experience with gastric cancer, the presence of targetable alterations alone is 
not sufficient for a response to HER2-targeted therapies.  
1.2. HER2 as a Therapeutic Target 
Receptor tyrosine-protein kinase erbB-2, also known as HER2, is a member of the epidermal 
growth factor receptor (EGFR) family of receptor tyrosine kinases. Heterodimerization of this 
receptor with other members of the EGFR family, typically owing to HER2 overexpression, 

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results in the autophosphorylation of tyrosine residues within the cytoplasmic domain of the 
heterodimer and initiates a variety of signaling pathways leading to cellular proliferation and 
tumorigenesis (Yarden 2001).  
HER2 is an established therapeutic target in a large subset of women with breast cancer; a 
variety of agents including trastuzumab, pertuzumab, lapatinib, neratinib and ado-trastuzumab 
emtansine have been approved for the treatment of HER2-positive (HER2+) breast cancer. HER2 
is also overexpressed in subsets of patients with other solid tumors. Notably, the addition of 
trastuzumab to first-line chemotherapy has improved the overall survival (OS) of patients with 
HER2+ gastric cancer and has become the standard-of-care treatment for this group of patients. 
However, studies involving pertuzumab, lapatinib and ado-trastuzumab emtansine have failed to 
provide significant improvements in the outcomes of patients with HER2+ gastric cancer.  
HER2-targeted therapies are also being tested in patients with other solid tumors harboring 
HER2 overexpression, and/or amplifications or other mutations of the gene encoding HER2, 
including BTC, CRC, NSCLC, and bladder cancer. The experience with gastric cancer suggests 
the successes observed in HER2+ breast cancer might not be replicated in these other tumor 
types, owing to differences in the level of HER2 overexpression and other aspects of disease 
biology. 
1.3. Adoptive T Cell Therapy 
Adoptive T cell transfer (ACT) using autologous T cells genetically engineered to express 
chimeric receptors is a promising approach to treat cancer (June 2018, Miliotou 2018). The 
introduction of a chimeric receptor into a patient’s T cells re-directs a patient’s own immune cells 
to tumor cells and provides mechanisms that lead to T cell activation and, consequently, tumor 
cell killing. Molecularly, this is achieved by the chimeric receptor via an extracellular 
antigen-specific binding domain, that mediates tumor cell recognition, and – in the case of 
chimeric antigen receptors (CARs) – an intracellular transactivation domain that induces T cell 
activation upon binding to the antigen.  
Effective clinical applications of such T cell therapies are frequently hampered by serious and 
potentially fatal adverse events (AEs). These include cytokine release syndrome (CRS), 
macrophage activation syndrome (MAS), hemophagocytic lymphohistiocytosis (HLH), and 
immune effector cell-associated neurotoxicity syndrome (ICANS; Barrett 2014, Maude 2016, 
Maude 2014a). In addition, insufficient in vivo T cell expansion and persistence, as well as 
premature T cell exhaustion as a result of tonic signaling may reduce the potency of the T cell 
product (Long 2015). Several of these features are likely a direct consequence of the specific 
design of the CAR protein and, particularly, attributed to its own signaling domain which 
activates T cells directly and without the endogenous T cell receptor (TCR). 
1.4. T Cell Antigen-Coupler Technology 
The manufacturing aspects of the T cell antigen-coupler (TAC) T cell therapy are similar to those 
of other engineered T cell products which involve an extraction of T cells from the subject, 
followed by the genetic engineering with a chimeric receptor using retro-/lenti-viral transduction, 

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expansion of engineered T cells ex vivo, and lastly, re-administration of engineered T cells to the 
subject.  
TAC T cells are T cells genetically engineered via lentiviral insertion of the HER2-directed TAC 
transgene which encodes a chimeric, partially humanized receptor that was designed to exert 
2 key functions: first, to redirect a T cell to tumor cells via the specific recognition of a tumor 
associated antigen expressed on the surface of tumor cells, and second, to activate that same 
T cell via recruitment of the TCR complex and its natural, downstream intracellular signaling 
pathways (Figure 2). Thus, TAC is expected to induce antitumor responses via a mechanism that 
mimics T cell activation under physiologic conditions (Helsen 2018). This mechanism contrasts 
with conventional chimeric receptors, such as CARs, that activate T cells independently of the 
endogenous TCR via their own intracellular signaling domain. 
Figure 2: TAC T Cell Receptor versus CARs and the Natural TCR Complex 
A 
 
 
  B 
 
(A) Outline of the 3 major protein domains in the chimeric TAC receptor. (B) Comparison of the molecular 
mechanisms that control T cell activation in TAC-expressing T cells (left), normal cells (middle), and T cells 
engineered with CARs (right). Left: The TAC receptor (cyan) re-directs the TCR-CD3 complex towards an antigen 
of choice. A single-chain variable antibody fragment (scFv) is used to recruit the TCR-CD3 complex. Co-receptor 
properties are incorporated by including the CD4 hinge, transmembrane region, and cytosolic tail (green). Middle: 
Naturally occurring TCR-CD3 complex (purple) interacts directly with the cancer antigen presented by the Major 
Histocompatibility Complex (MHC). Meanwhile, the CD8/CD4 co-receptor (CD8 shown in dark green) interacts 
with MHC I/II in an antigen-independent manner. Together, these interactions comprise the first step in T cell 
activation. Right: The CAR receptor (yellow) binds to a cancer antigen of choice and activates T cells 
independently of the TCR-CD3 complex by its own intracellular transactivation domain. 
The various functions of the TAC receptor are carried out by 3 main structural domains (Figure 
2):  
1. Antigen-binding domain: Antigen recognition is mediated by the N-terminal extracellular 
antigen-binding domain, such as a HER2-targeted designed ankyrin repeat protein 
(DARPin). In the absence of antigen, there are no signs of auto-activation or tonic 
signaling (Helsen 2018). 
2. TCR-recruitment domain: A central and extracellular protein domain (CD3-targeting 
scFv) facilitates the interaction of TAC with the TCR/CD3 complex. This CD3-binding 
domain is critically necessary for TAC activation. TAC constructs lacking this domain do 
not show activity (Helsen 2018). 

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3. Co-receptor domain: The C-terminal co-receptor domain consists of an extracellular 
hinge domain, as well as the transmembrane and cytoplasmic domains derived from the 
natural CD4 co-receptor, anchoring the TAC receptor into the cellular membrane. The 
cytoplasmic tail includes the lymphocyte-specific protein tyrosine kinase (Lck) binding 
site of CD4 which is expected to contribute to T cell activation upon recruitment of the 
TCR. In the absence of the cytoplasmic tail, surface expression of the TAC is greatly 
reduced, and T cell activation is impaired (unpublished data). 
1.5. TAC01-HER2 Investigational Product 
1.5.1. Product Name and Description 
TAC01-HER2 is an autologous T cell product comprising T cells expressing a HER2-specific 
TAC, a chimeric receptor that is genetically engineered into T cells via lentiviral transduction to 
furnish T cells with 2 main functions: (i) redirection to and specific recognition of HER2+ cells, 
and (ii) T cell activation via the endogenous TCR. 
1.5.2. Structure 
The chimeric TAC-HER2 receptor consists of 3 main functional domains: (Figure 3): (i) an 
extracellular HER2-binding domain provided by the H10-2-G3 designed ankyrin repeat protein 
(DARPin); (ii) an extracellular TCR/CD3ε-binding domain (huUCHT1 scFv); and (iii) a 
membrane-anchoring domain that consists of the transmembrane and cytoplasmic domains of 
CD4. The HER2-binding domain is designed to bind to the HER2 surface antigen expressed on 
HER2+ cells, including HER2+ non-malignant cells. The TCR/CD3ε binding domain is designed 
to recruit the endogenous TCR complex. The cytoplasmic tail includes the Lck binding site of 
CD4 which is expected to contribute to T cell activation upon recruitment of the TCR. 
Figure 3: Endo and Ectodomains of the TAC Receptor on the Surface of TAC T Cells 
 
The TAC receptor re-directs the TCR-CD3 complex (grey: α, β, γ, δ, ε, ζ chains) towards the HER2 antigen. The 3 
major TAC protein domains are shown. Purple: HER2-directed DARPin (H10-2-G3), blue: CD3-binding (scFv), 
dark green: CD4 co-receptor (membrane anchoring). 

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1.5.3. Dosage Form 
The TAC01-HER2 product is a suspension of genetically modified autologous T cells expressing 
the HER2-TAC receptor for infusion (i.e., HER2-targeted TAC T cells) containing 10% dimethyl 
sulfoxide (DMSO) in approximately 20 mL. 
1.5.4. Administration 
TAC01-HER2 will be administered as an intravenous (IV) infusion approximately 72 hours after 
completion of lymphodepleting chemotherapy (LDC). LDC will preferentially consist of 3 
consecutive days of fludarabine (30 mg/m2 IV) or clofarabine (52 mg/m2 IV) and 
cyclophosphamide (300 mg/m2 IV) with or without mesna IV. Central venous access is 
recommended for the infusion of TAC01-HER2.  
If fludarabine or clofarabine is unavailable (due to national shortages), subjects can be treated 
with 3 consecutive days of cyclophosphamide (300 mg/m2 IV) with or without mesna IV or with 
bendamustine 90 mg/m2 daily for 2 days for subjects who cannot tolerate cyclophosphamide. 
The dose intensity of either the primary (fludarabine or clofarabine + cyclophosphamide) or 
backup (cyclophosphamide or bendamustine) regimens can be modified based on a subject's 
complete blood count (CBC) and creatinine clearance, upon discussion with the Medical 
Monitor.  
1.6. Pembrolizumab  
1.6.1. Background 
Pembrolizumab is a potent humanized immunoglobulin G4 (IgG4) monoclonal antibody (mAb) 
with high specificity of binding to the programmed cell death protein 1 (PD-1) receptor, thus 
inhibiting its interaction with programmed cell death ligand 1 (PD-L1) and programmed cell 
death ligand 2 (PD-L2). Based on nonclinical in vitro data, pembrolizumab has high affinity and 
potent receptor blocking activity for PD-1. Pembrolizumab has an acceptable nonclinical safety 
profile and is in clinical development as an IV immunotherapy for advanced malignancies. 
Keytruda® (pembrolizumab) is indicated for the treatment of patients across a number of 
indications. For more details on specific indications refer to the Investigator’s Brochure (IB). 
Refer to the IB/approved labeling for detailed background information on MK-3475. 
1.6.2. Pharmaceutical and Therapeutic Background 
The importance of intact immune surveillance function in controlling outgrowth of neoplastic 
transformations has been known for decades (Disis 2010). Accumulating evidence shows a 
correlation between tumor-infiltrating lymphocytes in cancer tissue and favorable prognosis in 
various malignancies. In particular, the presence of CD8+ T-cells and the ratio of CD8+ effector 
T cells/FoxP3+ regulatory T-cells (Treg) correlates with improved prognosis and long-term 
survival in solid malignancies, such as ovarian, colorectal, and pancreatic cancer; hepatocellular 

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carcinoma; malignant melanoma; and renal cell carcinoma. Tumor-infiltrating lymphocytes can 
be expanded ex vivo and reinfused, inducing durable objective tumor responses in cancers such 
as melanoma (Dudley 2005, Hunder 2008). 
The PD-1 receptor-ligand interaction is a major pathway hijacked by tumors to suppress immune 
control. The normal function of PD-1, expressed on the cell surface of activated T cells under 
healthy conditions, is to down-modulate unwanted or excessive immune responses, including 
autoimmune reactions. PD-1 (encoded by the gene Pdcd1) is an immunoglobulin superfamily 
member related to CD28 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) that has 
been shown to negatively regulate antigen receptor signaling upon engagement of its ligands 
(PD-L1 and/or PD-L2; Greenwald 2005, Okazaki 2001). 
The structure of murine PD-1 has been resolved (Zhang 2004). PD-1 and its family members are 
type I transmembrane glycoproteins containing an Ig-variable–type (IgV-type) domain 
responsible for ligand binding and a cytoplasmic tail responsible for the binding of signaling 
molecules. The cytoplasmic tail of PD-1 contains 2 tyrosine-based signaling motifs, an 
immunoreceptor tyrosine-based inhibition motif, and an immunoreceptor tyrosine-based switch 
motif. Following T-cell stimulation, PD-1 recruits the tyrosine phosphatases, SHP-1 and SHP-2, 
to the immunoreceptor tyrosine-based switch motif within its cytoplasmic tail, leading to the 
dephosphorylation of effector molecules such as CD3 zeta (CD3ζ), protein kinase C-theta 
(PKCθ), and zeta-chain-associated protein kinase (ZAP70), which are involved in the CD3 T-cell 
signaling cascade (Okazaki 2001, Chemnitz 2004, Sheppard 2004, Riley 2009). The mechanism 
by which PD-1 down-modulates T cell responses is similar to, but distinct from, that of CTLA-4, 
because both molecules regulate an overlapping set of signaling proteins (Parry 2005 , 
Francisco 2010). As a consequence, the PD-1/PD-L1 pathway is an attractive target for 
therapeutic intervention in breast, lung, pancreatic, colorectal, gastric, endometrial, ovarian, and 
other solid tumor types. 
1.6.3. Nonclinical and Clinical Studies 
Therapeutic studies in mouse models have shown that administration of antibodies blocking the 
PD-1/PD-L1 interaction enhances infiltration of tumor-specific CD8+ T cells and ultimately 
leads to tumor rejection, either as a monotherapy or in combination with other treatment 
modalities (Hirano 2005, Blank 2004, Weber 2010, Strome 2003, Spranger 2014, Curran 2010, 
Pilon-Thomas 2010). Anti-mouse PD-1 or anti-mouse PD-L1 antibodies have demonstrated 
antitumor responses in models of squamous cell carcinoma, pancreatic carcinoma, melanoma, 
acute myeloid leukemia, and CRC (Strome 2003, Curran 2010, Pilon-Thomas 2010, Nomi 2007, 
Zhang 2004). In such studies, tumor infiltration by CD8+ T cells and increased interferon γ (IFN-
γ), granzyme B, and perforin expression were observed, indicating that the mechanism 
underlying the antitumor activity of PD-1 checkpoint inhibition involved local infiltration and 
activation of effector T cell function in vivo (Curran 2010). Experiments have confirmed the in 
vivo efficacy of anti-mouse PD-1 antibody as a monotherapy, as well as in combination with 
chemotherapy, in syngeneic mouse tumor models (see the IB). 

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1.6.4. Justification for Dose  
The planned dose of pembrolizumab for this study is 200 mg every 3 weeks (Q3W). Based on 
the totality of data generated in the Keytruda® development program, 200 mg Q3W is an 
appropriate dose of pembrolizumab for adults across all indications. As outlined below, this dose 
is justified by: 
• Clinical data from 8 randomized studies in melanoma and NSCLC indications 
demonstrating flat dose- and exposure-efficacy relationships from 2 mg/kg Q3W to 
10 mg/kg every 2 weeks (Q2W) representing an approximate 5- to 7.5-fold exposure 
range (refer to the IB) 
• Population pharmacokinetic (PK) analysis showing that both fixed-dosing and weight-
based dosing provides similar control of PK variability with considerable overlap in the 
distributions of exposures, supporting suitability of 200 mg Q3W 
• Clinical data showing meaningful improvement in benefit-risk including OS at 200 mg 
Q3W across multiple indications, and 
• Pharmacology data showing full target saturation in both systemic circulation (inferred 
from PK data) and tumor (inferred from physiologically based PK [PBPK] analysis) at 
200 mg Q3W. 
Among the 8 randomized dose-comparison studies, a total of 2262 participants were enrolled 
with melanoma and NSCLC, covering different disease settings (treatment naïve, previously 
treated, PD-L1 enriched, and all-comers) and different treatment settings (monotherapy and in 
combination with chemotherapy). Five studies compared 2 mg/kg Q3W versus 10 mg/kg Q2W 
(KN001 Cohort B2, KN001 Cohort D, KN002, KN010, and KN021), and 3 studies compared 
10 mg/kg Q3W versus 10 mg/kg Q2W (KN001 Cohort B3, KN001 Cohort F2, and KN006). All 
these studies demonstrated flat dose- and exposure-response relationships across the doses 
studied representing an approximate 5- to 7.5-fold difference in exposure. The 2 mg/kg (or 
200 mg fixed dose) Q3W provided similar responses to the highest doses studied. Subsequently, 
flat dose-exposure-response relationships were also observed in other tumor types including head 
and neck cancer, bladder cancer, gastric cancer, and classical Hodgkin Lymphoma, confirming 
200 mg Q3W as the appropriate dose independent of the tumor type. These findings are 
consistent with the mechanism of action of pembrolizumab, which acts by interaction with 
immune cells, and not via direct binding to cancer cells. 
Additionally, pharmacology data clearly show target saturation at 200 mg Q3W. First, PK data in 
KN001 evaluating target-mediated drug disposition (TMDD) conclusively demonstrated 
saturation of PD-1 in systemic circulation at doses much lower than 200 mg Q3W. Second, a 
PBPK analysis was conducted to predict tumor PD-1 saturation over a wide range of tumor 
penetration and PD-1 expression. This evaluation concluded that pembrolizumab at 200 mg 
Q3W achieves full PD-1 saturation in both blood and tumor. 

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Finally, population PK analysis of pembrolizumab, which characterized the influence of body 
weight and other participant covariates on exposure, has shown that the fixed-dosing provides 
similar control of PK variability as weight-based dosing, with considerable overlap in the 
distribution of exposures from the 200 mg Q3W fixed-dose and 2 mg/kg Q3W dose. Supported 
by these PK characteristics and given that fixed-dose has advantages of reduced dosing 
complexity and reduced potential of dosing errors, the 200 mg Q3W fixed-dose was selected for 
evaluation across all pembrolizumab protocols. 
1.6.5. Timing of Pembrolizumab Administration 
Pembrolizumab 200 mg IV will be administered Q3W starting on Day 21 or Day 14 from 
administration of TAC T cells. The initial combination dose-escalation cohort will have 
pembrolizumab administered on Day 21. For all remaining cohorts, pembrolizumab will be 
administered on Day 14 if no dose-limiting toxicities (DLTs) or safety issues are identified (as 
approved by the Data Safety Monitoring Committee [DSMC]). The Day 14 time point was 
chosen based on nonclinical in vivo data showing maximal TAC T cell expansion in the tumor 
around and after Day 7 post IV administration. The Day 21 time point for the initial 
pembrolizumab administration in the combination arm was chosen as an additional safety 
precaution to allow an extra week for any TAC T cell-related AEs to emerge and be managed, as 
appropriate.  
Dose modifications and discontinuations will follow the guidelines described in Appendix H and 
Appendix I. The recommended dosage modifications based on adverse reactions can also be 
found in Table 9. 
1.7. Study Rationale  
Despite recent therapeutic developments for patients with advanced, metastatic, unresectable 
HER2-positive (HER2+) solid tumors, a significant unmet medical need still exists, especially in 
solid tumors where there are no approved HER2-targeted therapies and/or in tumors with low or 
intermediate HER2 expression. The TAC technology is a novel approach to modifying a patient’s 
own T cells, herein referred to as TAC T cells, and using them in the treatment of solid tumors. 
TAC T cells are produced through genetic engineering, incorporating TAC receptors into a 
patient’s own T cells. This redirects these enhanced T cells to specific cancer antigens and, upon 
recognition, activates them by co-opting the natural signaling pathways of the endogenous TCR.  
In the TAC01-HER2 product, TAC T cells use the HER2 antigen, which is present on the surface 
of cancer cells, to recognize and eradicate tumor cells. Promising outcomes have been observed 
in mouse models, with TAC T cells accumulating within solid tumors, resulting in a robust 
antitumor efficacy profile paired with a favorable safety profile. TAC T cells can also persist for 
extended periods of time in mice and protect the host from tumor regrowth. Consequently, it is 
hypothesized TAC01-HER2 monotherapy will be safe and effective in treating patients with 
HER2+ solid tumors and can provide a significant therapeutic benefit in an area of high unmet 
medical need. 

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Phase 1 will evaluate escalating single doses of TAC01-HER2 (on Day 1) as a monotherapy, and 
in combination with a fixed approved prescription pembrolizumab dose (200 mg Q3W) 
beginning on either Day 21 or Day 14 to identify the recommended Phase 2 doses (RP2Ds) for 
TAC01-HER2 treatment in subjects with HER2+ solid tumors, who have progressed after 2 prior 
lines of therapy.  
In vitro nonclinical studies conducted by Triumvira suggest that TAC T cells specifically engage 
with HER2+ cancer cells. As part of this T cell activation process, TAC T cells, similar to any 
other activated T cell, can induce the expression of PD-1 and PD-L1, which can consequently 
lead to reduced TAC T cell activity. Blocking PD-1 signaling via an anti-PD-1 checkpoint 
blockade, such as pembrolizumab, can counteract this inhibitory function. Therefore, these 
observations highlight the importance of evaluating the combination of TAC01-HER2 treatment 
with PD-1 blockade to potentially enhance the antitumor activity of administered TAC T cells. 
Attenuating the eventual exhaustion of TAC T cells may also facilitate the recruitment of 
endogenous polyclonal immune cells to overcome tumor heterogeneity and to prevent antigen 
escape (Grosser 2019). Mechanistically, this occurs through first treatment with TAC01-HER2, 
followed by pembrolizumab to block PDL1 and PD-L2 ligands on cancer cells from binding to 
PD-1 receptors on the resultant circulating TAC T cells. 
In addition to 3+ HER2 tumors, subjects with low-HER2 expressing solid tumors (i.e., 2+ and 
1+) will also be allowed to participate in this trial. These subjects constitute an area of high 
unmet medical need, e.g., 60% of all breast cancer patients have low-HER2 expressing tumors 
(Modi 2022). Nonclinical studies have demonstrated that TAC T cells are equally effective in 
eliciting antitumor activity regardless of HER2 expression levels (Figure 7) and are active in 
killing tumor cells that are resistant to trastuzumab and pertuzumab. In addition, trastuzumab 
deruxtecan, a HER2-targeting antibody drug conjugate, has recently demonstrated significant 
success in treating low HER2-expressing tumors in breast cancer patients (i.e., with an objective 
response rate [ORR] of 37.0% in a Phase 1B trial [Modi 2020] and 52.3% in the Destiny 
Breast04 Phase 3 trial [Modi 2022]), with a median duration of response (DOR) of 10.7 versus 
6.8 months (in the Phase 3 trial) for trastuzumab deruxtecan treatment vs the physician’s choice 
of chemotherapy (Modi 2022).  
In conclusion, HER2 overexpression and/or amplification is observed in breast, gastric, lung, 
pancreatic, salivary, vaginal, endometrial, gall bladder, colorectal, and cervical cancers. It 
activates numerous oncogenic signaling pathways (e.g., PI3K/AKT and Ras/Raf/ERK) resulting 
in improved malignant cell survival, proliferation, migration, and resistance to immunotherapy 
(Vafaei 2022). HER2-targeted therapies continue to evolve in treating patients with varying 
levels of HER2 expression. However, continued advances using novel targeted therapies are still 
needed to treat patients more effectively and with fewer side-effects. 
1.8. TAC01-HER2 Monotherapy Rationale 
In vitro and in vivo pharmacology studies have characterized the mechanism of action, dose 
response relationships, efficacy, PK, biodistribution, improved safety parameters, and the 
potential influence on TAC01-HER2 bioactivity produced from multiple healthy donors of TAC 

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T cells, as compared with CAR-T cells. These nonclinical studies were carried out using a panel 
of cancer cell lines representative of human HER2+ malignancies, which included ovarian 
cancer (OVCAR-3), gastric cancer (NCI-N87) and gastroesophageal cancer (OE19). Cancer cells 
were either co-cultured transiently with TAC T cells in vitro or grown as subcutaneous tumor 
xenografts in immunodeficient NRG mice before TAC01-HER2 administration. The data 
demonstrate TAC T cells reproducibly lead to elimination of HER2+ tumor cells in vitro and in 
vivo. During these nonclinical studies, no treatment-related changes were observed in mobility, 
grooming, and overall constitution. In addition, a pivotal 60-day pharmacology/safety study was 
conducted in immunodeficient NRG mice carrying established OE19 tumor xenografts and did 
not reveal any TAC-related toxicities. The study observed the effects of TAC01-HER2 given as 
an IV tail vein injection at a therapeutic dose level (3 x 108 TAC T cells/kg) and at the maximally 
feasible dose level (6 x 108 TAC T cells/kg). The study observed tumor burden, survival, T cell 
expansion, serum cytokines, clinical chemistries, and histopathology of vital organs. Dose 
conversions from mouse to humans show that the therapeutic dose used in mice (3 x 108 TAC T 
cells/kg) was at least 3-times higher than the lowest dose in the proposed clinical study, and the 
highest dose levels used in mice (6 x 108 TAC T cells/kg) was at least 6-times greater (based on 
body surface area [BSA]) than the highest dose levels in the proposed clinical study. However, 
data produced in animal models should be interpreted with caution and are considered supportive 
information given the marked differences of TAC T cell host- interactions in these models 
compared with humans. See the IB for additional information. 
Dose levels used in nonclinical pharmacology studies in mice were determined empirically and 
typically ranged from 2.5 x 107 to 6 x 108 TAC T cells per kg (c/kg), assuming a mouse body 
weight of 20 g for various TAC01-HER2 products. The maximum feasible dose (MFD) was 
typically 3-fold higher (e.g., 6 x 108 c/kg). Human equivalent dose levels were calculated based 
on a direct c/kg conversion and separately on body surface area. These calculations indicated the 
proposed clinical monotherapy starting dose (i.e., Dose Level 1) was approximately 2-3 logs 
lower than dose levels used in mice. 
However, similar to other forms of cellular immune therapy, dose levels investigated in mice do 
not accurately predict dose levels in humans for several reasons (CAR T cell Products Draft 
Guidance 2022). Therefore, additional information was considered to estimate the starting dose 
in humans, such as, dose levels of YESCARTA® and KYMRIAH®, which were both safe and 
biologically active in studies in humans. 
In Group A of Phase 2, a second TAC01-HER2 dose may be administered ≥4 weeks after the first 
dose if the subject has tolerated the first TAC01-HER2 infusion and if additional 
inclusion/exclusion criteria are met (Section 4.3). Modeling multidosing in mice was considered; 
however, was not done as it cannot inform on dose regimens in humans. Thus, the most 
appropriate animal model for studying the nonclinical pharmacology and safety of TAC01-HER2 
are immunodeficient mice (NRG/NSG) carrying human, HER2-expressing tumor xenografts. 
However, these mice have deficient immune systems that do not recapitulate the complex 
immune system in humans and therefore present critical limitations in extrapolating mouse data 
to humans as follows: 

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• Nonclinical modeling of safety: A chief parameter for defining the timing of the second 
TAC01-HER2 dose is safety of the first infusion. However, immunocompromised mice do 
not represent an adequate model to assess immune-related toxicities and, therefore, lack the 
ability to observe a comprehensive spectrum of immune related toxicities relevant to humans. 
• Nonclinical modeling of PK: Multidose regimens are often guided by PK parameters seen in 
nonclinical models. However, PK of cell therapies is highly influenced by clearance 
mechanisms that are driven by the host immune system and for instance cause graft rejection. 
Immunodeficient mice do not provide the appropriate host background that will influence PK 
in humans and therefore are not appropriate models to evaluate multidose regimens. 
Furthermore, the PK profile of transferred T cells may be influenced by T cell trafficking to 
the tumor and in vivo T cell expansion, both of which cannot be anticipated in nonclinical 
models. 
• Immunocompromised mouse models are susceptible to graft versus host disease, which can 
confound efficacy and safety assessments of cell therapies.  
In the proposed clinical study, the second dose will be administered at least 4 weeks after the 
first dose. Therefore, the rationale for a single dose nonclinical study to support administering 
the second TAC01-HER2 dose in humans is in accordance with the ICH S9 guidance, which 
state a single dose nonclinical study supports a clinical schedule of once every 3-4 weeks 
(Nonclinical Evaluation for Anticancer Pharmaceuticals). Since nonclinical models are of limited 
value for cell therapies, additional information available from other cell therapies in clinical 
development for solid tumors were considered, such as 1 subject was safely administered a 
second TAC01-HER2 dose under IND 27239 and multiple clinical studies allowed 
administration of a second dose of CAR-T cells for the treatment of solid tumors. This additional 
information supports the rationale that administration of a second dose at least 28 days after the 
first dose would be expected to be safe for evaluation in a Phase 2 clinical study.  
1.9. Anti-PD-1 Combination Therapy Rationale 
1.9.1. Background 
PD-1, also known as CD279, is an immune checkpoint and surface receptor expressed on T cells 
and other immune cells that promotes self-tolerance and guards against autoimmunity. In T cells, 
it is upregulated after TCR-mediated T cell activation and functions in a negative feedback loop 
to inhibit T cell activity. The PD-1 inhibitory function requires interacting with its respective 
ligands, PD-L1 or PD-L2, expressed by normal cells including other T cells, often during an 
immune response to dampen it. 
PD-1 ligands, specifically PD-L1, are also frequently expressed on tumor cells to escape immune 
surveillance. Therefore, anti-PD-1 strategies, such as the anti-PD-1 mAb pembrolizumab, have 
successfully led to the reinvigoration of exhausted T cells and T cell-mediated antitumor 
responses. Tumors associated with improved clinical responses to checkpoint blockade are those 
with known high PD-L1 expression; however, responses can also be observed in tumors without 
PD-L1 expression (Garon 2015; Topalian 2012). In these tumor cells, PD-L1 expression is 

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believed to be induced by cytokines, such as IFN-γ and TNF-α which are secreted by T cells that 
have infiltrated the tumor bed, particularly after checkpoint blockade (Spranger 2013; Tumeh 
2014; Herbst 2014). Since TAC T cell activation can also impact the PD1/PD-L1 signaling axis 
(Section 1.9.2.1), this study will not mandate subjects have prerequisite PD-L1 tumor expression 
levels to be enrolled; however, PD-L1 levels will be determined at Screening/Baseline, or after 
enrollment using local laboratory results if necessary. 
1.9.2. Nonclinical Studies 
1.9.2.1. Nonclinical Rationale for Combining TAC01-HER2 with Pembrolizumab 
To assess the relevance of PD-1/PD-L1 signaling in TAC T cells, Triumvira conducted a series of 
nonclinical experiments evaluating the expression of these markers in scenarios of ongoing 
tumor cell killing. Collectively, these data show PD-1 and PD-L1 are specifically induced during 
TAC T cell-mediated antitumor responses and suggest that a prolonged expression of these 
markers can reduce the antitumor activity of TAC T cells. Accordingly, studies using isogenic 
cancer cells, which differ in PD-L1 expression levels, demonstrated that high PD-L1 levels 
expressed on tumor cells can limit TAC T cell activity which, in turn, can be restored by adding 
pembrolizumab. Relevant experiments are described as follows. 
In 1 example, PD-1 expression on T cells was evaluated in the HER2+ N87 gastric cancer mouse 
model. Mice with established human tumor xenografts were treated with TAC01-HER2, derived 
from a healthy donor, and TAC T cells were extracted 30 minutes and 7 days after dosing from 
blood and tumor tissue, respectively (Figure 4A). The Day 7 time point was chosen because it 
reflected a time point during tumor regression that is ideal for the observation of T cells that 
drive the antitumor response (Figure 4B). Isolated T cells were subjected to flow cytometry 
analysis to assess the status of T cells by determining CD69 (activation) and PD-1 (exhaustion). 
In agreement with the TAC T cell profile after manufacturing, the data show that TAC T cells 
lack expression of either marker at the Day 0 time point (blood) and indicate that these T cells 
have not yet encountered any HER2 antigen (Figure 4C). In contrast, TAC T cells recovered 
from HER2+ tumors on Day 7 had elevated expressions of CD69 and PD-1, indicative of 
specific T cell activation. If PD-1 expressed over an extended period of time, leads to T cell 
exhaustion, then blocking PD-1 signaling may effectively interfere with T cell exhaustion and 
increase the potency of TAC T cells. 

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Figure 4:  In Vivo Upregulation of PD-1 Levels in Activated TAC T Cells  
 
(A) Study Design. NSG mice carrying established, subcutaneous human N87 gastric cancer xenografts were given 
a single IV bolus of 6 x 106 TAC+ HER2-TAC T cells (TAC01-HER2, Day 0). An equivalent number of 
non-transduced T cells was given to a separate group of animals as negative controls. Blood and tumor tissue was 
collected 30 minutes and 7 days after treatment for further analysis. (B) Tumor volumes of mice treated with 
TAC01-HER2 (orange) and non-transduced T cells (blue). (C) Flow cytometry analysis of PD-1 and CD69 in 
T cells derived from blood (Day 0) and tumor (Day 7). 
 
In another example, PD-L1 expression was determined in HER2+ N87 tumor spheroids 
co-cultured with TAC01-HER2 for 4 days. While most spheroids were destroyed by the addition 
of TAC T cells (Figure 5A, B), some of the remaining spheroids (those exposed to lower number 
of TAC T cells) were formalin-fixed and paraffin-embedded, cut and used in 
immunohistochemistry (IHC) assays to investigate the antitumor mechanism of TAC T cells 
(Figure 5C). This analysis confirmed the migration of TAC T cells into spheroids, release of 
granzymes, and induction of apoptosis of tumor cells, according to the previously established 
mechanism of TAC T cell-mediated tumor killing. However, this analysis also revealed the 
specific induction of PD-L1 in these spheroids which is likely a consequence of TAC T cell 
activation and IFNγ secretion. Hence, both PD-1 and PD-L1 are induced upon TAC T cell 
mediated- antitumor responses, which if not countered by anti-PD-1 blockade, may lead to TAC 
T cell exhaustion. 

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Figure 5: In Vitro Upregulation of PD-L1 Levels in HER2+ Tumor Spheroids Upon 
Binding and Subsequent Eradication with TAC T Cells  
 
(A) Image of GFP-expressing N87 tumor spheroids (green) on Day 4 in co-culture with TAC T cells at various E:T 
ratios. Co-cultures with non-transduced T cells (NTD) served as controls. A loss of GFP fluorescence indicated the 
complete destruction of spheroids. Additional controls included spheroids cultured without T cells (medium) or 
with the apoptotic agent staurosporine (STS). (B) Quantification of viable N87 spheroids on Day 4. (C) IHC 
analysis of viable tumor spheroids harvested on Day 4 taken from wells with the lowest number of TAC T cells 
(E:T=2:1).  
 
To directly assess the effects of PD-L1 and anti-PD-1 blockade on TAC T cells, isogenic cancer 
cells that exhibit either low or high levels of PD-L1 were co-cultured with TAC T cells in the 
presence or absence of pembrolizumab (Figure 6). The results indicated that PD-L1 quenched the 
ability of TAC T cells to proliferate, which was restored by the addition of pembrolizumab 
(Figure 6B). 

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Figure 6: Loss of TAC T Cell Activity Induced by high PD-L1 Levels on Tumor Cells 
Reversed by Pembrolizumab Addition  
 
 (A) PD-L1 surface expression in isogenic BT-474 breast cancer and N87 gastric cancer cell lines as determined by 
flow cytometry (parental cells: dotted black; PD-L1 engineered cells: solid red). X axis reflects the median 
fluorescence intensity. (B) Proliferation of T cells co-cultured with isogenic cancer cells in the presence or absence 
of pembrolizumab (60 μg/mL). Data were normalized to those of non-transduced T cell co-cultures and presented 
as division indices.  
Summary: 
In vitro nonclinical studies suggest that TAC T cells specifically engage with HER2+ cancer cells 
and can induce expression of PD-1 and PD-L1, which can consequently lead to reduced TAC T 
cell activity. Blocking PD-1 signaling using an anti-PD-1 checkpoint blockade, such as 
pembrolizumab, can counteract this inhibitory function. Therefore, these observations highlight 
the importance of combining TAC T cell therapy with a PD-1 blockade to potentially enhance the 
antitumor activity of administered TAC T cells. Attenuating the eventual exhaustion of TAC T 
cells may also facilitate the recruitment of endogenous polyclonal immune cells to overcome 
tumor heterogeneity and to prevent antigen escape (Grosser 2019). 
1.9.2.2. TAC T Cell Activity Across Multiple HER-2 Expressing Cancer Cell Lines 
Previous studies demonstrated that TAC-engineered cells are not reactive towards 
antigen-negative cells and that TAC lacking an antigen binding domain (ΔTAC) is unable to 
activate T cells (Helsen 2018). To investigate a HER2-dependent activation of TAC01-HER2 
cells by cancer cells, TAC01-HER2 was cultured in the presence of various HER2-expressing 
cancer cells derived from a diverse set of human cancer types that includes breast (BT474, 
SKBR-3, HCC1954), ovarian (SK-OV-3), skin (LOX-IMVI), pancreatic (PANC-1), gastric 
(NCI-N87), and gastroesophageal cancer (OE19) (Table 1) (Lieber 1975; Fogh 1977; Lasfargues 
1978; Park 1990; Lewis 1993; Rockett 1997; Fodstad 1998; Gazdar 1998; Chakrabarty 2013; 
Walsh 2013; Deguchi 2017; Ikediobi 2006). HER2 surface expression was determined by flow 
cytometry and normalized to the mean fluorescence intensity (MFI) observed in SKOV-3 cells, 
an ovarian cancer cell line with high HER2 expression. This data showed that HER2 expression 
varied substantially among cancer cell models and included PANC-1 derived from an epithelial 
cell carcinoma of the pancreas that presented very low HER2 expression which was only ~2-fold 
higher compared to other human non-malignant cells (Table 1). 

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Table 1: 
HER2 Surface Expressions in Various Cancer Cell Lines 
Cell Lines/Non-malignant Cells 
Normalized HER2 
Expression 
Cancer Cells 
SKOV-3 
Ovary 
Adenocarcinoma 
1.000 
SKBR-3 
Breast 
Carcinoma 
1.000 
BT-474 
Breast 
Ductal carcinoma 
0.916 
HCC1954 
Breast 
Epithelial cell carcinoma 
0.756 
OE19 
Esophagus 
Carcinoma 
0.409 
PANC-1 
Pancreas 
Epithelial cell carcinoma 
0.036 
Non-malignant Cells 
AoSMC 
Aorta/Heart 
Smooth muscle cells 
0.019 
CCD-19 
Lung 
Fibroblasts 
0.012 
HCM 
Heart 
Cardiomyocytes 
0.021 
HS-27A 
Bone marrow 
Stromal cells 
0.020 
For assessing T cell activation, TAC01-HER2 was co-cultured with target cells for 4 days and 
analyzed via flow cytometry for their ability to produce cytokines. As negative controls, T cells 
alone (not exposed to tumor cells) and TAC01-HER2 co-cultured with HER2-negative K562 
cancer cells were used. K562 cells are myelogenous leukemia cells and were chosen because 
HER2 is commonly expressed in cells of epithelial origin. In addition, an isogenic K562 cell line 
overexpressing HER2, Figure 7B, was created to test the requirement of HER2 during TAC01-
HER2 activation. Cells derived from human bone marrow (HS-27A) endogenously expressing 
low levels of HER2 were included as a non-malignant reference. Activation of TAC01-HER2 
cells was evaluated by measuring intracellular levels of TNFα, IFNγ and IL-2 cytokines.  
The data revealed that TAC01-HER2 activity was minimal when exposed to the non-malignant 
HS-27A cells and was completely absent when exposed to HER2-negative K562 cells. In 
contrast, TAC01-HER2 was selectively activated when co-cultured with HER2 expressing K562 
cells, demonstrating that TAC01-HER2 activation is strictly dependent on the HER2 antigen 
(Figure 7B). TAC01-HER2 was active against all HER2 positive malignant cells (Figure 7A); 
however, the extent of cytokine production varied across different co-cultures. Strikingly, 
TAC01-HER2 was strongly activated by PANC1 cancer cells despite the fact that it expressed 
relatively low levels of HER2.  

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Figure 7: In Vitro Activation of TAC T Cells Across Various Levels of HER2-Expressing 
Cancer Cell Lines 
 
(A) TAC T cells or NTD cells were co-cultured with various cell lines for 4 hours in a 1:1 E:T ratio. (B) TAC T 
cells or NTD cells were co-cultured with K562 (HER2 negative) or K562 overexpressing HER2. Data shown 
represent the percentage of cells positive for indicated cytokines. In A and B, the mean of 2 different donors with 
error bars indicating the SEM are shown. 
In conclusion, the activity observed in this co-culture was comparable to other cancer cells 
expressing very high levels of HER2, such as SKBR1 and OE19, supporting the rationale for 
using TAC01-HER2 in the treatment of cancers exhibiting both high and low HER2 expression 
levels. 
CAR T Cell Studies: 
Similar results were reported with CAR T cells in nonclinical mouse models. For example, 
Adusumilli et al. found that tumor cells upregulated PD-L1 expression levels in response to CAR 
T cell-secreted cytokines, with PD-1 expression levels on CAR T cells also becoming 
upregulated (Adusumilli 2021). To overcome this tumor-mediated adaptive resistance, 
Adusumilli et al. added pembrolizumab following CAR T cell administration. Results indicated 

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that exhausted CAR T cells were rescued by pembrolizumab, yielding enhanced efficacy and 
longer persistence of the CAR T cells (Adusumilli 2021; Supplementary Materials: 
Section 3.2.6). 
1.9.3. Clinical Studies (Literature) 
The safety and clinical activity of adding pembrolizumab to HER2-targeted therapies has 
recently been demonstrated with trastuzumab in metastatic esophagogastric cancer (O'Donnell 
2019), and margetuximab in gastroesophageal adenocarcinoma (Catenacci 2020). 
Pembrolizumab was also combined with CD19-directed CAR T cell therapy in B cell 
lymphomas (Chong 2022) and to mesothelin-targeted CAR T cell therapy in metastatic lung and 
breast cancers, and malignant pleural mesothelioma (MPM; Adusumilli 2021).  
A review of a Phase 1 clinical study using the mesothelin-targeted CAR T cell + pembrolizumab 
combination (Adusumilli 2021) suggests that TAC T cells can be used in combination with 
pembrolizumab to yield safe and more effective outcomes in subjects with solid tumors. In the 
mesothelin study, 27 total patients were treated with CAR T cells: 25 had MPM, and 1 each had 
metastatic lung and metastatic breast cancers. Eight monotherapy dose escalation cohorts 
consisted of 3 patients each (unless otherwise noted): 1.3 x 105, 2.3 x 105, 3.1 x 106, 4.3 x 106, 
5.6 x 106, 6.1 x 107 (6 patients), 7.3 x 107, and 8.6 x 107 cells/kg. All patients, except the first 3, 
received a single dose of cyclophosphamide preconditioning (1500 mg/m2). From these 24 
cyclophosphamide + CAR T cell-treated patients, 23 had MPM, 18 of whom were treated with 
pembrolizumab 200 mg Q3W for a minimum 3 doses, with ≥3 months of follow-up after the 
third dose. The other 5 MPM patients did not receive pembrolizumab treatment and remained in 
the CAR T cell monotherapy group (i.e., cyclophosphamide + CAR T cell), with 1 breast cancer 
patient also not receiving pembrolizumab treatment. 
The most frequently occurring treatment-emergent adverse events (TEAEs) over the first month 
following CAR T cell infusion for all 27-treated patients can be found in Table 2 (i.e., before 
pembrolizumab treatment). 

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Table 2: 
Mesothelin Study: TEAEs in ≥15% of Patients Over First Month 
(Monotherapy; N=27) 
Adverse Event 
   Preferred Terms 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Any TEAE 
27 (100) 
27 (100) 
23 (85) 
15 (56) 
   Hyperglycemia 
27 (100) 
12 (44) 
3 (11) 
0 
   Hypoalbuminemia 
25 (93) 
8 (30) 
0 
0 
   Anemia 
24 (89) 
15 (56) 
6 (22) 
0 
   Hypocalcemia 
23 (85) 
9 (33) 
0 
0 
   Hypomagnesemia 
21 (78) 
1 (4) 
0 
0 
   White blood cell decreased 
19 (70) 
16 (59) 
13 (48) 
9 (33) 
   Platelet count decreased 
13 (48) 
0 
0 
0 
   Fatigue 
12 (44) 
2 (7) 
0 
0 
   INR increased 
12 (44) 
1 (4) 
0 
0 
   Lymphocyte count decreased 
11 (41) 
15 (56) 
16 (59) 
6 (22) 
   Fever 
9 (33) 
5 (19) 
0 
0 
   Pain 
8 (30) 
5 (19) 
0 
0 
   Cough 
8 (30) 
0 
0 
0 
   aPTT prolonged 
8 (30) 
3 (11) 
0 
0 
   Malaise 
5 (19) 
0 
0 
0 
   Dyspnea 
5 (19) 
2 (7) 
1 (4) 
0 
   Cytokine release syndrome 
5 (19) 
2 (7) 
0 
0 
   Chills 
4 (15) 
0 
0 
0 
   Nausea 
3 (11) 
1 (4) 
0 
0 
   Constipation 
2 (7) 
1 (4) 
2 (7) 
0 
   Hypotension 
1 (4) 
3 (11) 
0 
0 
TEAEs are listed in descending order in the proportion of patients with Grade 1 TEAEs. 
aPTT=activated partial thromboplastin time; INR=International Normalized Ratio; TEAE=treatment-emergent adverse event. 
The most frequently occurring TEAEs in >1 combination-treated patient up to 6 months 
following CAR T cell infusion can be found in Table 3. 
Table 3: 
Mesothelin Study: TEAEs Over First 6 Months (CAR T cell + Pembrolizumab; 
N=18) 
Adverse Events 
   Preferred Terms 
Grade 1 
Grade 2 
Grade 3 
Any TEAE 
15 (83) 
7 (39) 
2 (11) 
   Fatigue 
6 (33) 
0 
0 
   Chest wall pain 
5 (28) 
2 (11) 
0 
   Cough 
4 (22) 
1 (6) 
0 
   Anxiety 
3 (17) 
0 
0 
   Arthritis 
2 (11) 
0 
0 
   Hoarseness 
2 (11) 
0 
0 
   Dyspnea 
1 (6) 
2 (11) 
0 
TEAEs are listed in descending order in the proportion of patients with Grade 1 TEAEs. 
CAR=chimeric antigen receptor; TEAE=treatment-emergent adverse event. 
Overall, following CAR T cell infusion, a decrease in the incidence and severity of TEAEs 
observed at 6 months versus 1 month was demonstrated despite the addition of 3 doses of 

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pembrolizumab 200 mg Q3W. The combination arm included 18 of the 23 MPM patients. 
Notably, 7 of these patients (39%) had received ≥2 prior lines of therapy before CAR T cell 
infusion, and 3 of the 7 had received ≥3 prior lines of therapy. The median OS times were 23.9 
vs 6.1 months for the combination (N=18) vs monotherapy (CAR T cell + cyclophosphamide; 
N=5) groups, respectively.  
In summary, no DLTs or deaths were observed in the monotherapy or combination groups, and 
the incidence and severity of TEAEs over 6 months versus those observed at 1 month appeared 
to decrease despite the addition of pembrolizumab to CAR T cell therapy. Clinical activity was 
also markedly enhanced by the addition of pembrolizumab to CAR T cell monotherapy. 
Another Phase 1/2 study using a CAR T cell treatment targeting CD19 and CD22 followed by 
limited duration pembrolizumab treatment in patients with relapsed or refractory diffuse large B 
cell lymphoma (DLBCL; Osborne 2020) yielded similar results. Three CAR T cell dose levels 
were investigated: 50, 150, and 450 x 106 total cells. Patients received CAR T cells alone, or with 
3 doses of pembrolizumab 200 mg Q3W starting on Day 14 (regimen A), or with a single dose of 
pembrolizumab 200 mg on Day -1 (regimen B). As of Jan 21, 2020, dose escalation from 50 to 
450 x 106 cells was completed with pembrolizumab regimen A and B without any observed 
DLTs. Across all dose levels, no severe CRS events were observed with primary infusion, with 
5% of subjects having severe neurotoxicity (1/19), which resolved. There were no cases of 
severe CRS and no neurotoxicity of any grade at >50 x 106 cells. Overall, it was concluded that 
CAR T cells dose levels >50 x 106 used in combination with pembrolizumab induced complete 
responses (CRs) without severe CRS or neurotoxicities of any grade. 
The combination of CAR T cells + pembrolizumab have also been safely used to treat 3 patients 
with neuroblastoma, with no DLTs being observed (Heczey 2017). In this case, PD-1 inhibition 
was not found to enhance CAR T cell expansion or persistence, and antitumor responses were 
modest. It was speculated low PD-1 expression levels on CD4 (≤20.6%) and CD8 (≤9.04%) 
CAR T cells and the presence of additional immune suppressive mechanisms may have led to 
these results (Heczey 2017). 
Lastly, the clinical activity & safety of ICT01, an anti-BTN3A mAb which activates γ9δ2 T cells 
is being investigated as a monotherapy and in combination with pembrolizumab in patients with 
advanced solid tumors (De Gassart 2021). To date, the mAb/γδT cell + pembrolizumab treatment 
has been well-tolerated during the dose escalation phase, and cohort expansion is planned in 
multiple solid tumor types (SITC 36th annual meeting December 2021 & AACR 2022). 
1.9.4. Protocol TAC01-HER2-03 (Status Update) 
As of 23 April 2023, the Phase 1 monotherapy arm of the study was completed. 19 subjects with 
solid tumors were treated in Cohorts 1-4. Treatment with TAC01-HER2 displayed a manageable 
safety profile: 
• One DLT event of Grade 3 pneumonitis was reported in 1 subject in Cohort 4. 
• No neurotoxicity was reported. 

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• All subjects treated in Cohorts 3-4 experienced CRS, mostly Grade 1 or 2, which 
resolved with supportive therapy. 
• Serious adverse events (SAEs) related to TAC01-HER2 consisted of 1 Grade 3 
pneumonitis (as mentioned above), 1 Grade 3 CRS, 3 Grade 2 CRS and 1 Grade 1 CRS. 
• Most adverse events were related to LDC or the underlying malignancy. 
Efficacy Status: 
As of 23 April 2023, a 67% disease control rate (DCR) was observed in Cohorts 2-4 at 4 weeks 
restaging after TAC01-HER2 infusion and up to 3 months. For gastric/GEJ subjects in Cohorts 2-
4, DCR was 83%. Two subjects had an unconfirmed partial response (PR): 
• At Cohort 2, one subject with gastric cancer (3+ HER2) had reduction of measurable 
disease of 35%. This subject subsequently had stable disease for 4 months after 
TAC01-HER2 administration. 
• At Cohort 4, an unconfirmed PR was observed in a subject with GEJ (HER2 2+, FISH+) 
with 100% reduction of target lesion. This subject progressed 3 months after 
TAC01-HER2 infusion. This subject previously progressed on 4 prior lines of therapy, 
including trastzumab and trastuzumab/deruxtecan.  
• Based on the clinical benefit observed for gastric/GEJ cancer in Phase 1 (33% ORR at 
Cohorts 2-4) and given the current standard of care (trifluridine/tipiracil with ORR 4%) 
(Shitara 2018), Triumvira decided to pursue these indications in Phase 2. 
1.10. Lymphodepleting Chemotherapy Rationale 
It is widely believed LDC improves engraftment and activity of genetically modified T cells. 
However, the mechanism by which T cell engraftment is facilitated by LDC is not fully 
understood. The rationale for combining adoptive T cell immunotherapy with lymphodepleting 
therapy is multifold. 
First, LDC may enhance adoptively transferred tumor-specific T cells to proliferate in vivo 
through homeostatic proliferation (Grossman 2004, Stachel 2004). Second, chemotherapy may 
reduce or eliminate CD4-positive, CD25-positive regulatory T cells, which can suppress the 
function of tumor-targeted adoptively transferred T cells (Turk 2004). Third, LDC prior to 
adoptive T cell therapy may enhance the expression of stromal cell-derived factor 1 (SDF-1) in 
the bone marrow, enhancing the trafficking of modified T cells to the primary tumor site through 
binding of SDF-1 with C-X-C motif Chemokine Receptor 4 expressed on the T cell surface 
(Pinthus 2004). Finally, LDC leads to elimination of cytokine sinks (IL-2, IL-7, and IL-15) and 
increased expansion, function, and persistence of T cell therapies (Neelapu 2019). 
In this study, LDC will consist of fludarabine or clofarabine and cyclophosphamide administered 
daily for 3 consecutive days. The combination of fludarabine or clofarabine and 
cyclophosphamide has been used for lymphodepletion in CAR T cell studies with demonstrable 

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CAR T cell expansion, persistence, and antitumor activity and acceptable safety (Abramson 
2017, Kochenderfer 2015, Turtle 2016). 
The order of preference for LDC regimen is summarized in Section 5.2. 
1.11. ’Second Dose Rationale 
To date, cell therapies have struggled to induce durable responses in patients with solid tumors 
(Morotti 2021). Second infusions of engineered cells have been considered as an approach to 
improve TAC T cell trafficking, penetration, proliferation, and persistence to prolong the 
duration of clinical benefit for the longest duration possible. A recent Phase 1 study administered 
up to 3 equal doses of CLDN18.2-specific CAR T cells (CT041) in subjects with gastrointestinal 
cancer: 19/37 subjects (51.4%) received 1 dose, 15/37 (40.5%) received 2 doses, and 3/37 (8.1%) 
received 3 doses (Qi 2022). The median times to the second and third infusions were 72 and 101 
days, with wide ranges (35-211 and 81-140, respectively). Overall, the most frequently reported 
Grade ≥3 TEAEs were lymphopenia (100%), leukopenia (83.3%), neutropenia (67.6%), 
increased conjugated bilirubin (21.6%), and thrombocytopenia (16.2%), with most being related 
to preconditioning treatments. These TEAEs generally occurred within 28 days after the first 
dose, with hematologic toxicities recovering between 4-9 days post dose. No Grade ≥3 CRS 
TEAEs were observed; however, 94.6% of subjects had Grade 1 or 2 CRS events. No clear dose 
response relationship correlated to the incidence of CRS events. No safety differences were 
described for subjects who received a single dose compared with subjects who received multiple 
doses.  
Interim responses by subject and dose levels can be found in Figure 8. Most subjects treated with 
>1 dose showed longer duration of clinical benefit. Across all subjects, the median progression-
free survival (PFS) was 3.7 months, with a high OS rate of 80.1% at 6 months (Qi 2022). Lastly, 
CLDN18.2 expression levels were found to be similar after the first infusion and before the 
second infusion, indicating antigen escape was not occurring. A similar Phase 1/2 study for 
CT041 is currently open in the US, which includes redosing of subjects (NCT04404595). One of 
the subjects in this study achieved a CR after 2 doses of CT041 during the dose escalation phase 
of the study (Botta 2022). 
In addition, a Phase 2 trial of gavocel (genetically engineered T cells targeting mesothelin; 
NCT03907852) has incorporated in its design a second round of lymphodepletion and T cell 
administration (TCR2 Therapeutics). Subjects are re-dosed after they meet one of the following 
criteria: i) subjects with a confirmed response (CR or PR) that exhibit symptoms or signs of 
progressive disease (PD), or ii) subjects with stable disease (SD) for at least 8 weeks. 
Additional doses are also applied for the treatment of hematological malignancies using 
allogeneic cell therapies. For example, a safety and efficacy study evaluating CTX110 (a 
CD19-directed CAR-T cell; NCT04035434), included re-dosing of subjects after disease 
progression.  
 

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Figure 8:  Response (RECIST 1.1) by CLDN18.2-Specific CAR T Cells Dose Level (Investigator Assessed) 
 
Source: Qi 2022. 
CAR T=chimeric antigen receptor T cells; CLDN18.2=Claudin 18.2; Cont. resp.=continued response; GC=gastric cancer; PC=pancreatic cancer; PD=progressive 
disease; PR=partial response; RECIST 1.1=Response Evaluation Criteria in Solid Tumors Version 1.1; Re-inf.=reinfusion; SD=stable disease; 
Note: Yellow triangles indicate second and third doses, with the first dose administered on Day 1.  
 

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1.12. Statistical Design Rationale 
Phase 1 Dose Escalation: 
The dose finding part of this study will utilize the keyboard design (Yan 2017) to determine the 
safety and tolerability of various TAC01-HER2 dose levels in subjects with HER2+ solid tumors. 
The keyboard design is a novel Bayesian interval design that can be implemented in a simple 
way similar to the traditional 3+3 design but is more flexible and possesses superior operating 
characteristics. The keyboard design provides an upgrade to the modified toxicity probability 
interval (mTPI-2) design, with substantially lower risk of overdosing and a better precision to 
identify the maximum tolerated dose (MTD). Statistical analyses of the primary, secondary, and 
exploratory endpoints will be descriptive for the study. Summaries will be provided by dose 
level, overall, and by treatment arm. The incidence of DLTs, the incidence and severity of 
TEAEs, and laboratory abnormalities will be described and summarized. Subjects who are in 
DLT evaluation cohorts will be considered evaluable if they complete the defined DLT 
observation period. 
Phase 2 Dose Expansion: 
For Group A and Group B, a Simon 3-stage design will be used to evaluate potential efficacy 
responses, using predefined maximally ineffective and minimally effective ORRs derived from 
previous clinical studies (see Section 9.1 for additional details regarding the Simon 3-stage 
design and rationale for assumptions). 

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2. STUDY OBJECTIVES AND ENDPOINTS 
Table 4: 
Study Objectives and Endpoints 
Objectives 
Endpoints 
Primary 
Phase 1: To evaluate the safety of 
TAC01-HER2 monotherapy and 
pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
Incidence of DLTs 
Type, frequency, and severity of AEs (including 
clinically significant laboratory abnormalities). 
Phase 2: To evaluate the clinical activity of 
TAC01-HER2 monotherapy and 
pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
ORR 
DOR 
OS 
DCR 
PFS or 
Time to progression (TTP) 
 
Investigator-assessed imaging using Response 
Evaluation Criteria in Solid Tumors Version 1.1 
(RECIST 1.1) 
Secondary 
Phase 1: To determine the MTD or RP2D for 
TAC01-HER2 monotherapy and 
pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
Incidence of DLTs 
Phase 2: To evaluate the safety of 
TAC01-HER2 monotherapy and 
pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
Type, frequency, and severity of AEs (including 
clinically significant laboratory abnormalities). 
Phase 1 and Phase 2: To characterize the PK 
profile of TAC01-HER2 in subjects with 
HER2+ solid tumors 
Maximum concentration (Cmax), time to reach 
maximum concentration (Tmax), and area under 
the concentration time curve (AUC) of TAC T 
cells 
Duration of persistence of TAC T cells 
Phase 1: To evaluate the clinical activity of 
TAC01-HER2 monotherapy and 
pembrolizumab combination therapy in subjects 
with HER2+ solid tumors 
ORR 
DOR 
OS 
DCR 
PFS or 
TTP 
 
Investigator-assessed imaging using RECIST 1.1 

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Phase 1 and Phase 2: To evaluate the 
immunogenicity of TAC01-HER2 monotherapy 
and pembrolizumab combination therapy and to 
assess potential impacts on PK exposure and 
biological activity 
Immunogenicity of TAC T cells and 
pembrolizumab 
Phase 1 and Phase 2: To investigate candidate 
efficacy biomarkers and anti-tumor activity of 
TAC T cells utilizing pre- and post-treatment 
tumor biopsies 
Cytokines and TAC copies/ug genomic DNA 
(gDNA) 
Exploratory 
Phase 1 and Phase 2: To explore biomarkers 
that may predict pharmacologic activity or 
response to TAC01-HER2 monotherapy and 
pembrolizumab combination therapy  
Characterize T cells and correlate with clinical 
outcomes 
Describe profile of soluble immune factors and 
relationship to CRS, neurotoxicity, and TAC T 
cell engraftment  
 
3. STUDY DESIGN AND INVESTIGATIONAL PLAN 
3.1. Overall Study Design  
This is a first-in-human study investigating TAC01-HER2 monotherapy and combination therapy 
with pembrolizumab to evaluate the safety, MTD or RP2D, PK parameters, and clinical activity 
in subjects with HER2+ solid tumors. During the Phase 1 portion of the study, increasing dose 
levels of TAC01-HER2 monotherapy will be evaluated first using the keyboard design method 
(Table 5). 
Table 5: 
TAC01-HER2 Monotherapy Dose Escalation Schedule 
Dose Level 
TAC T Cells/kg body weight 
(Single Dose on Day 1) 
-1 
6 – 8 x 104 
1 (starting dose) 
1 – 3 x 105 
2 
6 – 8 x 105 
3 
1 – 3 x 106 
4 
6 – 8 x 106 
Once monotherapy dose escalation has been investigated, the safety data reviewed by the 
DSMC, and the RP2D is determined, combination therapy can begin in parallel with 
monotherapy dose expansion starting at a dose level that is 2 steps below the RP2D for 
TAC01-HER2. The RP2D has been determined by the DSMC to be Dose Level 4. Accordingly, 
the starting dose level will be Dose Level 2 (Table 6). The following TAC T cell dose levels will 
be investigated in the combination arm. 

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Table 6: 
Combination Therapy Dose Escalation Schedule 
Dose Level 
TAC T Cells/kg body weight 
(Single Dose on Day 1) 
Pembrolizumab 
 
1 
1 – 3 x 105 
200 mg Q3W 
2 (starting dose) 
6 – 8 x 105 
200 mg Q3W 
3 
1 – 3 x 106 
200 mg Q3W 
4  
6 – 8 x 106 
200 mg Q3W 
Subjects will be allocated to the group that allows the subject to start their treatment regimen in 
the shortest timeframe. Priority to enrollment will be for the combination dose escalation arm, 
with the following exceptions: within the safety gate interval, during DLT observation period, 
subject and Investigator preference, and if subject does not meet criteria to receive 
pembrolizumab.  
As an additional safety precaution, the first combination cohort will treat 3 subjects with TAC T 
cells and administer pembrolizumab on Day 21. After review of safety data by the DSMC, and in 
the absence of DLTs, an additional 3 subjects will be treated at this same initial combination TAC 
T cell dose level, with pembrolizumab administered on Day 14. Based on the results of these 
6 subjects, the DSMC will either recommend Day 21 or Day 14 for the start of pembrolizumab 
administration in all subsequent combination cohorts, followed by administration of 
pembrolizumab 200 mg Q3W for up to 2 years. 
The overall study design is outlined in Figure 9. Phase 1 will evaluate increasing dose levels of 
TAC01-HER2 as a monotherapy, and in combination with pembrolizumab, to identify RP2Ds in 
subjects with HER2+ solid tumors who have progressed after 2 prior lines of therapy. In Phase 2, 
dose expansion groups will further evaluate the safety, clinical activity, and PK of the RP2D for 
TAC01-HER2 in subjects with HER2+ gastric and esophageal adenocarcinoma who have 
progressed after 2 and no more than 4 prior lines of therapy in 2 groups: Group A 
(TAC01-HER2 monotherapy) and Group B (TAC01-HER2 in combination with 
pembrolizumab). Central laboratory confirmation of HER2+ by IHC and fluorescent in-situ 
hybridization (FISH) will be conducted. 

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Figure 9: Study Design 
 
Abbreviations: DSMC=Data Safety Monitoring Committee; HER2=human epidermal growth factor receptor 2; 
I/E=inclusion/exclusion; N=number of subjects; Pembro=pembrolizumab; PK=pharmacokinetics; 
RP2D=recommended Phase 2 dose; TAC=T cell antigen coupler. 
In Phase 2, a second dose may be administered in the monotherapy arm (see Section 3.4 for 
additional details and Section 4.3 for eligibility criteria).  
Upon enrollment, subjects will undergo leukapheresis to obtain T cells for TAC01-HER2 
manufacture. Subjects may receive bridging anticancer therapy (see Section 5.1), after 
leukapheresis and before LDC if deemed necessary by the Investigator. Bridging therapies must 
be discontinued at least 14 days prior to initiation of lymphodepletion, and subjects must 
continue to meet eligibility criteria pertaining to adequate organ function (except hematologic 
parameters), active infections, pregnancy, measurable disease confirmed by repeat imaging, and 
medication washout before initiation of lymphodepletion. If TAC01-HER2 cannot be 
manufactured from the first leukapheresis product, additional leukapheresis may be allowed after 
consultation with Triumvira. 
Upon the successful manufacturing of TAC01-HER2, subjects will enter the treatment phase. In 
the monotherapy arm, treatment will include LDC followed by a single dose of TAC01-HER2 
administered IV on Day 1. In the combination arm, treatments will include LDC, a single dose of 
TAC01-HER2 administered IV on Day 1, and pembrolizumab 200 mg administered IV Q3W 
starting on Day 21 or Day 14 based on recommendations from the DSMC. 
Subjects who receive 1 dose and subjects who receive combination therapy will follow 
procedures described in Appendix A1 and Appendix A2, respectively, for up to 24 months after 
the first dose, until the subject withdraws consent, or the subject is lost to follow-up. 
Radiographic disease assessments for PD and other responses in single-dose subjects will occur 

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at Day 29±2 days, then Q8W±2W for Year 1 and Q12W±2W for Year 2. If a single-dose subject 
has initial PD on the Day 29 scan, a confirmation scan should occur 28 days (± 14 days) later to 
confirm the initial PD was not a tumor flare.  
Subjects who receive 2 doses will follow procedures described in Appendix B for up to 
24 months after the first dose, until the subject withdraws consent, or the subject is lost to 
follow--up. Assessments for PD will occur on Day 29 ±2 days after the first dose on Day 1, then 
Q8W±2W until the second dose is administered. Once the second dose is administered (i.e., Day 
X), scans will be performed on Day X + 28 ±2 days, Q8W±2W after Day X for 1 year, and then 
Q12W±2W after Day X for up to 24 months after the first dose, until the subject withdraws 
consent, or the subject is lost to follow-up.  
If a subject has confirmed PD 3 months after the first dose, starts a new anticancer therapy, or is 
unwilling or unable to continue the respective procedures indicated in Appendix A1, Appendix 
A2, or Appendix B, then the subject will transition to the long-term follow-up (LTFU) protocol.  
The LTFU protocol has a reduced schedule of events that complies with regulatory requirements 
for follow-up and does not include radiographic disease assessments. After study completion, 
subjects will be followed for survival, long-term toxicity, and viral vector safety to be monitored 
for up to 15 years. 
The study sequence of events for the monotherapy arm is depicted in Figure 10. 

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Figure 10: Monotherapy Study Scheme 
 
Abbreviations: LDC=lymphodepleting chemotherapy; LTFU=Long Term Follow Up. 
Bridging anticancer therapy is permitted if needed.  
a TAC T cell infusion is considered Day 1 (Dose 1) or Day X (Dose 2) and described in Section 7.3.2. 
b Study assessments are described in Section 7, Appendix A1, Appendix A2, or Appendix B. 
c LTFU study is described in Section 7.8. 
 
The study sequence of events for the combination arm is depicted in Figure 11. 
Figure 11: Combination Therapy Study Scheme 
  
Flow chart of the sequence of events according to the study design. Bridging anticancer therapy is permitted if 
needed. Abbreviations: FLU=fludarabine; CYC=cyclophosphamide; LTFU=Long Term Follow Up; PD=progressive 
disease; Pembro=pembrolizumab; Q3W=every 3 weeks. 
3.2. Phase 1 Dose Escalation 
The TAC01-HER2 dose levels to be evaluated in the monotherapy arm are provided in Table 5, 
with the combination doses provided in Table 6. Dose escalation/de-escalation will follow the 
keyboard design with a target DLT rate of 30% and an equivalence interval of 25% to 35%. The 

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keyboard table in Appendix C provides the dose escalation and de-escalation guidelines based on 
the number of subjects treated at a dose level who experience a DLT. Dose escalation may be 
halted once a dose level with acceptable safety and satisfactory antitumor activity has been 
selected for evaluation in Phase 2. A MTD may not be defined in this study.  
The keyboard design is a seamless improvement to the mTPI-2 design, offering better overdose 
control and higher accuracy to identify the true MTD. For the mTPI-2, 3 decision intervals are 
specified after determining an estimated probability of toxicity (i.e., DLT). The 3 intervals are 
associated with dosing decisions (escalation, stay, or de-escalation). The probability of toxicity 
for each dose level is assumed to have an independent beta distribution. The mTPI-2 approach 
utilizes all subjects at the current dose level, as well as the total number of DLTs observed at that 
particular dose level to compute the normalized posterior probability in each interval in order to 
make subsequent dosing decisions. A normalized posterior probability statistic for each interval 
is calculated and is known as the unit probability mass (UPM). The largest UPM determines the 
dosing decision for the next cohort of subjects to be treated. 
Similar to the mTPI-2 design, the keyboard design relies on the posterior distribution of the 
toxicity probability to guide dose escalation and de-escalation. The innovation is that the 
keyboard design defines a series of equal-width dosing intervals (or keys) to present the potential 
locations of the true toxicity of a dose and guide the dose escalation and de-escalation, whereas 
the mTPI design uses the UPMs of 3 dosing intervals (i.e., underdosing, proper dosing and 
overdosing intervals) to determine the dose transition.  
The keyboard design requires pre-specification of the target toxicity rate (ptarget) and the target 
toxicity interval Ttarget=(ptarget–- ε1, ptarget + ε2) (referred to as the target key). For this study, the 
pre-defined values of these parameters are ptarget=0.30, ε1=0.05 and ε2= 0.05. Thus, the target 
toxicity interval is [0.25, 0.35] with a target toxicity of 0.30. Values lower than 0.25 would 
indicate that on average the probability of observing a toxicity at this dose level is too low based 
on our target probability, while those higher than 0.35 would be considered unacceptable 
toxicity. Since no prior information allows an accurate representation of the toxicity distribution, 
a non-informative beta (1, 1) distribution was assumed for the prior, which allow the results to be 
influenced more by the observed toxicity findings than the assumed distribution.  
The keyboard design divides the target toxicity interval into a series of equally sized keys that 
span the range of 0 to 1. The decision to escalate or de-escalate the dose, given the observed data, 
is based on the “strongest” key that has the highest posterior probability (i.e., the largest area 
under the posterior distribution curve of the DLT rate for the current dose). By continuously 
identifying the strongest key Tmax after each cohort, the dose assignment rules for the next cohort 
are: 
• If the strongest key is on the left side of the target key (Tmax <Ttarget), then escalate) to the 
next dose; 
• If the strongest key is the target key (Tmax – Ttarget), then stay (S) at the current dose; 
• If the strongest key is on the right side of the target key (Tmax>Ttarget), then de-escalate (D) 
to the previous dose.  

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A dose level with an unacceptable high toxicity level (probability >0.95) will result in 
de-escalation and will not be revisited. In addition, the study may be terminated based on the 
following criteria: 
• Toxicity at the lowest dose level is determined to be higher than the acceptable toxicity 
level, or 
• Sample size of 20 is reached.  
Other reasons for terminating the study early may be applicable depending upon the toxicity 
and/or safety considerations. Following study completion, the MTD may be calculated using 
accumulated information for all dose levels. Refer to Appendix C for operating characteristics of 
this design. 
In the monotherapy arm, for a dose level to be considered safe, at least 3 DLT-evaluable subjects 
must have completed the 28-day DLT evaluation period and the level estimated to be safe per the 
keyboard algorithm. In the combination arm, for a dose level to be considered safe, at least 
3 DLT-evaluable subjects must have completed the 42-day or 35-day DLT evaluation period, 
depending on if pembrolizumab was dosed on Day 21 and 14 respectively, and the level 
estimated to be safe per the keyboard algorithm. The decision to open a dose level for enrollment 
will be made by the DSMC based on results from the keyboard algorithm. 
The first 3 subjects in the monotherapy dose escalation will be treated with TAC01-HER2 at 
Dose Level 1 (1 x 105 to 3 x 105 TAC T cells/kg) and the first 3 subjects in the combination dose 
escalation will be treated with TAC01-HER2 at Dose Level 2 (6 – 8 x 105), which is 2 steps 
below the monotherapy RP2D. Within the first dose cohort for monotherapy dose escalation and 
combination dose escalation, treatment of the second subject must occur a minimum of 28 days 
after the first subject’s infusion. Treatment of the third subject must occur a minimum of 14 days 
after the second subject’s infusion. Assuming no DLT is identified, subsequent subjects within 
this dose cohort may be treated without staggering. At each higher dose level, the interval 
between treatment of the first and second subject must also be staggered by at least 28 days. 
After staggering has been completed, no more than 1 subject may be treated with TAC01-HER2 
in any dose cohort per day. 
As indicated in the study design, once monotherapy dose escalation has been investigated, the 
safety data reviewed by the DSMC, and RP2D is determined, combination therapy can begin in 
parallel with monotherapy dose expansion using the dose level that is 2 steps below the RP2D 
for TAC01-HER2.  
Overall, a minimum of 3 subjects will initially be treated at a dose level in the monotherapy and 
combination dose-escalation arms. If none of these 3 subjects experience a DLT, the dose will be 
escalated to the next higher dose level.  
However, there is an exception to this rule for the first combination treatment cohort only, where 
3 subjects will be dosed with pembrolizumab on Day 21, and if after review of the safety data by the 
DSMC and no DLTs are observed, this same dose level will be investigated with pembrolizumab 
being administering on Day 14 with approval of the committee. If a DLT is observed in the first 

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combination cohort, where pembrolizumab is administered on Day 21, then the expansion combination 
cohort will not occur where pembrolizumab is administered on Day 14 at the same TAC01-HER2 
dose. Instead, the following DLT-based dose directives based on the keyboard algorithm will continue 
to apply: 
If 1 of 3 subjects experiences a DLT at a dose level, then additional subjects will be enrolled at 
this dose level and dose escalation/de-escalation decisions will be made per the keyboard 
algorithm after the DLT data for these additional subjects are available. If 2 of 3 subjects 
experience a DLT at a dose level, then the dose will be de-escalated to the next lower dose level. 
If all 3 subjects experience a DLT at a dose level, the dose will be de-escalated, and this dose and 
all higher doses will be removed from further evaluation in the study. 
In the monotherapy dose escalation arm, a subject must have received TAC01-HER2 at the 
assigned dose, completed the 28-day evaluation period, or experienced a DLT prior to 
completing the 28-day evaluation period, to be considered evaluable for DLTs. Subjects who are 
not evaluable for DLTs will be replaced. 
In the combination dose escalation arm, a subject must have received TAC01-HER2 at the 
assigned dose and pembrolizumab, as well as completed the 42-day or 35-day DLT evaluation 
period, depending on if pembrolizumab was dosed on Day 21 and 14 respectively, or 
experienced a DLT prior to completing the 42-day or 35-day evaluation period, to be considered 
evaluable for DLTs. Subjects who are not evaluable for DLTs will be replaced. 
Based on the cumulative data from subjects treated in the dose finding phase, the MTD or RP2D 
will be selected for further evaluation in the dose expansion portion of the study. Once identified, 
an additional 3-6 subjects may be treated at the RP2D to confirm safety before proceeding to 
Phase 2. It is not necessary for the MTD to be determined per the keyboard algorithm to select 
the dose level to be evaluated in Phase 2. 
Dose Limiting Toxicity Criteria 
Toxicities will be evaluated and graded according to the National Cancer Institute (NCI) 
Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 (National Cancer 
Institute 2020), and CRS and neurotoxicity as per American Society for Transplantation and 
Cellular Therapy (ASTCT; Lee 2019) Consensus Grading as in Appendix D. 
In the monotherapy arm, a DLT is defined as: 
• Any Grade 4 or 5 event determined by the Investigator to be related to the investigational 
product, and not attributable to the underlying disease or LDC, with the exception of 
Grade 4 laboratory abnormalities (such as electrolyte abnormalities) that may be at least 
possibly related to the investigational product but are rapidly reversible or correctable 
without substantial safety concerns 
• Grade ≥3 TAC T cell-associated acute infusion reactions persisting for ≥24 hours 
• Grade ≥3 TAC T cell-associated CRS or neurotoxicity persisting for ≥72 hours 
• Grade ≥3 cardiovascular or pulmonary toxicity persisting for ≥72 hours 

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• Grade ≥3 immune-related toxicities (i.e., colitis, nephritis, hepatitis, myocarditis, 
hypophysitis, salivary gland toxicity, etc.) 
• Grade ≥3 organ toxicities or non-hematologic toxicities that do not improve to Baseline 
within 7 days 
• Clinically consequential Grade ≥3 neutropenia or thrombocytopenia lasting ≥30 days 
from TAC01-HER2 administration. Clinically consequential is defined as febrile 
neutropenia, serious infection, or bleeding events. 
In the combination arm, a DLT is defined as: 
Definitions from the monotherapy arm that also apply to the combination arm: 
• Any Grade 4 or 5 event determined by the Investigator to be related to the investigational 
product, and not attributable to the underlying disease or LDC, with the exception of 
Grade 4 laboratory abnormalities (such as electrolyte abnormalities) that may be at least 
possibly related to the investigational product but are rapidly reversible or correctable 
without substantial safety concerns 
• Grade ≥3 TAC T cell-associated acute infusion reactions persisting for ≥24 hours 
• Grade ≥3 TAC T cell-associated CRS or neurotoxicity persisting for ≥72 hours 
• Grade ≥3 cardiovascular or pulmonary toxicity persisting for ≥72 hours 
• Grade ≥3 immune-related toxicities (i.e., colitis, nephritis, hepatitis, myocarditis, 
hypophysitis, salivary gland toxicity, etc.) 
• Grade ≥3 organ toxicities or non-hematologic toxicities that do not improve to Baseline 
within 7 days 
Additional definitions of DLTs applicable to the combination arm:  
• Any event that meets the definition of a DLT for the monotherapy arm that occurs before 
pembrolizumab administration, will prevent pembrolizumab administration (subject will 
be discontinued from combination arm and will follow the monotherapy schedule of 
events in Appendix A1). 
• Grade 4 nonhematologic toxicity (not laboratory) 
• Any new or worsening clinically significant Grade ≥3 neutropenia or thrombocytopenia 
lasting ≥7 days that develops ≤3 days after pembrolizumab administration despite best 
institutional corrective treatment measures 
• Any Grade 4 hematological toxicity lasting ≥7 days after pembrolizumab administration 
despite best institutional corrective treatment measures 
• Any nonhematologic AE ≥Grade 3 in severity should be considered a DLT, with the 
following exceptions: Grade 3 fatigue lasting ≤3 days; Grade 3 diarrhea, nausea, or 
vomiting without use of anti-emetics or anti-diarrheals per standard of care; Grade 3 rash 
without use of corticosteroids or anti-inflammatory agents per standard of care. 
• Any Grade 3 or Grade 4 non-hematologic laboratory value if: 
o Clinically significant medical intervention is required to treat the participant 

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o The abnormality leads to hospitalization 
o The abnormality persists for >1 week 
o The abnormality results in a drug induced liver injury (DILI) 
o Exceptions: Clinically nonsignificant, treatable, or reversible laboratory 
abnormalities including liver function tests, uric acid, etc. 
• Febrile neutropenia Grade 3 or Grade 4: 
o Grade 3 is defined as absolute neutrophil count (ANC) <1000/mm3 with a single 
temperature of >38.3°C (101°F) or a sustained temperature of ≥38°C (100.4°F) 
for more than 1 hour. 
o Grade 4 is defined as ANC <1000/mm3 with a single temperature of >38.3°C 
(101°F) or a sustained temperature of ≥38°C (100.4°F) for more than 1 hour, with 
life-threatening consequences and urgent intervention indicated. 
• Prolonged delay (>2 weeks) in initiating Cycle 2 due to treatment-related toxicity 
• Any treatment-related toxicity that causes the participant to discontinue treatment during 
Cycle 1 
• Grade 5 toxicity 
DLT Evaluation Periods and Relatedness: 
In the monotherapy arm, DLTs will be assessed from the time of the TAC01-HER2 infusion on 
Day 1 through 28 days post dose. The DLT evaluation period may be extended through 42 days 
post dose should clinically consequential (i.e., events associated with febrile neutropenia, serious 
infections, or bleeding) Grade ≥3 neutropenia or thrombocytopenia occur. 
In the combination arm, DLTs will be assessed from the time of the TAC01-HER2 dose (Day 1) 
through Day 42 for cohorts that dosed pembrolizumab on Day 21, and through Day 35 for 
cohorts that dosed pembrolizumab on Day 14. In both scenarios, DLTs will include assessments 
over 1 cycle of pembrolizumab treatment (or 21 days after the initial dose of pembrolizumab).  
DLTs that occur after TAC01-HER2 administration but before pembrolizumab treatment will be 
attributable to TAC01-HER2. DLTs that occur after pembrolizumab administration will be 
attributable to both study therapies. Since TAC01-HER2 is a single dose infusion, all DLTs or 
other adverse reactions observed after pembrolizumab administration will follow the guidelines 
for dose modification or discontinuation criteria listed in Appendix H and Appendix I. 
The dose elimination rule in the keyboard design will be used as a stopping boundary for 
toxicity. Specifically, enrollment will be stopped if data indicate more than a 95% chance that the 
DLT rate exceeds 30%, corresponding to a strong signal that the RP2D previously selected was 
in error. 
Summary of DLT Evaluation Periods with Possible Extensions: 
As indicated in Table 7, only the monotherapy arm will have a 14-day extension of the DLT 
evaluation period if there are subjects with clinically consequential (i.e., events associated with 

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febrile neutropenia, serious infections, or bleeding) Grade ≥3 neutropenia or thrombocytopenia 
on Day 28. Also note, the following relevant DLT definition for the monotherapy arm: 
• Clinically consequential (i.e., events associated with febrile neutropenia, serious 
infections, or bleeding) Grade ≥3 neutropenia or thrombocytopenia lasting ≥30 days from 
TAC01-HER2 administration. 
Therefore, clinically consequential (i.e., events associated with febrile neutropenia, serious 
infections, or bleeding) Grade ≥3 neutropenia or thrombocytopenia prior to Day 30 will not be 
considered DLTs, as these AEs are always the result of LDC. 
Table 7: 
DLT Evaluation Periods and Possible Extensions by Treatment Arm 
ID Treatment Arms 
DLT Evaluation Period 
DLT Extension due to 
Clinically Consequential 
Grade ≥3 Neutropenia 
or Thrombocytopenia 
1 
Monotherapy Arm 
Day 1 through Day 28 
Day 29 through Day 42  
(or + 14) 
2 
Combination Arm for 
first pembrolizumab 
administration on Day 21 
Day 1 through Day 42; 
1 cycle of pembrolizumab 
after 1st dose, or 21 + 21=42 
None 
3 
Combination Arm for 
first pembrolizumab 
administration on Day 14 
Day 1 through Day 35; 
1 cycle of pembrolizumab 
after 1st dose, or 14 + 21=35 
None 
4 
Combination Arm for 
first pembrolizumab 
administration regardless 
of day of administration 
New or worsening Grade ≥3 
neutropenia or 
thrombocytopenia occurring 
≤3 days after first 
pembrolizumab 
administration and lasting 
≥7 days 
None 
3.3. Phase 2 Dose Expansion 
In Phase 2, treatment with TAC01-HER2 will be evaluated both as monotherapy, and in 
combination with pembrolizumab, in subjects with gastric and esophageal adenocarcinoma. The 
monotherapy Group A will consist of up to 36 subjects (treated with TAC01-HER2 at the RP2D) 
following a Simon 3-stage design. The combination therapy Group B will consist of up to 
34 subjects (treated with TAC01-HER2 at the RP2D) following a Simon 3-stage design (Figure 
9).  
All data from all available subjects (i.e., dose escalation and dose expansion phases) will be used 
when evaluating the potential efficacy of TAC01-HER2. Efficacy and safety of TAC01-HER2 
will be determined both as a monotherapy and in combination with pembrolizumab. The primary 

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efficacy analysis for each arm will be based on all subjects who have measurable disease at the 
last disease assessment, prior to initiation of study treatments (i.e., TAC01-HER2 monotherapy 
or TAC01-HER2 + pembrolizumab combination therapy) and who receive TAC T cells at the 
RP2D. For further details on the planned statistical analysis, see Section 9. 
The safety of TAC01-HER2 treatment in the monotherapy and combination arms will be 
monitored during Phase 2 to allow for adjustment of the RP2D dose or termination of enrollment 
in case the minimum threshold of clinical activity is not met.  
3.4. Administration of Second Dose (Phase 2 Monotherapy Group Only) 
A second dose may be administered >4 weeks from the date of the first dose. Administration of 
the second dose will be identical to the first dose and intrasubject dose escalation is not allowed. 
The >4 weeks are intended to allow for blood cell count recovery after initial LDC and ensure 
there are no residual toxicities related to immunogenicity resulting from the first dose. The 
purpose of the second dose is to improve TAC T cell trafficking, penetration, proliferation, and 
persistence and hence to prolong the duration of clinical activity for the longest duration 
possible. A second dose may be administered ≤1 year (to account for drug stability and study 
duration) from the date of the first dose.  
Detailed eligibility criteria for the second dose are described in Section 4.3.  
Ideally, the second dose should be administered within 2-3 weeks after the clinical criteria 
described in inclusion criterion #6 of Section 4.3 have been met, with LDC also being 
administered prior to the second dose. Subjects who progress on Day 29 ±2 days after the first 
dose and have confirmed PD 28 days ±14 days later are not eligible to receive a second dose. 
Subjects who progress at a later date are also not eligible to receive a second dose, unless their 
progression is documented as a mixed response (see Section 4.3 inclusion criterion #6 for the 
definition of a mixed response). If a subject experiences cytopenia that would preclude LDC 
administration and does not recover to Grade ≤2 within 7 days prior to LDC, a second dose may 
not be administered until recovery to Grade 2 given the subject did not experience confirmed 
radiographic disease progression. 
3.5. Duration of Subject Participation 
The study enrollment period is expected to take 21 months, and the follow-up period for each 
subject is approximately 24 months after TAC01-HER2 treatment on Day 1. Subjects in the 
monotherapy and combination therapy dose cohorts will continue the procedures indicated in 
Appendix A1, Appendix A2, or Appendix B, for up to 2 years, or until the subject withdraws 
consent, or the subject is lost to follow-up. If a subject has confirmed PD (i.e., with a 
confirmatory scan 28 days [± 7 days] after an initial scan indicating PD), or starts a new 
anticancer therapy, or the subject is unwilling or unable to continue the procedures indicated in 
Appendix A1, Appendix A2, or Appendix B, the subject will transition to the LTFU protocol. 
The LTFU protocol has a reduced schedule of events which complies with regulatory 
requirements for follow-up and does not include any radiographic disease assessments. 

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The time for an individual subject to complete the study is approximately 26 months, including 
Pre-Treatment (screening, leukapheresis, bridging anticancer therapy [if needed], and 
pre-treatment screening; collectively expected to be up to 2 months), Treatment #1, Treatment #2 
(if criteria in Section 3.4 are met), and Post-Treatment Follow-Up (up to 24 months after 
Treatment #1). Thus, the total duration of the study will be approximately 50 months. All 
subjects who receive TAC01-HER2 treatment will be eligible to enroll in the LTFU protocol 
after completing this study (see Section 7.8), which includes follow-up for up to 15 years. 
3.6. Subject Withdrawal from Study 
During the informed consent process, subjects will be advised that they are free to withdraw 
from the study at any time for any reason; however, all subjects who receive monotherapy or 
combination therapy should be encouraged to continue all study evaluations through the end of 
study (EOS) visit and to participate in the LTFU study. Triumvira must be notified if a subject is 
withdrawn from the study and the reason(s) for withdrawal must be documented. Subjects who 
withdraw consent or are lost to follow-up will be followed for survival through publicly available 
records. 
3.6.1. Subject Removal from Study 
A subject may be withdrawn from the study for any of the following reasons: 
• Subject did not receive TAC01-HER2 due to disease-related complications 
• Subject did not receive TAC01-HER2 due to interim treatment-related toxicities 
• Subject no longer meets eligibility criteria for reasons unrelated to disease complications 
or interim treatment 
• TAC01-HER2 could not be manufactured 
• Subject withdrew consent 
• Study termination by Triumvira, an Institutional Review Board (IRB)/Independent Ethics 
Committee (IEC), or a regulatory authority 
• Subject becomes lost to follow up 
• Subject death 
• Other 
If a subject is withdrawn prematurely from the study, the reason for study discontinuation must 
be recorded in the subject’s medical record and the case report form (CRF). 
A subject who withdraws due to a failure to manufacture a TAC01-HER2 dose, who also meets 
the criteria for product release, may re-enroll in the study later if the subject meets all eligibility 
criteria. 
3.6.2. Study Subject Replacement 
Subjects in the dose finding phase who sign the informed consent form (ICF) but do not receive 
TAC01-HER2 in the monotherapy arm may be replaced, and those subjects who fail to receive 

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TAC01-HER2 or pembrolizumab in the combination arm may also be replaced. The reason(s) for 
not receiving TAC01-HER2 or pembrolizumab must be recorded in the subject’s medical record 
and the CRF. Subjects in the dose finding phase who are not evaluable for DLTs may also be 
replaced (see Section 9.3.1.4 for the DLT-evaluable analysis set). Subject numbers will not be 
reused. 
3.6.3. Subject Discontinuation Prior to Lymphodepleting Chemotherapy or Prior to 
TAC01-HER2 Dose 
Subjects who undergo leukapheresis but do not receive LDC or TAC01-HER2 will remain on 
study and be followed for leukapheresis-related AEs and survival for at least 8 weeks, or until 
resolution of any leukapheresis-related AEs should they persist beyond 8 weeks. The same 
applies for subjects who receive LDC but fail to pass the pre-TAC01-HER2 treatment criteria. 
3.7. Study Suspension or Termination 
The study can be terminated at any time by Triumvira, the Health Authorities, or an IRB/IEC for 
any reason. Circumstances that may warrant suspension or termination include, but are not 
limited to: 
• Identification of unexpected, significant, or unacceptable risks to subjects 
• Determination of futility 
• Insufficient compliance with protocol requirements 
• Data that are not sufficiently complete and/or evaluable 
The Investigator may be informed of additional procedures to be followed to ensure adequate 
subject protection. The Investigator will be responsible for informing IRBs/IECs and any other 
local regulatory committee (as applicable) of the early study termination. Triumvira will be 
responsible for notifying any applicable regulatory authorities, such as the US Food and Drug 
Administration (FDA), of the early study termination. 
If the study is suspended temporarily, it may resume once concerns about safety, protocol 
compliance, and data quality are addressed to the satisfaction of Triumvira, the DSMC, the 
IRB/IEC, and any applicable regulatory authorities. 

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3.7.1. Criteria for Study Interruption 
The study will be paused pending notification of the DSMC and appropriate regulatory 
authorities if any of the following occur: 
• Grade 4 toxicity attributable to TAC01-HER2 or pembrolizumab that is unexpected and 
unrelated to LDC 
• Grade 4 neurotoxicity attributable to TAC01-HER2  
• More than one Grade 4 CRS episode attributable to TAC01-HER2 during dose escalation 
• Death related to TAC01-HER2 or pembrolizumab  
• Death within 30 days of administration of TAC01-HER2 or pembrolizumab, unless 
clearly unrelated to the study and the product.  
• Significant excessive toxicities, e.g., DLTs observed in >33% of subjects who received 
TAC01-HER2 or pembrolizumab (Phase 1 combination dose escalation cohorts only). 
According to the pembrolizumab label, expected Grade 4 toxicities, including fever, 
hypotension, hypoxia, tumor lysis syndrome (TLS), and disseminated intravascular coagulation 
(DIC), will not require study interruption. In addition, the need for dialysis, and/or the need for 
mechanical ventilation are also expected. These expected toxicities may also result in secondary 
toxicities of Grade 4 renal toxicity, hepatic toxicity, or other organ involvement, which also 
would not lead to study interruption. Any Grade 4 toxicity that is not considered a DLT (refer to 
Section 3.2) will not lead to study interruption. 
Adverse events observed after pembrolizumab treatment must be managed using the dose 
modification or discontinuation guidelines listed in Appendix H and Appendix I. 
3.7.2. Criteria for Study Termination 
The study will be terminated if any of the following occur: 
• Any subject develops replication-competent lentivirus (RCL) 
• Triumvira, IRB/IEC, or DSMC determines subject safety is compromised 
• Triumvira discontinues development of TAC01-HER2  
3.7.3. Continued Access to Pembrolizumab 
Participants who are still on pembrolizumab at the time of study completion/termination may 
continue to receive study intervention if they are experiencing clinical benefit. The continued 
access to pembrolizumab will end when a criterion for discontinuation is met or 35 (for Q3W 
dosing) doses of pembrolizumab have been administered.  

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4. STUDY POPULATION 
4.1. Inclusion Criteria 
Subjects must meet all the following criteria to participate in this study: 
1. Signed, written informed consent obtained prior to any study specific procedures. 
2. Age ≥18 years at the time of informed consent. 
3. For Phase 1 and Phase 2:  
• Phase 1 monotherapy: HER2 1+, 2+, 3+ by IHC by central laboratory confirmation 
• Phase 1 combination: therapy: HER2 2+, 3+ by IHC and FISH by central laboratory 
confirmation  
• Phase 2 monotherapy (Group A): HER2 2+, 3+ by IHC and FISH by central 
laboratory confirmation 
• Phase 2 combination therapy (Group B): HER2 2+, 3+ by IHC and FISH by central 
laboratory confirmation  
In both phases, subjects who are HER2+ via recent (preferably after last line of therapy or 
within 1 year) tissue biopsy local laboratory results using IHC, FISH, or next generation 
sequencing (NGS) assays may also be enrolled, as long as a recent (preferably fresh or 
archival within 1 year) tissue biopsy sample is available for central laboratory HER2+ 
confirmation after enrollment and/or after starting TAC01-HER2. In the instance of 
discordant results between central and local laboratories (i.e., central laboratory results 
are negative with regards to IHC or FISH), the subject will still be considered evaluable 
for safety and evaluation of DLTs. In the instance of discordant results between central 
and local laboratories, the subject may be replaced in Phase 2. 
Central laboratory confirmation of HER2+ tumor samples will occur by one of the 
following methods (in order of priority; also see Section 7.2.3.1):  
a. A fresh tumor tissue sample, if clinically feasible and safe 
b. An archival sample collected within 1 year prior to enrollment (samples may be 
collected >1 year prior to enrollment in Phase 1) 
c. A liquid biopsy to examine circulating tumor cells 
d. If a, b, or c are not obtainable, the most recent archival sample available 
regardless of when it was obtained during prior lines of therapy 
Fine needle aspirations, or brushing and scraping cytology samples, are not acceptable at 
Baseline or Screening. Since Phase 2 will be evaluating efficacy and since HER2 status 
often changes on progression after HER2-targeted therapies (e.g., trastuzumab), it is 
strongly recommended a fresh tumor tissue sample be obtained, if clinically feasible and 
safe, along with the corresponding pathology report for histological disease diagnosis 
confirming HER2-protein expression on the tumor cell surface.  

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4. Histologically confirmed advanced, metastatic, unresectable solid tumors (regardless of 
PD-L1 expression levels; Phase 1) and histologically confirmed advanced, metastatic, 
unresectable gastric or esophageal adenocarcinoma (regardless of PD-L1 expression 
levels for Phase 1 combination therapy and Phase 2) after at least 2 prior lines of therapy 
(Phase 1) or after at least 2 and no more than 4 prior lines of therapy (Phase 2). For the 
completed Phase 1 monotherapy subjects, HER2+ incurable malignancies for which no 
standard-of-care HER2 targeted therapy exists were enrolled regardless of the number of 
prior treatment lines, as long as in the opinion of the investigator the subject would be 
unlikely to tolerate or derive clinically meaningful benefit from other available treatment 
options. For breast cancer subjects, both prior lines of therapy must have included 
HER2-targeted agents per current standard-of-care. Subjects in the Phase 1 combination 
arm and Phase 2 can be enrolled if they have received less than 2 prior lines of therapy if, 
in the opinion of the investigator, the subject would not derive meaningful clinical benefit 
from an additional line of therapy.  
Subjects with solid tumors with genetic alterations and mutations (such as BRAF, BRCA, 
EGFR mutations, and ALK translocation) where approved targeted therapies were 
available to their specific cancers must have been previously treated with such approved 
therapies or refused such approved targeted therapy for their cancers prior to enrollment, 
or in the opinion of the investigator would be unlikely to tolerate or derive clinically 
meaningful benefit from these standard-of-care therapies. 
5. Measurable disease per RECIST 1.1 at time of enrollment. Lesions situated in a 
previously irradiated area are considered measurable if progression has been 
demonstrated in such lesions. 
6. ECOG performance status of 0 or 1 at Screening. 
7. Life expectancy of at least 12 weeks. 
8. Adequate organ and bone marrow reserve function prior to leukapheresis for 
monotherapy and combination arms can be found in Table 8 and Table 9, respectively. 
9. Recovery to Grade ≤1 or Baseline for any toxicities due to previous therapy. 
a. If a subject received major surgery, they must have recovered adequately from the 
procedure and/or complications from the procedure prior to starting 
TAC01-HER2 therapy. 
b. Toxicity that has not recovered to Grade ≤1 is allowed if it meets the inclusion 
requirements for laboratory parameters. 
c. For the combination arm only: Subjects with Grade ≤2 neuropathy may be 
eligible, as may subjects with endocrine-related Grade ≤2 AEs requiring treatment 
or hormone replacement. 

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10. Adequate vascular access for leukapheresis as per institutional guidelines 
11. For women physiologically capable of becoming pregnant, agreement to use highly 
effective methods of contraception starting 28 days prior to study treatment and for 1 year 
after the TAC01-HER2 dose. For men who have partners physiologically capable of 
becoming pregnant, agreement to use an effective barrier contraceptive method and 
refrain from donating sperm during study treatment and for 1 year after the TAC01-HER2 
dose. 
12. Subjects who are hepatitis B surface antigen (HBsAg) positive are eligible if they have 
received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks and have 
undetectable HBV viral load prior to enrollment. Note: Subjects should remain on 
anti-viral therapy throughout study intervention and follow local guidelines for HBV 
anti-viral therapy post completion of study intervention. 
13. Subjects with history of hepatitis C virus (HCV) infection are eligible if HCV viral load 
is undetectable at Screening. Note: Subjects must have completed curative anti-viral 
therapy at least 4 weeks prior to enrollment.  

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Table 8: 
Adequate Organ Function Laboratory Values for the Monotherapy Arm 
System 
Laboratory Value 
Hematologic a 
Absolute neutrophil count (ANC) 
≥1,000.0/µL 
Absolute lymphocyte count (ALC) 
≥450.0/µL d 
Platelets a 
≥75,000.0/µL 
Hemoglobin a 
≥8.0 g/dL 
Renal 
Creatinine AND 
Estimated glomerular filtration rate (eGFR) b OR  
measured creatinine clearance c 
≤1.5 X upper limit of normal (ULN) AND 
≥60.0 mL/min/1.73 m2 OR 
≥40 mL/min 
Hepatic 
Total bilirubin 
≤1.5 X ULN OR 
Direct bilirubin ≤ULN for subjects with total 
bilirubin levels >1.5 X ULN OR 
≤3 x ULN in the presence of liver metastases OR 
In subjects with known Gilbert’s disease, serum total 
bilirubin <3 mg/dL 
Aspartate aminotransferase (AST) and alanine 
aminotransferase (ALT) 
≤2.5 X ULN or, 
If liver metastases present ≤5 X ULN 
Alkaline phosphatase (AP) 
≤2.5 X ULN or ≤5 x ULN for subjects with liver 
metastases or bone lesions. 
Coagulation 
International normalized ratio (INR) or prothrombin time 
(PT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or partial 
thromboplastin time (PTT) is within therapeutic 
range of intended use of anticoagulants 
Activated partial thromboplastin time (aPTT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or PTT is within 
therapeutic range of intended use of anticoagulants 
Respiratory 
Adequate respiratory reserve 
Grade 0 or 1 dyspnea and peripheral oxygen (O2) 
saturation of ≥92% on room air 
Cardiac 
Echocardiogram (ECHO) or multigated acquisition 
(MUGA) Scan 
Left ventricular ejection fraction (LVEF) ≥45% 
a Hemoglobin and platelet requirements cannot be met by use of recent transfusion or growth factor support.  
b eGFR should be calculated per institutional standard. 
c Creatinine clearance should be calculated per institutional standard. 
d Subjects with an ALC below 450.0/µL should be discussed with Triumvira’s Medical Monitor for assessment of suitability for 
high volume leukapheresis based on the subject’s tolerance, underlying malignancy, and any latent effects from prior 
antineoplastic therapies. 
 

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Table 9: 
Adequate Organ Function Laboratory Values for the Combination Arm 
System 
Laboratory Value 
Hematologic a 
Absolute neutrophil count (ANC) 
≥1500/µL 
Absolute lymphocyte count (ALC) 
≥450.0/µL d 
Platelets  
≥100,000.0/µL 
Hemoglobin a 
≥9.0 g/dL or ≥5.6 mmol/L a 
Renal 
Creatinine AND 
Estimated glomerular filtration rate (eGFR) b OR  
measured creatinine clearance c 
≤1.5 X upper limit of normal (ULN) AND 
≥60.0 mL/min/1.73 m2 OR 
≥40 mL/min 
Hepatic 
Total bilirubin 
≤1.5 X ULN OR 
Direct bilirubin ≤ULN for subjects with total 
bilirubin levels >1.5 X ULN OR 
≤3 x ULN in the presence of liver metastases OR 
In subjects with known Gilbert’s disease, serum total 
bilirubin <3 mg/dL 
Aspartate aminotransferase (AST) and alanine 
aminotransferase (ALT) 
≤2.5 X ULN or, 
If liver metastases present ≤5 X ULN 
Alkaline phosphatase (AP) 
≤2.5 X ULN or ≤5 x ULN for subjects with liver 
metastases or bone lesions. 
Coagulation 
International normalized ratio (INR) or prothrombin time 
(PT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or partial 
thromboplastin time (PTT) is within therapeutic 
range of intended use of anticoagulants 
Activated partial thromboplastin time (aPTT) 
≤1.5 X ULN unless subject is receiving 
anticoagulant therapy as long as PT or PTT is within 
therapeutic range of intended use of anticoagulants 
Respiratory 
Adequate respiratory reserve 
Grade 0 or 1 dyspnea and peripheral oxygen (O2) 
saturation of ≥92% on room air 
Cardiac 
Echocardiogram (ECHO) or multigated acquisition 
(MUGA) scan 
Left ventricular ejection fraction (LVEF) ≥45% 
a Criteria must be met without packed red blood cell (pRBC) transfusion within the prior 2 weeks. Participants can be on stable 
dose of erythropoietin (≥approximately 3 months). 
b eGFR should be calculated per institutional standard. 
c Creatinine clearance should be calculated per institutional standard. 
d Subjects with an ALC below 450.0/µL should be discussed with Triumvira’s Medical Monitor for assessment of suitability for 
high volume leukapheresis based on the subject’s tolerance, underlying malignancy, and any latent effects from prior 
antineoplastic therapies. 
 

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4.2. Exclusion Criteria 
Subjects who meet any of the following criteria will be excluded from participation in this study: 
1. Intolerant to any component of TAC01-HER2. 
2. Prior treatment with any of the following: 
a. Adoptive cell transfer of any kind, including CAR T cells 
b. Gene therapy 
3. Investigational medicinal product within 5 half-lives or 21 days prior to leukapheresis, 
whichever is shorter. 
4. Has received a live or live-attenuated vaccine within 30 days prior to the first dose of 
study intervention. Note: Administration of killed vaccines are allowed. 
5. mAb, including PD-1 and PD-L1, therapies within 21 days prior to leukapheresis. 
6. Radiation within 28 days prior to leukapheresis. Palliative radiation is allowed up to 
14 days prior to leukapheresis if additional non-irradiated lesions are present. 
7. Chemotherapy or targeted small molecule therapy within 14 days prior to leukapheresis, 
or within 7 days prior to leukapheresis for erlotinib, gefitinib, afatinib, crizotinib, or 
tucatinib. 
8. Colony stimulating factors, including granulocyte-colony stimulating factor (G-CSF), 
granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin, and other 
hematopoietic cytokines, within 14 days prior to leukapheresis. 
9. Immunosuppressive medication within 14 days and corticosteroid treatment <72 hours 
prior to leukapheresis, except for physiological replacement doses (<12 mg/m2/24 hours) 
of hydrocortisone or equivalent and topical or inhaled steroids. 
10. History or presence of clinically relevant central nervous system (CNS) pathology such 
as epilepsy, seizure, paresis, aphasia, stroke, severe brain injury, dementia, Parkinson’s 
disease, cerebellar disease, organic brain syndrome, or psychosis. Has known active CNS 
metastases and/or carcinomatous meningitis. Participants with previously treated brain 
metastases may participate provided they are radiologically stable, i.e., without evidence 
of progression for at least 4 weeks by repeat imaging (note that the repeat imaging should 
be performed during study screening), clinically stable and without requirement of steroid 
treatment for at least 14 days prior to first dose of study treatment.  
11. Active inflammatory neurological disorders (e.g., Guillain-Barre Syndrome, amyotrophic 
lateral sclerosis, multiple sclerosis). 

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12. Active autoimmune disease (e.g., lupus, rheumatoid arthritis, Sjogren’s syndrome) 
requiring systemic treatment (i.e., disease modifying agents, corticosteroids, or 
immunosuppressive drugs) in the past 2 years. Replacement therapy (e.g., thyroxine, 
insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary 
insufficiency, etc.) is not considered a form of systemic treatment. 
13. Active or uncontrolled hepatitis B or C (HCV ribonucleic acid [RNA] positive) infection 
or any history of or active human immunodeficiency virus (HIV) infection. 
14. Uncontrolled, acute, or life-threatening bacteria, viral, or fungal infection. Subjects with 
ongoing use of prophylactic antibiotics, antifungals, or antivirals are eligible if no 
evidence of active infection, this includes COVID subjects. 
15. Class III or IV heart failure (as defined by the New York Heart Association [NYHA]), 
cardiac angioplasty or stenting, myocardial infarction, unstable angina, or other clinically 
significant cardiac disease within 6 months prior to Screening. 
16. Cardiac arrhythmia not controlled by medical management. 
17. Clinically significant thrombotic events within 6 months prior to leukapheresis and/or 
inability to stop anticoagulation for at least 2 half-lives prior to TAC01-HER2 infusion 
without compromising a subject’s health. 
18. Known additional malignancy that is progressing or requires active treatment. Exceptions 
include basal cell carcinoma of the skin, non-metastatic squamous cell carcinoma of the 
skin, or in situ cervical cancer that has undergone potentially curative therapy.  
19. Pregnant or nursing (lactating). Females physiologically capable of becoming pregnant 
must have a negative serum beta human chorionic gonadotropin (β-hCG) pregnancy test 
result at Screening and within 48 hours prior to initiating LDC. 
20. As determined by the Investigator, any uncontrolled medical, psychological, familial, 
sociological, or geographical condition(s) that do(es) not permit compliance with the 
protocol. 
21. Is currently participating in or has participated in a study using an investigational device 
within 4 weeks prior to the first dose of study treatment. 
22. Has a history or current evidence of any condition, therapy, or laboratory abnormality, or 
other circumstance that might confound the results of the study or interfere with the 
subject’s participation for the full duration of the study, such that it is not in the best 
interest of the subject to participate, in the opinion of the treating investigator. 
23. Has a known psychiatric or substance abuse disorder that would interfere with the 
participant’s ability to cooperate with the requirements of the study. 

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Combination Arm Only Specific Exclusion: 
24. Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.  
25. Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an 
agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4, 
OX-40, CD137), and was discontinued from that treatment due to a Grade 3 or higher 
immune-related AE (irAE). 
26. Removed; combined with exclusion #10 (protocol Version 6.0). 
27. Has received radiation therapy to the lung that is >30 Gy within 6 months of the first dose 
of trial treatment. 
28. Has a history of (non-infectious) pneumonitis/interstitial lung disease that required 
steroids or has current pneumonitis/interstitial lung disease. 
29. Has history of an allogeneic stem cell transplant or a solid organ transplant. 
30. Has a history of radiation pneumonitis. (Note: Cannot receive prior radiotherapy within 
2 weeks of start of pembrolizumab. Note: Participants must have recovered from all 
radiation-related toxicities and not require corticosteroids. A 1-week washout is permitted 
for palliative radiation [≤2 weeks of radiotherapy] to non-CNS disease; see Section 
7.3.3). 
4.3. Eligibility Criteria for Second Dose 
4.3.1. Inclusion Criteria 
1. ECOG performance status of 0 or 1 prior to second LDC.  
2. Adequate organ function and bone marrow reserves prior to second LDC as shown in 
Table 8.  
3. Completed 28 days of safety observation after the first dose to allow for any residual 
toxicity attributed to the initial dose to resolve. 
4. No history of Grade ≥3 CRS or ICANS after receiving the first dose. Ongoing CRS or 
ICANS of Grade 1 or Grade 2 have resolved at least 7 days prior to the second LDC 
preceding the second dose.  
5. Any Grade ≥3 cytopenias have resolved to Grade 2 at least 7 days prior to the second 
LDC preceding the second dose. 
6. Fulfilled any of the following clinical criteria: 
• Subject has a confirmed RECIST 1.1 response (CR or PR) at the 3-month visit 
scans, who shows signs or symptoms of clinical progression that have been 

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documented by the Investigator (e.g., increase in tumor markers, decreases in 
performance status, significant sudden weight loss, ascites, effusion, increased 
intensity of cancer pain, etc.). 
• Subject has an unconfirmed response (CR or PR) and shows signs or symptoms of 
clinical progression that have been documented by the Investigator (e.g., increase 
in tumor markers, decreases in performance status, significant sudden weight loss, 
ascites, effusion, increased intensity of cancer pain etc.). 
• Subject has a mixed response; defined as measurable disease with reduction in 
size by at least 15% compared to baseline, with concurrent evolution of new 
lesions or enlargement of non-target lesions. 
• Subject has SD at the 3-month visit scans, without turning into a response or who 
shows signs of clinical progression. For subjects with tumor growth above 
baseline on Day 29, but still within the margin of SD, a second dose may be 
administered. 
4.3.2. Exclusion Criteria 
Subjects who meet any of the following criteria will be excluded from receiving a second 
TAC01-HER2 dose: 
1. Residual toxicities attributed to the initial dose that have not resolved to grade 2 or lower. 
2. History of Grade ≥3 CRS or ICANS after receiving the first dose. Ongoing CRS or 
ICANS of Grade 1 or Grade 2 have not resolved at least 7 days prior to the second LDC 
preceding the second dose.  
3. Grade 3 cytopenias that have not resolved to Grade 2 at least 7 days prior to the second 
LDC.  
4. Unequivocal evidence of disease progression on Day 29 scans and confirmatory scans 
after the first dose.  
5. Active severe infection 
6. Pregnant until resolution or termination of pregnancy. 
7. Date of first dose more than 1 year before administration date of second dose. 
4.4. Contraception Requirements 
TAC01-HER2 and pembrolizumab may have adverse effects on a fetus in utero. Furthermore, it 
is not known if pembrolizumab has transient adverse effects on the composition of sperm. 
Participants should be informed that taking the study medication may involve unknown risks to 

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the fetus (unborn baby) if pregnancy were to occur during the study. If there is any question that 
a participant will not reliably comply with the requirements for contraception, that participant 
should not be entered into the study. 
Any female subject who does not meet at least one of the following criteria will be considered 
physiologically capable of becoming pregnant: 
• Post-menopausal for at least 12 consecutive months (i.e., no menses). 
• Undergone a sterilization procedure (hysterectomy, salpingectomy, or bilateral 
oophorectomy). Tubal ligation is not considered a sterilization procedure.  
Female subjects physiologically capable of becoming pregnant must have a negative serum 
pregnancy test at Screening and within 48 hours prior to starting LDC. Female subjects who are 
physiologically capable of becoming pregnant and are not sexually abstinent must agree to use 
two forms of birth control (one highly effective method and one additional method) before 
starting study treatment (at least 14 days prior to the initiation of study treatment for oral 
contraception), during study treatment, and for 1 year after receiving TAC01-HER2 and/or at 
least 120 days following the last dose of pembrolizumab. 
Male subjects who are sexually active with females physiologically capable of becoming 
pregnant must agree to use a highly effective method of birth control before starting study 
treatment, during study treatment, and for 1 year after receiving TAC01-HER2. In addition, men 
should not donate semen or sperm for 1 year after the last dose of study treatment 
(i.e., TAC01-HER2 or pembrolizumab). 
Highly effective forms of birth control include abstinence, intrauterine device (IUD), hormonal 
agents (birth control pills, injections, implants, patch), tubal ligation, and vasectomy. Additional 
effective forms of birth control include a male or female condom with or without spermicidal 
agent, or a diaphragm or cervical cap with spermicidal agent. 
4.5. Screen Failures 
Screen failures are defined as subjects who consent to participate in the study but do not meet all 
required eligibility criteria. A minimal set of screen failure data is required to ensure transparent 
reporting, to meet the Consolidated Standards of Reporting Trials publishing requirements, and 
to respond to queries from regulatory authorities. These data include, screen failure reasons, 
eligibility criteria, and if applicable, any SAEs. Blood and tissue samples obtained during 
Screening for subjects who are determined to be screen failures may be used by Triumvira for 
exploratory research.  
Subjects who do not meet the criteria for study participation (i.e., screen failures) may be 
rescreened if their situation changes. 

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5. STUDY THERAPIES 
5.1. Therapy for Disease Control During TAC01-HER2 Manufacturing 
The manufacturing and quality testing of TAC01-HER2 may take approximately 3 weeks 
following leukapheresis. During this time, subjects may receive short-term bridging anticancer 
therapy before LDC if deemed necessary by the Investigator. 
Phase 1: 
Since the dose escalation component of the study is primarily focused on the characterization of 
safety, evaluation of DLTs, and determination of the RP2D in a late-stage disease, heavily 
pretreated population, the following bridging anticancer therapies are allowed to slow the 
progression of the underlying malignancy: 
• Platinum-based immunochemotherapy 
• Standard-of-care (SOC) chemotherapy 
• Other potential bridging regimens in consultation with the Medical Monitor include low 
dose anthracyclines and HER2-targeted agents. Antibodies and investigational agents 
must be discussed with the Medical Monitor to ensure a proper washout period prior to 
initiation of lymphodepletion. 
Phase 2: 
Since the dose expansion component of the study is primarily focused on the characterization 
and detection of anti-neoplastic clinical activity across gastric and esophageal adenocarcinoma at 
the RP2Ds, the following bridging anticancer therapies are allowed: 
• Platinum-based immunochemotherapy 
• SOC chemotherapy 
HER2-targeted agents including investigational agents and antibodies are not allowed as a 
bridging therapy in Phase 2 due to potential confounding effects with the HER2-targeted 
TAC01-HER2 treatment. 
Duration of bridging therapy is limited to a maximum of 4 weeks, unless discussed with the 
Medical Monitor. All therapies must be discontinued at least 14 days prior to initiation of 
lymphodepletion and the time from leukapheresis to lymphodepletion cannot exceed 
8 weeks ± 1 week to allow for scheduling delays and coordination of subject potential travel. 
Subjects must have recovered from bridging therapy-related toxicities to Grade ≤2 (except for 
alopecia) prior to initiation of lymphodepletion. Subjects who cannot receive lymphodepletion 
within 8 weeks  ± 1 week after leukapheresis must be rescreened. 
Palliative radiation is permitted following discussion with the Medical Monitor. 

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Also, a short course of 40 mg dexamethasone (≤4 days) or equivalent for emergency use for 
palliation of symptoms is allowed after previous consultation with the Medical Monitor. 
If bridging anticancer therapy is necessary, appropriate disease measurements (e.g., CT scan) 
must be conducted or repeated prior to lymphodepletion to ensure the subject has measurable 
disease prior to initiating lymphodepletion. Subjects who respond to bridging anticancer therapy 
and may no longer have measurable disease must wait until their disease becomes measurable to 
be considered for monotherapy or combination arms of the study. 
5.2. Lymphodepleting Chemotherapy 
TAC01-HER2 will be administered as a single IV infusion approximately 72 hours after 
completion of LDC. Central venous access is recommended for the infusion of TAC01-HER2.  
LDC will preferentially consist of 3 consecutive days of fludarabine or clofarabine and 
cyclophosphamide with or without mesna IV. If fludarabine or clofarabine is unavailable (due to 
national shortages), subjects can be treated with 3 consecutive days of cyclophosphamide with or 
without mesna IV or with bendamustine for subjects who cannot tolerate cyclophosphamide. 
The LDC regimen, in order of preference, will consist of: 
1. 3 consecutive days of fludarabine (30 mg/m2 IV) and cyclophosphamide (300 mg/m2 IV) 
with or without mesna IV. 
2. 3 consecutive days of clofarabine (52 mg/m2 IV) and cyclophosphamide (300 mg/m2 IV) 
with or without mesna IV, if fludarabine is not available due to national shortages. 
3. 2 consecutive days of bendamustine (90 mg/m2) for subjects who cannot tolerate 
cyclophosphamide. 
4. 3 consecutive days of cyclophosphamide (300 mg/m2 IV) with or without mesna IV, if 
fludarabine or clofarabine is unavailable. 
The dose intensity of either the primary (fludarabine or clofarabine + cyclophosphamide) or 
backup (cyclophosphamide or bendamustine) regimens can be modified based on a subject's 
CBC and creatinine clearance, upon discussion with the Medical Monitor.  
The last dose of LDC should be administered approximately 72 hours (± 24 hours) prior to 
TAC01-HER2 administration. Ideally, LDC will be administered Days -4 through -2, Day -1 is a 
recovery day (there is no Day 0 in this protocol) and TAC01-HER2 infusion occurs on Day 1. A 
window up to 5 days is acceptable between completion of LDC and TAC01-HER2 infusion. 
Delay of LDC by more than 14 days from its initially planned start requires discussion with the 
Medical Monitor and may require rescreening. Subjects who cannot receive lymphodepletion 
within 8 weeks ± 1 week after leukapheresis must be rescreened. 

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Antiemetic therapy, except dexamethasone or other low dose steroids, may be given prior to 
LDC per institutional practice. 
Refer to the most recent package inserts for further details on the administration of these agents. 
5.3. TAC01-HER2 Infusion 
If a subject receives anticoagulation agents, therapy should be stopped at least 2 half-lives prior 
to TAC01-HER2 infusion and can be restarted 10 days after infusion. If neurotoxicity occurs, 
anticoagulation agents should be withheld until neurotoxicity has improved to Grade ≤1. 
5.3.1. Dosage Form 
The TAC01-HER2 product is a suspension of genetically modified autologous T cells expressing 
TAC-HER2 for infusion containing 10% DMSO in approximately 20 mL.  
5.3.2. Administration 
TAC01-HER2 will be administered as an IV infusion approximately 72 hours after completion of 
LDC. 
Central venous access is recommended for the infusion of TAC01-HER2. The subject’s identity 
must match the subject identifiers on the TAC01-HER2 product bag. 
The tubing should be primed with normal saline prior to infusion, and TAC01-HER2 should be 
infused within 30 minutes. After infusion of the TAC01-HER2, the tubing should be flushed with 
normal saline to ensure all product is delivered. See Product Administration Manual for details. 
In the event CRS or neurologic toxicities associated with this product class are observed, 
tocilizumab and emergency equipment must be readily available prior to infusion and during the 
recovery period. In case of a tocilizumab-shortage, as per institutional cell therapy guidelines 
anti-interleukin (IL) agents siltuximab or anakinra can be used instead. 
5.3.3. Premedication 
For TAC01-HER2, all subjects will receive acetaminophen (650 mg by mouth [PO] or IV) or 
diphenhydramine (25 to 50 mg PO or IV) or both at the discretion of the Investigator. These 
medications may be repeated every 6 hours as needed based on the Investigator’s assessment of 
symptoms. Premedication with steroids is not allowed.  
5.3.4. Dosing Regimen 
Each subject-specific single infusion bag will contain a dose of HER2-targeted viable TAC T 
cells as outlined in the Product Administration Manual.  

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5.3.5. How Supplied 
Following completion of manufacture, the TAC01-HER2 product will be stored at the 
manufacturing site in the vapor phase of liquid nitrogen in a continuously monitored storage tank 
at or below ‑135°C. At the time of shipment, the cryopreserved dose(s) will be placed in a 
validated charged liquid nitrogen dry shipper equipped with a continuous temperature monitor. 
The investigative site will be notified of the shipment and tracking number used.  
Prior to administration, the product will be thawed at or near bedside. 
Additional TAC01-HER2 product details are provided in the TAC01-HER2 Product 
Administration Manual.  
5.3.6. Non-Conforming Product 
TAC01-HER2 that meets the specified release criteria for safety, identity, and purity but is 
non-conforming to the assigned dose for a subject may be released for administration. The 
product deviation plan defines the assessment and decision-making process, whereby a 
recommendation can be made to treat a subject with a TAC01-HER2 product that does not meet 
the specified release criteria for dose. 
5.4. Pembrolizumab Infusion 
5.4.1. Dosage and Administration 
Pembrolizumab will be administered 200 mg IV for 30 minutes (-5 minutes/+10 minutes). Sites 
should make every effort to target infusion timing to be as close to 30 minutes as possible. 
However, given the variability of infusion pumps from site to site, a window between -5 minutes 
and +10 minutes is permitted (i.e., infusion time is 30 minutes [-5 minutes/+10 minutes]). 
The Pharmacy Manual contains specific instructions for the preparation of the pembrolizumab 
infusion and administration of infusion solution. 
For pembrolizumab, Triumvira will provide it at no cost to the subjects, and it will be in the form 
of injection: 100 mg/4 mL (25 mg/mL) clear to slightly opalescent, colorless to slightly yellow 
solution in a single-dose vial. 
5.4.2. Dose Modification and Toxicity Management for Immune-Related AEs Associated 
with Pembrolizumab 
AEs associated with pembrolizumab combination exposure, including coadministration with 
additional compounds may represent an immune-related response. These irAEs may occur 
shortly after the first dose or several months after the last dose of pembrolizumab combination 
treatment and may affect more than one body system simultaneously. Therefore, early 
recognition and initiation of treatment is critical to reduce complications. Based on existing 
clinical study data, most irAEs were reversible and could be managed with interruptions of 

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pembrolizumab combination treatment, administration of corticosteroids and/or other supportive 
care. For suspected irAEs, ensure adequate evaluation to confirm etiology or exclude other 
causes. Additional procedures or tests such as bronchoscopy, endoscopy, skin biopsy may be 
included as part of the evaluation. Dose modification and toxicity management guidelines for 
irAEs associated with pembrolizumab can be found in Appendix H. 
Attribution of Toxicity:  
When study interventions are administered in combination, attribution of an adverse event to a 
single component is likely to be difficult. Therefore, while the investigator may attribute a 
toxicity event to the combination, to TAC01-HER2 alone, or to pembrolizumab alone, for 
adverse events listed in Appendix H, both interventions must be held according to the criteria in 
Appendix H. Dose Modification and Toxicity Management Guidelines for Immune-related AEs 
Associated with Pembrolizumab.  
Holding Study Interventions:  
When study interventions are administered in combination, if the AE is considered immune 
related, pembrolizumab should be held according to recommended dose modifications. 
Restarting Study Interventions:  
Subjects may not have any dose modifications (no change in dose or schedule) of 
pembrolizumab in this study, as described in Appendix H. If the toxicity does not resolve or the 
criteria for resuming treatment are not met, the subject must be discontinued from 
pembrolizumab. 
If the toxicities do resolve and conditions are aligned with what is defined in Appendix H, 
pembrolizumab may be restarted at the discretion of the investigator. In these cases where the 
toxicity is attributed to the combination or to TAC01-HER2 alone, re-initiation of 
pembrolizumab as a monotherapy may be considered after communication with, and agreement 
by, Triumvira. 
5.4.3. Dose Modification and Toxicity Management of Infusion-Reactions Related to 
Pembrolizumab 
Pembrolizumab may cause severe or life-threatening infusion-reactions including severe 
hypersensitivity or anaphylaxis. Signs and symptoms usually develop during or shortly after drug 
infusion and generally resolve completely within 24 hours of completion of infusion. Dose 
modification and toxicity management guidelines on pembrolizumab associated infusion reaction 
can be found in Appendix I. 
5.4.4. Other Allowed Dose Interruptions for Pembrolizumab 
Pembrolizumab may be interrupted for situations other than treatment-related AEs such as 
medical or surgical events and/or unforeseen circumstances not related to study intervention. 

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However, study intervention is to be restarted within 3 weeks or 21 days for Q3W dosing of the 
originally scheduled dose and within 42 days for Q3W dosing of the previously administered 
dose, unless otherwise discussed with Triumvira. The reason for interruption is to be documented 
in the subject’s study record. 
5.4.5. Preparation and Storage 
Directions for the preparation of pembrolizumab (IV infusion), storage of the diluted solution, 
and administration rate and method can be found in Section 2.4 of the current USPI and the 
preparation and administration section of the current Canadian Product Monograph. Storage and 
handling of pembrolizumab can be found in Section 16 of the USPI. 
5.4.6. How Supplied 
Pembrolizumab will be provided by Triumvira. Shipping details for pembrolizumab are provided 
on the pembrolizumab order request form. 
5.5. Overdose 
Overdose, as defined for this protocol, refers to LDC (with fludarabine/cyclophosphamide, 
clofarabine/cyclophosphamide, single agent cyclophosphamide, single agent bendamustine), 
pembrolizumab, or TAC01-HER2. 
On a per-dose basis, an overdose is defined as: 
• IV: 10% over the protocol-specified dose. 
On a schedule or frequency basis, an overdose is defined as: 
• Anything more frequent than the protocol-required schedule or frequency. 
On an infusion rate basis, an overdose is defined as:  
• Any rate faster than the protocol-specified rate. 
Complete data about drug administration, including any overdose, regardless of whether the 
overdose was accidental or intentional, should be reported on the CRF. See Section 8.2.1. for the 
reporting of AEs associated with overdose. 
Pembrolizumab Overdose: 
For this study, an overdose of pembrolizumab will be defined as any dose of 1000 mg or greater. 
No specific information is available on the treatment of overdose of pembrolizumab. In the event 
of overdose, the participant should be observed closely for signs of toxicity. Appropriate 
supportive treatment should be provided if clinically indicated. 

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5.6. Supportive Care, Additional Treatment, and Monitoring 
LDC should be administered as per institutional standard. To monitor and manage any potential 
toxicities, hospitalization is required for all subjects prior to treatment with TAC01-HER2. 
Subjects should be hospitalized as per institutional cell-therapy guidelines for the day of 
infusion. Based on the Investigator’s judgement, the subject may be asked to remain within 
approximately 1 hour of the investigative site for 28 days after infusion with TAC01-HER2. 
Subjects and their caregivers must be instructed on the possible signs of early CRS, 
neurotoxicity, HLH, and MAS prior to treatment. 
Prophylactic treatment/measures are strongly recommended for subjects at risk for TLS, per 
institutional standards. 
Supportive care for CRS, neurotoxicity, HLH, and MAS management is detailed in Appendix E. 
Subjects who develop fever should be evaluated for infection and monitored for CRS. 
The use of red blood cells and platelet transfusions, and/or colony-stimulating factors is 
permitted after determination of eligibility at initial Screening, per institutional or clinical 
standards. However, filgrastim (G-CSF) and GM-CSF are prohibited starting 14 days prior to 
leukaphereses and 7 days prior to TAC01-HER2 infusion until 5 days after the infusion. 
Cytopenias can emerge as late as 7 days after completion of LDC. 
The use of prophylactic or empiric anti-infective agents is permitted per institutional standards. 
Prophylaxis may be provided for lymphopenia and/or neutropenia. 
5.7. Concomitant Medications 
5.7.1. Reporting Periods 
Reporting periods for concomitant medications are summarized in Table 10. 

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Table 10: Reporting Periods for Concomitant Medications 
Reporting Period 
What to Record/Report 
Informed consent to leukapheresis 
Medications taken at the time of AEs/SAEs related to 
protocol-mandated procedures. 
Leukapheresis to start of lymphodepleting 
chemotherapy 
Medications taken at the time of AEs related to 
protocol-mandated procedures and at the time of any 
SAE. 
Start of lymphodepleting chemotherapy to 
90 days post-TAC01-HER2 dose 
All medications. 
Monotherapy Arm Only: 91 days 
post-TAC01-HER2 dose to end of study 
Corticosteroids, anticancer therapies, and medications 
used to treat TAC T cell related AEs/SAEs. 
Combination Arm Only: 91 days 
post-TAC01-HER2 dose to end of treatment 
with pembrolizumab  
All medications. 
Combination Arm Only: After end of 
treatment with pembrolizumab to end of 
study 
Corticosteroids, anticancer therapies, and medications 
used to treat TAC01-HER2 or pembrolizumab-related 
AEs/SAEs. 
5.7.2. Concomitant Medications During Hospitalizations 
The following medications should not be recorded on the Concomitant Medication CRF during 
inpatient hospitalizations: 
• IV fluids (except boluses used to treat CRS, which should be recorded) 
• Heparin flushes 
• Stool softeners 
• Vitamins, minerals, health supplements 
• Saline 
• Lotions 
The following treatments should be recorded on the Concomitant Medication CRF during 
inpatient hospitalizations: 
• Vasopressors 
• Oxygen use 
• Corticosteroids 
5.8. Prohibited Medications 
G-CSF and GM-CSF are prohibited starting 14 days prior to leukapheresis and 7 days prior to 
TAC01-HER2 infusion until 5 days after the infusion. 

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Steroids are prohibited until disease progression or 2 years following TAC01-HER2 treatment, 
whichever comes first. Therapeutic doses of corticosteroids (defined as >20 mg/day prednisone 
or equivalent) must not be administered within 72 hour prior to leukapheresis and 72 hours 
before TAC01-HER2 administration. After TAC01-HER2 infusion, administration of therapeutic 
doses of corticosteroids is not permitted unless used for treatment of Grade ≥2 CRS or any grade 
of neurotoxicity or to modulate symptoms of an AE that is suspected to have an immunologic 
etiology. Therapeutic doses may be used in life-threatening situations and for other medical 
conditions when indicated. Pre-treatment containing steroids may be given for necessary 
medications (e.g., IV immunoglobulin) after discussion with the Medical Monitor. Physiologic 
replacement steroids (≤12 mg/m2/day hydrocortisone or equivalent [≤3 mg/m2/day prednisone or 
≤0.45 mg/m2/day dexamethasone]), topical steroids and inhaled steroids are permitted.  
The following medications are prohibited during the treatment and follow-up periods, unless 
used as an anticancer agent after inadequate response to TAC01-HER2 or disease progression: 
• Anticancer agents, (excluding bridging anticancer therapy, LDC and agents used for 
treatment of uncontrolled TAC T cell proliferation or CRS.). 
• Experimental agents. 
• Definitive radiation (palliative radiation for cancer symptoms including pain management 
is permitted). 
• Live or live attenuated vaccines within 30 days prior to the first dose of study treatment 
and while participating in the study. Note: Killed vaccines are allowed. Note: Any 
licensed COVID-19 vaccine (including for Emergency use) in a particular country is 
allowed in the study as long as they are mRNA vaccines, adenoviral vaccines, or 
inactivated vaccines. These vaccines will be treated just as any other concomitant 
therapy. 
6. POTENTIAL RISKS AND MANAGEMENT OF TREATMENT TOXICITIES 
A discussion of potential TAC01-HER2 associated risks is available in the current TAC01-HER2 
IB. 
With regards to pembrolizumab potential treatment risks and management of toxicities, refer to 
Appendix H and Appendix I.  
6.1. Cytokine Release Syndrome  
With CAR T cell administration, CRS is characterized by high fever, fatigue, nausea, headache, 
dyspnea, tachycardia, rigors, hypotension, hypoxia, myalgia/arthralgia, and anorexia. Clinical 
symptoms and severity of CRS are highly variable (Lee 2019), and management can be 
complicated by concurrent conditions. CRS symptoms appear a few days to weeks following 
administration of CAR T cells and may be severe and life-threatening (Lee 2019). 
Fever (temperature ≥38.5°C or ≥101.3°F) is a commonly observed hallmark of CRS and many 
features of CRS mimic infection. Hence, infection must be considered in all subjects presenting 

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with CRS symptoms, appropriate cultures must be obtained, to exclude other causes for the 
fever, and empiric antibiotic therapy initiated per institutional standard of care. 
Less common symptoms associated with CRS include cardiac dysfunction, adult respiratory 
distress syndrome, renal and/or hepatic failure, coagulopathies, DIC, and capillary leak 
syndrome.  
Neurological toxicity has been observed concurrently with CRS. 
CRS has been reported in a few cases to be associated with findings of MAS/HLH, and the 
physiology of the syndromes may overlap. Subjects should be evaluated for the presence of other 
immune-related toxicities. 
Refer to Appendix D for a detailed description of CRS management and treatment 
recommendations. 
6.2. Myelotoxicities 
Severe (Grade ≥3) and prolonged myelotoxicities, including anemia, leukopenia, neutropenia, 
and thrombocytopenia, may occur with either the LDC regimen and/or TAC01-HER2 
administrations. CBCs should be monitored both prior to and after a TAC01-HER2 infusion. 
Institutional guidelines should be followed in the event of Grade ≥3 myelotoxicities. 
6.3. Hypersensitivity Reactions  
Allergic reactions may occur with infusion of genetically engineered T-cells such as 
TAC01-HER2. If hypersensitivity reactions occur, these reactions would be expected to happen 
during or immediately following the infusion, and may include bronchospasm, wheezing, 
angioedema, pruritus, and hives. Although unlikely, serious hypersensitivity reactions may 
occur, including anaphylaxis. Subjects should be monitored closely during and following the 
infusion. When a hypersensitivity reaction is suspected, discontinue the infusion and institute 
appropriate supportive care as needed, including bronchodilators and resuscitation procedures, as 
necessary. 
6.4. Infusion Reactions  
Infusion reactions may occur following administration of TAC01-HER2. If an infusion reaction 
were to occur, it would be expected to happen during or immediately following the infusion. 
Some infusion reactions may be related to the presence of DMSO in the formulation.  
Infusion reactions can present with fever, rigors, rash, urticaria, dyspnea, hypotension, and/or 
nausea. To minimize the risk of infusion reactions, all subjects should be pre-medicated with 
acetaminophen and/or diphenhydramine. Mild infusion reactions should be managed with 
antipyretics, antihistamines, and anti-emetics. Corticosteroids should be avoided because of the 
potential impact on TAC01-HER2's efficacy. Rigors may be treated with meperidine. 
• The following guidelines should be followed for infusion reactions: 

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• Grade 1: Administer symptomatic treatment, continue TAC01-HER2 administration 
at the same dose and rate. 
• Grade 2: Stop TAC01-HER2 administration, administer symptomatic treatment, and 
resume TAC01-HER2 administration at a reduced rate only after symptoms resolve. 
• Grade 3: Stop TAC01-HER2 administration, administer symptomatic treatment, and 
resume TAC01-HER2 administration at a reduced rate only after symptoms resolve. 
If Grade 3 reaction recurs, discontinue TAC01-HER2 administration. 
• Grade 4: Discontinue TAC01-HER2 administration and administer symptomatic 
treatment, as necessary. 
6.5. Immune-Mediated Reactions 
6.5.1. Pneumonitis 
Monitor subjects for signs and symptoms of pneumonitis. Pneumonitis is considered an immune-
mediated AE and may occur as an isolated event or may occur in association with CRS. If 
pneumonitis is suspected, evaluate with radiographic imaging, and exclude other etiologies. 
Institutional guidelines for corrective treatment measures should be followed in the event of 
pneumonitis. 
6.5.2. Fever 
Subjects who develop a fever (temperature ≥38.5ºC or ≥101.3°F) with or without neutropenia 
should be evaluated for infection (e.g., blood cultures obtained, imaging as clinically required for 
identification of potential source of infection) and treated with antibiotics, fluids, and other 
supportive care measures per institutional standard.  
The possibility of CRS should be considered for all subjects with fever following TAC01-HER2 
administration. Any onset of fever within the first 2 weeks after TAC01-HER2 administration 
should be evaluated with hospitalization for observation. Febrile subjects should be monitored 
closely for hemodynamic instability and changing neurologic status. 
6.5.3. Neurologic Toxicities 
CAR T cell therapy is associated with unique neurologic toxicities. Neurologic symptoms may 
include altered mental status, aphasia, altered level of consciousness, and seizures or seizure-like 
activity. According to published references, neurologic symptoms may begin 2 to 14 days after 
CAR T cell infusion and in severe cases may require admission to the Intensive Care Unit (ICU) 
for frequent monitoring, respiratory support, or intubation for airway protection 
(Kochenderfer 2015, Turtle 2016, Davila 2014, Gardner 2016, Maude 2014b). The symptoms are 
variable and generally occur as CRS is resolving or after CRS resolution. 
Refer to APPENDIX C for a detailed description of neurotoxicity management and treatment 
recommendations. 

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6.5.4. Macrophage Activation Syndrome  
MAS is a serious disorder potentially associated with uncontrolled activation and proliferation of 
CAR T cells and subsequent activation of macrophages. There may be considerable overlap in 
clinical manifestations and laboratory findings between MAS and CRS. Subjects treated with 
TAC01-HER2 should be monitored for MAS, and cytokine-directed therapy should be 
considered as clinically indicated. 
6.5.5. Tumor Lysis Syndrome 
Both LDC and TAC01-HER2 may cause TLS. Subjects should be closely monitored for 
laboratory evidence of TLS (hyperuricemia, hyperkalemia, hyperphosphatemia, and 
hypocalcemia) and subjects at high risk for developing TLS, such as those with high disease 
burden and high cell turnover should receive prophylactic treatment per standard clinical 
practice. 
6.5.6. Uncontrolled T cell Proliferation 
TAC T cells, similar to CAR T cells, could theoretically proliferate out of control. If uncontrolled 
TAC T cell proliferation occurs, subjects may be treated with high-dose steroids (e.g., 
methylprednisolone 2 mg/kg/day, tapered over 2-3 weeks) or LDC doses of cyclophosphamide 
(1-3 g/m2 IV). If an Investigator suspects uncontrolled TAC T cell proliferation, Triumvira 
should be contacted immediately. 
6.5.7. Replication-Competent Lentivirus, Clonality, and Insertional Oncogenesis 
Lentiviral vectors used in gene transfer are engineered to be replication-defective; however, 
generation of RCL during manufacturing is still a possibility. Modern vector production systems 
have been improved to reduce the risk of RCL generation. To date, there have been no reports of 
RCL generated during lentiviral vector manufacturing, which may be due, at least in part, to the 
use of self-inactivating vectors (Rothe 2014). 
Concerns for possible vector integration into the host genome have arisen due to nonclinical 
studies that have shown retrovirus-mediated malignant transformation in mice (Li 2002, 
Modlich 2005) and monkeys (Donahue 1992), and a single clinical study reporting development 
of leukemia in subjects with X linked severe combined immunodeficiency (SCID) who received 
retroviral-modified CD34 positive hematopoietic stem cells (Hacein-Bey-Abina 2003), including 
1 subject who died (Couzin 2005). Of note, no instances of RCL generation during production or 
lentivirus-mediated malignant transformation in animals or subjects have been reported to date. 
Data have recently been published on the integration sites of retroviral and lentiviral vectors used 
for T cell modification in clinical studies (McGarrity 2013, Scholler 2012, Wang 2009). No 
clonality of integration sites was observed. In addition, there did not appear to be enrichment of 
integration sites near genes involved in clonal expansion or persistence. 

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Per the FDA guidelines (Testing of Retroviral Vector Based Gene Therapy Products Guidance 
2020, Long Term Follow-Up After Administration of Human Gene Therapy Products Guidance 
2020), all subjects treated with TAC01-HER2 will be followed for RCL and, if indicated, vector 
sequences for up to 15 years following TAC01-HER2 administration as part of the LTFU 
protocol. All subjects will be monitored for evidence of unexpected TAC01-HER2 expansion and 
the emergence of a new malignancy, particularly one of T cell origin. Investigators should 
contact Triumvira immediately if a new malignancy arises. 
7. STUDY ASSESSMENTS AND PROCEDURES 
7.1. Schedule of Events 
A monotherapy schedule of events (SOE) is provided in Appendix A1, with the combination 
therapy SOE provided in Appendix A2, and SOE for monotherapy subjects receiving 2 doses is 
provided in Appendix B. However, a very high-level summary is included as follows:  
The study schedule is divided into 3 parts: Pre-treatment, Treatment, and Post-treatment. 
Pre-treatment includes screening, leukapheresis, potentially bridging anticancer therapy and 
pre-treatment screening. 
Monotherapy Treatment #1 includes LDC and TAC01-HER2 administration on Day 1, as well as 
follow-up through Day 29.  
Monotherapy Treatment #2 includes LDC and TAC01-HER2 administration on Day X and post 
second dose procedures through Day X + 28 days. 
Monotherapy Post-treatment Follow-up for subjects who receive 1 dose (Treatment #1) begins 
on Day 43 and lasts through Month 24 (calculated from the first dose Day 1), unless a subject 
has PD, starts a new anticancer therapy, withdraws consent, or is lost to follow-up. If these occur, 
the subject will be discontinued from this study and enrolled in the LTFU study. 
Monotherapy Post-Treatment Follow-up for subjects who receive 2 doses (Treatments #1 and #2) 
begins on Day X + Day 43 and lasts through Month 24 (calculated from the first dose Day 1), 
unless a subject had PD, starts a new anticancer therapy, withdraw consent, or is lost to 
follow-up during this time. If these occur, the subject will be discontinued from this study and 
enrolled in the LTFU study. 
Subjects who receive 1 dose (Phase 1 monotherapy) and subjects who receive combination 
therapy will follow procedures described in Appendix A1 and Appendix A2, respectively, for up 
to 24 months after the first dose, until the subject withdraws consent, or the subject is lost to 
follow-up. Radiographic disease assessments for PD and other responses in single-dose subjects 
will occur on Day 29±2 days, then Q8W±2W for Year 1 and Q12W±2W for Year 2. If a subject 
who receives 1 dose has initial PD on the Day 29 (±2 days) scan, a confirmation scan should 
occur 28 days (± 7 days) later to confirm the initial PD was not a tumor flare.  

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Subjects who receive 2 doses will follow procedures described in Appendix B for up to 
24 months after the first dose, until the subject withdraws consent, or the subject is lost to 
follow-up. Assessments for PD will occur on Day 29 (±2 days) after the first dose on Day 1, then 
Q8W±2W until the second dose is administered in Year 1. Once the second dose is administered, 
(i.e., Day X), scans will be performed on Day X + 28±2 days, Q8W±2W after Day X for 1 year, 
and then Q12W±2W after Day X for up to 24 months after the first dose, until the subject 
withdraws consent, or the subject is lost to follow-up. If a subject who receives 2 doses has PD 
on the Day X + 28±2 days scan, no confirmation scan is required to confirm PD. 
For subjects who receive 1 dose (Treatment #1), all subsequent visits/procedures/laboratory 
assessments will be based on Day 1, when the only TAC01-HER2 dose was administered. 
For subjects receiving 2 doses (Treatments #1 and #2), all subsequent 
visits/procedures/laboratory assessments will be based on Day 1, except scans and those 
specifically designed to monitor PK and other laboratory assessments occurring 42 days after 
Day X, see Appendix B for clarity (e.g., Day X, X+5, X+8, X+15, X+29). 
Combination Treatment includes LDC, a single dose of TAC01-HER2 on Day 1, and 
pembrolizumab administration on Day 21 or Day 14 and then continuing Q3W for up to 
24 months.  
Combination Therapy Post-treatment continues from the last dose of pembrolizumab through 
Month 24 unless the subject withdraws consent, or the subject is lost to follow-up. Subjects 
starting a new anticancer therapy should transition to the LTFU protocol. 
All procedures and clinical laboratory assessments on days that LDC, TAC01-HER2, or 
pembrolizumab are administered must be performed pre-dose unless otherwise specified. 
Clinical laboratory assessments may be performed within 1 day prior to start of LDC, 
TAC01-HER2, or pembrolizumab administration. Results from clinical laboratory assessments 
must be reviewed prior to initiation of LDC, TAC01-HER2, or pembrolizumab administration. 
The Month 24 visit will be the EOS visit unless a subject discontinues early.  
Subjects who experience disease progression after the initial dose of TAC01-HER2 should 
complete the PD visit to confirm PD 28 days (± 7 days) after their initial PD scans. If 
confirmatory scans indicate PD the subject should be permanently discontinued from 
pembrolizumab, unless the subject is considered by the Investigator to derive clinical benefit, is 
clinically stable, and there is agreement from Triumvira. Clinical stability is defined by the 
following: absence of new symptoms and signs indicating clinically significant PD, no decline in 
ECOG performance status, absence of rapid progression of disease or progressive tumor at 
critical anatomical sites requiring urgent alternative medical intervention. 
If a Day 29 (±2 days) PD is confirmed 28 days later (±7 days) after Dose 1 or a new anticancer 
therapy is initiated, the subject should transition to the LTFU protocol. For subjects who 

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withdraw from the study before the Month 24 visit, the EOS visit should be completed at the 
time of study withdrawal. 
If subjects are not able to come to the investigational site for protocol specified visits due to the 
COVID-19 pandemic, alternative methods for safety assessments (e.g., phone contact, virtual 
visit, alternative location for assessment, including local laboratory tests or imaging centers) may 
be implemented, when necessary, feasible, and sufficient to assure the safety of study 
participants. Any protocol deviations, missing data, or subject withdrawals related to COVID-19 
must be documented. 
7.2. Pre-Treatment 
7.2.1. Screening 
Screening will begin when the subject signs the IRB/IEC-approved ICF and continues until the 
subject is enrolled or is determined to be a screen failure. 
The following assessments will be performed during screening: 
• Eligibility assessment. 
• Clinically significant medical history review, including disease diagnosis and history, 
hematopoietic stem cell transplant (HSCT) history if applicable, and chemotherapy, 
radiation, and surgical history. May include history of toxicities related to prior 
treatments and allergies. 
• Physical examination, including neurological examination, vital signs, height, and weight 
within 2 weeks prior to enrollment. 
• ECOG performance status assessment within 2 weeks prior to enrollment (see 
Appendix G). 
• 12-lead electrocardiogram (ECG) (may be performed up to 8 weeks prior to enrollment). 
• Cardiac echocardiogram (ECHO) or multigated acquisition (MUGA) scan (may be 
performed up to 8 weeks prior to enrollment). 
• Local laboratory assessments (chemistry, coagulation, hematology, viral serology, serum 
pregnancy) within 2 weeks prior to enrollment. 
• Tumor sample and pathology report availability confirmation. 
• If a fresh biopsy is not feasible, then an archival sample collected within 1 year prior to 
enrollment (samples may be collected >1 year prior to enrollment in Phase 1). If this is 
not feasible, a liquid biopsy to examine circulating tumor cells should be performed. 
Lastly, if this is not feasible, the most recent archival sample available regardless of when 
it was obtained during prior lines of therapy is acceptable. 
• Record AEs/SAEs related to protocol mandated procedures and associated concomitant 
medications. 

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7.2.2. Leukapheresis 
Following enrollment in the study, leukapheresis will be performed on each subject to obtain 
enough quantity of peripheral blood mononuclear cells (PBMCs) for the production of 
TAC01-HER2. If a technical issue arises during the procedure or in the immediate processing of 
the leukapheresis and it cannot be used for TAC01-HER2 production, the subject may have 
additional leukapheresis procedures performed. Further information is provided in the 
Leukapheresis Collection Manual. 
The following assessments will be conducted on the day of leukapheresis: 
• Peripheral blood sample collection for local clinical laboratory evaluations, including: 
o Hematology (CBC with differential) 
o Serum chemistry 
o Coagulation 
• Hematology results must be evaluated prior to leukapheresis. To ensure results are 
available, the sample may be collected up to 24 hours prior to leukapheresis. 
• Vital signs (before leukapheresis) 
• Record all AEs related to protocol-mandated procedures, all SAEs, and concomitant 
medications. 
7.2.3. Pre-treatment Screening and Baseline Evaluations 
The subject must continue to meet eligibility criteria pertaining to adequate organ function 
except for hematologic parameters (platelet count of ≥30,000/mm3 is permitted prior to LDC, but 
neutrophil count must be ≥1,000.0/µL, hemoglobin ≥8 g/dL, and absolute lymphocyte count 
[ALC] ≥450.0/µL), and also meet eligibility requirements for active infections, pregnancy, 
measurable disease, and washout of prior therapy before initiation of LDC (see Section 5.2). An 
adequate and recent set of scans must be available to serve as a baseline scan for tumor 
assessments that will be obtained post TAC01-HER2 infusion.  
Pre-treatment screening (Baseline) evaluations must occur within 14 days prior to initiation of 
LDC and must occur after the completion of any bridging chemotherapy. For subjects who 
receive bridging chemotherapy with potentially cardiotoxic drugs, a repeat ECHO or MUGA 
scan must be performed within 7 days prior to initiation of LDC. Evaluations will be performed 
as indicated in the respective monotherapy and combination therapy SOEs (see Appendix A1, 
Appendix A2, or Appendix B). 
7.2.3.1. Tumor and Correlative Studies Tissue Collection  
All subjects enrolled into this study must be able to provide a newly obtained biopsy (fine needle 
aspirate is not adequate) to be submitted for characterization. If this is not clinically feasible and 
safe, subjects can instead provide an adequate archival sample collected within 1 year prior to 
enrollment (samples may be collected >1 year prior to enrollment in Phase 1). If this is not 
feasible, the most recent archival sample available is acceptable. 

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Exploratory biopsies should be limited to percutaneous lesions that are palpable, or guided by 
imaging/endoscopy if necessary, and not be obtained from any lesions that are in proximity to 
vital visceral, cardio‑pulmonary, or neurovascular structures. When feasible biopsy sites should 
be selected so that subsequent biopsies, if needed, can be performed at the same location. Tumor 
lesions that are inaccessible or contraindicated due to subject’s safety concerns will not be 
biopsied. 
For the Phase 1 portion of the trial, tumors must be HER2+ by IHC. For the Phase 2 portion of 
the trial, tumors must be HER2 2+ or 3+ by IHC and FISH.  
Refer to the laboratory manual for additional details 
7.2.4. Pre-treatment Evaluations for Phase 2 TAC01-HER2 Second Dose 
The subject must continue to meet eligibility criteria pertaining to adequate organ function (Table 
8) except for hematologic parameters (platelet count of ≥30,000/mm3 is permitted prior to LDC, 
but absolute neutrophil count must be ≥1000.0/µL, hemoglobin ≥8 g/dL, and ALC ≥450.0/µL), 
and also meet eligibility requirements for second dose as described in Section 4.3. 
Subjects who receive palliative radiation may receive a second dose but not those who receive 
curative radiation, or another systemic antineoplastic therapy, should be discontinued from the 
study and enrolled in the separate LTFU protocol. Anticoagulation requirements listed in 
Section 5.3 also apply to the second dose. 
7.3. Study Treatments 
7.3.1. Lymphodepleting Chemotherapy 
Subjects should have a hemoglobin level ≥8 g/dL, a platelet count of ≥30,000/mm3, and an ALC 
≥450.0/µL prior to lymphodepletion; red blood cell transfusions and other supportive measures 
may be used. 
The following assessments will be performed on each day of LDC, prior to administration of 
LDC: 
• Physical examination, including routine neurological examination, vital signs 
• Weight (first day only)  
• ECOG performance status assessment (first day only) 
• Local laboratory assessments, including hematology, coagulation, and serum chemistries. 
The assessments prior to the second and third day of LDC are to guide supportive care 
and medical decision making. 
• Record all AEs and concomitant medications. 

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7.3.2. TAC01-HER2 Treatment 
7.3.2.1. TAC01-HER2 Infusion Criteria (Day -1) 
Note: For the second dose, Day -1 will be the study day before the second dose date  
Treatment should be delayed for subjects who meet at least one of the following criteria within 
24 hours prior to the scheduled TAC01-HER2 infusion: 
• Significant worsening in clinical status in the Investigator’s opinion and would increase 
the risk of TAC01-HER2 treatment-related AEs 
• Suspected or active systemic infection 
• Onset of fever ≥38.5°C/101.3°F not related to underlying disease 
• Presence of progressive radiographic abnormalities on chest x-ray, or requirement for 
supplemental oxygen to keep saturation greater than 91% 
• Cardiac arrhythmia not controlled with medical management 
• Hypotension requiring vasopressor support 
• New-onset or worsening of non-hematologic organ dysfunction Grade ≥3 
• Taking any of the prohibited medications as described in Section 5.8 
In the case of a delayed infusion, lymphodepletion may need to be repeated after discussion with 
the Medical Monitor. 
7.3.2.2. TAC01-HER2 Infusion Day 1 (Dose 1 and 2) 
TAC01-HER2 will be administered as described in Section 5.3.2. Evaluations will be performed 
as indicated in the respective monotherapy and combination therapy SOEs (see Appendix A1, 
Appendix A2, or Appendix B). Additionally, vital signs (see Section 7.13.4) will be measured 
within approximately 15 minutes (± 5 minutes) before and 15 minutes (± 5 minutes) after 
infusion, then approximately every 15 minutes thereafter for the first hour and hourly 
(± 15 minutes) for the next 3 hours. Thereafter, vital signs should continue to be monitored until 
stable and as clinically indicated. 
7.3.3. Pembrolizumab (Starting Day 21 or Day 14 then Q3W; Combination Arm Only) 
To receive pembrolizumab, subjects must have adequate organ function as defined in Table 9. 
Specimens must be collected within 10 days prior to the start of pembrolizumab. Window does 
not apply to ECHO/MUGA.  
Subjects must not have received prior radiotherapy within 2 weeks of start of pembrolizumab. 
Note: Participants must have recovered from all radiation-related toxicities and not require 
corticosteroids. A 1-week washout is permitted for palliative radiation (≤2 weeks of 
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If organ function is not adequate as defined in Table 9, a dose delay of the first dose of 
pembrolizumab of up to 14 days is allowed. If the subject still does not meet the adequate organ 
function criteria after the 14-day dose delay, the subject will be discontinued from the 
combination arm and will follow the monotherapy schedule of events in Appendix A1.  
Pembrolizumab will be administered and monitored according to the USPI and the Canadian 
Product Monograph or per institutional standards-of-care (also see Appendix H and Appendix I), 
also see Section 5.4.1. Evaluations, examinations, imaging, and laboratory procedures will be 
performed as indicated in the SOE (Appendix A2). 
7.3.4. Confirmed Disease Progression and Treatment Beyond PD (PD Visit) 
The assessments listed for PD (Appendix A1, Appendix A2, or Appendix B) will be performed 
approximately 28 days (± 7 days) after disease progression is initially suspected by a primary 
(Day 29 ± 2 days) scan(s).  
In monotherapy arms, if confirmatory scans indicated PD, the subjects should be enrolled in the 
LTFU protocol. Subjects who experience disease progression 28 days after the second dose do 
not require a confirmatory scan 28 days later and should be discontinued from the study and 
enrolled in the LTFU protocol.  
In combination therapy arms, if confirmatory scans indicate PD, the subject should be 
permanently discontinued from pembrolizumab, unless the subject is considered by the 
Investigator to derive clinical benefit, is clinically stable, and there is agreement from Triumvira. 
Clinical stability is defined by the following: absence of new symptoms and signs indicating 
clinically significant PD, no decline in ECOG performance status, absence of rapid progression 
of disease or progressive tumor at critical anatomical sites requiring urgent alternative medical 
intervention. If the subject is permanently discontinued from pembrolizumab, the subject should 
be enrolled in the LTFU protocol.  
7.4. Post-treatment Evaluations 
See the respective SOEs for the monotherapy and combination treatment arms in Appendix A1, 
Appendix A2, or Appendix B. Subjects with confirmed PD and/or who start a new anticancer 
therapy should be followed according to the LTFU protocol. 

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7.5. Unscheduled Evaluations 
If the Investigator determines that a subject needs to be evaluated at a time other than a protocol-
specified visit, the subject may be asked to come into the clinic for an unscheduled evaluation. 
The following assessments, as well as any additional evaluations deemed appropriate by the 
Investigator, may be performed as clinically indicated: 
• Physical examination 
• Vital signs  
• ECOG performance status assessment  
• Clinical laboratory evaluations or tissue assessments 
• Positron emission tomography (PET) and/or computed tomography (CT) scan or 
magnetic resonance imaging (MRI) if indicated 
• Tumor biopsy 
• Other 
7.6. Subject Death and Autopsy 
In the event of a subject’s death, an autopsy may be requested as per institutional guidelines. If 
an autopsy is performed, tissue samples may be requested and sent to Triumvira for evaluation of 
the presence of TAC T cells in brain, liver, kidney, lungs, bone marrow, blood, heart, 
reproductive organs, and any sites of disease. Every effort will be made to assay for RCL in a 
sample of the pertinent autopsy tissue. 
7.7. Early Withdrawal 
If a subject withdraws prematurely from the study, an EOS visit will be scheduled as soon as 
possible, and all the assessments listed for the EOS visit (Appendix A1, Appendix A2, or 
Appendix B) will be performed. The reason for early withdrawal will be captured on the CRF. 
7.8. Long-Term Follow-Up 
Because this protocol involves gene transfer, follow up for lentiviral vector safety, disease status, 
and long-term survival will continue in this study until Month 24 and under a separate LTFU 
protocol for up to 15 years after TAC01-HER2 administration. For subjects who cannot or do not 
want to be followed for 24 months on the study protocol as per Appendix A1, Appendix A2, or 
Appendix B, the LTFU protocol outlines a reduced schedule of events that complies with 
regulatory requirements.  
If a Day 29 (±2 days) PD is confirmed 28 days (± 14 days) after Dose 1 or if PD occurs any time 
at or after 28 days following Dose 2, or if a new anticancer therapy is initiated, an EOS visit 
should be conducted, and all subjects will enroll in the separate LTFU protocol. For subjects who 
withdraw from the study before the Month 24 visit (calculated from the first dose Day 1), the 
EOS visit should be completed at the time of study withdrawal. 

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7.9. Study Procedures 
7.9.1. Administrative Procedures 
7.9.1.1. Informed Consent 
The Investigator or qualified designee must obtain documented consent from each potential 
subject or each subject’s legally acceptable representative prior to participating in this clinical 
study or Future Biomedical Research (FBR). 
7.9.1.2. General Informed Consent 
Consent must be documented by the subject’s dated signature or by the subject’s legally 
acceptable representative’s dated signature on a consent form along with the dated signature of 
the person conducting the consent discussion.  
A copy of the signed and dated consent form will be given to the subject before participation in 
the study. 
The initial ICF, any subsequent revised written ICF and any written information provided to the 
subject must receive the IRB/IEC’s approval or favorable opinion in advance of use. The subject 
or his/her legally acceptable representative should be informed in a timely manner if new 
information becomes available that may be relevant to the subject’s willingness to continue 
participating in the study. The communication of this information will be provided and 
documented via a revised consent form or addendum to the original consent form that captures 
the subject’s dated signature or by the subject’s legally acceptable representative’s dated 
signature. 
The informed consent will adhere to IRB/IEC requirements, applicable laws, regulations, and 
Triumvira requirements. 
7.9.1.3. Consent for Future Biomedical Research 
The Investigator or qualified designee will explain the FBR consent to the subject, answer all 
his/her questions, and obtain written informed consent before performing any procedure related 
to FBR. A copy of the informed consent will be given to the subject. 
7.9.2. Inclusion/Exclusion Criteria 
All inclusion and exclusion criteria will be reviewed by the Investigator or qualified designee to 
ensure that the subject qualifies for the study. 
7.9.3. Subject Identification Card 
All subjects will be given an IRB/IEC approved Subject Identification Card identifying them as 
participants in a research study. The card will contain study site contact information (including 

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direct telephone numbers) to be utilized in the event of an emergency. The Investigator or 
qualified designee will provide the subject with a Subject Identification Card immediately after 
the subject provides written informed consent. 
7.10. Medical History 
A medical history will be obtained by the Investigator or qualified designee. Medical history will 
include all active conditions, and any condition diagnosed within the prior 10 years that are 
considered clinically significant by the Investigator. Details regarding the subject’s cancer will be 
recorded separately and not listed as medical history. 
7.11. Prior and Concomitant Medications Review 
7.11.1. Prior Medications 
The Investigator or qualified designee will review prior medication use and record prior 
medication taken by the subject within 28 days before starting the study. Treatment for the 
disease for which the subject has enrolled in the study will be recorded separately and not listed 
as a prior medication. 
7.11.2. Concomitant Medications 
The Investigator or qualified designee will record medication, if any, taken by the subject during 
the study through the Safety Follow-up visit as outlined in Section 7.4. Record all medications 
taken for SAEs. 
7.11.3. Prior Cancer Treatment Details 
The Investigator or qualified designee will review all prior cancer treatments including but not 
limited to systemic treatments, prior transplantation, radiation, and surgeries and record in the 
study database. 
7.12. Assignment of Subject Identification Number 
All consented subjects will be assigned a unique subject identification (ID) number that will be 
used to identify the subject. Subject IDs will be assigned sequentially across the study; therefore, 
subjects within a single investigative site may not be sequential. Subjects will retain their 
assigned Subject ID from consent through study completion or screen failure. Subject IDs must 
not be re used for different subjects. 
If a subject is enrolled and fails the pre-treatment Screening/Baseline evaluation, the subject will 
retain the assigned subject ID. 
If a subject is re-screened prior to enrollment, a new Subject ID will be assigned; however, a link 
between the 2 Subject IDs will be maintained.  

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Specific details on the Screening visit requirements are provided in Section 7.2. 
7.13. Clinical Procedures 
7.13.1. Oncologic Disease Details 
The Investigator or qualified designee will obtain prior and current details regarding oncologic 
disease status. 
7.13.2. Full Physical Examination 
The Investigator or qualified designee will perform a complete physical examination during the 
Screening period. At this visit, clinically significant abnormal findings should be recorded as 
medical history. A full physical examination should be performed during Screening and repeated 
as per the frequency defined in Appendix A1, Appendix A2, or Appendix B. After the TAC01-
HER2 dose, new clinically significant abnormal findings should be recorded as AEs. 
The neurological examination should include, at minimum, a physical examination to assess 
cranial nerves, motor and sensory skills, coordination, and balance. 
7.13.3. Cardiac Evaluations 
A standard 12-lead ECG will be performed, as well as an ECHO or MUGA scan using local 
standard procedures at Screening. Clinically significant abnormal findings should be recorded as 
medical history. 
7.13.4. Vital Signs 
The Investigator or qualified designee will take vital signs as specified in Appendix A1, 
Appendix A2, or Appendix B. Vital signs should include temperature, pulse, respiratory rate, 
oxygen (O2) saturation by pulse oximetry, and blood pressure. 
7.13.5. Eastern Cooperative Oncology Group Performance Status 
The Investigator or qualified designee will assess ECOG performance status (Appendix G) at 
Screening and repeated as per the frequency defined in Appendix A1, Appendix A2, or 
Appendix B. 
7.13.6. Adverse Event Monitoring 
The Investigator or qualified designee will assess each subject to evaluate for potential new or 
worsening AEs as specified in the SOE (Appendix A1, Appendix A2, or Appendix B) and more 
frequently if clinically indicated. AEs will be graded and recorded throughout the study and 
during the follow-up period according to NCI CTCAE Version 5.0 (National Cancer Institute 
2020; Section 8) and CRS and neurotoxicity per ASTCT criteria (Lee 2019; Appendix D). 

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Toxicities will be characterized in terms regarding seriousness, causality, toxicity grading, and 
action taken with regard to study treatment. 
Refer to Section 8 for detailed information regarding the assessment and recording of AEs. 
7.13.7. Disease Assessments 
7.13.7.1. Monotherapy Disease Assessment During Study – Single Dose 
In the monotherapy arms following Appendix A1, radiographic disease assessments will be 
performed pre-treatment, at Day 29±2 days for first scan, then Q8W±2W for Year 1 (i.e., Weeks 
12, 20, 28, 36, 44, 52), then Q12W±2W for Year 2. There is a ± 2-day window for assessments 
performed after Day 1, and a ± 14-day window for assessments after Day 29. 
7.13.7.2. Monotherapy Disease Assessment During Study – Two Doses 
In the monotherapy arm following Appendix B, radiographic disease assessments will be 
performed pre-treatment, at Day X +28±2 days for first scan, then Q8W±2W for Year 1 after the 
second dose, then Q12W±2W for Year 2 after the second dose. There is a ± 2-day window for 
assessments performed after Day 1, and a ± 14-day window for assessments after Day 29. 
7.13.7.3. Combination Therapy Disease Assessment During Study 
In the combination arm following Appendix A2, radiographic disease assessments will be 
performed at Week 8 for the first scan to allow adequate time after the 1st pembrolizumab 
administration for clinical activity to develop, then Q8W±2W for Year 1 (i.e., Weeks 16, 24, 32, 
40, and 48 [± 3 days]), then Q12W±2W for Year 2 (i.e., Weeks 60, 72, 84, and 96 [± 3 days]). 
7.13.7.4. Disease Assessment of Immunotherapeutic Agents  
Immunotherapeutic agents such as TAC01-HER2 may produce antitumor effects by potentiating 
endogenous cancer-specific immune responses, which may be functionally anergic. The response 
patterns seen with such an approach may extend beyond the typical time course of responses 
seen with cytotoxic agents and can manifest a clinical response after an initial increase in tumor 
burden or even the appearance of new lesions. Standard response assessment criteria may not 
provide a CR assessment of immunotherapeutic agents. However, imaging should occur at any 
time where there is clinical suspicion of progression, and it should be confirmed by second set of 
scans 28 days after the Day 29 scans (± 14 days). 
7.13.8. Assessment of Disease and Tumor Response 
7.13.8.1. Disease Response Assessment 
Disease assessments should be performed using CT (or MRI if indicated) scans at Baseline 
(Screening and/or after bridging anticancer therapy), and confirmation of CRs and PRs at the 

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next scheduled scan. Scans will be reviewed and assessed locally by the Investigator and 
radiology using RECIST 1.1.  
RECIST 1.1 will be used as the primary measure for assessment of tumor response, date of 
disease progression, and as a basis for all protocol guidelines related to disease status (e.g., 
discontinuation of study treatment). Although RECIST 1.1 references a maximum of 5 target 
lesions in total and 2 per organ, this protocol allows a maximum of 10 target lesions in total and 
5 per organ, if clinically relevant to enable a broader sampling of tumor burden. 
The Investigator or qualified designee must review pre-study images to confirm the subject has 
measurable disease prior to LDC. Central laboratory review of scans may be requested by 
Triumvira. Response assessment is based on the immune responses assigned to RECIST 1.1 
described in Appendix F.  
An MRI may replace CT scans following discussion with the Medical Monitor. See the Imaging 
Manual for details. 
7.13.8.2. Tumor and Correlative Studies Blood Collection 
For Phase 1 and Phase 2:  
In both phases, in addition to subjects who are HER2+ by central laboratory confirmation (i.e., 
IHC+ and FISH+), subjects who are HER2+ via recent (preferably after last line of therapy or 
within 1 year) local laboratory results using IHC, FISH, or next generation sequencing (NGS) 
assays may also be enrolled, as long as a recent (preferably fresh or archival within 1 year) tissue 
biopsy sample is available for central laboratory HER2+ confirmation after enrollment or starting 
TAC01-HER2. In the instance of discordant results between central and local laboratories (i.e., 
central laboratory results are negative with regards to IHC or FISH), the subject will still be 
considered evaluable for safety and evaluation of DLTs. In the instance of discordant results 
between central and local laboratories, the subject may be replaced in Phase 2. 
Central laboratory confirmation of HER2+ tumor samples will occur by one of the following 
methods (in order of priority):  
a. A fresh tumor tissue sample, if clinically feasible and safe 
b. An archival sample collected within 1 year prior to enrollment (samples may be collected 
>1 year prior to enrollment in Phase 1) 
c. A liquid biopsy to examine circulating tumor cells 
d. If a, b, or c are not obtainable, the most recent archival sample available regardless of 
when it was obtained during prior lines of therapy 
Fine needle aspirations, or brushing and scraping cytology samples, are not acceptable at 
Baseline or Screening. Since Phase 2 will be evaluating efficacy and since HER2 status often 
changes on progression after HER2-targeted therapies (e.g., trastuzumab), it is strongly 
recommended a fresh tumor tissue sample be obtained, if clinically feasible and safe, along with 

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the corresponding pathology report for histological disease diagnosis confirming HER2-protein 
expression on the tumor cell surface. 
ASCO/College of American Pathologists (CAP) guidelines will be followed for assessment of 
breast and gastric specimens. For all other tumor types, the assessment guidelines for breast 
cancer specimens will be followed.  
Exploratory biopsies should be limited to percutaneous lesions that are palpable, or guided by 
imaging if necessary, and not be taken from any lesions that are in proximity to vital visceral, 
cardio-pulmonary, or neurovascular structures. When feasible biopsy sites should be selected so 
that subsequent biopsies can be performed at the same location. Tumors that are inaccessible or 
contraindicated due to subject’s safety concerns are exempt from being biopsied.  
For Phase 1, tumor biopsies on Days 11 and 29 post-TAC01-HER2 infusion and at disease 
progression are optional and should not preclude subjects from participating in the study. An 
FNA may be performed as an alternative to the Day 11 and Day 29 biopsies when appropriate.  
For Phase 2, these biopsies are mandatory if clinical feasible and safe, unless discussed with, and 
waived by, the Medical Monitor. Subjects who refuse the post-treatment mandatory biopsy 
requirements will not be precluded from enrollment, nor discontinued from the study, and 
exceptions may be made after discussion with the Medical Monitor or designee on a case-by-
case basis. 
Tumor biopsies will be collected as per Table 11. These time points were updated from 
Amendment 4 (i.e., from pre-dose and Day 8) to screening and Days 11 and 29, to better evaluate 
the presence of TAC T cells in the tumor microenvironment, as recent nonclinical data indicate 
PK/PD effects are best evaluated 2-4 weeks post TAC01-HER2 dosing.  
Table 11:  Tumor Tissue Assessments 
Type of Biopsy 
Timing of Biopsy 
Tumor Tissue 
Screening, Day 11, Day 29, at disease progression, or as clinically 
indicated 
In the monotherapy and combination therapy arms, blood for correlative biomarker studies 
should be collected as per Table 12 for subjects who receive a single dose and Table 13 for 
subjects who receive a second dose (monotherapy only).  

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Table 12:  Monotherapy and Combination Therapy Blood Collection for Pharmacokinetic 
and Correlative Biomarkers Studies 
Indication 
Timing of Correlative Blood Collection 
Whole blood for PK studies 
Pre-LDC, Days 3, 4 or 5, 8, 11, 14/15a, 18, 21/22a, 25, 29, 42, 
Months 3, 6, 9, 12, 18, 24 or EOS, and at the confirmatory PD visit 
Whole blood for biomarker 
studies  
Pre-LDC, Days 8, 11, 14/15a, 21/22a, 29, 42, Months 3, 6, 9, 12, 18, 
24 or EOS, and at the confirmatory PD visit 
Serum for cytokine studies 
Pre-LDC, Days 3, 4 or 5, 8, 11, 14/15a, 18, 21/22a, 25, 29, 42, 
Months 3, 6, 9, 12, 18, 24 or EOS, and at the confirmatory PD visit 
Whole blood for RCL testing 
Pre-LDC, Months 3, 6, 12, and 24 
PD=progressive disease; PK=pharmacokinetics; RCL=replication-competent lentivirus 
a Note: Day 15 and 22 correspond to monotherapy (see Appendix A1) and Day 14 and 21 correspond to combination 
therapy (see Appendix A2).  
Table 13:  Pharmacokinetic, Biomarker, Cytokine Blood Collection (After Second Dose) 
Indication 
Timing of Correlative Blood Collection 
Whole blood for PK studies 
Pre-LDC, Days X+2, X+3 or 4, X+7, X+10, X+14, X+17, X+21, 
X+24, X+28, X+41, Months 3, 6, 9, 12, 18, 24 or EOS 
Whole blood for biomarker 
studies  
Pre-LDC, Days X+7, X+10, X+14, X+21, X+28, X+41, Months 3, 
6, 9, 12, 18, 24 or EOS 
Serum for cytokine studies 
Pre-LDC, Days X+2, X+3 or 4, X+7, X+10, X+14, X+17, X+21, 
X+24, X+28, X+41, Months 3, 6, 9, 12, 18, 24 or EOS 
PD=progressive disease; PK=pharmacokinetics; RCL=replication-competent lentivirus 
7.13.9. Laboratory Safety Evaluations  
Screening and other laboratory evaluations (see Table 14) will be performed at study visits 
indicated in Appendix A1, Appendix A2, or Appendix B. Additional assessments should be 
performed between scheduled study visits as clinically required to diagnose and monitor AE or 
expected events. Requirements for reporting laboratory abnormalities are provided in 
Section 8.5.2. 
Laboratory tests for hematology, chemistry, urinalysis, and other laboratory tests are specified in 
Table 14. Except for analyses of PK, biomarkers, or other prognostic indicators (proteomics, 
genetics, transcriptional analysis, antibodies), all tests will be conducted locally. 

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Table 14:  Laboratory Tests 
Hematology 
Chemistry 
Urinalysis 
Other 
Hematocrit 
Albumin 
Blood 
Serum β-human chorionic 
gonadotropin (β-hCG) a 
Hemoglobin 
Alkaline phosphatase 
Glucose 
Prothrombin time (PT), 
International Normalized Ratio 
(INR) 
Platelet count 
Alanine aminotransferase 
(ALT) 
Protein 
Activated partial thromboplastin 
time (aPTT) 
White blood cell 
count (total and 
differential) 
Aspartate aminotransferase 
(AST) 
Specific gravity  
Fibrinogen 
Red blood cell 
count 
Bicarbonate 
Microscopic 
examination if 
abnormal results are 
noted  
C-reactive protein (CRP) 
Absolute neutrophil 
count 
Blood urea nitrogen 
 
Ferritin 
Absolute 
lymphocyte count 
Calcium 
 
Triglycerides 
 
Chloride 
 
Human immunodeficiency virus 
(HIV) 1/2 
 
Creatinine 
 
Hepatitis B, C 
 
Glucose 
 
Immunoglobulin G (IgG) 
 
Lactate Dehydrogenase 
(LDH) 
 
Triiodothyronine (T3) or free T3 
(FT3), free thyroxine (FT4), and 
thyroid stimulating hormone 
(TSH) 
 
Phosphorus 
 
Central Laboratory Analysis: 
 
Potassium 
 
Blood for PK  
 
Sodium 
 
Blood for biomarkers  
 
Total Bilirubin 
 
Blood for cytokines 
 
Direct Bilirubin if total 
bilirubin is elevated above 
the upper limit of normal 
 
Blood for replication-competent 
lentivirus (RCL)  
 
Total protein 
 
Tumor biopsy specimen for human 
epidermal growth factor 2 (HER2) 
status and biomarker analysis  
 
Uric acid 
 
 
a Perform on women of childbearing potential only. 
 

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7.13.10. Blood Collection for Human Anti-Mouse Antibodies 
The human anti-mouse antibodies (HAMA) sample is part of the biomarker analysis. Sample 
collection, storage, and shipment instructions will be provided in the Laboratory Manual. 
Biomarker samples should be drawn according to the schedule in Appendix A1, Appendix A2, or 
Appendix B. 
7.13.11. Future Biomedical Research 
The following specimens are to be obtained as part of FBR: 
Tumor including primary and potential metastatic sites and blood for genomics use: 
• Unused tumor tissue biopsies 
• Unused correlative blood samples 
• Unused TAC01-HER2 product 
• Unused leukapheresis product 
7.13.12. Other Procedures 
7.13.12.1. Central Laboratory Analysis Samples 
Testing and analysis of samples will follow the SOE in Appendix A1, Appendix A2, or 
Appendix B. Allocation of samples to specific testing may be modified where sample material is 
limited; however, the total volume and type of material collected will not be modified beyond 
what is described in the Laboratory Manual.  
Detailed information regarding the collection, handling, and shipment of samples for PK, 
cytokine, biomarker, and RCL assessments is provided in the Laboratory Manual. 
7.13.12.2. Pharmacokinetic Assessments 
Assessment of TAC T cell expansion and persistence in blood will be determined by quantitative 
polymerase chain reaction (qPCR) to detect the TAC-HER2 transgene and by flow cytometry to 
enumerate the number and immunophenotypic TAC T cells. 
7.13.12.3. Cytokine Assessments 
Assessment of various cytokine levels will be determined in serum samples by immunoassay. 
7.13.12.4. Biomarker Assessments 
Biomarker assessments will be performed to evaluate HER2+ tumor status, and immune system 
characteristics that may be associated with TAC01-HER2 toxicity, clinical activity, and 
resistance mechanisms to TAC01-HER2 treatment. See the Laboratory Manual for further 
details. 

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7.13.12.5. PD-L1 Expression Level Assessment 
All subjects receiving pembrolizumab are required to have their tumors assessed for the level of 
PD-L1 expression at Baseline. Previously determined local results are acceptable. New biopsies 
and local analyses are required to be performed, if no other results or samples are available. 
7.13.12.6. Replication Competent Lentivirus Assessment 
RCL testing will be performed using an analytically validated polymerase chain reaction 
(PCR)-based assay to detect the viral envelope sequence in peripheral blood. If all samples 
collected within the first year after the final dose of TAC01-HER2 are negative, subsequent 
samples will be archived at a central laboratory. However, if any of the samples are positive, 
additional testing will be performed to confirm the result. If the repeat test is also positive, 
further analysis of the RCL will be undertaken to ascertain the nature of the RCL and potential 
effects such as vector integration with detailed sequencing and other relevant assays. PBMCs and 
deoxyribonucleic acid (DNA), processed according to validated laboratory procedures in a 
CAP/Clinical Laboratory Improvements Amendments (CLIA) licensed laboratory, will be 
archived at each specimen collection point for retrospective assessments if indicated. 
Any confirmed positive result from RCL testing will be reported as an adverse event in the form 
of an Investigational New Drug (IND) safety report. 
If a subject develops a new or recurrent neoplasm, Triumvira will request a sample of the 
neoplastic tissue for assessment of RCL. 
7.14. Withdrawal/Discontinuation 
When a subject discontinues/withdraws from participation in the study, all applicable activities 
scheduled for the final study visit should be performed at the time of discontinuation. Any AEs 
which are present at the time of discontinuation/withdrawal should be followed in accordance 
with the safety requirements outlined in Section 8. 
7.14.1. Withdrawal from Future Biomedical Research 
Subjects may withdraw their consent for FBR and have their leftover specimens and all 
derivatives destroyed. Subjects may withdraw consent at any time by contacting the Investigator 
for the main study. If medical records for the main study are still available, the Investigator will 
contact Triumvira. Subsequently, the subject’s specimens will be removed from the biorepository 
and destroyed. A notification will be sent from Triumvira to the Investigator confirming the 
destruction. It is the responsibility of the Investigator to inform the subject of completion of 
destruction. Any analyses in progress at the time of request for destruction or already performed 
prior to the request being received by Triumvira will continue to be used as part of the overall 
research study data and results. No new analyses will be generated after the request is received. 
In the event that the medical records for the main study are no longer available (e.g., if the 
Investigator is no longer required by regulatory authorities to retain the main study records) or 

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the specimens have been completely anonymized, there will no longer be a link between the 
subject’s personal information and their specimens. In this situation, the request for specimen 
destruction cannot be processed. 
8. SAFETY MONITORING AND REPORTING 
8.1. Overview 
AEs will be assessed throughout the study according to CTCAE Version 5.0 (National Cancer 
Institute 2020), and CRS and neurotoxicity per ASTCT (Lee 2019) Consensus Criteria. AEs, 
SAEs, and laboratory abnormalities (type, frequency, and severity) will be collected. Potential 
TAC T cell related toxicities may include infusion reactions, CRS, neurotoxicity, macrophage 
activation syndrome, and TLS; with the list of these risks being updated during the study based 
on any observed safety signals. RCL and, if positive, follow-up viral vector sequence, testing 
will be performed at specified time points during the study using PCR-based assays. 
Progression of the cancer under study is not considered an AE unless it results in hospitalization 
or death. AE, SAEs, and other reportable safety events will be reported by the participant (or, 
when appropriate, by a caregiver, surrogate, or the participant’s legally authorized 
representative). See Section 8.5.4 for timeframes where death due to PD is considered an SAE. 
The Investigator, who is a qualified physician, and any designees are responsible for detecting, 
assessing, documenting, and reporting events that meet the definition of an AE or SAE as well as 
other reportable safety events. Investigators remain responsible for following up AE, SAEs, and 
other reportable safety events for outcome. 
All AEs or events of clinical interest (ECIs) from the time of treatment allocation through 
30 days following cessation of study treatment must be reported by the investigator.  
8.2. Definitions 
8.2.1. Adverse Event Definition 
In accordance with ICH E2A guideline and United States (US) Code of Federal Regulation 
(CFR), Title 21 Part 312.32, an AE is defined as any untoward medical occurrence in a clinical 
study subject, administered a pharmaceutical product, which does not necessarily have a causal 
relationship with this treatment. 
Abuse, withdrawal, sensitivity, or toxicity to an investigational product should be reported as an 
AE. Overdose, whether or not it is associated with an AE, should be reported on the Study Drug 
Administration CRF even if there is no reported injury. Any sequela of an overdose of an 
investigational product should be reported as an AE on the AE CRF. If the sequela of an 
overdose is an SAE, it must be reported on a SAE report form. The overdose resulting in the 
SAE should be identified as the cause of the event on the SAE report form and CRF but should 
not be reported as an SAE itself. 

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In the event of overdose, the subject should be monitored as appropriate and should receive 
supportive measures, as necessary. There is no known specific antidote for TAC01-HER2, 
fludarabine/cyclophosphamide, clofarabine/cyclophosphamide, single agent cyclophosphamide 
or single agent bendamustine overdose. Actual treatment should depend on the severity of the 
clinical situation and the judgment of the treating physician. 
8.2.2. Serious Adverse Event Definition 
An SAE is defined as an event that, at any dose, meets any of the criteria in Table 15. Special 
considerations for SAE reporting, including events that should always be reported as SAEs in 
this study, are presented in Table 16. 
Table 15:  Definitions of SAEs 
Criteria 
Description 
Fatal 
The AE resulted in death. 
Life-threatening 
The AE placed the subject at immediate risk of death. This 
classification does not apply to an AE that hypothetically might have 
caused death if it had been more severe. 
Hospitalization/prolongation of 
hospitalization 
The AE resulted in hospitalization or prolongation of hospitalization. 
Disability/incapacity 
The AE resulted in a disability, significant incapacity, or substantial 
disruption of the subject’s ability to conduct normal life functions. 
Congenital anomaly/birth 
defect 
The AE was an adverse outcome in a child or fetus of a subject 
exposed to the study treatment regimen before conception or during 
pregnancy. 
Medically important 
The AE was a medically important event that did not meet any of the 
above criteria but may have jeopardized the subject and may have 
required medical or surgical intervention to prevent 1 of the 
outcomes listed above (examples include allergic bronchospasm that 
required treatment in an emergency room, seizures that do not result 
in hospitalization, or blood dyscrasias). 
 

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Table 16:  Special Considerations for SAE Reporting 
Criteria 
Description 
Events that should always be 
reported as SAEs 
• 
New/secondary malignancies 
• 
New onset or exacerbation of a pre-existing neurologic disorder 
• 
New onset or exacerbation of rheumatologic or other autoimmune 
disorder 
• 
New onset hematologic disorder 
• 
Rare and unexpected disorders with an unknown etiology 
(e.g., Guillain-Barre, Stevens-Johnson’s syndrome) 
Hospitalization/prolongation of 
hospitalization 
 
Complications and/or 
prolonged admissions for 
routine treatment or procedure 
do require SAE reporting. 
This classification does not apply to hospital admissions for the 
following reasons: 
• 
Social or situational reasons in the absence of any clinical AE. 
• 
At the Investigator’s discretion for lymphodepleting 
chemotherapy or TAC01-HER2 administration.  
• 
Elective or pre-planned treatment or procedure for a pre-existing 
condition that is unrelated to the condition under study and has 
not worsened since providing informed consent. 
• 
Routine treatment (e.g., platelet transfusion) or monitoring of the 
condition under study that is not associated with any deterioration 
in condition.  
• 
Routine procedures (e.g., bone marrow aspiration) associated 
with the disease under study.  
• 
Emergency outpatient treatment or observation that does not 
result in admission, unless fulfilling other seriousness criteria 
above. 
 
8.2.3. Pembrolizumab Events of Clinical Interest 
Selected non-serious AEs and SAEs are also known as ECIs and must be reported to Triumvira 
within 24 hours of awareness. 
Pembrolizumab ECIs for this trial include:  
1. An overdose of pembrolizumab (as defined in Section 5.5), that is not associated with 
clinical symptoms or abnormal laboratory results. 
2. An elevated AST or ALT laboratory value that is ≥3 x ULN and an elevated total bilirubin 
laboratory value that is ≥2 x ULN and, at the same time, an alkaline phosphatase 
laboratory value that is <2 x ULN, as determined by way of protocol-specified laboratory 
testing or unscheduled laboratory testing.* 

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*Note: These criteria are based upon available regulatory guidance documents. The purpose of 
the criteria is to specify a threshold of abnormal hepatic tests that may require an additional 
evaluation for an underlying etiology. The trial site guidance for assessment and follow up of 
these criteria can be made available. It may also be appropriate to conduct additional evaluation 
for an underlying etiology in the setting of abnormalities of liver blood tests including AST, ALT, 
bilirubin, and alkaline phosphatase that do not meet the criteria noted above. In these cases, the 
decision to proceed with additional evaluation will be made through consultation between the 
study investigators and the Medical Monitor. However, abnormalities of liver blood tests that do 
not meet the criteria noted above are not ECIs for this trial. 
8.3. Grading and Intensity of Adverse Events 
AEs will be graded using the NCI CTCAE Version 5.0 (National Cancer Institute 2020) and CRS 
and neurotoxicity per ASTCT (Lee 2019) criteria for CRS and neurotoxicity as outlined in 
Appendix D. The reported verbatim term should be the most descriptive medical diagnosis and 
does not have to be found in CTCAE. 
8.4. Relationship to Investigational Product 
The assessment of the relationship of an AE to the administration of the investigational product 
(related or not related) is a clinical decision based on all available information and the 
considerations listed in Table 17. There are 2 investigational products in this study: 
TAC01-HER2 and pembrolizumab. 
Table 17:  Assessment of Relationship for Adverse Events 
Relationship 
Considerations 
Related 
There is at least a reasonable possibility and/or evidence to suggest a causal 
relationship between investigational product and the AE/SAE and no other more 
likely alternative cause (concomitant drugs, therapies, disease complications, etc.) 
is suspected. 
Not related 
There is no reasonable possibility and/or evidence to suggest a causal relationship 
between investigational product and the AE/SAE and another more likely 
alternative cause (concomitant drugs or therapies, disease complications, etc.) is 
suspected. 
8.5. Recording and Reporting of Adverse Events 
AEs recorded on the CRF must be supported by documentation in the subject’s study records.  

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AEs/SAEs recorded on the CRF will be evaluated for: 
• Duration (onset and resolution dates) 
• Outcome 
• Seriousness (see Section 8.2.2) 
• Severity (see Section 8.3) 
• Causal relationship with TAC T cells (see Section 8.4) 
8.5.1. Recording a Diagnosis versus Signs and Symptoms 
Whenever possible, a unifying diagnosis should be reported as opposed to a listing of individual 
symptoms. However, symptoms should be grouped into a diagnosis only if each sign or symptom 
is a medically confirmed component of that diagnosis as evidenced by current standard medical 
literature. If any aspect of a sign or symptom does not fit into a classic pattern of the diagnosis, 
the individual symptom should be reported as a separate AE. 
Two exceptions to reporting a diagnosis as opposed to symptoms are the events of CRS and 
neurotoxicity. If a subject experiences CRS and/or neurotoxicity, a diagnosis of CRS and/or 
neurotoxicity and any grade changes for the event should be reported as an AE. Individual signs 
and symptoms of CRS and/or neurotoxicity, and the maximum grade for those signs and 
symptoms, should be entered on the respective CRS and neurotoxicity 
8.5.2. Clinical Laboratory Abnormalities and Other Abnormal Assessments 
Any laboratory abnormality (e.g., clinical chemistry or hematology) or other abnormal 
assessment findings (e.g., ECG or vital signs) that meets any of the following criteria should be 
recorded as an AE/SAE: 
• Requires medical or surgical intervention 
• Leads to product discontinuation, delay, or interruption 
• Associated with clinical signs and/or symptoms 
• Otherwise clinically significant as determined by the Investigator 
Whenever possible, the clinical diagnosis, rather than the laboratory result, should be reported 
(e.g., anemia versus low hematocrit).  
Clinically significant abnormal laboratory values occurring during the study will be evaluated, 
graded, and followed per the CTCAE v5.0 until repeat tests return to normal or baseline, 
stabilize, or are no longer clinically significant. 
8.5.3. Recording Serious Adverse Events 
The following should be considered when recording SAEs: 

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• Death is an outcome of an event. The event that resulted in death should be recorded on 
the CRF and reported on the SAE report form. 
• For hospitalizations or surgical or diagnostic procedures, the illness leading to the 
surgical or diagnostic procedure should be recorded as the SAE, not the procedure itself. 
The procedure should be captured in the narrative as part of the action taken in response 
to the illness. 
• Events related to disease progression must be reported to Triumvira’s Pharmacovigilance 
Team if they meet serious criteria. When reporting a disease progression SAE, specific 
manifestations of the progression (e.g., “new bone pain” or “worsening anemia and renal 
failure”) should be reported, rather than the general term “disease progression.” 
Additionally, any SAE brought to the attention of an investigator at any time outside of the time 
periods specified above must be reported immediately to Triumvira if the event is considered to 
be drug related. 
8.5.4. Death Reports 
Deaths must be reported as an SAE on the Death CRF and to Triumvira’s Pharmacovigilance 
Team per the reporting periods described in Table 18 and Table 19. 
A death due to disease progression must be reported to Triumvira’s Pharmacovigilance provider 
as an SAE if it occurs from the start of leukapheresis to within 90 days after TAC01-HER2 
administration in the monotherapy arm, or up to 90 days after the last dose of pembrolizumab in 
the combination arm. Deaths that occur in the monotherapy arm more than 90 days after TAC01-
HER2 infusion will be captured on the Death CRF and reported as an SAE only if considered 
related to any protocol mandated procedure and/or TAC T cells. Deaths that occur in the 
combination arm more than 90 days after the last pembrolizumab infusion will be captured on 
the Death CRF and reported as an SAE only if considered related to any protocol mandated 
procedure, TAC T cells, and/or pembrolizumab. 
8.5.5. Pregnancy Reporting 
Subjects will be instructed to continue using appropriate methods of contraception until 1 year 
after their last dose of TAC01-HER2 or 120 days after their last pembrolizumab dose or 30 days 
after their last pembrolizumab dose if the subject starts a new anticancer therapy, whichever is 
longer. If a participant inadvertently becomes pregnant while on treatment with pembrolizumab, 
the participant will be immediately discontinued from treatment. The site will contact the 
participant at least monthly and document the participant’s status until the pregnancy has been 
completed or terminated. 
Any pregnancy that occurs in a female subject or the female partner of a male subject within 
1 year after their last TAC01-HER dose, while on treatment with pembrolizumab, or within 
120 days of their last pembrolizumab dose should be recorded on a Clinical Study Pregnancy 
Form and submitted to the Triumvira’s Pharmacovigilance provider within 24 hours of 
awareness. Any SAE experienced during pregnancy must be reported on the SAE Report Form. 

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Abortion, whether accidental, therapeutic, or spontaneous, should be reported as an SAE. Deaths, 
and congenital anomalies/birth defects, as defined by the “seriousness criteria” in Section 8.2.2, 
should be reported as SAEs. 
All pregnancies that occur within the timelines above should be monitored for the full duration, 
and all perinatal and neonatal outcomes should be reported without delay. The study investigator 
will make every effort to obtain permission to follow the outcome of the pregnancy and report 
the condition of the fetus or newborn to Triumvira. 
In summary, all pregnancies and exposure during breastfeeding, from the time of treatment 
allocation through 1 year after their last TAC01-HER2 dose, 120 days after their last dose of 
pembrolizumab, or 30 days after their last dose of study treatment if the participant initiates new 
anticancer therapy must be reported by the investigator. 
8.5.6. Use in Nursing Women 
It is unknown whether pembrolizumab is excreted in human milk. Since many drugs are excreted 
in human milk, and because of the potential for serious adverse reactions in the nursing infant, 
participants who are breastfeeding are not eligible for enrollment. 
8.5.7. Adverse Event Reporting Periods 
Reporting periods are summarized in Table 18 (AEs and SAEs) and Table 19 (AEs, ECIs, and 
SAEs). 
SAEs will be followed until they resolve or return to baseline, the event stabilizes or is no longer 
considered clinically significant by the Investigator, the subject dies or withdraws consent, or the 
study is closed. All non-serious AEs will be followed through the safety reporting period 
described in Table 18 and Table 19. Certain non-serious AEs, as requested by Triumvira, may be 
followed until resolution, return to baseline, or study closure. 
8.5.8. Serious Adverse Event Reporting 
SAEs that are considered related to TAC01-HER2, pembrolizumab, or both must be reported to 
Triumvira within 24 hours of awareness. Clinical conditions listed in Section 8.2.2 must be 
reported within 24 hours of awareness regardless of relationship to the investigational product. 
The Investigator is required to send the completed SAE Form and any supporting documentation 
(e.g., hospital admission notes, test results) to Triumvira’s Pharmacovigilance Team according to 
the instructions on the SAE report form. Within 24 hours of receipt of follow-up information, the 
Investigator must submit an updated SAE report and/or supporting documentation per the same 
procedure. SAEs must also be reported to the reviewing IRB/IEC per IRB/IEC requirements. A 
copy of any IRB/IEC submission must be retained and filed in the Investigator Site File. 

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For initial SAE reports, the following minimum criteria must be reported on the SAE form: 
• Subject number 
• Event onset date 
• Event description 
• Study treatment 
• Relationship to study treatment 
Table 18:  Reporting Periods for AEs and SAEs in the Monotherapy Arm 
Time Period 
Events to Record 
Informed consent to leukapheresis 
AEs/SAEs related to protocol-mandated 
procedures 
Leukapheresis to lymphodepleting chemotherapy 
start 
AEs related to protocol-mandated procedures and 
all SAEs 
From lymphodepleting chemotherapy start to 
90 Days post-TAC01-HER2 dose (or 30 days post 
last lymphodepleting chemotherapy dose if 
discontinued before TAC01-HER2 administration) 
All AEs/SAEs 
Subjects starting a non-chemotherapeutic 
anticancer therapy prior to 90 days 
post-TAC01-HER2 dose 
All AE/SAEs for 90 days following final 
TAC01-HER2 infusion or for 30 days following 
subsequent therapy, whichever is longer. 
Subjects starting a chemotherapeutic anticancer 
therapy prior to 90 days post-TAC01-HER2 dose 
After initiation of subsequent therapy, only AEs 
and SAEs related to TAC01-HER2 or a protocol-
mandated procedure. 
91 days Post-TAC01-HER2 dose to end of study 
(EOS) 
Only AEs and SAEs related to TAC01-HER2 or 
a protocol-mandated procedure. 

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Table 19:  Reporting Periods for AEs, ECIs, and SAEs in the Combination Arm 
Time Period 
Events to Record 
Informed consent to leukapheresis 
AEs/SAEs related to protocol-mandated 
procedures 
Leukapheresis to lymphodepleting chemotherapy 
start 
AEs related to protocol-mandated procedures and 
all SAEs 
From lymphodepleting chemotherapy start to 
90 days after the last pembrolizumab dose  
All AEs/SAEs 
Subjects starting a non-chemotherapeutic 
anticancer therapy prior to 90 days after the last 
pembrolizumab dose 
All AE/SAEs for 90 days after the last 
pembrolizumab dose or for 30 days following 
subsequent therapy, whichever is longer. 
Subjects starting a chemotherapeutic anticancer 
therapy prior to 90 days after the last 
pembrolizumab dose 
After initiation of subsequent therapy, only AEs 
and SAEs related to pembrolizumab or 
TAC01-HER2 or a protocol-mandated procedure 
and all SAEs for 90 days after the last 
pembrolizumab dose or 30 days after the last 
pembrolizumab dose .if the subject initiates 
further anticancer therapy, 
91 days after the last pembrolizumab dose to EOS 
Only AEs and SAEs related to pembrolizumab or 
TAC01-HER2 or a protocol-mandated procedure. 
Triumvira is responsible for reporting serious, unexpected AEs/experiences to the relevant 
competent regulatory authority. 
The Investigator and Triumvira (or their delegated Medical Monitor) will determine whether 
expedited reporting is necessary for SAEs depending on their assessment of seriousness, 
expectedness, and relationship. IND/CTA Safety Reports will be implemented as appropriate and 
sent to the relevant competent regulatory authority within the regulatory timeframe appropriate 
for the outcome of their assessment. 
8.5.8.1. Expedited Reporting 
Any AE/experience that is unexpected and is assessed as serious and related to study treatment is 
subject to expedited reporting requirements (e.g., Suspected Unexpected Serious Adverse 
Reaction [SUSAR]). 
In accordance with the CFR, Title 21 Part 312.32 and the ICH Guidelines for Clinical Safety 
Data Management Definitions and Standards for Expedited Reporting (E2A guideline), 
Triumvira must submit written documentation in the form of an IND/CTA Safety Report. Written 

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submission must be made to the relevant competent regulatory authority as soon as possible and 
no later than 15 calendar days after Triumvira’s initial notification of the event/experience. 
In addition, any unexpected fatal or life-threatening events associated with the use of the study 
product must be reported to the relevant competent regulatory authority by either telephone or 
facsimile transmission as soon as possible and no later than 7 calendar days after initial 
notification of the event/experience. 
8.5.8.2. Non-Expedited Reporting 
All SAEs that do not require expedited reporting will be submitted to the relevant competent 
regulatory authority in the annual development safety update reports to the INDs/CTAs. 
8.6. Data Safety Monitoring Committee 
A DSMC will be established prior to enrollment of the first subject. The DSMC will be 
responsible for reviewing safety on a regular basis and clinical activity data at the time of interim 
analysis. An introductory meeting will be held to describe the roles and responsibilities of the 
DSMC members and discuss potential data format and process issues and agree upon a charter.  
Detailed description of the DSMC membership and meeting frequency will be outlined in the 
DSMC charter.  
It is envisioned that the DSMC may make the following types of recommendations, namely: 
At time of safety review: 
• No safety issues, ethical to continue the study as planned; 
• Serious safety concerns precluding further study treatment; 
• Recommendation to continue the study but proposing an amendment to the protocol  
(e.g., incorporate an additional safety assessments). 
At time of interim analysis: 
• No safety issues, ethical to continue the study as planned; 
• Ethical to continue the study but recommend an amendment to the protocol  
(e.g., incorporate additional or more frequent safety examinations); 
• Serious safety concerns precluding further study treatment; 
• Insufficient evidence of clinical activity, not ethical to continue the study as planned. 
DSMC recommendations will be provided in compliance with the DSMC charter. 

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9. STATISTICAL METHODS 
9.1. Overview and Sample Sizes 
In Phase 1, the keyboard dose escalation design (Appendix C) will govern the number of subjects 
to be enrolled. It is estimated 27 to 54 subjects may be enrolled, i.e., ~3-6 subjects for each of the 
4 dose levels across 2 arms (monotherapy and combination therapy; Figure 9). Based on the 
cumulative data from subjects treated in the dose finding phase, the MTD or RP2D will be 
selected for further evaluation in the dose expansion portion of the study. Once identified, an 
additional 3-6 subjects may be treated at the RP2D to confirm safety before proceeding to 
Phase 2.  
In Phase 2, up to 36 subjects will be enrolled in monotherapy Group A using a Simon 3 stage 
design assessing futility to show a maximum- ineffective ORR of 6.0% and a minimum effective 
ORR of 20%. If 0 subjects have a response among the first 11 subjects in the cohort, the study 
will be stopped for a lack of efficacy. If >0 subjects have a response, then another 14 subjects 
will be enrolled, for a total of 25 monotherapy subjects. If ≤2 of the 25 subjects have a response, 
the study will be stopped for lack of efficacy. If >2 subjects have a response, then another 
11 subjects will be enrolled in the third stage, for a total of 36 monotherapy subjects. If ≤4 of the 
36 subjects have a response, then treatment with TAC01-HER2 as a monotherapy will not be 
considered as having adequate efficacy to continue investigation in HER2+ subjects. If >4 of the 
36 subjects have a response, then treatment with TAC01-HER2 as a monotherapy will be 
considered efficacious and continued clinical study investigations will be warranted. The 
assumed ORR was selected based on the results of the TAGS study for Trifluridine/tipiracil, 
which enrolled gastric cancer and GEJ AC subjects after 2 prior lines of therapy. Since the ORR 
in that study was 4% (Shitara 2018), it was considered that the assumed 20% ORRs for Group A 
is clinically meaningful.  
In Phase 2, up to 34 subjects will be enrolled in combination therapy Group B using a Simon 
3-stage design assessing futility to show a maximum ineffective ORR of 8.4% and a minimum 
effective ORR of 25%. If 0 subjects have a response among the first 9 subjects in the cohort, the 
study will be stopped for a lack of efficacy. If >0 subjects have a response, then another 
10 subjects will be enrolled, for a total of 19 combination therapy subjects. If ≤2 of the 
19 subjects have a response, the study will be stopped for lack of efficacy. If >2 subjects have a 
response then another 15 subjects will be enrolled in the third stage, for a total of 34 combination 
therapy subjects. If ≤5 of the 34 subjects have a response, then treatment with TAC01-HER2 in 
combination with pembrolizumab will not be considered as having adequate efficacy to continue 
investigation in HER2+ subjects. If >5 of the 34 subjects have a response, then treatment with 
TAC01-HER2 in combination with pembrolizumab will be considered efficacious and continued 
clinical study investigations will be warranted. The assumed clinically meaningful ORR for 
group B was also selected based on the results of the TAGS study for Trifluridine/tipiracil. Since 
the ORR in that study was 4% (Shitara 2018) and given the anticipated add on benefit for the 
combination it was considered that the assumed 25% ORRs for group B is clinically meaningful. 

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Simon Three-Stage Design Sample Size and Cutoff Requirements for Phase 2 (Dose Expansion) 
Parameter 
Group A 
Group B 
Maximum non-effective rate 
6.0% 
8.4% 
Minimum effective rate 
20.0% 
25.0% 
First stage total N 
11 
9 
First stage cutoff 
0 
0 
Second stage total N 
25 
19 
Second stage cutoff 
2 
2 
Final stage total N 
36 
34 
Final stage cutoff 
4 
5 
All data from all available subjects (i.e., dose escalation and dose expansion phases) will be used 
when evaluating the potential efficacy of TAC01-HER2. Efficacy and safety of TAC01-HER2 
will be determined both as a monotherapy and in combination with pembrolizumab. In addition, 
efficacy of TAC01-HER2 will be explored for subjects who received bridging therapy versus 
those who did not and subjects who received 1 dose of TAC01-HER2 versus those that received 
a second dose versus those who were eligible for a second dose but did not receive a second 
dose. In addition, safety will also be explored for subjects who received 1 dose versus those who 
received a second dose versus those who were eligible for a second dose but did not receive a 
second dose. Additional details and other subgroup analyses will be described in the Statistical 
Analysis Plan (SAP). 
Subjects who are in DLT evaluation cohorts will be considered evaluable if they complete the 
defined DLT observation period. Estimates of ORR and other response proportions (e.g., DCR) 
will be presented together with 95% confidence intervals calculated using the Clopper-Pearson 
method. Kaplan-Meier estimations will be used for the analysis of time-to-event endpoints, 
including DOR, OS, and PFS. 
The cellular kinetics of TAC01-HER2 will be determined from individual concentration-time 
profiles of circulating TAC T cells and characterized in peripheral blood and summarized by 
treatment arm. 
9.2. General Considerations 
All analyses will be separated by monotherapy and combination therapy treatment arms and dose 
levels, unless otherwise specified. In the Phase 1 portion of the study, summaries will be 
prepared by treatment arm, and summarized by dose level and overall. Data from Phase 1 at the 
RP2D and data from Phase 2 will be pooled for analysis. Analyses may be refined in a detailed 
statistical analysis plan following further discussion with regulatory authorities. 
By-subject listings will be provided. Summary tables for continuous variables will contain the 
following statistics: N (number in population), n (number with data), mean, standard deviation, 

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95% CIs on the mean as appropriate, median, minimum, and maximum. Summary tables for 
categorical variables will include the following: N, n, percentage, and 95% CIs on the percentage 
as appropriate. Kaplan-Meier (KM) estimation will be used for the analysis of time to event 
endpoints, including DOR and OS. 
For the efficacy analysis, the ITT population is defined as any subject that received at least 
1 course of TAC01-HER2. 
Subjects in the monotherapy arm who do not receive TAC01-HER2 will be included in 
by-subject listings but will not be included in data summaries unless otherwise specified. 
Subjects in the combination therapy arm who receive TAC01-HER2 but not ≥1 dose of 
pembrolizumab will be included in the monotherapy arm. 
Subjects who receive non-conforming product of TAC01-HER2 will be analyzed separately. 
9.3. Analysis Sets 
9.3.1. Analysis Sets for Phase 1 
9.3.1.1. Screened Analysis Set 
The screened analysis set includes all subjects who have signed informed consent. 
9.3.1.2. Leukapheresis Analysis Set 
The leukapheresis analysis set includes all subjects who have signed informed consent and who 
undergo leukapheresis. 
9.3.1.3. Safety Analysis Set 
The safety analysis set includes all subjects who receive TAC01-HER2. 
9.3.1.4. Monotherapy Dose Limiting Toxicity-Evaluable Analysis Set 
The monotherapy DLT-evaluable analysis set includes all subjects who have received 
TAC01-HER2 at the assigned dose level, and who have either experienced a DLT or were 
followed for the full DLT evaluation period. This analysis set will be used for the determination 
of the MTD or RP2D. The monotherapy DLT-evaluable period is defined as Days 1 through 28, 
for a total evaluation period of 28 days following TAC01-HER2 infusion, and up to 42 days 
should clinically consequential (i.e., events associated with febrile neutropenia, serious 
infections, or bleeding) Grade ≥3 neutropenia or thrombocytopenia occur. 
9.3.1.5. Combination Therapy Dose Limiting Toxicity-Evaluable Analysis Set 
The combination DLT-evaluable analysis set includes all subjects who have received 
TAC01-HER2 at the assigned dose level and ≥1 dose of pembrolizumab, and who have either 

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experienced a DLT or were followed for the full DLT evaluation period. This analysis set will be 
used for the determination of the MTD or RP2D.  
The combination DLT-evaluable period is defined as Days 1 to 42 for subjects who receive 
pembrolizumab on Day 21 and Days 1 to 35 for subjects who receive pembrolizumab on Day 14.  
9.3.1.6. Monotherapy Efficacy Analysis Set 
The monotherapy efficacy analysis set in Phase 1 includes all subjects who have received 
TAC01-HER2, have measurable disease at the last disease assessment prior to receiving 
TAC01-HER2, and who have at least 1 post-infusion disease response assessment. 
9.3.1.7. Combination Therapy Efficacy Analysis Set 
The combination therapy efficacy analysis set in Phase 1 includes all subjects who have received 
TAC01-HER2, have measurable disease at the last disease assessment prior to receiving 
TAC01-HER2, received ≥1 dose of pembrolizumab, and who have at least 1 post-infusion 
disease response assessment following a pembrolizumab. 
9.3.1.8. Pharmacokinetic Analysis Set 
The PK analysis set includes subjects in the safety analysis set who have the necessary PK 
measurements to provide interpretable results for the specific parameters of interest. 
9.3.2. Analysis Sets for Subjects Treated at the RP2D 
9.3.2.1. Safety Analysis Set 
The safety analysis set includes all subjects who receive TAC01-HER2 at the RP2D. This 
analysis set will be used in the analyses of safety endpoints. 
9.3.2.2. Monotherapy Efficacy Analysis Set 
The monotherapy efficacy analysis set includes all subjects across Phase 1 and Phase 2 of the 
study who have measurable disease at the last disease assessment prior to TAC01-HER2 infusion 
and who receive product at the RP2D. All efficacy endpoints will be analyzed using this analysis 
set. 
9.3.2.3. Combination Therapy Efficacy Analysis Set 
The combination therapy efficacy analysis set includes all subjects across Phase 1 and Phase 2 of 
the study who have measurable disease at the last disease assessment prior to TAC01-HER2 
infusion and who receive TAC01-HER2 at the RP2D and receive ≥1 dose of pembrolizumab. All 
efficacy endpoints will be analyzed using this analysis set. 

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9.3.2.4. Additional Analysis Sets 
The Phase 2 screened set, leukapheresis analysis set, and PK analysis set will follow the same 
definitions as in Phase 1. Additional analysis sets may be defined in the SAP. 
9.4. Planned Analyses 
9.4.1. Subject Disposition and Baseline Characteristics 
Descriptive summaries of demographics, baseline characteristics, and subject disposition will be 
provided for each analysis set. 
9.4.2. Primary Endpoints in Phase 1 Dose Escalation 
The primary endpoints are: 
• Incidence of DLTs 
• The type and incidence of DLTs will be summarized by dose level and total. The rates of 
DLT at each dose level and the MTD will be estimated using isotonic regression as 
described in Yan, Mandrekar and Yuan (2017). 
• Type, frequency, and severity of AEs 
All AEs will be listed and summarized (see Section 8 for details). 
9.4.3. Secondary Endpoints in Phase 1 Dose Escalation 
Separate MTD or RP2D will be determined for the monotherapy and combination arm of the 
study. Additional secondary endpoints are: 
• Cmax, Tmax, and AUC of TAC T cells. 
Determination of these parameters will be based on data obtained after the TAC01-HER2 
infusion through the Day 29 visit. Cmax is the maximal concentration of TAC T cells (or peak cell 
expansion) after infusion. Tmax is the first study day the Cmax is reached. AUC will be calculated 
using the trapezoid rule.  
Duration of persistence of TAC T cells: Persistence will be defined as the time between the first 
measurement of transgene above the limit of detection until the last observed quantifiable level 
of transgene (Clast).  
ORR is defined as the percentage of treated subjects with a CR or PR; DOR is defined as time 
from first response to disease progression, end of study, start of another anticancer therapy, or 
death; OS is defined as time from infusion to death from any cause according to RECIST 1.1 as 
assessed by the Investigator; DCR is defined as the percentage of treated subjects with SD, PR, 
and CR; and PFS is defined as the time from infusion to disease progression or death from any 

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cause according to RECIST 1.1 as assessed by the Investigator. Subjects without any reported 
disease response assessments will be considered non responders. 
In addition, immunogenicity to treatment will be assessed, as well as any correlations with PK 
and efficacy characteristics. Candidate efficacy biomarkers will also be investigated. 
9.4.4. Primary Endpoints in Phase 2 Expansion 
ORR will be calculated as the proportion of subjects with a best overall response of either CR or 
PR based on RECIST 1.1 (Schwartz 2016). Exact 95% confidence limits for ORR will be 
calculated using the Clopper-Pearson method. DCR will also be calculated taking into account 
stable disease, PR, and CR.  
DOR will be defined as the time from the first date when measurement criteria are met for PR or 
CR (whichever status is recorded first) to the date that measurement criteria are first met for PD 
or the date of death, whichever is sooner. For subjects not known to have died as of the data 
cutoff date and who do not have PD, DOR will be censored at the last progression-free 
assessment date. For responding subjects who receive subsequent anticancer therapy prior to 
disease progression, DOR will be censored at the date of last progression-free assessment prior 
to the initiation of a new anticancer therapy.  
OS will be calculated as the time from the date of TAC01-HER2 infusion to the date of death 
from any cause. For a subject who is still alive as of the data cut-off date, OS time will be 
censored on the subject’s date of last contact.  
PFS will be calculated as the time from the date of TAC01-HER2 infusion to the date of disease 
progression of from death from any cause. For a subject who is still alive as of the data cut-off 
date and has not been evaluated with PD, PFS time will be censored on the subject’s date of last 
contact.  
Time-to-event endpoints, including DOR, OS and PFS, will be summarized descriptively and 
graphically using KM methodology. KM estimates for the median, first, and third quartiles will 
be determined along with 95% CIs. The Brookmeyer-Crowley method will be used for the CI 
calculations. For the subset of subjects who have a CR or PR, DOR will be summarized similarly 
using the Kaplan-Meier method. TTR will be defined from TAC01-HER2 infusion to the first 
documented CR or PR and will be summarized descriptively as a continuous variable. 
ORR and other efficacy endpoints will be examined within subgroups defined by the following 
factors:  
• Age: <40 versus ≥40 years at the time of TAC01-HER2 infusion 
• Level of HER 2 expression: 1+, 2+, 3+ (Phase 1) and 2+ and 3+ (Phase 2) 
• PD-L1 expression for pembrolizumab treated subjects  

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• Subjects who received 1 TAC01-HER2 dose versus subjects who received a second 
TAC01-HER2 dose versus subjects who were eligible for a second TAC01-HER2 dose 
but did not receive it. 
• Subjects who received anticancer bridging therapy versus subjects who did not receive 
bridging therapy. 
9.4.5. Secondary Endpoints in Phase 2 Expansion 
Secondary endpoints are: 
• Type, frequency, and severity of AEs. 
All AEs will be listed and summarized (see Section 8 for details). 
Additional secondary endpoints are: 
• Cmax, Tmax, and AUC of TAC T cells. 
Determination of these parameters will be based on data obtained after the TAC01-HER2 
infusion through the Day 29 visit. Cmax is the maximal concentration of TAC T cells (or peak cell 
expansion) after infusion. Tmax is the first study day the Cmax is reached. AUC will be calculated 
using the trapezoid rule.  
Duration of persistence of TAC T cells: Persistence will be defined as the time between the first 
measurement of transgene above the limit of detection until the last observed quantifiable level 
of transgene (Clast).  
In addition, we will assess immunogenicity to treatment, as well as any correlations with PK and 
efficacy characteristics. We will also investigate candidate efficacy biomarkers. 
9.4.6. Safety Analyses 
Safety analyses will be based on the safety analysis set. 
9.4.6.1. Adverse Events 
All AEs will be listed. The focus of AE summarization will be on TEAEs.  
In the monotherapy arm, a TEAE is defined as an AE that starts any time from initiation of 
TAC01-HER2 administration through and including 90 days following the TAC01-HER2 dose as 
well as any pre-existing AE that worsens after study treatment. Any AE occurring after the 
initiation of another anticancer treatment will not be considered a TEAE. 
In the combination arm, a TEAE is defined as an AE that starts any time after initiation of 
TAC01-HER2 administration until 90 days after the last dose of pembrolizumab. 

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Once a subject starts a new anticancer therapy and transfers to the minimal study procedures in 
the LTFU protocol, TEAEs will no longer be collected. 
Reporting of AEs will be based on the Medical Dictionary for Regulatory Activities (MedDRA), 
NCI CTCAE Version 5.0 (National Cancer Institute 2020) and CRS and neurotoxicity per 
ASTCT criteria (Lee 2019) as outlined in Appendix D. The incidence of TEAEs will be 
summarized by system organ class, preferred term, and severity. A subject who reports multiple 
occurrences of TEAEs within the same system organ class and preferred term is counted only 
once using the maximum severity grade for summaries. 
9.4.6.2. Laboratory Data 
All laboratory data will be listed. The focus of laboratory data summarization (including 
hematology and serum chemistry) will be on treatment-emergent laboratory abnormalities.  
In the monotherapy arm, a treatment-emergent laboratory abnormality is defined as an 
abnormality when, compared to baseline, worsens by at least 1 grade within 90 days following 
the TAC01-HER2 infusion.  
In the combination arm, a treatment-emergent laboratory abnormality is defined as an 
abnormality when, compared to baseline, worsens by at least 1 grade up to 90 days after the last 
dose of pembrolizumab. 
The baseline value is defined as the last available recorded value on or prior to the date of the 
TAC01-HER2 infusion. 
If baseline data are missing, then any graded abnormality (i.e., an abnormality that is Grade ≥1 in 
severity) will be considered treatment emergent. Hematological and serum biochemistry data 
will be graded according to NCI CTCAE Version 5.0 when applicable. Grade 0 includes all 
non-missing values that do not meet the criteria for an abnormality of at least Grade 1. Grade 5 
will not be used. Some laboratory tests have criteria for both increased and decreased levels; 
analyses for each direction (i.e., increased, decreased) will be presented separately.  
The following summaries will be presented for selected analytes: 
• Raw values and changes from Baseline will be summarized by visit for numerical 
laboratory results in conventional units. 
• Number of subjects by CTCAE, with corresponding percentages at each visit, and 
maximum post-Baseline severity grade. 
• Number and percentage of subjects with a treatment emergent CTCAE Grade 3 or 4 
laboratory abnormality. 
• Shift tables showing the change in CTCAE severity grade from Baseline to the maximum 
severity grade post Baseline. For laboratory tests where CTCAE grade does not exist, the 
shift table will present the low/normal/high shift. 

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9.4.6.3. Other Safety Analyses 
Vital signs will be summarized using descriptive statistics and listed. All other safety data will be 
listed. 
9.4.6.4. Safety Subgroup Analyses 
Safety summaries will be prepared for all subjects in the safety analysis set, and for subgroups 
based on: 
• Age: <40 versus ≥40 years at the time of the TAC01-HER2 infusion 
• Subjects who received 1 TAC01-HER2 dose versus subjects who received a second 
TAC01-HER2 dose versus subjects who were eligible for a second TAC01-HER2 dose 
but did not receive it. 
• Subjects who received anticancer bridging therapy versus subjects who did not receive 
bridging therapy. 
9.4.7. Concomitant Medications 
Prior and concomitant medications will be coded with the World Health Organization Drug 
Dictionary (WHO-DD) and listed. All concomitant medications and blood product transfusions 
administered after the TAC01-HER2 infusion will be summarized. 
Specific treatments for CRS (e.g., corticosteroids, tocilizumab) will be summarized, as will 
specific treatments for neurotoxicity. 
Anticancer interventions will be summarized. 
9.4.8. Pharmacokinetic Analyses 
Individual concentration-time profiles of circulating TAC T cells will be obtained from 
peripheral blood samples. Graphs of serum concentration curves will be prepared overall and for 
individual subjects. 
9.4.8.1. Cellular Kinetic Parameters for TAC01-HER2 
Parameters will be estimated by noncompartmental methods using Phoenix (Pharsight, Version 
6.4). Derived parameters of interest will include AUC (0 – 29 days) and AUC (0 – 3 months) 
(reflecting expansion of the modified T cells following infusion of TAC01-HER2), Cmax, and 
Tmax. AUC will be calculated using the linear trapezoidal rule. Cmax corresponds to the maximum 
(peak) expansion of TAC T cells, while Tmax corresponds to the time at which this maximum 
expansion is observed. Conventional methods will be used to derive additional cellular kinetic 
parameters, such as Clast (the last observed quantifiable level of transgene), Tlast (the level of 
transgene at the last quantifiable time point), and T1/2. T1/2 will be calculated as ln 2/λz, for which 

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λz (the apparent terminal elimination rate constant) is estimated by linear regression of the 
terminal log-linear portion of the concentration-time curve. 
Summary statistics of cellular kinetic parameters from peripheral blood will be presented overall 
and by Day 29. Measures of persistence, including Tlast and Clast, will be used as indicators of the 
duration that TAC T cells are present in peripheral blood and tissues.  
PK parameters will be summarized using descriptive statistics for all subjects in the PK analysis 
set and for subgroups based on: 
• Age: <40 versus ≥40 years at the time of the TAC01-HER2 infusion 
• Cellular and/or humoral immunogenicity present (positive) or absent (negative) 
9.4.9. Exploratory Endpoints 
The exploratory endpoints for the study are listed in Table 4. Details of the exploratory analyses 
are provided in the SAP. 
9.5. Timing of Analyses 
9.5.1. Interim Analysis 
In addition to assessing safety data for the occurrence of dose limiting toxicities, a Simon 3-stage 
design will be used to assess the futility of treatment with TAC01-HER2 among HER2+ gastric 
and esophageal adenocarcinoma subjects as monotherapy and in combination with 
pembrolizumab (see Section 9.1). 
In Phase 2, up to 36 subjects will be enrolled in monotherapy Group A using a Simon 3 stage 
design assessing futility to show a maximum- ineffective ORR of 6.0% and a minimum effective 
ORR of 20%. If 0 subjects have a response among the first 11 subjects in the cohort, the study 
will be stopped for a lack of efficacy. If >0 subjects have a response, then another 14 subjects 
will be enrolled, for a total of 25 monotherapy subjects. If ≤2 of the 25 subjects have a response, 
the study will be stopped for lack of efficacy. If >2 subjects have a response, then another 
11 subjects will be enrolled in the third stage, for a total of 36 monotherapy subjects. If ≤4 of the 
36 subjects have a response, then treatment with TAC01-HER2 as a monotherapy will not be 
considered as having adequate efficacy to continue investigation in HER2+ subjects. If >4 of the 
36 subjects have a response, then treatment with TAC01-HER2 as a monotherapy will be 
considered efficacious and continued clinical study investigations will be warranted. The 
assumed ORR was selected based on the results of the TAGS study for Trifluridine/tipiracil, 
which enrolled gastric cancer and GEJ AC subjects after 2 prior lines of therapy. Since the ORR 
in that study was 4% (Shitara 2018), it was considered that the assumed 20% ORRs for Group A 
is clinically meaningful.  
In Phase 2, up to 34 subjects will be enrolled in combination therapy Group B using a Simon 
3-stage design assessing futility to show a maximum ineffective ORR of 8.4% and a minimum 
effective ORR of 25%. If 0 subjects have a response among the first 9 subjects in the cohort, the 

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study will be stopped for a lack of efficacy. If >0 subjects have a response, then another 
10 subjects will be enrolled, for a total of 19 combination therapy subjects. If ≤2 of the 
19 subjects have a response, the study will be stopped for lack of efficacy. If >2 subjects have a 
response then another 15 subjects will be enrolled in the third stage, for a total of 34 combination 
therapy subjects. If ≤5 of the 34 subjects have a response, then treatment with TAC01-HER2 in 
combination with pembrolizumab will not be considered as having adequate efficacy to continue 
investigation in HER2+ subjects. If >5 of the 34 subjects have a response, then treatment with 
TAC01-HER2 in combination with pembrolizumab will be considered efficacious and continued 
clinical study investigations will be warranted. The assumed clinically meaningful ORR for 
group B was also selected based on the results of the TAGS study for Trifluridine/tipiracil. Since 
the ORR in that study was 4% (Shitara 2018), and given the anticipated add on benefit for the 
combination it was considered that the assumed 25% ORRs for group B is clinically meaningful. 
9.5.2. Final Analysis 
The final analyses will be carried out after all subjects have completed or discontinued the study 
for any reason. No formal hypothesis testing will be performed at the final analysis. 
10. DATA MANAGEMENT 
10.1. Data Collection System 
An electronic data capture (EDC) system will be used for data collection. The EDC system will 
be a fully validated, secure system that conforms to 21 CFR Part 11 requirements. Access to the 
EDC system will be role-based, and login credentials will be provided only after completion of 
the assigned role-based training. 
10.2. Data Quality 
Investigative site personnel will enter data on the CRFs in the EDC system. A Monitor will 
verify data recorded on the CRFs is consistent with the source documents. 
To ensure complete and accurate data, automated data validation checks programmed within the 
EDC system will flag missing and non-conformant data during data entry. Data review by the 
Triumvira project team may result in additional queries. All data entry and subsequent data 
changes and query resolutions are logged in an audit trail in the EDC system.  
The Investigator is responsible for ensuring the data entered on the CRFs are complete and 
accurate and will electronically sign the CRFs attesting to this for each subject prior to database 
lock. Following database lock, an electronic copy of the final subject casebook will be provided 
to the investigative site for archival. 

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11. STUDY ADMINISTRATION 
11.1. Regulatory and Ethical Compliance 
The study will be conducted in accordance with the ICH Harmonised Tripartite Guidelines for 
Good Clinical Practice (GCP), the protocol, and any other applicable national, state, and/or local 
regulatory requirements (e.g., US CFR Title 21, and World Medical Association Declaration of 
Helsinki). 
11.2. Regulatory Authority Review 
Before initiation of this study, the protocol must be reviewed and approved by the appropriate 
competent regulatory authorities. 
11.3. Institutional Review Board/Independent Ethics Committee Approval 
It is the Investigator’s responsibility to ensure the appropriate IRB/IEC or equivalent local 
committee has reviewed and approved this protocol prior to study initiation. The IRB/IEC or 
equivalent local committee must also review and approve the investigative site’s ICF and all 
applicable subject materials.  
If the protocol or ICF are amended during the study the Investigator is responsible for ensuring 
the IRB/IEC or equivalent local committee has reviewed and approved these amended 
documents. IRB/IEC or equivalent local committee approval of the amended documents must be 
obtained before implementation and before new subjects are consented to participate in the study 
using the amended ICF. 
11.4. Subject Informed Consent 
The Investigator, or a qualified designee, will be responsible for explaining the nature, purpose, 
benefits, and risks of participation in the study to each subject, subject’s legally acceptable 
representative, or impartial witness. Written informed consent must be obtained before the 
initiation of any study specific procedure. Sufficient time must be allowed to discuss any 
questions raised by the subject. The Investigator or qualified designee will document this process 
in the study records. The Investigator must use the current IRB/IEC or equivalent local 
committee approved consent form for documenting written informed consent. The subject or the 
subject’s legally authorized representative must appropriately sign and date each consent form. 
Signatures required by local policies (e.g., the person obtaining consent) must also be complete. 
Informed consent must be obtained in compliance with all national regulations, GCP/ICH 
requirements, and local laws. 
If the ICF is amended during the study, the Investigator must follow all applicable regulatory 
requirements pertaining to approval of the amended ICF by the IRB/IEC. The investigative site 
must use the amended ICF for all new subjects. If required by the IRB/IEC, the investigative site 
must also repeat the consent process with the amended ICF for any subject already enrolled in 
the study. 

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11.5. Investigator Responsibilities 
The Investigator is responsible for ensuring all investigative site personnel conduct the study in 
compliance with the Declaration of Helsinki and the ICH E6 Guideline for GCP. 
The Investigator will also ensure adherence to the basic principles of GCP, as outlined in 21 CFR 
312, Subpart D, “Responsibilities of Sponsors and Investigators,” 21 CFR, Part 50, 1998, and 
21 CFR, Part 56, 1998, or local regulatory guidelines for the country of location. 
The Investigator and all study staff will comply with 21 CFR, Part 54, 1998, providing 
documentation of any financial conflict of interest. This documentation must be provided prior to 
the Investigator or Sub-Investigators’ participation in the study. The Investigator and 
Sub-Investigator(s) agree to notify Triumvira of any change in reportable interests during the 
study and for 1 year following completion of the study at the investigative site. 
If an amendment to either the protocol or study ICF is necessary, the Investigator will be 
responsible for ensuring the IRB/IEC or equivalent local committee reviews and approves the 
amended documents, and that subjects are informed of applicable changes and updates. 
The Investigator will sign and return to Triumvira or designee the Protocol Signature Page for all 
pertinent versions of the protocol and will provide current medical licenses, curriculum vitae, 
and other forms requested by Triumvira. All forms must be updated as applicable throughout the 
study. 
In accordance with applicable regulatory requirements, the Investigator is solely responsible for 
informing the IRB/IEC or equivalent local committee of study progress and notifying the 
IRB/IEC or equivalent local committee of study closure. The Investigator must also provide 
Triumvira or designee with copies of all IRB/IEC or equivalent local committee correspondence 
related to study approvals, renewals, updates, or changes. 
11.6. Access to Information for Monitoring 
In accordance with regulations and guidelines, the Monitor or designee must have direct access 
to the Investigator’s source documentation to verify the accuracy of the data recorded on the 
CRF. 
The Monitor or designee is responsible for routine review of the study records and CRFs at 
regular intervals throughout the study to verify adherence to GCP and protocol and the 
completeness, consistency, and accuracy of the data. The Investigator must agree to cooperate 
with the Monitor or designee to ensure any problems detected are resolved. 
11.7. Quality Assurance 
Triumvira or their designee may perform quality assurance checks of this study. Before the first 
subject enrollment, Triumvira or designee personnel will provide training to the Investigator, 
Sub-Investigators, and investigative site personnel regarding the informed consent process, 

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protocol, IB, CRF completion, and SAE reporting. Investigative site visits will be performed by 
Monitors or designees periodically throughout the study. During these site visits, information 
recorded on the CRFs may be verified against source documents, and requests for clarification or 
correction may be made. The CRFs will be reviewed for safety information, completeness, 
accuracy, and logical consistency. Computer programs that identify data inconsistencies may be 
used to help monitor the clinical study. Requests for clarification or correction will be sent to 
Investigators via data queries. 
11.8. Public Notification of Study Conduct 
In compliance with Section 113 of the Food and Drug Modernization Act of 1997 and with 
publication requirements of the International Committee of Medical Journal Editors, Triumvira 
will be responsible for ensuring this study is listed on the ClinicalTrials.gov website per the US 
FDA requirement as well as on local study registries as required by health authorities and that 
information on the website relating to study design and conduct is appropriately updated during 
the study. 
11.9. Study Termination 
Upon completion or early termination of the study, the Investigator will return all study data 
(electronic and non-electronic) to Triumvira (the Investigator will be provided with a copy of the 
CRF data for their site), complete all data clarifications and/or resolutions, and allow a final 
Monitor review of study records for completeness. 
11.10. Investigative Site Termination 
Triumvira may terminate an Investigator’s participation at any time for any reason. Termination 
and any required follow-up will be performed in compliance with 21 CFR Parts 312.50 and 
312.56 and any applicable local regulations. 
11.11. Records Retention 
The Investigator must maintain adequate and accurate records to enable the conduct of the study 
to be fully documented and the study data to be subsequently verified in compliance with ICH 
GCP E6. Subject records, source documents, monitoring visit logs, regulatory documents, and 
correspondence pertaining to the study must be maintained at the investigative site. Source 
documents include but are not limited to all recordings, observations, or notations of clinical 
activities and all reports and records necessary for the evaluation and reconstruction of the 
clinical study. This includes any electronic records. Study records will be retained in a secure file 
for the period required by the institution or investigative site policy. Prior to the transfer or 
destruction of study records, Triumvira must be notified in writing and be given the opportunity 
to further store such records. Records are required to be retained as per applicable local laws, 
regulations, and/or guidelines. 

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11.12. Confidentiality 
Subjects’ names will remain confidential and will not be included in the study database. All study 
data and findings will be stored in electronic databases. The Investigator will maintain a subject 
ID list to ensure records can be linked to a specific subject. 
11.13. Publication Plan 
This study is intended for publication, even if terminated prematurely. Publication may include 
any or all of the following: posting of a synopsis online, abstract and/or presentation at a 
scientific conference, or publication of a full manuscript.  
Authorship credit should be based on 1) substantial contributions to conception and design, or 
acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it 
critically for important intellectual content; and 3) final approval of the version to be published. 
Authors must meet conditions 1, 2 and 3. Significant contributions to study execution may also 
be considered to determine authorship, provided that contributions have also been made to all 
3 of the preceding authorship criteria. Although publication planning may begin before 
conducting the study, final decisions on authorship and the order of authors’ names will be made 
based on participation and actual contributions to the study and writing, as discussed above. The 
first author is responsible for defending the integrity of the data, method(s) of data analysis and 
the scientific content of the manuscript. 
Triumvira must have the opportunity to review all proposed abstracts, manuscripts, or 
presentations regarding this study at least 30 days prior to submission for 
publication/presentation. Any information identified by Triumvira as confidential must be 
deleted prior to submission; this confidentiality does not include efficacy and safety results. 
Triumvira review can be expedited to meet publication timelines. 

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12. REFERENCES 
Abramson JS, Palomba ML, Gordon LI, et al. High CR rin relapsed/refractory (R/R) aggressive 
B-NHL treated with the CD19-directed CAR T cell product JCAR017 (TRANSCEND NHL 
001). J Clin Oncol. 2017;35(15_suppl):7513. 
Adusumilli PS, Zauderer MG, Rivière I, et al. A Phase I trial of regional mesothelin-targeted 
CAR T-cell therapy in patients with malignant pleural disease, in combination with the anti-PD-1 
agent pembrolizumab. Cancer Discov. 2021;11:2748-63.  
Barrett DM, Teachey DT, Grupp SA. Toxicity management for patients receiving novel T-cell 
engaging therapies. Curr Opin Pediatr. 2014;26:43-9. 
Blank C, Brown I, Peterson AC, et al., PD-L1/B7H-1 inhibits the effector phase of tumor 
rejection by T cell receptor (TCR) transgenic CD8+ T cells. Cancer Res, 2004;64:1140-5. 
Botta GP, Becerra CR, Jin Z et al. Multicenter phase Ib trial in the U.S. of salvage CT041 
CLDN18.2-specific chimeric antigen receptor T-cell therapy for patients with advanced gastric 
and pancreatic adenocarcinoma. J Clin Oncol. 2022;40(16_suppl):2538. 
Catenacci DVT, Kang YK, Park H, et al. Margetuximab plus pembrolizumab in patients with 
previously treated, HER2-positive gastro-oesophageal adenocarcinoma (CP-MGAH22-05): a 
single-arm, phase 1b-2 trial. Lancet Oncol. 2020;21:1066-76.  
Chakrabarty A, Bhola NE, Sutton C, et al. Trastuzumab-resistant cells rely on a HER2-
PI3K-FoxO-survivin axis and are sensitive to PI3K inhibitors. Cancer Res. 2013;73:1190-200.  
Chemnitz JM, Parry RV, Nichols KE, et al. SHP-1 and SHP-2 associate with immunoreceptor 
tyrosine-based switch motif of programmed death 1 upon primary human T cell stimulation, but 
only receptor ligation prevents T cell activation. J Immunol.2004;173:945–54. 
Chmielecki J, Ross JS, Wang K, et al. Oncogenic alterations in ERBB2/HER2 represent potential 
therapeutic targets across tumors from diverse anatomic sites of origin. The Oncologist. 
2015;20:7-12. 
Chong EA, Alanio C, Svoboda J, et al. Pembrolizumab for B-cell lymphomas relapsing after or 
refractory to CD19-directed CAR T-cell therapy. Blood. 2022;139:1026-38.  
Couzin J. Gene therapy. As Gelsinger case ends, gene therapy suffers another blow. Science. 
2005;307:1028b. 
Curran MA, Montalvo W, Yagita H, et al. PD-1 and CTLA-4 combination blockade expands 
infiltrating T cells and reduces regulatory T and myeloid cells within B16 melanoma tumors. 
Proc Natl Acad Sci U S A, 2010;107:4275-80. 

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Davila ML, Riviere I, Wang X, et al. Efficacy and toxicity management of 19-28z CAR T cell 
therapy in B cell acute lymphoblastic leukemia. Sci Transl Med. 2014;6:224ra225. 
De Gassart A, Le KS, Brune P, et al. Development of ICT01, a first-in-class, anti-BTN3A 
antibody for activating Vγ9Vδ2 T cell-mediated antitumor immune response. Sci Transl Med. 
2021;13:eabj0835.  
Deguchi Y, Okabe H, Oshima N, et al. PTEN loss is associated with a poor response to 
trastuzumab in HER2-overexpressing gastroesophageal adenocarcinoma. Gastric Cancer. 
2017;20:416-27.  
Disis ML. Immune regulation of cancer. J Clin Oncol. 2010;28:4531-8. 
Donahue RE, Kessler SW, Bodine D, et al. Helper virus induced T cell lymphoma in nonhuman 
primates after retroviral mediated gene transfer. J Exp Med. 1992;176:1125-35. 
Dudley ME, Wunderlich JE, Yang, JC, et al. Adoptive cell transfer therapy following 
non-myeloablative but lymphodepleting chemotherapy for the treatment of patients with 
refractory metastatic melanoma. J Clin Oncol. 2005;23:2346-57. 
Fodstad O, Aamdal S, McMenamin M, et al. A new experimental metastasis model in athymic 
nude mice, the human malignant melanoma LOX. Int J Cancer. 1988;41:442-9.  
Fogh J, Fogh JM, Orfeo T. One hundred and twenty-seven cultured human tumor cell lines 
producing tumors in nude mice. J Natl Cancer Inst. 1977;59:221-6. 
Food and Drug Administration. Draft Guidance for Industry: Considerations for the 
Development of Chimeric Antigen Receptor (CAR) T Cell Products. U.S. Department of Health 
and Human Services, Center for Biologics Evaluation and Research; March 2022. 
Food and Drug Administration. Guidance for Industry: Long Term Follow-Up After 
Administration of Human Gene Therapy Products. U.S. Department of Health and Human 
Services, Center for Biologics Evaluation and Research; 2020. 
Food and Drug Administration. Guidance for Industry: Testing of Retroviral Vector-Based 
Human Gene Therapy Products for Replication Competent Retrovirus During Product 
Manufacture and Patient Follow-up. U.S. Department of Health and Human Services, Center for 
Biologics Evaluation and Research; 2020. 
Francisco LM, Sage PT, and Sharpe AH. The PD-1 pathway in tolerance and autoimmunity. 
Immunol Rev.2010;219-42. 
Gardner RA, Finney O, Smithers H, et al. Prolonged functional persistence of CD19CAR t cell 
products of defined CD4:CD8 composition and transgene expression determines durability of 
MRD-negative ALL remission. J Clin Oncol. 2016;35(15_suppl):3048. 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 140 of 177 
 
 
Garon EB, Rizvi NA, Hui R, et al. Pembrolizumab for the treatment of non-small-cell lung 
cancer. N Engl J Med. 2015;372:2018-28.  
Gazdar AF, Kurvari V, Virmani A, et al. Characterization of paired tumor and non-tumor cell 
lines established from patients with breast cancer. Int J Cancer. 1998;78:766-74. 
Greenwald RJ, Freeman GJ, and Sharpe AH. The B7 family revisited. Annu Rev Immunol. 2005; 
23:515–48. 
Grossman Z, Min B, Meier-Schellersheim M, et al. Concomitant regulation of T-cell activation 
and homeostasis. Nat Rev Immunol. 2004;4:387-95. 
Grosser R, Cherkassky L, Chintala N, et al. Combination immunotherapy with CAR T cells and 
checkpoint blockade for the treatment of solid tumors. Cancer Cell. 2019;36:471-82. 
Hacein-Bey-Abina S, Von Kalle C, Schmidt M, et al. LMO2-associated clonal T cell 
proliferation in two patients after gene therapy for SCID-X1. Science. 2003;302:415-9. 
Heczey A, Louis CU, Savoldo B, et al. CAR T Cells Administered in Combination with 
Lymphodepletion and PD-1 Inhibition to Patients with Neuroblastoma. Mol Ther. 
2017;25:2214-24.  
Helsen CW, Hammill JA, Lau VWC, et al. The chimeric TAC receptor co-opts the T cell receptor 
yielding robust anti-tumor activity without toxicity. Nat Commun. 2018;9:3049. 
Herbst RS, Soria JC, Kowanetz M, et al. Predictive correlates of response to the anti-PD-L1 
antibody MPDL3280A in cancer patients. Nature. 2014;515:563-7.  
Hirano F, Kaneko K, Tamura H, et al., Blockade of B7-H1 and PD-1 by monoclonal antibodies 
potentiates cancer therapeutic immunity. Cancer Res. 2005;65): 1089-96. 
Hunder NN, Wallen H, Cao J, et al. Treatment of metastatic melanoma with autologous CD4+ T 
cells against NY-ESO-1. N Engl J Med 2008;358:2698-703. 
Ikediobi ON, Davies H, Bignell G, et al. Mutation analysis of 24 known cancer genes in the 
NCI-60 cell line set. Mol Cancer Ther. 2006;5:2606-12.  
June CH, O'Connor RS, Kawalekar OU, et al. CAR T cell immunotherapy for human cancer. 
Science. 2018;359:1361-5. 
Kochenderfer JN, Dudley ME, Kassim SH, et al. Chemotherapy-refractory diffuse large B-cell 
lymphoma and indolent B-cell malignancies can be effectively treated with autologous T cells 
expressing an anti-CD19 chimeric antigen receptor. J Clin Oncol. 2015;33:540-9. 
Lasfargues EY, Coutinho WG, Redfield ES. Isolation of two human tumor epithelial cell lines 
from solid breast carcinomas. J Natl Cancer Inst. 1978;61:967-78. 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 141 of 177 
 
 
Lee DW, Santomasso BD, Locke FL, et al. ASTCT Consensus Grading for cytokine release 
syndrome and neurologic toxicity associated with immune effector cells. Biol Blood Marrow 
Transplant. 2019;25:625-38. 
Lewis GD, Figari I, Fendly B, et al. Differential responses of human tumor cell lines to 
anti-p185HER2 monoclonal antibodies. Cancer Immunol Immunother. 1993;37:255-63. 
Li Z, Düllmann J, Schiedlmeier B, et al. Murine leukemia induced by retroviral gene marking. 
Science. 2002;296:497-497. 
Lieber M, Mazzetta J, Nelson-Rees W, et al. Establishment of a continuous tumor-cell line (panc-
1) from a human carcinoma of the exocrine pancreas. Int J Cancer. 1975;15:741-7. 
Long AH, Haso WM, Shern JF, et al. 4-1BB costimulation ameliorates T cell exhaustion induced 
by tonic signaling of chimeric antigen receptors. Nat Med. 2015;21:581-90. 
Maude S, Barrett DM. Current status of chimeric antigen receptor therapy for haematological 
malignancies. Br J Haematol. 2016;172:11-22. 
Maude SL, Barrett D, Teachey DT, et al. Managing cytokine release syndrome associated with 
novel T cell-engaging therapies. Cancer J. 2014a;20:119-22. 
Maude SL, Frey N, Shaw PA, et al. Chimeric antigen receptor T cells for sustained remissions in 
leukemia. New Eng J Med. 2014b;371:1507-17. 
McGarrity GJ, Hoyah G, Winemiller A, et al. Patient monitoring and follow-up in lentiviral 
clinical trials. J Gene Med. 2013;15:78-82. 
Miliotou AN, Papadopoulou LC. CAR T-cell Therapy: A New Era in Cancer Immunotherapy. 
Curr Pharm Biotechnol. 2018;19:5-18. 
Modi S, Park H, Murthy RK, et al. Antitumor Activity and Safety of Trastuzumab Deruxtecan in 
Patients with HER2-Low-Expressing Advanced Breast Cancer: Results from a Phase Ib Study. 
J Clin Oncol. 2020;38:1887-96. 
Modi S, Jacot W, Yamashita T, et al. Trastuzumab din previously treated HER2-low advanced 
breast cancer. N Engl J Med. 2022;387:9-20.  
Modlich U, Kustikova OS, Schmidt M, et al. Leukemias following retroviral transfer of 
multidrug resistance 1 (MDR1) are driven by combinatorial insertional mutagenesis. Blood. 
2005;105:4235-46. 
Morotti M, Albukhari A, Alsaadi A, et al. Promises and challenges of adoptive T-cell therapies 
for solid tumors. Br J Cancer. 2021 May;124:1759-76. 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 142 of 177 
 
 
National Cancer Institute. Common Terminology Criteria for Adverse Events (CTCAE) v5.0. In: 
U.S. Dept. of Health and Human Services, National Institutes of Health, National Cancer 
Institute; 2020. 
Neelapu SS. CAR-T efficacy: is conditioning the key? Blood. 2019;133:1799-800. 
Neelapu SS, Tummala S, Kebriaei P, et al. Chimeric antigen receptor T-cell therapy-assessment 
and management of toxicities. In. Vol 15: Nature Publishing Group; 2018:47-62. 
Nomi T, Sho M, Akahori T, et al., Clinical significance and therapeutic potential of the 
programmed death-1 ligand/programmed death-1 pathway in human pancreatic cancer. Clin 
Cancer Res. 2007;13: p. 2151-7. 
O'Donnell JS, Teng MWL, Smyth MJ. Cancer immunoediting and resistance to T cell-based 
immunotherapy. Nat Rev Clin Oncol. 2019;16:151-67. 
Oh DY, Bang YJ. HER2-targeted therapies - a role beyond breast cancer. Nat Rev Clin Oncol. 
2020;17:33-48. 
Okazaki T, Maeda A, Nishimura H, et al. PD-1 immunoreceptor inhibits B cell receptor-mediated 
signaling by recruiting src homology 2-domain-containing tyrosine phosphatase 2 to 
phosphotyrosine. Proc Natl Acad Sci U S A 2001;98:13866-71. 
Oken MM, Creech RH, Tormey DC, et al. Toxicity and response criteria of the Eastern 
Cooperative Oncology Group. Am J Clin Oncol. 1982;5:649-55. 
Osborne W, Marzolini M, Tholouli E, et al. Phase I Alexander study of AUTO3, the first 
CD19/22 dual targeting CAR T cell therapy, with pembrolizumab in patients with 
relapsed/refractory (r/r) DLBCL. J Clin Oncol. 2020;38:15_suppl, 8001.  
Park JG, Frucht H, LaRocca RV, et al. Characteristics of cell lines established from human 
gastric carcinoma. Cancer Res. 1990;50:2773-80.  
Parry RV, Chemnitz JM, Frauwirth KA., et al. CTLA-4 and PD-1 receptors inhibit T-cell 
activation by distinct mechanisms. Mol Cell Biol, 2005;25:9543-53. 
Pilon-Thomas S, Mackay A, Vohra N, et al., Blockade of programmed death ligand 1 enhances 
the therapeutic efficacy of combination immunotherapy against melanoma. J Immunol 
2010;184:3442-9. 
Pinthus JH, Waks T, Malina V, et al. Adoptive immunotherapy of prostate cancer bone lesions 
using redirected effector lymphocytes. J Clin Invest. 2004;114:1774-81. 
Qi C, Gong J, Li J, et al. Claudin 18.2-specific CAR T cells in gastrointestinal cancers: phase 1 
trial interim results. Nat Met 2022;28:1189-98. 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 143 of 177 
 
 
Riley JL. PD-1 signaling in primary T cells. Immunol Rev. 2009; 229:114-25. 
Rockett JC, Larkin K, Darnton SJ, et al. Five newly established oesophageal carcinoma cell 
lines: phenotypic and immunological characterization. Br J Cancer. 1997;75:258-63.  
Rothe M, Modlich U, Schambach A. Biosafety challenges for use of lentiviral vectors in gene 
therapy. Curr Gene Ther. 2014;13:453-68. 
Scholler J, Brady TL, Binder-Scholl G, et al. Decade-long safety and function of 
retroviral-modified chimeric antigen receptor T cells. Sci Transl Med. 2012;4:132ra153. 
Schram A, Won HH, Andre F, et al. Abstract LB-103: Landscape of somatic ERBB2 Mutations: 
Findings from AACR GENIE and comparison to ongoing ERBB2 mutant basket study. Cancer 
Res. 2017;77(13_suppl):LB-103. 
Schwartz LH, Litiere S, de Vries E, et al. RECIST 1.1-Update and clarification: From the 
RECIST committee. Eur J Cancer. 2016;62:132-137. 
Sheppard K-A, Fitz LJ, Lee JM, et al. PD-1 inhibits T-cell receptor induced phosphorylation of 
the ZAP70/CD3zeta signalosome and downstream signaling to PKCtheta. FEBS Lett 
2004;574:37-41.  
Shitara K, Doi T, Dvorkin M, et al. Trifluridine/tipiracil versus placebo in patients with heavily 
pretreated metastatic gastric cancer (TAGS): a randomized, double-blind, placebo-controlled, 
phase 3 trial. Lance Oncol 2018;19:1437-48. 
Spranger S, Koblish HK, Horton B, et al., Mechanism of tumor rejection with doublets of 
CTLA-4, PD-1/PD-L1, or IDO blockade involves restored IL-2 production and proliferation of 
CD8(+) T cells directly within the tumor microenvironment. J Immunother Cancer, 2014;2:3. 
Spranger S, Spaapen RM, Zha Y, et al. Up-regulation of PD-L1, IDO, and T(regs) in the 
melanoma tumor microenvironment is driven by CD8(+) T cells. Sci Transl Med. 
2013;5:200ra116.  
Stachel D, Futterer A, Haas RJ, Schmid I. Enhanced lymphocyte proliferation responses in 
pediatric patients early after myelosuppressive chemotherapy. Pediatr Blood Cancer. 
2004;43:644-50. 
Strome SE, Dong H, Tamura H, et al. B7-H1 blockade augments adoptive T-cell immunotherapy 
for squamous cell carcinoma. Cancer Res. 2003;63: 6501-5. 
TCR2 Therapeutics (28 Sep 2022). Gavo-cell continues to demonstrate clinical benefit in solid 
tumors with additional RECIST responses in ovarian cancer and mesothelioma (Press Release) 
GlobNewWire by Notified. Available from: 
https://www.globenewswire.com/en/search/organization/TCR2%2520Therapeutics 

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Page 144 of 177 
 
 
Topalian SL, Hodi FS, Brahmer JR, et al. Safety, activity, and immune correlates of anti-PD-1 
antibody in cancer. N Engl J Med. 2012;366:2443-54. 
Tumeh PC, Harview CL, Yearley JH, et al. PD-1 blockade induces responses by inhibiting 
adaptive immune resistance. Nature. 2014;515:568-71. 
Turk MJ, Guevara-Patiño JA, Rizzuto GA, et al. Concomitant tumor immunity to a poorly 
immunogenic melanoma is prevented by regulatory T cells. J Exp Med. 2004;200:771-82. 
Turtle CJ, Hanafi L-A, Berger C, et al. Rate of durable complete response in ALL, NHL, and 
CLL after immunotherapy with optimized lymphodepletion and defined composition CD19 
CAR-T cells. J Clin Oncol. 2016;34(15_suppl):102-102. 
Vafaei S, Zekiy AO, Khanamir RA, et al. Combination therapy with immune checkpoint 
inhibitors (ICIs); a new frontier. Cancer Cell Int. 2022;22:2. 
Walsh N, Kennedy S, Larkin A, et al. EGFR and HER2 inhibition in pancreatic cancer. Invest 
New Drugs. 2013;31:558-66.  
Wang GP, Levine BL, Binder GK, et al. Analysis of lentiviral vector integration in HIV+ study 
subjects receiving autologous infusions of gene modified CD4+ T cells. Molecular therapy: the 
journal of the American Society of Gene Therapy. 2009;17:844-50. 
Weber J. Immune checkpoint proteins: a new therapeutic paradigm for cancer-nonclinical 
background: CTLA-4 and PD-1 blockade. Semin Oncol. 2010;37:430-9. 
World Medical Association Declaration of Helsinki: Ethical principles for medical research 
involving human subjects. JAMA. 2013:310:2191-4. 
Yan F, Mandrekar, SJ and Yuan Y. Keyboard: A novel bayesian toxicity probability interval 
design for Phase I clinical trials. Clinical Cancer Research 2017;23: 3994-4003. 
Yarden Y, Sliwkowski MX. Untangling the ErbB signalling network. In. Vol 2: Nat Rev Mol Cell 
Biol; 2001:127-37. 
Zehir A, Benayed R, Shah RH, et al. Mutational landscape of metastatic cancer revealed from 
prospective clinical sequencing of 10,000 patients. Nature Med. 2017;23:703-13. 
Zhang X, Schwartz J-C D, Guo X, et al. Structural and functional analysis of the costimulatory 
receptor programmed death-1. Immunity. 2004;20:337-47. 

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13. APPENDICES 
APPENDIX A1.  
MONOTHERAPY SCHEDULE OF EVENTS (SUBJECTS WHO RECEIVE ONE DOSE) 
Visit Schedule a, Days, unless 
specified 
 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
PD 
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusione 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 ±2 ±14 ±14 ±14 ±14 ±14 ±14 
4 wk 
after 
initial 
PD 
Administrative Procedures 
Informed Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed Consent for Future 
Biomedical Research 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Eligibility Criterias 
X 
 
X 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification Card 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification 
Number 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Demographics & Medical 
History 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior & Concomitant 
Medication Review 
X 
X 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Clinical Procedures/Assessments 
Leukapheresis 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Optional Bridging Treatment 
q 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lymphodepleting 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Visit Schedule a, Days, unless 
specified 
 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
PD 
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusione 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 ±2 ±14 ±14 ±14 ±14 ±14 ±14 
4 wk 
after 
initial 
PD 
Chemotherapy (LDC) 
TAC01-HER2 
Administrationf 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Physical Examinationi 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
ECOG Performance Status 
X 
 
X 
 
Xg 
 
 
 
 
 
 
 
 
 
 
X 
X 
 
X 
 
X 
 
X 
X 
Height 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Weight 
X 
 
 
 
Xg 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
Vital Signs 
X Xn 
X 
 
X 
Xo 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
 
 
 
 
 
 
 
12-lead ECG 
X 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ECHO/MUGA Scan 
X 
 
Xb  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
CTp 
X 
 
Xh 
 
 
 
 
 
 
 
 
 
 
 
 
At Day 29±2 days for first scan, then 
Q8W±2W for Year 1 (i.e., Weeks 12, 20, 28, 
36, 44, 52), then Q12W±2W for Year 2. If at 
any time, a scan indicates a CR or PR, a 
confirmation scan should occur at the next 
scheduled scan. 
X 
Disease Response 
Assessment 
X 
 
Xh 
 
 
 
 
 
 
 
 
 
 
 
 
X 
Adverse Events 
X 
X 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Laboratory Procedures: analysis performed by local laboratory 
Viral Serology 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Serum Pregnancy Test 
Xc 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 

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Visit Schedule a, Days, unless 
specified 
 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
PD 
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusione 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 ±2 ±14 ±14 ±14 ±14 ±14 ±14 
4 wk 
after 
initial 
PD 
Hematology 
X Xd 
X 
 
X 
Xj 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
Coagulation 
X Xd 
X 
 
X 
Xj 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
 
 
 
 
 
 
 
Serum Chemistry 
X Xd 
X 
 
X 
Xj 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
CRP, Ferritin & 
Triglycerides 
 
 
X 
 
 
Xj 
X 
X 
X 
X 
X 
X 
 
X 
 
X 
X 
 
 
 
 
 
 
 
IgG levels 
 
 
X 
 
 
 
 
 
X 
 
 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
Urine analysis 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Laboratory Procedures: analysis performed by central laboratory 
Fresh Tumor Biopsy 
Xl 
 
 
 
 
 
 
 
 
 
Xk 
 
 
 
 
Xk 
 
 
 
 
 
 
 
X 
PK Blood Sample 
 
 
X 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Cytokine Blood Sample 
 
 
X 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Biomarker Blood Sample 
 
 
X 
 
 
 
 
 
 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
RCL Blood Sample 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
 
X 
 
Xm 
 
HAMA 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
Abbreviations: CRP=C-reactive protein; CT=computed tomography; ECG=electrocardiogram; ECHO=echocardiogram; ECOG=Eastern Cooperative Oncology 
Group; EOS=end of study; IgG=immunoglobulin G; LDC=lymphodepleting chemotherapy; MUGA=multiple-gated acquisition; PD=progressive disease; 
PK=pharmacokinetics; RCL=replication-competent lentivirus. 
a 
Assessments are scheduled relative to the subject’s Triumvira TAC01-HER2 dose. 
b 
Only required for subjects who receive potential cardiotoxic drugs as bridging therapy. Must be conducted within 7 days prior to lymphodepletion. 
c 
Must be done at Screening and within 48 hours prior to initiating LDC. 

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d 
May be done up to 24 hours prior to leukapheresis. 
e 
All evaluations should be performed daily prior to LDC administration unless otherwise indicated. Ideally, following LDC completion, after a 48-hour (± 24 
hours) window, TAC01-HER2 should be infused. A window up to 5 days is acceptable between completion of LDC and TAC01-HER2 infusion.  
f 
All evaluations should be performed prior to TAC01-HER2 administration unless otherwise indicated. TAC01-HER2 administration is described in 
Section 7.3.2. Premedication is summarized in 5.3.3.First day of lymphodepletion only. 
g 
If a subject received bridging therapy, measurable disease needs to be confirmed prior to LDC.  
h 
Physical examination can be performed by non-study personnel operating within their license. 
i 
Must be collected prior to receiving TAC01-HER2 treatment. 
j 
For Phase 1, optional post-treatment tumor biopsies (in subjects with accessible disease where it is clinically safe) will be obtained at 11 ± 1 day and 
29 ± 2 days following the TAC01-HER2 dose. A fine needle aspiration (FNA) may be performed as an alternative when a fresh surgical or core needle 
biopsy is not clinically feasible. For Phase 2, the post-treatment biopsies are mandatory on Days 11 ± 1 and 29 ± 2 (as long as it is clinically feasible and 
safe). Subjects who refuse the post-treatment mandatory biopsy requirements will not be precluded from enrollment, nor discontinued from the study, and 
exceptions may be made after discussion with the Medical Monitor on a case-by-case basis. 
k 
If a fresh biopsy is not feasible, then an archival sample collected within 1 year prior to enrollment (samples may be collected >1 year prior to enrollment in 
Phase 1). If this is not feasible, a liquid biopsy to examine circulating tumor cells should be performed. Lastly, if this is not feasible, the most recent archival 
sample available regardless of when it was obtained during prior lines of therapy is acceptable. 
l 
If prior RCL testing is negative, sample will be archived and analyzed as needed.  
m 
Vital signs should be assessed prior to leukapheresis. Vital signs may be monitored during and after the procedure as clinically indicated. 
n 
Vitals signs should be assessed approximately 15 minutes (± 5 min) prior to the TAC01-HER2 infusion, approximately every 15 minutes (± 5 min) after the 
infusion for the first hour, and approximately hourly (± 15 min) for the next 3 hours. After 4 hours post-infusion, vital signs should be monitored until stable 
and as clinically indicated. 
o 
CT scans are requested at every imaging time point, unless MRI is used. The same imaging technique, methodology, and preferably the same equipment 
should be used on a subject throughout the study 
p 
Bridging therapy is optional. Duration of bridging therapy is limited to a maximum of 4 weeks. All therapies must be discontinued at least 14 days prior to 
initiation of lymphodepletion and the time from leukapheresis to lymphodepletion cannot exceed 8 weeks ± 1 week.  
q 
Post-Treatment Follow-Up begins on Day 43. If a subject has confirmed PD (i.e., with a confirmatory scan 28 days [± 7 days] after an initial scan indicating 
PD), or starts a new anticancer therapy, or the subject is unwilling or unable to continue the procedures, the subject will transition to the LTFU protocol. 
r 
Eligibility checklists are to be submitted at least 24 hours before leukapheresis, LDC, and first infusion.  
 

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APPENDIX A2.  
COMBINATION THERAPY SCHEDULE OF EVENTS 
 
Pre-
Treatment 
Treatment 
During or Post  
Pembro-Treatmentr 
PD  
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
LDC 
TAC01-HER2 on  
Day 1 only 
Pembro 
Cycle 1 
Cycles 
2  
to End 
(Q3W) 
Cycle 2 
Day 42 
only 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
 
Visit Schedule a, Days, 
unless specified 
(Pembrolizumab Cycle 
Days) 
 
 
≤14 to LDC 
≤4 weeks 
-4 to -2 e 
1 
2 
3 
4 
or 
5 
8 
11 14/ 
21 
(1) 
18/ 
25 
(5) 
21/ 
28 
(8) 
25/ 
32 
(12) 
29/ 
36 
(16) 
35/ 
41 
(1) 
42/ 
49 
(8) 
 
 
 
 
 
 
4 wk 
after 
initial 
PD 
Visit Window, Days, 
unless specified 
 
 
 
 
  
 
 
 
+1 ±1 ±1 ±2 
 
±2 
 
±2 
±2 t 
±2 
±14 ±14 ±14 ±14 ±14 ±14 
±7 
Administrative Procedures 
Informed Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed Consent for Future 
Biomedical Research 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Eligibility Criteriaw 
X 
 
X 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification Card 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification 
Number 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Demographics, Medical 
History, Baseline Symptoms 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior & Concomitant 
Medication Review 
X X X 
 
X 
X X X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Clinical Procedures/Assessments 
Leukapheresis 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Bridging Treatment q 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lymphodepleting 
Chemotherapy (LDC) 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TAC01-HER2 Admin. f 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Pre-
Treatment 
Treatment 
During or Post  
Pembro-Treatmentr 
PD  
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
LDC 
TAC01-HER2 on  
Day 1 only 
Pembro 
Cycle 1 
Cycles 
2  
to End 
(Q3W) 
Cycle 2 
Day 42 
only 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
 
Visit Schedule a, Days, 
unless specified 
(Pembrolizumab Cycle 
Days) 
 
 
≤14 to LDC 
≤4 weeks 
-4 to -2 e 
1 
2 
3 
4 
or 
5 
8 
11 14/ 
21 
(1) 
18/ 
25 
(5) 
21/ 
28 
(8) 
25/ 
32 
(12) 
29/ 
36 
(16) 
35/ 
41 
(1) 
42/ 
49 
(8) 
 
 
 
 
 
 
4 wk 
after 
initial 
PD 
Visit Window, Days, 
unless specified 
 
 
 
 
  
 
 
 
+1 ±1 ±1 ±2 
 
±2 
 
±2 
±2 t 
±2 
±14 ±14 ±14 ±14 ±14 ±14 
±7 
Pembrolizumab Admin f 
Day 21 or Day 14 v, then 
Q3W 
 
 
 
 
 
 
 
 
 
 
 
X v 
 
X v 
 
 
X 
 
 
 
 
 
 
 
 
Physical Examination i 
X 
 
X 
 
X 
X X X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
ECOG Performance Status 
X 
 
X 
 
X 
g 
 
 
 
 
 
 
X 
 
 
 
 
X 
X 
 
 
 
 
 
 
X 
Height 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Weight 
X 
 
 
 
X 
g 
 
 
 
 
 
X 
 
 
 
 
X 
 
 
 
 
 
 
 
X 
Vital Signs 
X Xn X 
 
X X o X X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
 
 
 
 
 
 
 
12-lead ECG 
X 
 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X 
ECHO/MUGA Scan 
X 
 X b 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
CT p 
X 
 X h 
 
 
 
At Week 8±2W for the first scan, then Q8W±2W for Year 1 (i.e., Week 16, 24, 32, 40, 48 [± 3 
days]), then Q12W±2W for Year 2 (i.e., Week 60, 72, 84, 96 [± 3 days]) from TAC01-HER2 
dose. If at any time, a scan indicates a CR or PR, a confirmation scan should occur at the next 
scheduled scan. 
X 
Disease response 
assessments  
X 
 X h 
 
 
 
X 
Adverse Events 
X X X 
 
X 
X X X 
X 
X 
X 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
PD-L1 Expression Level  
X s  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Local Laboratory Procedures 
Viral Serology 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
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Page 151 of 177 
 
 
 
Pre-
Treatment 
Treatment 
During or Post  
Pembro-Treatmentr 
PD  
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
LDC 
TAC01-HER2 on  
Day 1 only 
Pembro 
Cycle 1 
Cycles 
2  
to End 
(Q3W) 
Cycle 2 
Day 42 
only 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
 
Visit Schedule a, Days, 
unless specified 
(Pembrolizumab Cycle 
Days) 
 
 
≤14 to LDC 
≤4 weeks 
-4 to -2 e 
1 
2 
3 
4 
or 
5 
8 
11 14/ 
21 
(1) 
18/ 
25 
(5) 
21/ 
28 
(8) 
25/ 
32 
(12) 
29/ 
36 
(16) 
35/ 
41 
(1) 
42/ 
49 
(8) 
 
 
 
 
 
 
4 wk 
after 
initial 
PD 
Visit Window, Days, 
unless specified 
 
 
 
 
  
 
 
 
+1 ±1 ±1 ±2 
 
±2 
 
±2 
±2 t 
±2 
±14 ±14 ±14 ±14 ±14 ±14 
±7 
Serum Pregnancy Test 
X 
c 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
Hematology 
X X 
d 
X 
 
X 
Xj X X 
X 
X 
X X u 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Coagulation 
X X 
d 
X 
 
X 
Xj X X 
X 
X 
X X u 
 
 
 
 
 
X 
 
 
 
 
 
 
X 
Serum Chemistry 
X X 
d 
X 
 
X 
Xj X X 
X 
X 
X X u 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Thyroid Function Tests 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
Every 6 weeks  
(T3 or FT3, FT4, TSH) 
 
CRP, Ferritin & 
Triglycerides 
 
 
X 
 
 
Xj X X 
X 
X 
X X u 
 
 
 
 
 
X 
 
 
 
 
 
 
X 
IgG levels 
 
 
X 
 
 
 
 
 
X 
 
 
X u 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Urine analysis 
 
 
X 
 
 
 
 
 
 
 
 
X u 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Central Laboratory Procedures 
Fresh Tumor Biopsy 
X l  
 
 
 
 
 
 
 
 
X k 
 
 
 
 
Xk 
 
 
 
 
 
 
 
 
X 
PK Blood Sample 
 
 
X 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
Cytokine Blood Sample 
 
 
X 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
Biomarker Blood Sample 
 
 
X 
 
 
 
 
 
 
X 
X 
X 
 
X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
RCL Blood Sample 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
 
X 
 
X 
Xm 

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Confidential 
Page 152 of 177 
 
 
 
Pre-
Treatment 
Treatment 
During or Post  
Pembro-Treatmentr 
PD  
Visitr 
Screening 
Leukapheresis 
Pre-LDC 
Bridging q 
LDC 
TAC01-HER2 on  
Day 1 only 
Pembro 
Cycle 1 
Cycles 
2  
to End 
(Q3W) 
Cycle 2 
Day 42 
only 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
 
Visit Schedule a, Days, 
unless specified 
(Pembrolizumab Cycle 
Days) 
 
 
≤14 to LDC 
≤4 weeks 
-4 to -2 e 
1 
2 
3 
4 
or 
5 
8 
11 14/ 
21 
(1) 
18/ 
25 
(5) 
21/ 
28 
(8) 
25/ 
32 
(12) 
29/ 
36 
(16) 
35/ 
41 
(1) 
42/ 
49 
(8) 
 
 
 
 
 
 
4 wk 
after 
initial 
PD 
Visit Window, Days, 
unless specified 
 
 
 
 
  
 
 
 
+1 ±1 ±1 ±2 
 
±2 
 
±2 
±2 t 
±2 
±14 ±14 ±14 ±14 ±14 ±14 
±7 
Blood for ctDNA 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
HAMA 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
Abbreviations: CRP=C-reactive protein; CT=computed tomography; ctDNA=circulating tumor DNA; ECG=electrocardiogram; ECHO=echocardiogram; 
ECOG=Eastern Cooperative Oncology Group; EOS=end of study; FT3=free triiodo thyronine; FT4=free thyroxine; IgG=immunoglobulin G; 
LDC=lymphodepletion chemotherapy; MUGA=multiple-gated acquisition; PD=progressive disease; PK=pharmacokinetics; RCL=replication-competent 
lentivirus; T3=triiodothyronine; TSH=thyroid stimulating hormone. 
a 
Assessments are first scheduled relative to the subject’s TAC01-HER2 dose; however, after the first pembrolizumab dose, visits are scheduled based on 
pembrolizumab cycle days, but scans are always relative to the TAC02-HER2 dose on Day 1. 
b 
Only required for subjects who receive potential cardiotoxic drugs as bridging therapy. Must be conducted within 7 days prior to lymphodepletion. 
c 
Must be done at Screening and within 48 hours prior to initiating LDC. 
d 
May be done up to 24 hours prior to leukapheresis. 
e 
All evaluations should be performed daily prior to LDC administration unless otherwise indicated. Ideally, following LDC completion, after a 48-hour (± 24 
hours) window, TAC01-HER2 should be infused. A window up to 5 days is acceptable between completion of LDC and TAC01-HER2 infusion.  
f 
All evaluations should be performed prior to TAC01-HER2 administration or pembrolizumab administration, unless otherwise indicated. TAC01-HER2 
administration is described in Section 7.3.2. Premedication is summarized in 5.3.3. 
g 
First day of lymphodepletion only. 
h 
If a subject received bridging therapy, measurable disease needs to be confirmed prior to LDC.  
i 
Physical examination can be performed by non-study personnel operating within their license. 
j 
Must be collected prior to receiving TAC01-HER2 treatment. 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
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Confidential 
Page 153 of 177 
 
 
k 
For Phase 1, optional post-treatment tumor biopsies (in subjects with accessible disease where it is clinically safe) will be obtained approximately 11 ± 1 day 
and 29 ± 2 days following the TAC01-HER2 dose. A fine needle aspiration (FNA) may be performed as an alternative when a fresh surgical or core needle 
biopsy is not clinically feasible. For Phase 2, the post-treatment biopsies are mandatory on Days 11 ± 1 and 29 ± 2 (as long as it is clinically feasible and 
safe). Subjects who refuse the post-treatment mandatory biopsy requirements will not be precluded from enrollment, nor discontinued from the study, and 
exceptions may be made after discussion with the Medical Monitor on a case-by-case basis. 
l 
If a fresh biopsy is not feasible, then an archival sample collected within 1 year prior to enrollment (samples may be collected >1 year prior to enrollment in 
Phase 1). If this is not feasible, a liquid biopsy to examine circulating tumor cells should be performed. Lastly, if this is not feasible, the most recent archival 
sample available regardless of when it was obtained during prior lines of therapy is acceptable. 
m 
If prior RCL testing is negative, sample will be archived and analyzed as needed.  
n 
Vital signs should be assessed prior to leukapheresis. Vital signs may be monitored during and after the procedure as clinically indicated. 
o 
Vitals signs should be assessed approximately 15 minutes (± 5 min) prior to the TAC01-HER2 infusion, approximately every 15 minutes (± 5 min) after the 
infusion for the first hour, and approximately hourly (± 15 min) for the next 3 hours. After 4 hours post-infusion, vital signs should be monitored until stable 
and as clinically indicated 
p 
CT scans are requested at every imaging time point, unless MRI is used. The same imaging technique, methodology, and preferably the same equipment 
should be used on a subject throughout the study. 
q 
Bridging therapy is optional. Duration of bridging therapy is limited to a maximum of 4 weeks. All therapies must be discontinued at least 14 days prior to 
initiation of lymphodepletion and the time from leukapheresis to lymphodepletion cannot exceed 8 weeks ± 1 week.  
r 
Post-Treatment Follow-Up begins on Day 43. If a subject has confirmed PD (i.e., with a confirmatory scan 28 days [± 7 days] after an initial scan indicating 
PD), or starts a new anticancer therapy, or the subject is unwilling or unable to continue the procedures, the subject will transition to the LTFU protocol. 
s 
All subjects receiving pembrolizumab are required to have their tumors assessed for the level of PD-L1 expression at Baseline. Previously determined local 
results are acceptable. New biopsies and local analyses are required to be performed, if no other results or samples are available. 
t 
If the scheduled pembrolizumab dose occurs outside of the ± 2-day visit window, the subsequent pembrolizumab dose should be based on the actual date of 
the previous dose (i.e., Q3W ± 2 days from the previous dose). 
u 
Laboratory tests should be taken prior to pembrolizumab infusion. 
v 
Pembrolizumab administration will either begin on Day 14 OR Day 21 (i.e., at the Day 22 [± 2 days] visit), then occur Q3W for up to 2 years. Only a single 
dose should be administered either on Day 14 OR Day 21 as the start of pembrolizumab therapy. For additional details, see Section 3.2. 
w 
Eligibility checklists are to be submitted at least 24 hours before leukapheresis, LDC, and first infusion.  

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
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Confidential 
Page 154 of 177 
 
 
APPENDIX B.  
MONOTHERAPY SCHEDULE OF EVENTS (SUBJECTS WHO RECEIVE 2 DOSES [ON DAY 1 AND 
DAY X]) 
Visit Schedule a, Days 
unless specified 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
Based on Day 1 
Screening 
Leukapheresis 
Pre-LDC 
Bridging b 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Day X 
Can occur any time after 
Day 29 
(2nd dose) 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless 
specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusionc 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 
±2 
2-3 weeks after criteria 
are met 
±14 ±14 ±14 ±14 ±14 ±14 
Informed Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed Consent for 
Future Biomedical 
Research 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Eligibility Criterias 
X 
 
X 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification 
Card 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject Identification 
Number 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Demographics/Medical 
History 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior and Concomitant 
Medication Review 
X X 
X 
 
X 
X X X X X X X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Leukapheresis 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Optional Bridging 
Treatmentb 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lymphodepleting 
Chemotherapy (LDC) 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Day X-4 to X-2, as 
appropriate 
 
 
 
 
 
 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 155 of 177 
 
 
Visit Schedule a, Days 
unless specified 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
Based on Day 1 
Screening 
Leukapheresis 
Pre-LDC 
Bridging b 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Day X 
Can occur any time after 
Day 29 
(2nd dose) 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless 
specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusionc 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 
±2 
2-3 weeks after criteria 
are met 
±14 ±14 ±14 ±14 ±14 ±14 
TAC01-HER2 
Administration d 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
Physical Examination e X 
 
X 
 
X 
X X X X X X X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
ECOG Performance 
Status 
X 
 
X 
 
Xf 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
 
X 
 
X 
 
X 
Height 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Weight 
X 
 
 
 
Xf 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
Vital Signs 
X Xg X 
 
X 
Xh X X X X X X 
 
X 
 
X 
X 
X 
 
 
 
 
 
 
12-lead ECG 
X 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ECHO/MUGA Scan 
X 
 
Xi  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
CT j 
X 
 
Xk  
 
 
 
 
 
 
 
 
 
 
 
Scans follow 
Phase 1 SOE 
until Day X 
Day X +28, then Q8W (±2W) 
in Year 1, Q12W (±2W) in 
Year 2.  
If CR or PR, confirmation 
occurs at next scheduled scan 
 
 
 
 
 
 
Disease Response 
Assessment 
X 
 
Xk  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Adverse Events 
X X 
X 
 
X 
X X X X X X X 
 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Viral Serology 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Serum Pregnancy Test Xl 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
Hematology 
X Xm X 
 
X 
Xp X X X X X X 
 
X 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
X 
X 
X 
X 
X 
X 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 156 of 177 
 
 
Visit Schedule a, Days 
unless specified 
Pre-Treatment 
Treatment 
Post-Treatment Follow-upr 
Based on Day 1 
Screening 
Leukapheresis 
Pre-LDC 
Bridging b 
Lympho-
depletion 
Day 1 
Day 2 
Day 3 
Day 4 or 5 
Day 8 
Day 11 
Day 15 
Day 18 
Day 22 
Day 25 
Day 29 
Day 42 
Day X 
Can occur any time after 
Day 29 
(2nd dose) 
Month 3 
Month 6 
Month 9 
Month 12 
Month 18 
Month 24 or 
EOS 
Visit Window 
Days, unless 
specified 
 
 
≤14 
Prior 
to 
LDC 
 
-4 to -2 
Prior to 
Infusionc 
 
 
 
+1  ±1 ±1 ±2 ±2 ±2 ±2 ±2 
±2 
2-3 weeks after criteria 
are met 
±14 ±14 ±14 ±14 ±14 ±14 
Coagulation 
X Xm X 
 
X 
Xp X X X X X X 
 
X 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
 
 
 
 
 
 
Serum Chemistry 
X Xm X 
 
X 
Xp X X X X X X 
 
X 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
X 
X 
X 
X 
X 
X 
CRP, Ferritin, and 
Triglycerides 
 
 
X 
 
 
Xp X X X X X X 
 
X 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
 
 
 
 
 
 
IgG levels 
 
 
X 
 
 
 
 
 
X 
 
 
X 
 
 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
X 
X 
X 
X 
X 
X 
Urinalysis 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X, X+4, X+7, X+14, 
X+28 
X 
X 
X 
X 
X 
X 
Fresh Tumor Biopsy 
Xn 
 
 
 
 
 
 
 
 
 
Xo 
 
 
 
 
Xo 
 
 
 
 
 
 
 
 
PK Blood Sample  
 
 
X 
 
 
 
 
X X X X X X X X X 
X 
Days X+2, X+3 or 4, X+7, 
X+10, X+14, X+17, X+21, 
X+24, X+28, X+41 
X 
X 
X 
X 
X 
X 
Cytokine Blood 
Sample 
 
 
X 
 
 
 
 
X X X X X X X X X 
X 
Days X+2, X+3 or 4, X+7, 
X+10, X+14, X+17, X+21, 
X+24, X+28, X+41 
X 
X 
X 
X 
X 
X 
Biomarker Blood 
Sample 
 
 
X 
 
 
 
 
 
 
X X X 
 
X 
 
X 
X 
Days X+7, X+10, X+14, 
X+21, X+28, X+41 
X 
X 
X 
X 
X 
X 
RCL Blood Sample 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
 
X 
 
Xq 
HAMA 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X 
 
X+28 
 
 
 
 
 
 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 157 of 177 
 
 
Abbreviations: CR=complete response; CRP=C-reactive protein; CT=computed tomography; ECG=electrocardiogram; ECHO=echocardiogram; ECOG=Eastern 
Cooperative Oncology Group; EOS=end of study; IgG=immunoglobulin G; LDC=lymphodepleting chemotherapy; MUGA=multigated acquisition; 
nab=nanoparticle albumin-bound; PD=progressive disease; PK=pharmacokinetics; PR=partial response; RCL=replication-competent lentivirus. 
a 
Assessments are scheduled relative to the subject’s TAC01-HER2 dose. 
b 
Duration of bridging anticancer therapy is limited to a maximum of 4 weeks. All therapies must be discontinued at least 14 days prior to initiation of LDC. If 
the time from leukapheresis to the first LDC exceeds 8 weeks ± 1 week, subjects must be rescreened.  
c 
All evaluations should be performed daily prior to LDC.  
d 
All evaluations should be performed prior to TAC01-HER2 administration unless otherwise indicated. TAC01-HER2 administration is described in 
Section 7.3.2. Premedication is summarized in 5.3.3. 
e 
Physical examination can be performed by non-study personnel operating within their license. 
f 
First day of LDC only. 
g 
Vital signs should be assessed prior to leukapheresis. Vital signs may be monitored during and after the procedure as clinically indicated. 
h 
Vitals signs should be assessed approximately 15 minutes (± 5 min) prior to TAC01-HER2 administration, approximately every 15 minutes (± 5 min) after 
the infusion for the first hour, and approximately hourly (± 15 min) for the next 3 hours. After 4 hours post-infusion, vital signs should be monitored until 
stable and as clinically indicated. 
i 
Only required for subjects who receive potential cardiotoxic drugs as bridging anticancer therapy. Must be conducted within 7 days prior to LDC. 
j 
CT scans are required at every imaging time point, unless MRI is used. The same imaging technique, methodology, and preferably the same equipment 
should be used for a subject throughout the study. 
k 
If a subject received bridging anticancer therapy, measurable disease needs to be confirmed prior to LDC.  
l 
Must be done at Screening and within 48 hours prior to initiating LDC. 
m 
May be done up to 24 hours prior to leukapheresis. 
n 
If a fresh biopsy is not feasible, then an archival sample collected within 1 year prior to enrollment (samples may be collected >1 year prior to enrollment in 
Phase 1). If this is not feasible, a liquid biopsy to examine circulating tumor cells should be performed. Lastly, if this is not feasible, the most recent archival 
sample available regardless of when it was obtained during prior lines of therapy is acceptable. 
o 
Optional for Phase 1, mandatory for Phase 2 (see Section 7.13.8). 
p 
Must be collected prior to TAC01-HER2 administration. 
q 
If prior RCL testing is negative, sample will be archived and analyzed as needed.  
r 
Post Treatment Follow Up begins on Day 43. 
s 
Eligibility checklists are to be submitted at least 24 hours before leukapheresis, LDC, and first infusion.  

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 158 of 177 
 
 
APPENDIX C.  
DOSE ESCALATION & DE-ESCALATION GUIDELINE 
Keyboard Decision Table (Dose Finding) 
Number of Subjects Treated at the Current Dose Level 
Number 
of DLTs 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
0 
 
 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
1 
 
 
S 
S 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
2 
 
D 
D 
D 
D 
S 
S 
S 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
E 
3 
 
 
X 
X 
D 
D 
D 
D 
S 
S 
S 
S 
E 
E 
E 
E 
E 
E 
E 
E 
4 
 
 
 
X 
X 
X 
D 
D 
D 
D 
D 
S 
S 
S 
S 
S 
E 
E 
E 
E 
5 
 
 
 
 
X 
X 
X 
X 
X 
D 
D 
D 
D 
D 
S 
S 
S 
S 
S 
S 
6 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
D 
D 
D 
D 
D 
D 
S 
S 
S 
7 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
D 
D 
D 
D 
D 
D 
D 
8 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
D 
D 
D 
D 
9 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
D 
10 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
11 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
12 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
N=20, Ptarget=0.30, ε1=0.05 and ε2= 0.05 
The table will be applied separately for each dose level. Column indicates number of subjects treated within a given dose level; row 
indicates number of subjects with DLTs at that dose level. 
E=Escalate to the next higher dose 
S=Stay at the same dose 
D=De-escalate to the previous lower dose 
X=De-escalate to the previous lower dose and eliminate the current dose from further use in the study 

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After all subjects have been evaluated for DLT, the MTD will be selected based on isotonic regression as specified in Yan, Mandrekar 
and Yuan (Yan 2017). Specifically, the MTD is selected as the dose level with the isotonic estimate closest to the target DLT rate. If 
there are ties, select the higher dose level when the isotonic estimate is lower than the target toxicity rate and select the lower dose 
level when the isotonic estimate is greater than or equal to the target toxicity rate. 
Note: Once the MTD is determined, up to 50 additional subjects will receive TAC01-HER2 at the RP2D. For subject safety, the dose 
elimination rule in the table above will be used as a stopping boundary for toxicity monitoring. With this rule, enrollment would be 
terminated if observed data indicate more than a 95% chance that the DLT rate is above the toxicity target (30%). 
Operating Characteristics: 
Table 20 shows the operating characteristics of the study design based on 1000 simulations of the study using shiny app “Keyboard” 
available at http://www.trialdesign.org. The operating characteristics show that the design selects the true MTD, if any, with high 
probability and allocates more subjects to the dose levels with the DLT rate closest to the target of 0.30. 

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Table 20: Operating Characteristics of the Keyboard Design 
 
Dose Level -1 
Dose Level 1 
Dose Level 2 
Dose Level 3 
Dose Level 4 
Number of 
Subjects 
% Early 
Stopping 
Scenario 1 
 
 
 
 
 
 
 
True DLT rate 
0.30 
0.47 
0.53 
0.58 
0.64 
 
 
Selection % 
58.2 
19.3 
5.7 
1.6 
0.4 
 
14.8 
# Pts treated 
9.35 
5.62 
2.26 
0.91 
0.35 
18.5 
 
Scenario 2 
 
 
 
 
 
 
 
True DLT rate 
0.11 
0.30 
0.45 
0.56 
0.67 
 
 
Selection % 
19.3 
53.8 
21.5 
5 
0.2 
 
0.2 
# Pts treated 
4.33 
8.5 
4.7 
1.87 
0.57 
20 
 
Scenario 3 
 
 
 
 
 
 
 
True DLT rate 
0.02 
0.07 
0.13 
0.30 
0.47 
 
 
Selection % 
0.1 
1.7 
23 
55.4 
19.8 
 
0 
# Pts treated 
0.25 
2.1 
5.06 
7.62 
4.96 
20 
 
Scenario 4 
 
 
 
 
 
 
 
True DLT rate 
0.05 
0.08 
0.12 
0.15 
0.30 
 
 
Selection % 
0.1 
1.4 
5.7 
24.8 
68 
 
0 
# Pts treated 
0.29 
1.98 
2.62 
5.09 
10.02 
20 
 
Note: “% Early Stopping” refers to early stopping due to excessive DLT. 

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APPENDIX D.  
CYTOKINE RELEASE SYNDROME AND NEUROTOXICITY GRADING 
Cytokine Release Syndrome (CRS) Grading 
Grade 
 
Toxicity ASTCT Consensus Gradingb 
Grade 1 
 
Parameter 
Fever 
Temperature greater than or equal to 38°C. 
With Hypotension 
None. 
And/or Hypoxia 
None. 
Grade 2 
 
Parameter 
Fever 
Temperature greater than or equal to 38°C. 
With Hypotension 
Does not require vasopressors. 
And/or Hypoxia 
Requires low-flow nasal cannula (less than 6L/min 
via nasal prongs). 
Grade 3 
 
Parameter 
Fever 
Temperature greater than or equal to 38°C. 
With Hypotension 
Requires a vasopressor (with or without vasopressin). 
And/or Hypoxia 
Requires high-flow nasal cannula (more than 6L/min 
via nasal prongs), facemask. 
Grade 4 
 
Parameter 
Fever 
Temperature greater than or equal to 38°C. 
With Hypotension 
Requires multiple vasopressors (excluding 
vasopressin). 
And/or Hypoxia 
Requires positive pressure (Continuous positive 
airway pressure [CPAP], BiPAP, intubation and 
mechanical ventilation). 
a. 
b Adapted From: Lee 2019. ASTCT Consensus Grading for Cytokine Release Syndrome and Neurologic Toxicity Associated with Immune Effector Cells. Biology of 
Blood and Marrow Transplantation. https://www.bbmt.org/article/S1083-8791(18)31691-4/fulltext5 

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Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS) Gradinga 
Parameter: 
GRADE 1 
GRADE 2 
GRADE 3 
GRADE 4 
ICE Scoreb 
(See Form) 
Score 7-9 
Score 3-6 
Score 0-2 
Score 0 (subject unarousable/unable 
to perform ICE). 
Depressed Level 
of Consciousness 
Awakens 
spontaneously. 
Awakens to 
voice. 
Awakens only to tactile stimulation. 
Unarousable; requires vigorous tactile 
stimulation to rouse; stupor or coma. 
Seizure 
N/A 
N/A 
Any clinical seizure (focal or generalized) 
that rapidly resolves or non-convulsive on 
electroencephalogram (EEG) that resolves 
with intervention 
Life-threatening prolonged seizure 
(over 5 minutes) or repetitive clinical 
or electrical seizures without return to 
baseline between. 
Motor Findings 
N/A 
N/A 
N/A 
Deep focal motor weakness such as 
hemi- or paraparesis. 
Elevated ICP/ 
Cerebral Edema 
N/A 
N/A 
Focal/local edema on neuroimaging. 
Diffuse cerebral edema on 
neuroimaging; decerebrate or 
decorticate posturing; or cranial nerve 
VI palsy; or Papilledema; or 
Cushing’s Triad. 
a. 
Adapted From: Lee 2019. ASTCT Consensus Grading for Cytokine Release Syndrome and Neurologic Toxicity Associated with Immune Effector Cells. Biology of 
Blood and Marrow Transplantation. https://www.bbmt.org/article/S1083-8791(18)31691-4/fulltext5 
b. 
The assessment can be performed by non-study personnel operating within their license. 
 
 

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APPENDIX E.  
ASSESSMENT AND MANAGEMENT CONSIDERATIONS CRS, NEUROTOXICITY AND MAS/HLH 
Three Step Approach to Assessing and Managing TAC T cell Toxicity 
Adapted from Neelapu 2018. 
These are management recommendations for subjects who experience CRS, neurotoxicity, and/or MAS/HLH after TAC T cells. 
Step 1: Monitor the subject’s clinical and biological symptoms to determine the nature of the TAC T cell related toxicity, in order to 
diagnose CRS, neurotoxicity, and MAS/HLH.  
Step 2: Grade the severity of CRS, neurotoxicity, and MAS/HLH using the criteria provided in Appendix D, Appendix E, and the NCI 
CTCAE Version 5.0, respectively.  
Step 3: Treat the toxicities according to the management algorithms provided for CRS (Appendix D), neurotoxicity (Appendix E), and 
MAS/HLH (Appendix E). 
Determining TAC T 
Cell Toxicity 
CRS 
Neurotoxicity 
MAS/HLH 
Step 1 
• 
Fever 
• 
Hypotension 
• 
Hypoxia 
• 
Organ Toxicity 
o 
Cardiac 
o 
Respiratory 
o 
Gastrointestinal 
o 
Hepatic 
o 
Renal 
o 
Dermatological 
o 
Coagulopathy 
• 
Orientation/Alertness 
o 
Name Objects 
o 
Writing 
o 
Counting 
• 
Seizures 
o 
Convulsive 
o 
Non-convulsive 
• 
Increased ICP 
o 
CSF Opening Pressure 
o 
Papilloedema 
o 
Cerebral Edema 
• 
Motor Weakness 
• 
Ferritin Level 
• 
Hepatic Toxicity 
• 
Renal Toxicity 
• 
Pulmonary Toxicity 
• 
Hemophagocytosis 
Step 2 
Grade CRS 
Grade Neurotoxicity 
Grade Organ Toxicity per NCI CTCAE Version 
5.0 
Step 3 
Manage According to CRS Grade 
Manage According to Neurotoxicity 
Grade 
Manage as per Algorithm. 

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Cytokine Release Syndrome (CRS) Management 
Grading refers to Lee 2019. 
Adapted from Neelapu 2018. 
CRS Grade 
Symptom or Sign 
Management 
Grade 1 
Fever or Organ Toxicity 
• 
Acetaminophen and hypothermia blanket for fever. 
• 
Ibuprofen can be used as second treatment option for fever, if not contraindicated. 
• 
Assess for infection using blood and urine cultures, and chest radiography. 
• 
Empiric broad‑spectrum antibiotics and filgrastima if neutropenic. 
• 
Maintenance IV fluids for hydration. 
• 
Symptomatic management of constitutional symptoms and organ toxicities. 
• 
Consider tocilizumabb 8 mg/kg IV for persistent (lasting >3 days) and refractory fever. 
Grade 2 
Hypotension 
• 
IV fluid bolus of 500–1,000 ml of normal saline 
• 
Can administer a second IV fluid bolus if systolic blood pressure (SBP) remains <90 mmHg 
• 
Tocilizumabb 8 mg/kg IV for the treatment of hypotension that is refractory to fluid boluses; tocilizumab can be 
repeated after 8 hours if needed. 
• 
If hypotension persists after 2 fluid boluses and anti‑IL‑6 therapy, start vasopressors, consider transfer to ICU, 
obtain echocardiogram (ECHO), and initiate other methods of hemodynamic monitoring. 
• 
In subjects at high-riskc or if hypotension persists after 1–2 doses of anti‑IL‑6 therapy, dexamethasone can be 
used at 10 mg IV every 6 hours. 
• 
Manage fever and constitutional symptoms as in Grade 1. 
Hypoxia 
• 
Supplemental oxygen. 
• 
Tocilizumabb with or without corticosteroids and supportive care, as recommended for the management of 
hypotension. 
Organ Toxicity 
• 
Symptomatic management of organ toxicities, as per standard guidelines. 
• 
Tocilizumabb with or without corticosteroids and supportive care, as indicated for hypotension. 

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CRS Grade 
Symptom or Sign 
Management 
Grade 3 
Hypotension 
• 
IV fluid boluses as needed, as recommended for the treatment of Grade 2 CRS. 
• 
If not administered previously, tocilizumabb as recommended for Grade 2 CRS. 
• 
Vasopressors as needed. 
• 
Transfer to ICU, obtain ECHO, and perform hemodynamic monitoring as in the management of Grade 2 CRS. 
• 
Dexamethasone 10 mg IV every 6 hours; if refractory, increase to 20 mg IV every 6 hours. 
• 
Manage fever and constitutional symptoms as indicated for Grade 1 CRS. 
Hypoxia 
• 
Supplemental oxygen including high‑flow oxygen delivery and non‑invasive positive pressure ventilation. 
• 
Tocilizumabb plus corticosteroids and supportive care, as described above. 
Organ Toxicity 
• 
Symptomatic management of organ toxicities as per standard guidelines. 
• 
Tocilizumabb plus corticosteroids and supportive care, as described above. 
Grade 4 
Hypotension 
• 
IV fluids, anti‑IL‑6 therapy, vasopressors, and hemodynamic monitoring as defined for the management of 
Grade 3 CRS. 
• 
Methylprednisolone 1 g/day IV. 
• 
Manage fever and constitutional symptoms as in Grade 1 CRS. 
Hypoxia 
• 
Mechanical ventilation. 
• 
Tocilizumabb plus corticosteroids and supportive care, as described above. 
Organ Toxicity 
• 
Symptomatic management of organ toxicities as per standard guidelines. 
• 
Tocilizumabb plus corticosteroids and supportive care, as described above. 
a 
Use of filgrastim is not permitted 7 days prior until 10 days after TAC01-HER2 treatment (see Section 5.8) 
b 
Maximum amount of tocilizumab per dose is 800 mg. If subject is unresponsive to 2-3 doses of tocilizumab, consider using siltuximab 11 mg/kg IV or 
anakinra 100 mg/day subcutaneous (SC) as per institutional cell therapy guidelines. Tocilizumab should be used as per label for CRS. In case of a 
tocilizumab-shortage, siltuximab or anakinra that are normally used as second line treatments as per institutional cell therapy guidelines can be used as first 
line.  
c 
High‑risk subjects include those with bulky disease, those with comorbidities, and those who develop early onset CRS within 3 days of TAC T cell infusion. 
 

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Neurotoxicity Management 
Adapted from Neelapu 2018. 
NT Grade 
Management 
Grade 1 
• 
Vigilant supportive care; aspiration precautions; IV hydration. 
• 
Withhold oral intake of food, medicines, and fluids, and assess swallowing. 
• 
Convert all oral medications and/or nutrition to IV if swallowing is impaired. 
• 
Avoid medications that cause central nervous system depression. 
• 
Low doses of lorazepam (0.25–0.5 mg IV every 8 hours) or haloperidol (0.5 mg IV every 6 hours) can be used, with careful monitoring, for 
agitated subjects. 
• 
Neurology consultation. 
• 
Fundoscopic examination to assess for papilloedema as per Investigator discretion 
• 
MRI of the brain with and without contrast; diagnostic lumbar puncture with measurement of opening pressure; MRI spine if the subject has 
focal peripheral neurological deficits; CT scan of the brain can be performed if MRI of the brain is not feasible. 
• 
Daily 30 min EEG until toxicity symptoms resolve; if no seizures are detected on EEG, continue levetiracetam 750 mg every 12 hours. 
• 
If EEG shows non-convulsive status epilepticus, treat as per algorithm in Appendix E. 
• 
Consider anti-IL-6 therapy with tocilizumaba 8 mg/kg IV, if neurotoxicity is associated with concurrent CRS. 
Grade 2 
• 
Supportive care and neurological work-up as described for Grade 1 neurotoxicity. 
• 
Tocilizumaba 8 mg/kg IV if associated with concurrent CRS. 
• 
Dexamethasone 10 mg IV every 6 hours or methylprednisolone 1 mg/kg IV every 12 hours if refractory to anti-IL-6 therapy or for 
neurotoxicity without concurrent CRS. 
• 
Consider transferring subject to ICU if neurotoxicity associated with Grade ≥2 CRS. 
Grade 3 
• 
Supportive care and neurological work-up as indicated for Grade 1 neurotoxicity. 
• 
ICU transfer is recommended. 
• 
Anti-IL-6 therapy if associated with concurrent CRS, as described for Grade 2 neurotoxicity and if not administered previously. 
• 
Corticosteroids as outlined for Grade 2 neurotoxicity if symptoms worsen despite anti-IL-6 therapy, or for neurotoxicity without concurrent 
CRS; continue corticosteroids until improvement to Grade 1 neurotoxicity and then taper. 
• 
Stage 1 or 2 papilloedema with CSF opening pressure <20 mmHg should be treated as per algorithm presented in Appendix E. 
• 
Consider repeat neuroimaging (CT or MRI) every 2–3 days if subject has persistent Grade ≥3 neurotoxicity. 

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NT Grade 
Management 
Grade 4 
• 
Supportive care and neurological work-up as outlined for Grade 1 neurotoxicity. 
• 
ICU monitoring; consider mechanical ventilation for airway protection. 
• 
Anti-IL-6 therapy and repeat neuroimaging as described for Grade 3 neurotoxicity. 
• 
High-dose corticosteroids continued until improvement to Grade 1 neurotoxicity and then taper; for example, methylprednisolone IV 1 g/day 
for 3 days, followed by rapid taper at 250 mg every 12 hours for 2 days, 125 mg every 12 hours for 2 days, and 60 mg every 12 hours for 
2 days. 
• 
For convulsive status epilepticus, treat as per algorithm in Appendix E. 
• 
Stage ≥3 papilloedema, with a CSF opening pressure ≥20 mmHg or cerebral edema, should be treated as per algorithm in Appendix E. 
a       Maximum amount of tocilizumab per dose is 800 mg. If subject is unresponsive to 2-3 doses of tocilizumab, consider using siltuximab 11 mg/kg IV or anakinra 
100 mg/day SC as per institutional cell therapy guidelines. Tocilizumab should be used as per label for CRS. In case of a tocilizumab-shortage, siltuximab or 
anakinra that are normally used as second line treatments as per institutional cell therapy guidelines can be used as first line.  

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Status Epilepticus Management After TAC T cell Therapy  
Adapted from Neelapu 2018. 
Non‑Convulsive Status Epilepticus 
• Assess airway, breathing, and circulation, check blood glucose. 
• Lorazepam* 0.5 mg IV, with additional 0.5 mg IV every 5 minutes, as needed, up to a 
total of 2 mg to control electrographic seizures. 
• Levetiracetam 500 mg IV bolus, as well as maintenance doses. 
• If seizures persist, transfer to ICU, and treat with phenobarbital loading dose of 60 mg IV. 
• Maintenance doses after resolution of non-convulsive status epilepticus are as follows: 
lorazepam 0.5 mg IV every 8 hours for 3 doses; levetiracetam 1,000 mg IV every 
12 hours; phenobarbital 30 mg IV every 12 hours.  
Convulsive Status Epilepticus 
• Assess airway, breathing, and circulation, check blood glucose. 
• Transfer to ICU. 
• Lorazepam* 2 mg IV, with additional 2 mg IV to a total of 4 mg to control seizures. 
• Levetiracetam 500 mg IV bolus, as well as maintenance doses. 
• If seizures persist, add phenobarbital treatment at a loading dose of 15 mg/kg IV. 
• Maintenance doses after resolution of convulsive status epilepticus are lorazepam 0.5 mg 
IV every 8 hours for 3 doses; levetiracetam 1,000 mg IV every 12 hours; phenobarbital 
1–3 mg/kg IV every 12 hours. 
• Continuous electroencephalogram monitoring should be performed if seizures are 
refractory to treatment. 
*Lorazepam is the recommended benzodiazepine because it is short-acting, compared with 
diazepam, and has been widely used in the management of seizures. 
 
 

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Raised Intracranial Pressure Management After TAC01-HER2 Therapy  
Adapted from Neelapu 2018. 
Stage 1 or 2 papilloedema* with CSF opening pressure of <20 mmHg without cerebral edema 
• Acetazolamide 1,000 mg IV, followed by 250–1,000 mg IV every 12 hours (adjust dose 
based on renal function and acid–base balance, monitored 1–2 times daily)  
Stage 3, 4, or 5 papilloedema* with any sign of cerebral edema on imaging studies or a CSF 
opening pressure of ≥20 mmHg  
• Use high-dose corticosteroids with methylprednisolone IV 1 g/day, as recommended for 
Grade 4 neurotoxicity. 
• Elevate head end of the subject’s bed to an angle of 30 degrees. 
• Hyperventilation to achieve target partial pressure of arterial carbon dioxide (PaCO2) of 
28–30 mmHg but maintained for no longer than 24 hours. 
• Hyperosmolar therapy with either mannitol (20 g/dL solution) or hypertonic saline (3% 
or 23.4%, as detailed below): 
• Mannitol: Initial dose 0.5–1 g/kg; maintenance at 0.25–1 g/kg every 6 hours while 
monitoring metabolic profile and serum osmolality every 6 hours and withhold mannitol 
if serum osmolality is ≥320 mOsm/kg, or the osmolality gap is ≥40. 
• Hypertonic Saline: Initial 250 mL of 3% hypertonic saline; maintenance at 
50-75 mL/hour while monitoring electrolytes every 4 hours, and withhold infusion if 
serum Na levels reach ≥155 mEq/L. 
• For Subjects with Imminent Herniation: Initial 30 ml of 23.4% hypertonic saline; repeat 
after 15 minutes, if needed. 
• If subject has ommaya reservoir, drain CSF to target opening pressure of <20 mmHg. 
• Consider neurosurgery consultation and IV anesthetics for burst-suppression pattern on 
electroencephalography. 
• Metabolic profiling every 6 hours and daily CT scan of head, with adjustments in usage 
of the medications to prevent rebound cerebral edema, renal failure, electrolyte 
abnormalities, hypovolemia, and hypotension. 
*Papilloedema grading should be performed according to the modified Frisén scale. 
 
 

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Diagnostic Criteria for TAC T Cell Related MAS/HLH  
Adapted from Neelapu 2018. 
A subject might have MAS/HLH if he/she had a peak serum ferritin level of >10,000 ng/mL 
during the cytokine-release syndrome phase of TAC T cell therapy (typically the first 5 days after 
cell infusion for CAR T cell therapy) and subsequently developed any 2 of the following:  
• Grade ≥3 increase in serum bilirubin, aspartate aminotransferase (AST), or alanine 
aminotransferase (ALT) levels*. 
• Grade ≥3 oliguria or increase in serum creatinine levels*.  
• Grade ≥3 pulmonary edema*. 
• Presence of hemophagocytosis in bone marrow or organs based on histopathological 
assessment of cell morphology and/or CD68 immunohistochemistry TAC; HLH, 
hemophagocytic lymphohistiocytosis; MAS, macrophage- activation syndrome.  
*Grading as per Common Terminology Criteria for Adverse Events, version 5.0. 
TAC T Cell Related MAS/HLH Management Recommendations 
Adapted from Neelapu 2018. 
MAS/HLH should initially be managed according to the guidelines for CRS (Appendix E), with 
appropriate subsequent laboratory testing to monitor response to treatment. If the results of these 
tests reveal no improvement within 48 hours, escalation of treatment should be considered. 
• Manage Grade ≥3 organ toxicity with anti-IL-6 therapy + corticosteroids as per the CRS 
treatment algorithm (Appendix E). 
• Monitor blood ferritin, lactate dehydrogenase, ﬁbrinogen, transaminases, bilirubin, 
creatinine levels. 
If no improvement is seen after 48 hours, consider 
• Adding etoposide to treatment. 
• Consider intrathecal cytarabine for neurotoxicity. 

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APPENDIX F.  
RESPONSE CRITERIA 
Time Point Response: Subjects with Target (+/– Non-Target) Disease 
Target Lesions 
Non-Target Lesions 
New Lesions 
Overall Response 
CR 
CR 
No 
CR 
CR 
Non-CR/Non-PD 
No 
PR 
CR 
Not evaluated 
No 
PR 
PR 
Non-PD or not all 
evaluated 
No 
PR 
SD 
Non-PD or not all 
evaluated 
No 
SD 
Not All Evaluated 
Non-PD 
No 
NE 
PD 
Any 
Yes or No 
PD 
Any 
PD 
Yes or No 
PD 
Any 
Any 
Yes 
PD 
CR=complete response, PR=partial response, SD=stable disease,  
PD=progressive disease, and NE=non-evaluable 
 
Time Point Response: Subjects with Non-Target Disease Only 
Non-Target Lesions 
New Lesions 
Overall Response 
CR 
No 
CR 
Non-CR/Non-PD 
No 
Non-CR/Non-PDa 
Not All Evaluated 
No 
NE 
Unequivocal PD 
Yes or No 
PD 
Any 
Yes 
PD 
CR=complete response, PD=progressive disease, and NE=non-evaluable 
a ‘Non-CR/Non-PD’ is preferred over ‘stable disease’ for non-target disease since SD is increasingly used as endpoint for 
assessment of efficacy in some studies so to assign this category when no lesions can be measured is not advised. 
 

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Best Overall Response When Confirmation of CR and PR Required 
Overall Response 
First Time Point 
Overall Response 
Subsequent Time Point 
Best Overall Response 
CR 
CR 
CR 
CR 
PR 
SD, PD or PRa 
CR 
SD 
SD provided minimum criteria for SD duration 
met, otherwise, PD 
CR 
PD 
SD provided minimum criteria for SD duration 
met, otherwise, PD 
CR 
NE 
SD provided minimum criteria for SD duration 
met, otherwise, NE 
PR 
CR 
PR 
PR 
PR 
PR 
PR 
SD 
SD 
PR 
PD 
SD provided minimum criteria for SD duration 
met, otherwise, PD 
PR 
NE 
SD provided minimum criteria for SD duration 
met, otherwise, NE 
NE 
NE 
NE 
CR=complete response, PR=partial response, SD=stable disease,  
PD=progressive disease, and NE=non-evaluable 
a If a CR is truly met at first time point, then any disease seen at a subsequent time point, even disease meeting PR criteria 
relative to baseline, makes the disease PD at that point (since disease must have reappeared after CR). Best response would 
depend on whether minimum duration for SD was met. However, sometimes ‘CR’ may be claimed when subsequent scans 
suggest small lesions were likely still present and in fact the subject had PR, not CR at the first time point. Under these 
circumstances, the original CR should be changed to PR and the best response is PR. 
 
 
 

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APPENDIX G. ECOG SCALE (AND CONVERSION FROM KARNOFSKY SCALE) 
Adapted from Oken 1982. 
ECOG Status 
ECOG 
Grade 
Karnofsky 
Grade 
Karnofsky Status 
Fully active, able to carry on all 
pre-disease performance without 
restriction 
0 
100 
Normal, no complaints 
Restricted in physically strenuous activity 
but ambulatory and able to carry out work 
of a light or sedentary nature, e.g., light 
housework, office work 
1 
90 
Able to carry on normal activities. 
Minor signs or symptoms of disease 
Restricted in physically strenuous activity 
but ambulatory and able to carry out work 
of a light or sedentary nature, e.g., light 
housework, office work 
1 
80 
Normal activity with effort 
Ambulatory and capable of all self-care 
but unable to carry out any work activities. 
Up and about more than 50% of waking 
hours 
2 
70 
Care for self. Unable to carry on normal 
activity or to do active work 
Ambulatory and capable of all self-care 
but unable to carry out any work activities. 
Up and about more than 50% of waking 
hours 
2 
60 
Requires occasional assistance, but able 
to care for most of his needs 
Capable of only limited self-care, confined 
to bed or chair more than 50% of waking 
hours 
3 
50 
Requires considerable assistance and 
frequent medical care 
Capable of only limited self-care, confined 
to bed or chair more than 50% of waking 
hours 
3 
40 
Disabled. Requires special care and 
assistance 
Completely disabled. Cannot carry on any 
self-care. Totally confined to bed or chair 
4 
30 
Severely disabled. Hospitalization 
indicated though death not imminent 
Completely disabled. Cannot carry on any 
self-care. Totally confined to bed or chair 
4 
20 
Very sick. Hospitalization necessary. 
Active supportive treatment necessary 
Completely disabled. Cannot carry on any 
self-care. Totally confined to bed or chair 
4 
10 
Moribund 
Dead 
5 
0 
Dead 
 

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APPENDIX H.  
DOSE MODIFICATION AND TOXICITY MANAGEMENT 
GUIDELINES FOR IMMUNE-RELATED AES ASSOCIATED 
WITH PEMBROLIZUMAB  
General instructions: 
1. Severe and life-threatening immune-related adverse events (irAEs) should be treated with intravenous (IV) 
corticosteroids followed by oral steroids. Other immunosuppressive treatment should begin if the irAEs are 
not controlled by corticosteroids. 
2. Pembrolizumab must be permanently discontinued if the irAE does not resolve or the corticosteroid dose is 
not ≤10 mg/day within 12 weeks of the last pembrolizumab treatment. 
3. The corticosteroid taper should begin when the irAE is ≤Grade 1 and continue at least 4 weeks. 
4. If pembrolizumab has been withheld, pembrolizumab may resume after the irAE decreased to ≤Grade 1 
after corticosteroid taper. 
irAEs 
Toxicity grade 
(CTCAE V5.0) 
Action with 
pembrolizumab 
Corticosteroid and/or 
other therapies 
Monitoring and 
follow-up 
Pneumonitis  
Grade 2 
Withhold  
Administer 
corticosteroids (initial 
dose of 1 to 2 mg/kg 
prednisone or 
equivalent) followed by 
taper 
Add prophylactic 
antibiotics for 
opportunistic infections 
Monitor participants for 
signs and symptoms of 
pneumonitis 
Evaluate participants 
with suspected 
pneumonitis with 
radiographic imaging 
and initiate 
corticosteroid treatment 
Recurrent 
Grade 2,  
Grade 3 or 4  
Permanently 
discontinue 
Diarrhea/Colitis  
Grade 2 or 3 
Withhold 
Administer 
corticosteroids (initial 
dose of 1 to 2 mg/kg 
prednisone or 
equivalent) followed by 
taper 
Monitor participants for 
signs and symptoms of 
enterocolitis (i.e., 
diarrhea, abdominal 
pain, blood, or mucus in 
stool with or without 
fever) and of bowel 
perforation (ie. 
peritoneal signs and 
ileus) 
Participants with ≥Grade 
2 diarrhea suspecting 
colitis should consider 
GI consultation and 
performing endoscopy to 
rule out colitis 
Participants with 
diarrhea/colitis should be 
advised to drink liberal 
quantities of clear fluids. 
If sufficient oral fluid 
intake is not feasible, 
fluid and electrolytes 
should be substituted via 
Recurrent Grade 3 
or Grade 4 
Permanently 
discontinue 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
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irAEs 
Toxicity grade 
(CTCAE V5.0) 
Action with 
pembrolizumab 
Corticosteroid and/or 
other therapies 
Monitoring and 
follow-up 
IV infusion 
AST or ALT 
elevation or 
Increased 
Bilirubin 
Grade 2 a 
Withhold 
Administer 
corticosteroids (initial 
dose of 0.5 to 1 mg/kg 
prednisone or 
equivalent) followed by 
taper 
Monitor with liver 
function tests (consider 
weekly or more 
frequently until liver 
enzyme value returned to 
baseline or is stable) 
Grade 3 b or 4 c 
Permanently 
discontinue 
Administer 
corticosteroids (initial 
dose of 1 to 2 mg/kg 
prednisone or 
equivalent) followed by 
taper 
Type 1 diabetes 
mellitus (T1DM) 
or Hyperglycemia 
New onset T1DM 
or  
Grade 3 or 4 
hyperglycemia 
associated with 
evidence of -cell 
failure 
Withhold d 
Initiate insulin 
replacement therapy for 
participants with T1DM 
Administer 
antihyperglycemic in 
participants with 
hyperglycemia 
 
Monitor participants for 
hyperglycemia or other 
signs and symptoms of 
diabetes 
Hypophysitis 
Grade 2 
Withhold 
Administer 
corticosteroids and 
initiate hormonal 
replacements as 
clinically indicated 
Monitor for signs and 
symptoms of 
hypophysitis (including 
hypopituitarism and 
adrenal insufficiency) 
Grade 3 or 4 
Withhold or 
permanently 
discontinue d 
Hyperthyroidism 
Grade 2 
Continue 
Treat with nonselective 
beta-blockers (e.g., 
propranolol) or 
thionamides as 
appropriate 
Monitor for signs and 
symptoms of thyroid 
disorders 
Grade 3 or 4 
Withhold or 
permanently 
discontinue d 
Hypothyroidism 
Grade 2, 3 or 4 
Continue 
Initiate thyroid 
replacement hormones 
(e.g., levothyroxine or 
liothyronine) per 
standard of care 
Monitor for signs and 
symptoms of thyroid 
disorders 
Nephritis: 
grading according 
to increased 
creatinine or 
acute kidney 
injury 
Grade 2 
Withhold 
Administer 
corticosteroids 
(prednisone 
1 to 2 mg/kg or 
equivalent) followed by 
taper 
Monitor changes of renal 
function 
Grade 3 or 4 
Permanently 
discontinue 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 176 of 177 
 
 
irAEs 
Toxicity grade 
(CTCAE V5.0) 
Action with 
pembrolizumab 
Corticosteroid and/or 
other therapies 
Monitoring and 
follow-up 
Neurological 
Toxicities 
Grade 2 
Withhold 
Based on severity of 
AE administer 
corticosteroids 
Ensure adequate 
evaluation to confirm 
etiology and/or exclude 
other causes 
Grade 3 or 4 
Permanently 
discontinue 
Myocarditis 
Asymptomatic 
cardiac enzyme 
elevation with 
clinical suspicion 
of myocarditis 
(previously 
CTCAE v4.0 
Grade 1) 
Withhold 
Based on severity of 
AE administer 
corticosteroids 
Ensure adequate 
evaluation to confirm 
etiology and/or exclude 
other causes 
 
Grade 2, 3 or 4 
Permanently 
discontinue 
Exfoliative 
Dermatologic 
Conditions 
Suspected SJS, 
TEN, or DRESS 
Withhold 
Based on severity of 
AE administer 
corticosteroids 
Ensure adequate 
evaluation to confirm 
etiology or exclude other 
causes 
Confirmed SJS, 
TEN, or DRESS 
Permanently 
discontinue 
All Other irAEs 
Persistent Grade 2 
Withhold 
Based on severity of 
AE administer 
corticosteroids 
Ensure adequate 
evaluation to confirm 
etiology or exclude other 
causes 
Grade 3 
Withhold or 
discontinue 
based on the 
event e  
Recurrent Grade 3 
or Grade 4  
Permanently 
discontinue 
AE(s)=adverse event(s); ALT= alanine aminotransferase; AST=aspartate aminotransferase; CTCAE=Common Terminology 
Criteria for Adverse Events; DRESS=Drug Rash with Eosinophilia and Systemic Symptom; GI=gastrointestinal; 
IO=immuno-oncology; ir=immune related; IV=intravenous; SJS=Stevens-Johnson Syndrome; T1DM=type 1 diabetes mellitus; 
TEN=toxic epidermal necrolysis; ULN=upper limit of normal. 
Note: Non-irAE will be managed as appropriate, following clinical practice recommendations. 
a. AST/ALT: >3.0 to 5.0 x ULN if baseline normal; >3.0 to 5.0 x baseline, if baseline abnormal; bilirubin:>1.5 to 3.0 x ULN if 
baseline normal; >1.5 to 3.0 x baseline if baseline abnormal 
b. AST/ALT: >5.0 to 20.0 x ULN, if baseline normal; >5.0 to 20.0 x baseline, if baseline abnormal; bilirubin:>3.0 to 
10.0 x ULN if baseline normal; >3.0 to 10.0 x baseline if baseline abnormal 
c. AST/ALT: >20.0 x ULN, if baseline normal; >20.0 x baseline, if baseline abnormal; bilirubin: >10.0 x ULN if baseline 
normal; >10.0 x baseline if baseline abnormal 
d. The decision to withhold or permanently discontinue pembrolizumab is at the discretion of the investigator or treating 
physician. If control achieved or ≤Grade 2, pembrolizumab may be resumed. 
e. Events that require discontinuation include but are not limited to encephalitis and other clinically important irAEs (e.g., 
vasculitis and sclerosing cholangitis). 

Protocol TAC01-HER2-03, Version 6.0 – 25 Oct 2023 
 
Triumvira Immunologics, Inc. 
Confidential 
Page 177 of 177 
 
 
APPENDIX I.  
PEMBROLIZUMAB INFUSION REACTION DOSE 
MODIFICATION AND TREATMENT GUIDELINES 
NCI CTCAE Grade 
Treatment 
Premedication at 
Subsequent Dosing 
Grade 1 
Mild reaction; infusion 
interruption not indicated; 
intervention not indicated 
• Increase monitoring of vital signs as medically indicated 
until the participant is deemed medically stable in the 
opinion of the investigator. 
None 
Grade 2 
Requires therapy or 
infusion interruption but 
responds promptly to 
symptomatic treatment 
(e.g., antihistamines, 
NSAIDs, narcotics, IV 
fluids); prophylactic 
medications indicated for 
≤24 hrs. 
• Stop Infusion. 
• Additional appropriate medical therapy may include but is 
not limited to: 
• IV fluids 
• Antihistamines 
• NSAIDs 
• Acetaminophen 
• Narcotics 
• Increase monitoring of vital signs as medically indicated 
until the participant is deemed medically stable in the 
opinion of the investigator. 
• If symptoms resolve within 1 hour of stopping drug 
infusion, the infusion may be restarted at 50% of the 
original infusion rate (e.g., from 100 mL/hr. to 50 mL/hr.). 
Otherwise, dosing will be held until symptoms resolve and 
the participant should be premedicated for the next 
scheduled dose. 
Participants who develop Grade 2 toxicity despite 
adequate premedication should be permanently 
discontinued from further study drug treatment 
Participant may be 
premedicated 1.5 h 
(± 30 minutes) prior 
to infusion of study 
intervention with: 
Diphenhydramine 
50 mg po (or 
equivalent dose of 
antihistamine). 
Acetaminophen 
500-1000 mg po (or 
equivalent dose of 
analgesic). 
Grades 3 or 4 
Grade 3: 
Prolonged (i.e., not rapidly 
responsive to symptomatic 
medication and/or brief 
interruption of infusion); 
recurrence of symptoms 
following initial 
improvement; 
hospitalization indicated 
for other clinical sequelae 
(e.g., renal impairment, 
pulmonary infiltrates) 
 
Grade 4: 
Life-threatening; pressor 
or ventilator support 
indicated 
• Stop Infusion. 
• Additional appropriate medical therapy may include but is 
not limited to: 
• Epinephrine** 
• IV fluids 
• Antihistamines 
• NSAIDs 
• Acetaminophen 
• Narcotics 
• Oxygen 
• Pressors 
• Corticosteroids 
• Increase monitoring of vital signs as medically indicated 
until the participant is deemed medically stable in the 
opinion of the investigator. 
• Hospitalization may be indicated. 
**In cases of anaphylaxis, epinephrine should be used 
immediately. Participant is permanently discontinued from 
further study drug treatment. 
No subsequent 
dosing 
Appropriate resuscitation equipment should be available at the bedside and a physician readily available during the period of drug 
administration. For further information, please refer to the Common Terminology Criteria for Adverse Events v5.0 (CTCAE) at 
http://ctep.cancer.gov.