Conditions: Multiple Myeloma
Keywords: Relapsed or Relapsed and Refractory Multiple Myeloma CD123 SL-401/pom/dex TAG/pom/dex R/R MM
Allocation: NON_RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 9
Healthy volunteers: no

Brief summary:
A Phase 1/2, Open Label Study of SL-401 in Combination with Pomalidomide and Dexamethasone In Relapsed and Refractory Multiple Myeloma

Detailed description:
This study is a phase 1/2 multicenter, open-label study of SL-401 (tagraxofusp-erzs) in combination with standard doses of pomalidomide and dexamethasone in patients with relapsed and refractory multiple myeloma (MM). The study will be conducted in 2 phases: Phase 1 is the dose-escalation phase to determine the maximum tested dose (MTD) of SL-401 in combination with standard doses of pomalidomide and dexamethasone. In Phase 1, each evaluated SL-401 dose level will incorporate an initial "Run-in Cycle" (i.e. cycle 1) of single agent SL-401 in at least 3 patients; following the Run-in Cycle, patients who have not experienced a dose-limiting toxicity (DLT) will receive combination SL-401/pomalidomide and dexamethasone in cycles 2 and beyond. All patients in Phase 2 will receive 1 cycle of SL-401 monotherapy in cycle 1, followed by combination of SL-401/pomalidomide/dexamethasone in cycle 2 and beyond. The dose of SL-401 will be the MTD of SL-401 or MTD given in combination with pomalidomide/dexamethasone determined during Phase 1.

Arms:
arm 1: Dose Level 1: single-agent SL-401 7 µg/kg/day on Days 1-5 during the initial 28-day run-in cycle followed by a combination of SL-401/pomalidomide/dexamethasone (pom/dex) if there was no dose-limiting toxicity during the run-in cycle arm 2: Dose Level 2: SL-401 9 µg/kg/day in combination with pom/dex

Interventions: intervention 1: SL-401 7 µg/kg/day intervention 2: SL-401 9 µg/kg/day
Intervention descriptions: intervention 1: SL-401 7 µg/kg/day in combination with pom/dex intervention 2: SL-401 9 µg/kg/day in combination with pom/dex

Protocol document:
Prot_000.pdf: 







































































































































































































































SAP_001.pdf: 
 
 
STATISTICAL ANALYSIS PLAN 
 
A Phase 1/2 Open Label Study of SL-401 in Combination with Pomalidomide 
and Dexamethasone in Relapsed or Relapsed and Refractory Multiple 
Myeloma 
 
 
 
Protocol Number: 
Protocol Version and Date: 
 
STML-401-0414 
Amendment 2: 27 March 2018 
Amendment 1: 29 June 2016 
Original: 
04 May 2015 
 
Name of Test Drug: 
SL-401 (Tagraxofusp) 
Phase: 
Phase 1/2 
Methodology: 
Non-randomized, open-label, dose escalation study. 
Sponsor: 
Stemline Therapeutics, Inc. 
750 Lexington Avenue, 11th Floor 
New York, NY 10022 
Tel: (646) 502-2310 
Fax: (646) 389-0968 
Sponsor Representative: 
Debra Sieminski, MS, PA-C 
Vice President, Clinical and Medical Affairs 
Analysis Plan Date: 
14 October 2021 
Analysis Plan Version: 
Final Version 1.0 
 
Confidentiality Statement 
The information contained herein is confidential and the proprietary property 
of Stemline Therapeutics, Inc. and any unauthorized use or disclosure 
of such information without the prior written authorization of 
Stemline Therapeutics, Inc. is expressly prohibited. 


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APPROVAL SIGNATURE PAGE 
Protocol Title: 
A Phase 1/2 Open Label Study of SL-401 in Combination with 
Pomalidomide and Dexamethasone in Relapsed or Relapsed 
and Refractory Multiple Myeloma 
Sponsor: 
Stemline Therapeutics, Inc. 
750 Lexington Avenue, 11th Floor 
New York, NY 10022 
Protocol Number: 
STML-401-0414 
Document Date / Version: 
14 October 2021 / Final Version 1.0 
Veristat, LLC Author: 
 
Approval Signature 
Job Title 
 
 
Sponsor Approval 
 
By signing this document, I acknowledge that I have read the document and approve of the 
planned statistical analyses described herein. I agree that the planned statistical analyses are 
appropriate for this study, are in accordance with the study objectives, and are consistent with 
the statistical methodology described in the protocol, clinical development plan, and all 
applicable regulatory guidances and guidelines. 
 
I have discussed any questions I have regarding the contents of this document with the 
biostatistical author. 
 
I also understand that any subsequent changes to the planned statistical analyses, as described 
herein, may have a regulatory impact and/or result in timeline adjustments. All changes to the 
planned analyses will be described in the clinical study report. 
Sponsor Signatory: 
Approval Signature 
Job Title 
 


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TABLE OF CONTENTS 
1. 
Information From the Study Protocol ................................................................................. 8 
1.1. 
Introduction and Objectives ................................................................................... 8 
1.1.1. 
Tagraxofusp (SL-401) ............................................................................. 8 
1.1.2. 
Study Objectives ..................................................................................... 9 
1.1.3. 
Purpose of this Document ..................................................................... 10 
1.2. 
Study Design ........................................................................................................ 10 
1.2.1. 
Synopsis of Study Design ..................................................................... 10 
1.2.2. 
Randomization Methodology ................................................................ 13 
1.2.3. 
Treatment Discontinuation .................................................................... 13 
1.2.4. 
Study Procedures ................................................................................... 14 
1.2.5. 
Efficacy, Pharmacokinetic, Immunogenicity, and Safety 
Parameters ............................................................................................. 14 
1.2.5.1. Efficacy Parameters ................................................................ 14 
1.2.5.2. Safety Parameters ................................................................... 14 
1.2.5.3. Pharmacokinetic and Immunogenicity Parameters ................ 14 
2. 
Patient Population............................................................................................................. 15 
2.1. 
Population Definitions .......................................................................................... 15 
2.2. 
Protocol Violations ............................................................................................... 15 
3. 
General Statistical Methods.............................................................................................. 16 
3.1. 
Sample Size Justification ...................................................................................... 16 
3.2. 
General Methods .................................................................................................. 16 
3.3. 
Computing Environment ...................................................................................... 16 
3.4. 
Baseline Definitions ............................................................................................. 17 
3.5. 
Methods of Pooling Data ...................................................................................... 17 
3.6. 
Adjustments for Covariates .................................................................................. 17 
3.7. 
Multiple Comparisons/Multiplicity ...................................................................... 17 
3.8. 
Subgroup Analyses ............................................................................................... 17 
3.9. 
Withdrawals, Dropouts, Loss to Follow-up .......................................................... 17 
3.10. Missing, Unused, and Spurious Data ................................................................... 17 
3.11. Visit Windows ...................................................................................................... 17 
3.12. Timing of Analysis ............................................................................................... 18 
4. 
Study Analyses ................................................................................................................. 19 


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4.1. 
Patient Disposition ............................................................................................... 19 
4.2. 
Demographics and Baseline Characteristics ......................................................... 19 
4.3. 
Efficacy Evaluation .............................................................................................. 19 
4.3.1. 
Progression Free Survival ...................................................................... 19 
4.3.2. 
Response Rate ....................................................................................... 20 
4.3.3. 
Duration of Response ............................................................................ 20 
4.3.4. 
Overall Survival .................................................................................... 20 
4.3.5. 
Exploratory Efficacy Assessments ......................................................... 20 
4.4. 
Safety Analyses .................................................................................................... 21 
4.4.1. 
Study Drug Exposure ............................................................................ 21 
4.4.2. 
Adverse Events ..................................................................................... 21 
4.4.2.1. Capillary Leak Syndrome ....................................................... 23 
4.4.3. 
Laboratory Data .................................................................................... 23 
4.4.4. 
Vital Signs and Physical Examination ................................................... 24 
4.4.5. 
Electrocardiogram ................................................................................. 25 
4.4.6. 
Concomitant Medications and Subsequent Treatments ........................ 25 
4.4.7. 
Pre-Treatment Medications ................................................................... 25 
5. 
Changes to Planned Analyses .......................................................................................... 26 
6. 
References ........................................................................................................................ 27 
7. 
Study Flow Charts ............................................................................................................ 28 


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TABLES AND FIGURES INCLUDED IN THE TEXT 
 
Figure 1-1 
Schematic of Tagraxofusp Construction ................................................................ 9 
Table 1-1 
Dose Levels to be Tested ..................................................................................... 11 
Figure 4-1 
Hy’s Law Candidates Scatterplot ......................................................................... 24 
Table 7-1 
Schedule of Events ............................................................................................... 29 


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LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
Abbreviation 
Definition 
 
AE 
AESI 
Adverse event 
Adverse event of special interest 
ALT 
Alanine aminotransferase 
AML 
Acute myeloid leukemia 
AST 
Aspartate aminotransferase 
ATC 
BM 
BP 
BUN 
CBC 
CPK 
CBR 
Anatomic therapeutic class 
Bone Marrow 
Blood Pressure 
Blood Urea Nitrogen 
Complete Blood Count 
Creatine Phophokinase 
Clinical Benefit Rate 
CI 
Confidence interval 
CLS 
Capillary leak syndrome 
CR 
Complete response 
CSC 
Cancer stem cell 
CSR 
Clinical study report 
CTCAE 
DEX 
DLT 
DOR 
DSRC 
Common Terminology Criteria for Adverse Events 
Dexamethasone 
Dose-limiting toxicity 
Duration of Response 
Data Safety Review Committee 
DT 
Diphtheria toxin 
ECOG 
Eastern Cooperative Oncology Group 
ECG 
Electrocardiogram 
FLC 
Free light chain 
IL-3 
Interleukin-3 
IL-3R 
Interleukin-3 receptor 
MedDRA 
Medical Dictionary for Regulatory Activities 
mITT 
MM 
MR 
Modified Intent-to-Treat 
Multiple Myeloma 
Minimal Response 
MRD 
Minimal residual disease 


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MTD 
ORR 
Maximum tolerated dose 
Overall response rate 


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Abbreviation 
Definition 
OS 
pDC 
Overall survival 
Plasmacytoid dendritic cell 
PCS 
Potentially clinically significant 
PFS 
Progression free survival 
PFS-6 
Progression free survival at 6 months 
PK 
Pharmacokinetic 
PT 
Preferred Term 
SAP 
Statistical analysis plan 
sCR 
Stringent Complete Response 
SD 
Standard deviation 
SOC 
System organ class 
TEAE 
Treatment-emergent adverse event 
ULN 
Upper limit of normal 
WHO 
World Health Organization 


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1. 
INFORMATION FROM THE STUDY PROTOCOL 
1.1. 
Introduction and Objectives 
The overall purpose of study STML-401-0414 is to support the development of tagraxofusp 
(SL-401), to evaluate the safety of the product as a single agent in an initial run-in cycle, and to 
assess the safety and clinical efficacy of tagraxofusp in combination with pomalidomide (POM) 
and dexamethasone (DEX) in the treatment of patients with relapsed or relapsed and refractory 
multiple myeloma (RRMM). 
 
Multiple myeloma (MM) is a heterogeneous clonal B-cell malignancy characterized by the 
accumulation of abnormal antibody producing plasma cells in the bone marrow (BM). The 
disease is associated with a variety of clinical manifestations including lytic bone lesions, 
hypercalcemia, renal impairment, and anemia. MM is the second most common hematologic 
malignancy and accounts for approximately 11,000 deaths per year in the United States and 
19,000 in Europe (ACS 2013). 
The molecular mechanism by which MM cells evade drug–induced cytotoxicity and acquire 
drug resistant phenotypes include interaction of MM cells with the BM microenvironment 
which is composed of extracellular matrix (ECM) proteins such as fibronectin, collagen, and 
laminin, along with cellular elements such as hematopoietic stem cells, immune cells, BM 
endothelial cells, and bone marrow stromal cells (BMSCs). Adhesion of MM cells to ECM 
proteins and accessory cells leads to increased expression of factors such as IL-6, insulin-like 
growth factor (IGF-1), and vascular endothelial growth factor (VEGF), which in turn further 
stimulates growth and survival of the malignant clone (Chauhan 1996; Agarwal 2013). 
In addition, early studies using both in vitro and in vivo MM models, have demonstrated 
increased numbers of plasmacytoid dendritic cells (pDCs) in the BM microenvironment, which 
promotes MM cell growth and survival (Chauhan et al. 2009). These studies also showed 
increased interleukin-3 (IL-3) levels resulting from pDCs and MM cell interaction, which in 
turn, trigger MM cell growth and pDC survival. 
 
The field of cancer stem cells (CSCs) is a new area of cancer biology that may fundamentally 
alter the approach to oncology drug development. CSCs have been identified in virtually all 
major tumor types, including leukemia and cancers of the brain, breast, colon, prostate, and 
pancreas (Jordan et al. 2006). CSCs are the highly malignant “seeds” of a tumor that self-renew 
and generate more mature cells that comprise the bulk of the tumor, or “the tumor bulk.” As 
such, CSCs appear to be responsible for tumor initiation, propagation, and metastasis. Many of 
the characteristics of CSCs, such as their slow growth, anti-cell death mechanisms, and presence 
of multi-drug resistance proteins, may enable CSCs to resist therapeutic agents traditionally 
used to treat cancer. This may be due to the many challenging characteristics of CSCs, including 
slow growth, presence of multi-drug resistance proteins, anti-cell death mechanisms, and 
increased activity of cellular mechanisms that repair damaged deoxyribonucleic acid. CSCs are 
particularly resistant to chemotherapy, radiation, or targeted therapy relative to tumor bulk. 
 
1.1.1. 
Tagraxofusp (SL-401) 
 
Diphtheria toxin (DT) IL-3 fusion protein, named tagraxofusp following Biologics Licensing 
Application (designated SL-401 during clinical development by Stemline Therapeutics, Inc.), is 


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a novel biologic targeted therapy directed to the IL-3 receptor. Tagraxofusp is comprised of 
recombinant human IL-3 genetically fused to a truncated DT, in which the binding domain of 
DT has been replaced with IL-3. As depicted in Figure 1-1, the IL-3 domain of tagraxofusp is 
able to target the agent to leukemia blasts and CSCs that over-express IL-3R, leading to 
receptor-mediated endocytosis and localization of tagraxofusp to early endosomes. The 
translocation domain of DT changes conformation in the acidic environment of the endosome, 
and the RXRR motif (residues 191-194) located between the catalytic and translocation domains 
of DT is cleaved by endosomal furin. The translocation domain of DT then inserts into the 
endosomal membrane. As the TAT-like domain of DT (residues 201-230) interacts with 
cytosolic heat shock protein 90 (Hsp90) and thioreduxin reductase, the catalytic domain (A 
fragment) unfolds, is reduced, and translocates to the cytosol. Upon release into the cytosol, the 
A fragment refolds and catalytically inactivates cellular protein synthesis by ADP-ribosylating 
the diphthamide residue in domain IV of elongation factor 2, leading to apoptosis (Yamaizumi 
et al. 1978; Deng et al. 2008; FitzGerald et al. 1989; Perentesis et al. 1992; Louie et al. 1997; 
Ratts et al. 2005; Thorburn et al. 2004). 
 
Figure 1-1 
Schematic of Tagraxofusp Construction 
 
 
1.1.2. 
Study Objectives 
The following objectives are as defined in the Study Protocol (Amendment 2, 27 March 2018). 
Primary Objectives 
• Evaluate the safety of single agent tagraxofusp in an initial run-in cycle in patients with 
MM. 
• Determine the maximum tolerated dose (MTD) or the maximum tested dose of 
tagraxofusp given in combination with POM/DEX for the treatment of relapsed or 
RRMM. 
• Characterize the safety and tolerability profiles of tagraxofusp in combination with 
POM/DEX at the MTD 
Secondary Objectives: 
• Evaluate the immunogenicity of tagraxofusp in combination with POM/DEX. 
• Evaluate the pharmacokinetics (PK) of tagraxofusp as single agent and when 
administered in combination with POM/DEX. 
• Evaluate the activity of the combination of tagraxofusp/POM/DEX regiment in terms of: 


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o Overall response rate (complete response [CR]+ very good partial response [VGPR] 
+ partial response [PR]) and clinical benefit rate (CBR) (CR + VGPR + PR + 
minimal response [MR]) based on the International Myeloma Working Group 
(IMWG) defined response criteria and the duration of response (DOR) in RRMM 
patients. 
o Progression-free survival (PFS) and PFS at 6 months (PFS-6). 
o Overall Survival (OS). 
Exploratory objectives: 
• Characterize expression of IL-3 receptor (IL-3R)/CD123 (and other potentially relevant 
markers) on MM cells, pDCs and associated cell populations in peripheral blood (PB) 
and BM prior to and during/following therapy. 
• Evaluate the treatment effects on IL-3R/CD123-expressing pDCs in the BM 
microenvironment prior to, during, and following therapy. Specifically, assess (i) the 
relative abundance of tumor cells to pDCs; (ii) immunohistochemistry (IHC) on BM 
biopsy specimens and flow cytometry analysis using antibodies specific against pDCs, 
to evaluate potential reduction in the pDC population in MM BM; and (iii) MM cell 
growth-promoting activity of pDCs will be determined by assessment of their ability to 
stimulate MM cell proliferation ex-vivo. 
• Evaluate therapy-related effects on the levels of circulating cytokines/factors (i.e., IL-3 
and others) associates with pDCs and MM cell growth, survival, and immune 
dysfunction using serum and plasma samples prior to, during, and following therapy. 
• Identify surrogate markers of therapy-related anti-osteolytic activity. Specifically, assess 
the levels of bone turnover markers (potentially to include N and C telopeptide, 
osteocalcin, and bone alkaline phosphatase) prior to, during, and following therapy. 
1.1.3. 
Purpose of this Document 
 
This statistical analysis plan (SAP) is designed to outline the methods to be used in the analysis 
of study data to answer the study objective(s). Populations for analysis, data handling rules, 
statistical methods, and formats for data presentation are provided. The statistical analyses and 
summary tabulations described in this SAP will provide the basis for the results sections of the 
clinical study report (CSR) for this trial. 
 
This SAP will also outline any differences in the currently planned analytical objectives relative 
to those planned in the study protocol. 
1.2. 
Study Design 
1.2.1. 
Synopsis of Study Design 
 
This study is a Phase 1/2 non-randomized, open-label, dose escalation, multicenter study of 
tagraxofusp in combination with standard doses of POM and DEX. The study will be conducted 
as a modified Fibonacci 3 + 3 dose escalation design to determine the MTD of tagraxofusp in 


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combination with standard doses of POM and DEX. The study will be conducted in 2 phases. 
Each evaluated tagraxofusp dose level will also incorporate an initial “Run-in Cycle” of single 
agent tagraxofusp in at least 3 patients; following the Run-in Cycle, patients who have not 
experienced a dose-limiting toxicity (DLT) will receive combination tagraxofusp/POM/DEX. 
All patients in phase 2 will initiate therapy with the combination of tagraxofusp/POM/DEX at 
the MTD or maximum tested dose established in phase 1. 
Phase I 
 
Run-In Cycle: Tagraxofusp will be administered as a single agent during a Run-in Cycle. Upon 
completion of the Run-in Cycle patients will be evaluated for safety and response. 
• Patients who do not experience a DLT during the Run-in Cycle will have POM/DEX 
added to their regimen at the assigned cohort dose. 
• Patients who experience a DLT during the Run-in Cycle will be discontinued from the 
study. 
 
Table 1-1 details the Tagraxofusp/POM/DEX dose levels, beginning with dose level 1 to be 
evaluated. 
 
Table 1-1 
Dose Levels to be Tested 
 
Cohorts of 3-6 patients will be treated at each dose level. All patients within a cohort must 
complete the Run-in Cycle and the first cycle of combination therapy (Cycle 1) before patients 
can be enrolled into the subsequent cohort of tagraxofusp (single-agent) at the next higher dose. 
No intra-patient dose escalation is allowed. The first cohort of patients will receive tagraxofusp 
single agent at a dose of 7 µg/kg/day followed by tagraxofusp with POM/DEX. 
 
The period for evaluation for DLT will include the Run-in Cycle and Cycle 1 (the first cycle of 
combination therapy). 
 
A decision to allow treatment at the next higher does level will depend on the number of 
patients who experience a DLT during the first cycle of combination therapy. 


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If after 3 patients complete Cycle 1 of combination therapy: 
• None of the initial 3 patients treated (0/3) experiences a DLT), then dose escalation will 
proceed, and 3 new patients will be treated at the next higher dose. 
• If 1 of the initial 3 patients treated (1/3) experiences a DLT, the cohort will be expanded 
to include an additional 3 patients treated at the same dose. 
 
o If only 1 patient (1/6) from this expanded cohort experiences a DLT then 3 new 
patients will be treated at the next higher dose. 
• If 2 or more patients within a cohort have a DLT, then the MTD will be exceeded, and 
further dose escalation will not occur. 
 
If the highest planned treatment dose is completed and determined to be safe and the MTD is 
not exceeded, the available safety data will be reviewed to assess whether further dose 
escalation is justified. 
 
The MTD of the combination therapy is defined as the dose preceding the dose level at which 2 
or more patients experience a DLT during the Run-in Cycle and Cycle 1 of combination 
therapy. The MTD of the combination will be used in phase 2 of the study. If the highest 
planned treatment dose is completed and determined to be safe and the MTD is not exceeded, 
the available PK and safety data will be reviewed to assess whether further dose escalation is 
justified. A patient who does not complete the first cycle of treatment for reasons other than the 
occurrence of DLT will be replaced by another patient who will receive the same dose regimen 
if necessary to evaluate that cohort (e.g., if a patient is not evaluable for DLT but 2 others have 
experience a DLT within the cohort, there will be not a need to replace the patient as the MTD 
will have been exceeded). 
In the event that a DLT occurs in 2 or more patients treated at the 7 μg/kg/day dose level, 
5 μg/kg/day will be considered by the Data Safety Review Committee (DSRC) as an alternative 
starting dose. In this event, a new cohort of 3 patients will receive 5 μg/kg/day for the first cycle. 
The same DLT rules will apply to this does level. If 2 or more patients experience a DLT at the 
5 μg/kg/day dose level, the study will be halted. 
DLT Assessment 
Run-in Cycle: 
 
Patients are evaluable for DLT assessment during the Run-in Cycle of single agent tagraxofusp 
after receiving at least one dose of tagraxofusp. Patients who experience a DLT during the Run- 
in Cycle will not be further dosed. 
Combination Therapy: 
 
Patients who receive at least 1 infusion of tagraxofusp and 1 dose of POM during Cycle 1 are 
evaluable for DLT assessment of the combination therapy. Patients should receive a minimum 
of 8 doses of POM during Cycle 1 and complete the 28 days of observation unless the patient 


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experiences DLT (patients who discontinue prior to this juncture because of disease progression 
or for reasons unrelated to study therapy will be replaced). 
 
During phase 1, DLT is defined as any of the following AEs that are possibly, probably, or 
definitely related to therapy: 
• Any grade ≥4 neutropenia lasting greater than 7 days or grade ≥3 neutropenia associated 
with fever. 
• Any grade ≥4 thrombocytopenia lasting greater than 7 days or grade ≥3 
thrombocytopenia associated with bleeding. 
• Any grade ≥3 non-hematologic toxicity except: 
o Grade 3 nausea, vomiting, or diarrhea lasting no longer than 48 hours (with 
resolution to grade ≤1 or baseline) with optimal supportive care. 
 
o Grade 3 arthralgia, myalgia, fever, in the absence of neutropenia, lasting no longer 
than 48 hours (with resolution to grade ≤1 or baseline). 
o Grade 3 fatigue lasting <7 days. 
o Grade 3 laboratory abnormalities that are asymptomatic and not considered clinically 
significant by the Investigator, that respond to or do not require intervention and 
resolve to grade ≤1 or baseline ≤28 days after the last infusion of tagraxofusp 
• Grade 4 transaminase or creatine phosphokinase (CPK) elevation (confirmed within 
24 hours of initial identification) regardless of duration or relationship to tagraxofusp. 
Phase 2: Expansion 
 
During phase 2, at least 14 additional patients (total 20 patients) will be treated at the MTD or 
maximum tested dose at which multiple DLTs are not observed (identified in phase 1). During 
phase 2, the Run-in Cycle will no longer be administered. However, the first 6 patients treated at 
the MTD without the Run-in Cycle will also be assessed for DLT during the first cycle of 
therapy. If more than one DLT is identified in these initial 6 patients, consideration will be 
given to the administration of a reduced tagraxofusp dose in the remainder of phase 2, or 
reinstitution of the tagraxofusp single agent Run-in Cycle for the remainder of phase 2. 
1.2.2. 
Randomization Methodology 
As this is a single-agent study, randomization is not applicable. 
1.2.3. 
Treatment Discontinuation 
Tagraxofusp treatment could be discontinued for any of the following reasons: 
• Patient withdrawal of consent 
• Occurrence of unacceptable toxicity, including DLT 


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• Tagraxofusp related anaphylaxis or grade ≥3 hypersensitivity reaction 
• Tagraxofusp-related grade ≥3 CLS 
• Disease recurrence/progression 
• Intercurrent illness that prevents further administration of tagraxofusp 
• Patient non-compliance 
• Occurrence of pregnancy 
• Completion of 6 cycles of treatment 
• Investigator’s decision 
The reason for tagraxofusp discontinuation and the date of discontinuation are recorded in the 
electronic case report form (eCRF). 
1.2.4. 
Study Procedures 
The schedules of assessments, as outlined in the study protocol, are presented in Table 7-1. 
1.2.5. 
Efficacy, Pharmacokinetic, Immunogenicity, and Safety Parameters 
1.2.5.1. 
Efficacy Parameters 
 
Efficacy assessments include M-protein determination, serum free light chain results, bone 
marrow aspirate/biopsy results, plasmacytoma evaluations, skeletal survey, tumor assessments, 
ORR, and clinical benefit rate (CR + VGPR+PR+MR) based on the IMWG defined response 
criteria, as well as DOR and OS. Definitions for each efficacy assessment are described in in 
Section 4.3. 
1.2.5.2. 
Safety Parameters 
 
Safety evaluations performed during the study included physical examinations, Eastern 
Cooperative Oncology Group (ECOG) performance status, measurement of vital signs, 12-lead 
electrocardiograms (ECGs), clinical laboratory evaluations (hematology, serum chemistry, 
coagulation, and urinalysis), and monitoring of adverse events (AE) (including serious AEs 
[SAEs]), DLTs, and concomitant medications (CM). 
 
Further details on the definitions and analysis methods for safety endpoints are provided in 
Section 4.4. 
1.2.5.3. 
Pharmacokinetic and Immunogenicity Parameters 
 
Noncompartmental PK parameter summaries are described in a separate Modeling and 
Simulation Plan. 
Summary of immunogenicity parameters are described in a separate plan. 


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2. 
PATIENT POPULATION 
2.1. 
Population Definitions 
The following patient populations will be evaluated and used for presentation and analysis of 
the data: 
• Modified Intent-to-Treat (mITT) Population: All patients who are eligible based on the 
screening criteria, had baseline disease assessments, and had their disease re-evaluated, 
and who received at least 1 dose of tagraxofusp, POM, or DEX. Patients who meet the 
criteria for mITT will be considered “evaluable.” Patients will be grouped according to 
the planned dose level at time of enrollment. 
• Safety Population: All patients enrolled in the study who received at least 1 dose of 
tagraxofusp, POM, or DEX. Patients will be grouped according to the actual dose level 
received. 
 
The mITT population is the primary population for the analysis of efficacy parameters. The 
safety population is the primary population for the analysis of safety parameters. 
2.2. 
Protocol Violations 
All protocol violations will be presented in a data listing. 


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3. 
GENERAL STATISTICAL METHODS 
3.1. 
Sample Size Justification 
The primary objectives of phase 1 of the study are to evaluate the safety of tagraxofusp as a 
single agent in an initial Run-in Cycle, to determine the MTD or the maximum tested dose 
where multiple DLTs are not observed, and to further characterize the safety profile of 
tagraxofusp/POM/DEX at the MTD. Based on such, a recommended dose for phase 2 studies 
will be defined. The number of patients to be enrolled in the dose-escalation portion of the study 
is dependent on the dose levels at which DLTs are seen, and the number of dose levels 
investigated to determine the MTD; 3 to 6 patients are planned to be treated at each dose level. 
The anticipated sample size is sufficient to evaluate these objectives. A secondary objective is to 
characterize the antitumor activity of tagraxofusp /POM/DEX in terms of ORR, CBR, PFS, and 
PFS-6. 
 
During phase 2, if approximately 14 patients are enrolled at the recommended phase 2 dose as 
defined in phase 1 over 12 months and follow-up continues for 12 months after the last enrolled 
patient, the total of 20 patients treated at this dose has approximately 60% power with a 1-sided 
type I error rate of 6% to reject the null hypothesis that the PFS-6 is <40% if the true rate is 
60%. 
3.2. 
General Methods 
All data listings that report an evaluation date will include a relative study day (Rel Day). 
Pre-treatment and on-treatment study days are numbered relative to the day of the first dose of 
Tagraxofusp which is designated as Day 1. The preceding day is Day -1, the day before that is 
Day -2, etc. The last day of any study drug is designated with an “L” (e.g., Day 26L). Post- 
treatment study days are numbered relative to the last dose and are designated as Day 1P, 
Day 2P, etc. 
 
All output will be incorporated into Microsoft Word files, sorted, and labeled according to the 
International Council for Harmonisation (ICH) recommendations, and formatted to the 
appropriate page size(s). 
 
Tabulations will be produced for appropriate demographic, baseline, efficacy, and safety 
parameters. For categorical variables, summary tabulations of the number and percentage of 
patients within each category (with a category for missing data) of the parameter will be 
presented. Two-sided 95% confidence intervals (CIs) will be computed using the Clopper Exact 
method. For continuous variables, the number of patients, mean, median, standard deviation 
(SD), minimum, and maximum values will be presented. Time-to-event data will be 
summarized using Kaplan-Meier methodology using 25th, 50th (median), and 75th percentiles 
with associated 2-sided 95% CIs, as well as percentage of censored observations. 
3.3. 
Computing Environment 
All descriptive statistical analyses will be performed using SAS statistical software Version 9.4, 
unless otherwise noted. Medical history and AEs will be coded using the Medical Dictionary for 
Regulatory Activities (MedDRA) Version 19.0 or higher. Concomitant medications will be 
coded using the World Health Organization (WHO) Drug Dictionary (December, 2016). 


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3.4. 
Baseline Definitions 
For all analyses, baseline will be defined as the most recent measurement prior to the first 
administration of tagraxofusp or tagraxofusp/POM/DEX. 
3.5. 
Methods of Pooling Data 
Overall summaries of safety parameters will be presented by stage of enrollment for MM patient 
groups across all dose levels. 
3.6. 
Adjustments for Covariates 
Due to the small sample size, no formal statistical analyses that adjust for possible covariate 
effects are planned. 
3.7. 
Multiple Comparisons/Multiplicity 
Multiplicity is not of concern for this Phase 1 study. 
3.8. 
Subgroup Analyses 
No subgroup analyses will be performed. 
3.9. 
Withdrawals, Dropouts, Loss to Follow-up 
At the discretion of the Sponsor, additional patients may be enrolled to supplement patient data 
that are compromised due to premature study dropout or other reasons. 
3.10. 
Missing, Unused, and Spurious Data 
In general, there will be no substitutions made to accommodate missing data points. All data 
recorded on the eCRF will be included in data listings that will accompany the CSR. 
 
When tabulating AE data, partial dates will be handled as follows: If the day of the month is 
missing, the onset day will be set to the first day of the month unless it is the same month and 
year as study treatment. In this case, to conservatively report the event as treatment-emergent, 
the onset date will be assumed to be the first day of treatment. If the onset day and month are 
both missing, the day and month will be assumed to be January 1, unless the event occurred in 
the same year as the study treatment. In this case, the event onset will be set to the first day of 
treatment in order to conservatively report the event as treatment emergent. A missing onset 
date will be set to the first day of treatment. 
3.11. 
Visit Windows 
It is expected that all visits should occur according to the protocol schedule. All data will be 
tabulated per the evaluation visit as recorded on the eCRF even if the assessment is outside of 
the visit window. In data listings, the relative day of all dates will be presented (see Section 3.2). 


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3.12. 
Timing of Analysis 
Safety data were summarized in support of a Biologics Licensing Application (data cutoff: 
07MAY2017) and in support of a Marketing Authorization Application (data cutoff: 
31JAN2018) for the licensing of tagraxofusp in the United States and Europe, respectively. 
Efficacy data were not summarized at that time. The respective analyses were described in a 
separate SAP. 
 
There were no planned interim efficacy analyses. The final, end of study analysis for the CSR 
using data from the locked database, will be supported from the analyses described in this 
document. 


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4. 
STUDY ANALYSES 
4.1. 
Patient Disposition 
Patient disposition will be tabulated and will include the number of patients screened, the 
number treated in total, the number in each patient population for analysis, and the number who 
withdrew prior to completing the study and reason(s) for withdrawal. The summary will be 
presented by dose level. 
 
A data listing of study completion information, including the reason for premature study 
withdrawal, if applicable, will be presented. 
4.2. 
Demographics and Baseline Characteristics 
Demographics and baseline characteristics will be summarized and presented by disease and 
dose level. Age, height, and weight will be summarized using descriptive statistics (number of 
patients, mean, SD, median, minimum, and maximum). The number and percentage of patients 
in each gender, ethnicity, race, and ECOG performance status category will be presented. 
 
Medical history will be tabulated. Disease history, including MM baseline diagnosis, time 
since MM diagnosis, prior MM treatment, response to prior treatment, and date of relapse, 
if applicable, will be summarized. 
Demographic and baseline data for each patient will be provided in data listings. 
4.3. 
Efficacy Evaluation 
The study will evaluate the activity of the tagraxofusp/POM/DEX regimen. 
 
Secondary efficacy endpoints will include PFS and PFS-6; ORR (CR + VGPR + PR) and 
clinical benefit rate (CR + VGPR + PR + MR) based on the IMWG defined response criteria, as 
well as DOR, and OS. 
Data for all efficacy endpoints will be presented in by-patient listings. 
 
Time to response, DOR, and survival will be estimated using the product-limit method of 
Kaplan and Meier. Exact 1-sided 95% CIs will be calculated for ORR and clinical benefit rates, 
and the distributions for DOR, PFS, PFS-6 and OS will be estimated by Kaplan-Meier 
methodology. 
4.3.1. 
Progression Free Survival 
 
Progression-free survival is defined as the time from the date of first infusion of tagraxofusp to 
the date of PD or death from any cause, whichever occurred first. Patients who do not progress 
and are still alive at the time of analysis will be censored on the date of the last disease 
assessment prior to the analysis cutoff date. The distribution for PFS will be estimated by 
Kaplan-Meier methodology and the 25th percentile, median, 75th percentile, number and 
percentage of events and censored observations, and appropriate CIs will be presented. 


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Progression-free survival at 6 months, PFS-6, will also be calculated for patients who do not 
progress and are still alive 6 months after the date of first treatment. 
4.3.2. 
Response Rate 
 
Response rates and depth of response will be calculated as the percent of evaluable patients that 
have confirmed sCR/CR/VGPR or PR. For CR, ORR, and CBR, Clopper Exact 95% CIs will be 
presented. 
 
Complete response rate will be presented as the number and percentage of patients who 
achieved CR after treatment. 
 
Overall Response (ORR) is defined as the percentage of evaluable patients that have confirmed 
CR, VGPR, or PR 
• ORR = (CR+ VGPR + PR) 
Clinical Benefit Rate is defined as the percentage of evaluable patients that have confirmed 
CR/VFPR/PR or MR 
• CBR = (CR + VGPR + PR + minimal response [MR]) 
4.3.3. 
Duration of Response 
 
Duration of response is defined as the time from when the criteria are first met for CR until the 
date that the criteria for relapse after CR are met. This could be the occurrence of PD or relapse. 
In the case that PR or SD follows CR and there is no evidence that response rebounds to CR, 
duration of CR will end at the time of first reduction of response to below CR. Patients who are 
lost to follow-up or who do not relapse after CR as of the cut-off for analysis will be censored 
on the latter of the date of last treatment with tagraxofusp or date of last disease assessment 
recorded prior to the analysis cutoff date. 
4.3.4. 
Overall Survival 
 
Overall survival is defined as the time from the date of first infusion of tagraxofusp/POM/DEX 
to the date of death from any cause. Patients who are still alive or lost to follow-up at the time of 
the analysis will be censored on the last date known to be alive prior to the analysis cutoff date, 
as determined by in-person visit or telephone contact. The overall distribution for OS will be 
estimated by Kaplan-Meier methodology in a similar manner as PFS. 
4.3.5. 
Exploratory Efficacy Assessments 
Exploratory efficacy assessment analyses will include: 
• M-protein determination actual values and changes from baseline will be summarized 
over time by visit and included in by-patient data listings using both of the following 
procedures: 
o SPEP and serum protein immunofixation with quantitative immunoglobulins; and 


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o UPEP and urine protein immunofixation (all using the same 24-hour urine collection) 
• Serum FLC results actual values and changes from baseline, including FLC Kappa, FLC 
Lambda, FLC Kappa/Lambda ratio, will be summarized over time by visit and included 
in a by-patient data listing 
• BM to quantify percent MM cell involvement results actual values and changes from 
baseline will be summarized over time by visit and included in a by-patient data listing 
• Plasmacytoma evaluation results will be included in a by-patient data listing 
only 
• Skeletal survey, serum β2 microglobulin, and cytogenetic analysis/FISH from BM 
aspirate results will be included in by-patient data listings only 
4.4. 
Safety Analyses 
All safety tabulations will be presented by dose. 
4.4.1. 
Study Drug Exposure 
 
Duration of study drug exposure will be calculated as the number of days and number of cycles 
patients were administered each study drug. 
 
𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 = (𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑠𝑠𝑠𝑠 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 − 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 𝑆𝑆𝑆𝑆𝐷𝐷𝐷𝐷𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠) + 1 
 
Duration in cycles of drug exposure will be defined the total number of cycles of each study 
drug initiated while the patient is on study. Total dose administered will be summarized for each 
study drug overall and by cycle. 
Relative Dose Intensity will be computed using the following definition: 
 
 
𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 (%) = 100 ∗ 
𝑆𝑆𝑆𝑆𝐷𝐷𝐷𝐷𝑆𝑆𝑆𝑆(𝐶𝐶𝐶𝐶𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑙𝑙𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝐶𝐶𝐶𝐶𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑙𝑙𝑠𝑠𝑠𝑠) 
 
 
𝑆𝑆𝑆𝑆𝐷𝐷𝐷𝐷𝑆𝑆𝑆𝑆(𝑃𝑃𝑃𝑃𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑠𝑠𝑠𝑠𝑠𝑠𝑆𝑆 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝐶𝐶𝐶𝐶𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑙𝑙𝑠𝑠𝑠𝑠) 
Exposure to tagraxofusp, POM, and DEX will be presented in by-patient data listings. 
4.4.2. 
Adverse Events 
 
All AEs will be coded using the MedDRA coding system and displayed in tables and data 
listings using system organ class (SOC) and preferred term (PT). 
 
Analyses of AEs will be performed for those events that are considered treatment-emergent, 
where treatment-emergent is defined per protocol as any AE with onset after the first 
administration of tagraxofusp or tagraxofusp/POM/DEX through 30 days after the last dose of 
tagraxofusp/POM/DEX, or any event that was present at baseline but worsened in intensity or 
was subsequently considered drug-related by the Investigator through 30 days after the last dose 
of Tagraxofusp/POM/DEX. 


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The number and percentage of patients with any treatment-emergent AE (TEAE), any TEAE 
assessed by the Investigator as related to any study treatment (definitely, probably, or possibly 
related), any Grade ≥3 TEAE as per the Common Terminology Criteria for Adverse Events 
(CTCAE), any SAE, any AE leading to discontinuation of any study treatment, and any AE 
leading to any dose modification will be summarized by dose group and overall. In these 
tabulations, each patient will contribute only once (i.e., the most related occurrence or the most 
intense occurrence) to each of the incidence rates in the descriptive analysis, regardless of the 
number of episodes. Summaries of related TEAEs will also be presented for relationship to each 
study drug (SL-401, Pomalidomide, and Dexamethasone). 
 
Treatment-emergent AEs summarized by patient incidence rates are not tabulated by severity or 
relationship to study treatment; therefore, in such tabulations, a patient contributes only once to 
the count for a given AE SOC or PT. For tabulations that include classification by relationship 
to any study treatment, AEs with missing relationship to any study treatment will be considered 
related. 
 
Adverse events of special interest (AESIs) will be determined using MedDRA version 19.0 
standardized medical queries (SMQs), high-level terms, or PTs, as follows: 
• Possible hypersensitivity events, based on the SMQ Hypersensitivity (broad search). 
• Vascular capillary leak syndrome (CLS), based on the MedDRA SMQ (to be provided) in 
addition to PTs of hypoalbuminemia, blood albumin decreased, and proteinuria. 
• Possible drug-induced liver injury events, based on the SMQ drug-related hepatic disorders 
(broad search). 
Summary tables of AESIs will be presented as follows: 
• AESIs overall and by PT, 
• AESIs by PT overall and by grouped cycle (Run-in, Cycle 1, Cycle 2, Cycles ≥ 3), 
• Grade ≥3 AESIs overall and by PT, 
• Serious AESIs overall and by PT, 
• AESIs resulting in any drug interruption overall and by PT, 
• AESIs resulting in dose reduction overall and by PT, 
• AESIs resulting in any study drug discontinuation overall and by PT, 
• AESIs resulting in death overall and by PT. 
These tabulations will be completed for all MM patients by dose group. AESIs will also be 
included in data listings. 


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4.4.2.1. 
Capillary Leak Syndrome 
 
In addition to the summaries described in Section 4.4.2, a summary will be provided presenting 
the number and grade of CLS events, exposure to tagraxofusp prior to onset of CLS, and time to 
first onset, and time to resolution of CLS events. 
4.4.3. 
Laboratory Data 
Clinical laboratory values will be expressed in Système International (SI) units. 
 
The actual value and change from baseline (Day 1) to each on-study evaluation through cycle 6 
will be summarized for each clinical laboratory parameter, including hematology, clinical 
chemistry, coagulation, and urinalysis. In the event of repeat values, the last non-missing value 
per study day/time will be used. 
 
Shift tables of change in CTCAE grade of laboratory parameters from baseline to worst value 
and from baseline to last value on study will be presented. Both scheduled and unscheduled 
visits will be included in shift tables. 
Results from pregnancy test results will be tabulated by patient. 
 
To assess for possible drug-induced liver injury (FDA 2009), a figure plotting peak alanine 
aminotransferase (ALT) versus peak total bilirubin (both on a logarithmic scale × upper limit of 
normal [ULN]) will be produced similar to that recommended by Watkins et al (Watkins, et al. 
2008) so that values within the normal reference range (<ULN) for ALT and total bilirubin are 
found in the left lower quadrant and Hy’s Law case candidates are in the upper right quadrant 
(ALT >3 × ULN and total bilirubin >2 × ULN). Patients with Gilbert’s syndrome or cholestasis 
are typically found in the upper left quadrant, and patients with ALT elevations without 
significant hepatic abnormality (i.e., without increased total bilirubin) are found in the lower 
right quadrant. The peak total bilirubin value plotted will be the peak within ± 7 days of the 
peak ALT value. If at least 5 patients are identified as potential Hy’s Law Cases, a summary 
table will be produced for the number and percentage of patients who have values of aspartate 
aminotransferase (AST) (>3 to ≤5 × ULN, >5 to ≤10 × ULN, >10 to ≤20 × ULN, >20 × ULN), 
ALT (>3 to ≤5 × ULN, >5 to ≤10 × ULN, >10 to ≤20 × ULN, >20 × ULN), alkaline 
phosphatase (>1.5 × ULN), or total bilirubin (>1.5 to ≤2 × ULN, >2 × ULN) after initiation of 
study drug. In this table, a patient may be counted only once. For instance, a patient with a result 
of AST of 11 × ULN will be counted in the category of >10 to ≤20 × ULN. 
This plot will be repeated for peak aspartate aminotransferase (AST) by total bilirubin. 
An example of the scatterplot is provided in Figure 4-1. 


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Figure 4-1 
Hy’s Law Candidates Scatterplot 
 
Time to first onset of elevated AST and ALT will be analyzed using Kaplan-Meier analyses and 
presented as figures. 
 
All laboratory data will be provided in by-patient data listings. A by-patient listing will also be 
presented for all laboratory values with CTCAE Grade ≥3. 
4.4.4. 
Vital Signs and Physical Examination 
 
The actual value and change from baseline (Day 1) to each on-study evaluation and to the last 
on study evaluation will be summarized for vital signs. 
 
A summary table of the number and percent of patients with treatment-emergent potentially 
clinically significant (PCS) vital signs parameters will be tabulated based on the following 
criteria: 
 
Variable Name 
PCS – Low if: 
PCS – High if: 
Observed 
Value is: 
AND 
Decrease from 
Baseline is: 
Observed 
Value is: 
AND 
Increase from 
Baseline is: 
Systolic Blood Pressure 
<90 mmHg 
≥20 mmHg 
>180 mmHg 
≥20 mmHg 
Diastolic Blood 
Pressure 
<50 mmHg 
≥10 mmHg 
>105 mmHg 
≥10 mmHg 
Heart Rate 
<50 bpm 
≥15 bpm 
>120 bpm 
≥15 bpm 
PCS= potentially clinically significant. 
All tables summarizing vital sign measurements only include visits in which at least 10% of the 
analysis population had measurements. Vital sign measurements will be presented for each 
patient in a data listing. 
 
All physical examination findings and ECOG performance status findings will be tabulated by 
visit and presented in data listings. 


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4.4.5. 
Electrocardiogram 
 
ECG results will be summarized descriptively, including the number and percentage of patients 
with normal, abnormal, and clinically significant abnormal results at baseline and each study 
visit. Actual values and change from baseline will be summarized for QTc intervals. All tables 
summarizing ECG measurements only include visits in which at least 10% of the analysis 
population had measurements. 
 
The number and percentage of patients whose mean QTcF or QTcB value at any time point 
meets any of the following categories will be summarized: 
• >450 msec 
• >480 msec 
• >500 msec 
• increase from baseline >30 msec 
• increase from baseline >60 msec 
QTcF and QTcB will be derived using QT interval and heart rate using the formulas: 
𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 
𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 
𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄 = 
𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻 𝑅𝑅𝑅𝑅𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑠𝑠𝑠𝑠1/3 
𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄𝑄 = 
𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻 𝑅𝑅𝑅𝑅𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑠𝑠𝑠𝑠1/2 
ECG and echocardiogram/multigated acquisition scan (MUGA) data for each patient will be 
provided in data listings. 
4.4.6. 
Concomitant Medications and Subsequent Treatments 
 
Concomitant medications will be coded using the WHO Drug Dictionary. Results will be 
tabulated by anatomic therapeutic class (ATC) and PT. 
 
Concomitant medications will be tabulated by dose group, where any medications that were not 
discontinued prior to the first dose of study drug will be included. If an end date is missing or 
the medication is ongoing at the time of first dose, the medication will be considered 
concomitant. 
 
The use of concomitant medications and subsequent treatment(s) will be included in by-patient 
data listings. 
4.4.7. 
Pre-Treatment Medications 
 
Pre-treatment medications will be coded using the WHO Drug Dictionary. Results will be 
tabulated by ATC and PT. In addition, the number and percent of patients who receive 
pre-treatment medication at least once will be summarized by dose group. 
Pre-treatment medications will be included in by-patient data listings. 


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5. 
CHANGES TO PLANNED ANALYSES 
As of this date, there have been no changes between the protocol-defined statistical analyses and 
those presented in this SAP. All changes from procedures outlined in this SAP will be 
summarized in the study report. Decisions to deviate from planned analyses will be documented 
at the time they are made. 


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6. 
REFERENCES 
Agarwal A, Ghobrial I. Monoclonal Gammopathy of Undetermined Significance and Smoldering 
Multiple Myeloma: A Review of the Current Understanding of Epidemiology, Biology, Risk 
Stratification, and Management of Myeloma Precursor Disease. Clin Cancer Res 2013;19:985–94. 
 
American Cancer Society. Cancer Facts and Figures 2013. Available from: 
http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc- 
036845.pdf 
 
Chauhan D, Ray A, Brooks C et al. A Novel Agent SL-401 Targeting Interleukin-3 (IL-3)- Receptor 
Blocks Plasmacytoid Dendritic Cell (pDC)-induced Myeloma Cell Growth and Overcomes Drug 
Resistance. J Clin Oncol 2013; 31;(suppl; abstr 8582). 
 
Chauhan, D, Uchiyama, H, Akbarali, Y, et al. Multiple myeloma cell adhesion induced 
interleukin-6 expression in bone marrow stromal cells involves activation of NF-kappa B. Blood 
1996;87:1104–1112. 
 
Deng Q and Barbieri JT. Molecular mechanisms of the cytotoxicity of ADP-ribosylating toxins. 
Annu Rev Microbiol 2008;62:271-288. 
 
FDA. Guidance for Industry: Drug-Induced Liver Injury: Premarketing Clinical Evaluation. 
2009. 
 
FitzGerald, D. Pastan, I. Targeted Toxin Therapy for the Treatment of Cancer. J Natl Cancer 
Institute 1989;81(19):1455-1463. 
Jordan CT, Guzman ML, Noble M. Cancer Stem Cells. N Engl J Med 2006;355:1253-1261. 
 
Louie GV, Yang W, Bowman ME Choe S. Crystal structure of the complex of diptheria toxin 
with an extracellular fragment of its receptor. Molecular Cell 1997; 1:67–78. 
 
Perentesis J, Miller SP, Bodley JW. Protein toxin inhibition of protein synthesis. Biofactors 
1992;3:173-184. 
 
Ratts R, Trujillo C, Bharti A, et al. A conserved motif in transmembrane helix 1 of diptheria 
toxin mediates catalytic domain delivery to the cytosol. Proc Natl Acad Sci U S A 
2005;102(43):15635-40. 
 
Thorburn A, Thorburn J, Frankel AE. Induction of apoptosis by tumor cell-targeted toxins. 
Apoptosis 2004; 90:19-25. 
 
Watkins PB, Seligman PJ, Pears JS, Avigan MI, and Senior JR. Using controlled clinical trials 
to learn more about acute drug-induced liver injury. Hepatology. 2008;48(5):1680-9. 
 
Yamaizumi M, Mekada E, Uchida T, et al. One molecule of diptheria toxin fragment A 
introduced into a cell can kill the cell. Cell 1978;15:245-250 


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7. 
STUDY FLOW CHARTS 
The following Study Flow Chart is from Protocol Amendment 2. 


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Table 7-1 
Schedule of Events 
 
Evaluation 
Screening 
Baseline 
Run in Cycle 
Cycle is 28 days 
Cycles 1 - 6 v 
Each Cycle is 28 days 
EOTw 
30-day 
Post- 
Tx F/U 
F/Ux 
D-21 to -1 
D 
1 
D 
2 
D 
3 
D 
4 
D 
5 
D 
8 
D 
15 
D 
22 
D 
1 
D 
2 
D 
3 
D 
4 
D 
5 
D 
8 
D 
15 
D 
22 
Informed Consent & Pomalyst 
REMSa 
X 
Entry Criteria Review 
X 
Medical and Myeloma Historyb 
X 
Physical Examinationc 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Performance Status (ECOG) 
X 
X 
X 
X 
Height (Baseline only) / Weight 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Vital Signs (HR, Temperature, 
RR, BP)d 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
ECG 
X 
X 
X 
ECHO/MUGA 
Xe 
Pregnancy testing [FCBP) and 
counseling f 
X 
Xf 
X 
Xf 
Xf 
Xf 
X 
Hematologyg 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Xg 
X 
X 
X 
X 
X 
X 
X 
X 
Serum Chemistryh 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
PT / INR aPTT 
X 
X 
X 
Urinalysis i 
X 
X 
X 
X 
Plasmacytoma Evaluation j 
X 
Xj 
X 
As needed 
Skeletal Survey k 
X 
As needed 
Bone Marrow Aspiration and 
biopsyl 
X 
Xl 
X 
Peripheral blood for correlative 
studiesm 
X 
Xm 
X 


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Evaluation 
Run in Cycle 
Cycle is 28 days 
Cycles 1 - 6 v 
Each Cycle is 28 days 
EOTw 
30-day 
Post- 
Tx F/U 
F/Ux 
D 
1 
D 
2 
D 
3 
D 
4 
D 
5 
D 
8 
D 
15 
D 
22 
D 
1 
D 
2 
D 
3 
D 
4 
D 
5 
D 
8 
D 
15 
D 
22 
Myeloma-specific Laboratory 
Testsn 
X 
X 
X 
As needed 
PK (SL-401)o 
X 
X 
X 
C2 
X 
C2 
Immunogenicity (SL-401)p 
X 
X 
X 
X 
SL-401 Pre-medicationq 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
SL-401 Administrationr 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Pomalidomides 
Days 1 - 21 
Dexamethasone 
X 
X 
X 
X 
Vision assessment 
X 
X 
X 
Adverse Event monitoringt 
← X → 
X 
Prior/Concomitant Medicationu 
← X → 
X 
 
a. 
Informed consent All patients must sign an IRB approved informed consent prior to screening and agree to enroll in the Pomalyst REMS program prior to starting POM. 
b. 
Medical History: Includes relevant history of previous/associated pathologies other than the tumor. Myeloma History: Includes date of initial diagnosis, stage, and 
extent of the disease both at diagnosis and at study entry, previous anti-tumor therapy (including surgical, radiation and systemic therapy; for systemic therapy, includes 
approximate dates of administration, best response and approximate dates of disease progression). 
c. 
Physical Examination: Consists of examination of major body systems including neurologic, digestive, respiratory, any evaluable sites of extramedullary disease. 
Physical examination is required at screening/baseline and Day 1 of each treatment cycle. Symptom directed physical examination may also be performed on other 
treatment days or mid-cycle evaluations if there are symptoms or vital sign abnormalities warranting examination. 
d. 
Vitals signs: HR, temperature, RR, BP, and pulse oximetry to be taken pre- SL-401 infusion, end of SL-401 infusion, 30, 60 and 240 minutes post-infusion and as 
clinicallyindicated for all doses of the Run-in Cycle. Cycle 1 +, vital signs are to be taken pre-infusion, at end of infusion, and then every 30 minutes through 4 hours 
post-infusion, and as clinically indicated. For temperature ≥38°C, draw blood cultures ×2 and collect urine for urinalysis and culture. 
e. 
ECHO/MUGA: may be performed within 28 days before baseline. 
f. 
Pregnancy tests for FCBP at screening, test must be repeated within 10 – 14 days prior to initiation of POM therapy (before Cycle 1) and again within 24 hours prior 
to initiation of POM therapy (before Cycle 1). While on POM, repeat pregnancy test every week for the first 4 weeks and then every 28 days while on therapy and 
during interruptions in therapy and 28 days following discontinuation of POM. Women with irregular menstruation must have pregnancy testing every 14 days while 
on therapy and during interruptions and 14 and 28 days after discontinuation of POM. All patients enrolled into this study, must be registered in and must comply with 
all requirements of the POMALYST REMS™ program. A FCBP is a female of childbearing potential is a sexually mature woman who: 1) has not undergone a 


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hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 24 consecutive months. 
g. 
Hematology: CBC to be performed and reviewed by clinician prior to SL-401 dosing on Days 1 – 5 and Days 8, 15 and 22 or as clinically indicated. The Run in and 
Cycle1, Day 1, results must remain within the entry criteria values to initiate therapy. 
h. 
Serum Chemistry: to be performed and reviewed by clinician prior to SL-401 dosing on Days 1 – 5 and Days 8, 15, and 22 or as clinically indicated. The Run in and 
Cycle1 Day 1 results must remain within the entry criteria values to initiate therapy. Chemistry includes: glucose (fasting at baseline), albumin, total protein, AST, 
ALT, bilirubin(total and direct), alkaline phosphatase, LDH, CPK, sodium, potassium, chloride, bicarbonate/carbon dioxide, calcium, magnesium, phosphate, uric acid, 
BUN, serum creatinine and estimated creatinine clearance (Cockroft-Gault formula Appendix 15.7). Albumin, transaminases (AST/ALT) and creatinine must be 
evaluated prior to each SL-401 dose. 
i. 
Urinalysis: Appearance, color, pH, specific gravity, ketones, leukocytes, protein, glucose, bilirubin, urobilinogen, and occult blood. To be performed at baseline, Day 
1 ofeach cycle, and EOT. 
j. 
Plasmacytoma Assessment Disease: For patient with known or suspected plasmacytomas, assess by physical exam and/or radiologic evaluation at baseline and as 
clinicallyindicated. Disease that can be assessed by physical exam should be evaluated on Day 1 of each cycle. Disease that can be assessed by radiologic evaluation 
should be assessed according the IMWG criteria for evaluation of response. This may include computerized tomography (CT) scan, ultrasound, PET/CT or MRI. The 
same method ofassessment should be used at each evaluation for any individual patient. Assess the need to evaluate for suspected new, worsening, or improved 
plasmacytomas to confirm response or progression every cycle. Evaluations may be performed on Day 1 of a cycle or during the 7 days prior to Day 1 of the Cycle as 
needed for scheduling. 
k. 
Skeletal Survey: Plain film X-rays to including skull, vertebrae, all long bones, pelvis and chest are required. PET/CT MRI may be done to supplement X-rays 
of any disease site at Investigators discretion. Also required at any time when clinically indicated, for suspected progression per IMWG response criteria. 
l. 
Bone Marrow Aspiration: Bone marrow aspiration + biopsy for cytogenetic analysis both by FISH and standard karyotyping, and morphologic evaluation including 
assessment of plasma cell percentage is required at screening/baseline (within 21 days prior to study drug administration. Bone marrow aspirate should be repeated if 
CR or stringent complete response (sCR) is suspected to confirm achievement of response according to IMWG criteria, and at End of therapy. BM biopsy material 
should be fixed, and 10 unstained slides from sequential tissue sections should be shipped to the laboratory listed for further translational analysis. Additional BM 
aspirate material (10-15cc iffeasible) and biopsy for correlative studies are to be collected at baseline and any time a specimen is obtained to confirm response. 
m. Peripheral blood for correlative studies should be obtained at baseline, for phase 1 Day 1 of Cycles 1, 3, and 5 and for phase 2 on Day 1 of Cycles 2, 4, and 6 and at 
EOTfor all patients. Four 10 mL tubes in total (2 green top, 1 lavender top; 1 red top/serum separator tube). Whole blood will be evaluated for circulating MM/plasma 
cells (and other mononuclear cells of interest); serum and plasma will be for evaluated for potentially relevant circulating cytokines, and surrogate markers of osteolytic 
activity. 
n. 
Myeloma-specific laboratory tests: β2 Microglobulin (at baseline only), serum and 24-hour urine immunoelectrophoresis, serum immunoglobulin assay, serum/urine 
immunofixation and serum FLC with kappa/lambda ratio to be performed at baseline, every cycle prior to study drug administration thereafter and at end of treatment 
(if last tests were >4 weeks) and for patients who discontinue therapy for reasons other than disease progression. Myeloma laboratory tests will be repeated every 
month until disease progression or initiation of subsequent therapy. Response assessment will be done at the beginning of every cycle. Following pre-treatment 
evaluations on Day 1 of the first cycle evaluations may be performed on Day 1 of a subsequent cycle or during the 7 days prior to Day 1 of the Cycle as needed for 
scheduling. (Note that an evaluation performed during the final week of Cycle 1 should nonetheless be recorded as the evaluation for the beginning of Cycle 2, with 
similar assignments for subsequentcycles). 
o. 
Pharmacokinetic Assessment: phase 1 only. PK samples (plasma) are to be obtained at the following time points: pre-infusion, immediately after infusion then 15, 
30, 45, 60, 90, 120, 180, and 240 minutes post-infusion in Phase 1 on Days 1 and 5 of the Run-in Cycle and Cycle 2. See Table 8. Pomalidomide will be administered 
approximately 4-6 hours post SL-401 end of infusion for the purpose of obtaining PK samples on the day of infusion 1 and 5 of Cycle 2. 
p. 
Immunogenicity: Serum for immunogenicity evaluation will be collected prior to the infusion during the run-in Cycle 1 on Days 1 and 5 and on Day 1 pre-infusion 
at thebeginning of all subsequent cycles, and at End-of-therapy. If infusions are held (postponed) for any reason, an immunogenicity sample must be collected within 
3 ± 3 daysafter completion of the last SL-401 infusion for the cycle. 
q. 
Pre-medication: Approximately 60 minutes prior to each dose of SL-401, patients shall receive pre-medication with acetaminophen, diphenhydramine, 
methylprednisolone,and ranitidine according to Section 7.3.3.1. 


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r. 
SL-401 administration: SL-401 will be given by iv infusion over 15 minutes on Days 1 – 5 of each 28 day cycle (Run-in Cycle and Cycles 1 – 6) with delays 
permitted as delineated in relevant protocol sections such that administration on days 6-10 of any cycle is also permitted (5 doses may be administered over 10 days, if 
necessary). Dose modifications are permitted following the Run-in Cycle and Cycle 1; 5 doses of SL-401 may be administered over the initial 10-day period of each 
cycle. See Protocol Section 7.3 for drug administration instructions and for Protocol Section 7.7 dose modification guidelines. 
s. 
Pomalidomide: Pomalidomide will be administered approximately 4-6 hours post SL-401 end of infusion for the purpose of obtaining SL-401 PK samples on the 
days ofinfusion 1 and 5 of Cycle 2. Pomalidomide should be taken on an empty stomach 2 hours before or after a meal. Capsules should not be opened, broken or 
chewed. 
t. 
AE monitoring: Patients to be observed for AEs at least 4 hours post each infusion. All AEs, including AEs of new onset as well as worsening of baseline signs and 
symptoms are to be reported from the signing of the informed consent to 30 days following the last administration of any study drug. After the 30-day follow-up all 
ongoing and new related AEs, and all the SAEs regardless of causal relationship are to be followed up to resolution or stabilization. 
u. 
Prior/concomitant medication should be recorded including medications taken during the 28 days prior to initial study therapy, at any/all times during 
studytherapy/participation, and through approximately 30 days following the last dose of investigational therapy. 
v. 
Patients with evidence of MM stabilization or response and without unacceptable toxicity will receive the Run-in Cycle and 6 cycles of SL-401/POM/DEX. If, 
following completion of these cycles, there is ongoing evidence of MM stabilization or response, patients may receive additional therapy on-study if the Investigator 
believes the potential risk/benefit of additional therapy is justifiable. During Cycle 7 and beyond, SL-401 will be administered on Day 1-5 of every other cycle 
(every 56 days), POMadministered on Days 1-21, and DEX administered on Days 1, 8, 15 and 22 of each cycle. 
w. EOT: Evaluations should be completed at the time a decision is made to discontinue study therapy, and approximately 30 ±7 days following the last dose of study 
therapyregardless for the reason of discontinuation, unless patient withdraws consent and refuses further evaluation. 
x. 
Follow-up: Patients who discontinue therapy for reasons other than MM progression will be followed for response every month until progression of disease or 
initiation of subsequent therapy. Patients who have discontinued study therapy and have had MM progression should be contacted approximately every 3 months 
(telephone contact is permitted) to assess overall survival status for 1 year; patients who discontinue therapy for reasons other than disease progression and are no 
longer willing to follow-up for evaluation of disease progression should also be contacted for survival status whenever feasible. Patients who undergo stem cell 
transplant will be followed for the occurrence of VOD as part of long-term follow-up.