# EDGAR Filing Document

**Accession Number:** 0001778016
**File Stem:** 0000950170-25-095288
**Filing Date:** 2025-7
**Character Count:** 27966
**Document Hash:** 54b6fb0c6ee98b3cfd4a85384ecde2f6
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950170-25-095288.hdr.sgml**: 20250711

**ACCESSION NUMBER**: 0000950170-25-095288

**CONFORMED SUBMISSION TYPE**: 6-K/A

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20250711

**FILED AS OF DATE**: 20250711

**DATE AS OF CHANGE**: 20250711

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** I-Mab
- **CENTRAL INDEX KEY:** 0001778016
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** E9
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 6-K/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39173
- **FILM NUMBER:** 251119039

**BUSINESS ADDRESS:**
- **STREET 1:** SUITE 400, 2440 RESEARCH BLVD
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850
- **BUSINESS PHONE:** (301) 670 2800

**MAIL ADDRESS:**
- **STREET 1:** SUITE 400, 2440 RESEARCH BLVD
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

**FORM 6-K/A**

**REPORT OF FOREIGN PRIVATE ISSUER**

**PURSUANT TO RULE 13a-16 OR 15d-16 UNDER**

**THE SECURITIES EXCHANGE ACT OF 1934**

For the month of July 2025

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Commission File Number: 001-39173

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**I-MAB**

2440 Research Boulevard, Suite 400

Rockville, MD 20850

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

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**EXPLANATORY NOTE**

This Amendment No. 1 (this "Amendment No. 1") to the Report on Form 6-K, originally furnished with the U.S. Securities and Exchange Commission on July 2, 2025, File No. 001-39173 (the "Initial Report"), is being furnished in order to incorporate Exhibits 99.1 and 99.2 furnished as part of the Initial Report into the Registration Statements on Form F-3 (File No. 333-286954) and Form S-8 (File No. 333-239871, File No. 333-256603, File No. 333-265684 and File No. 333-279842) (including any prospectuses forming a part of such registration statements) of I-MAB (the "Company"). Except as set forth herein, there are no other changes to the Initial Report.

**DOCUMENTS INCORPORATED BY REFERENCE**

Exhibits 99.1 and 99.2 included with this Amendment No. 1 shall be deemed to be incorporated by reference into the Company's Registration Statements on Form F-3 (File No. 333-286954) and Form S-8 (File No. 333-239871, File No. 333-256603, File No. 333-265684 and File No. 333-279842) (including any prospectuses forming a part of such registration statements) and to be a part thereof from the date on which this Amendment No. 1 is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

**EXHIBIT INDEX**

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| | |
|:---|:---|
| **<u>Exhibit No.</u>** | **<u>Description</u>** |
| [<u>99.1</u>](imab-ex99_1.htm)<br>| [<u>Press Release - I-Mab Presents Positive Givastomig Phase 1b Dose Escalation Data in Combination with Immunochemotherapy in Patients with 1L Gastric Cancers at ESMO GI 2025</u>](imab-ex99_1.htm)<br>|
| [<u>99.2</u>](imab-ex99_2.htm)<br>| [<u>Presentation - A Phase 1b dose escalation study of givastomig, a CLDN18.2 x 4-1BB bispecific antibody, in combination with immunochemotherapy in HER2-negative, CLDN18.2-positive gastric, esophageal or gastro-esophageal junction adenocarcinoma</u>](imab-ex99_2.htm)<br>|

---

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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| | | |
|:---|:---|:---|
| I-MAB | I-MAB | I-MAB |
| By | : | /s/ Joseph Skelton |
| Name | : | Joseph Skelton |
| Title | : | Chief Financial Officer |

---

Date: July 11, 2025

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## Exhibit 99.1

**Exhibit 99.1**

![img44095488_0.jpg](img44095488_0.jpg)

**I-Mab Presents Positive Givastomig Phase 1b Dose Escalation Data in Combination with Immunochemotherapy in Patients with 1L Gastric Cancers at ESMO GI 2025** 

*Data show confirmed ORR of 83% (10/12) at doses selected for ongoing expansion study*

*Median follow-up of 9.0 months as of the updated data cutoff* 

*Responses observed in patients with low PD-L1 and/or CLDN18.2 expression*

*Company to host investor event on Tuesday, July 8*<sup>th</sup>

ROCKVILLE, MD, July 2, 2025 (Globe Newswire) – I-Mab (NASDAQ: IMAB) (the Company), a U.S.-based, global biotech company, focused on the development of precision immuno-oncology agents for the treatment of cancer, today announced the presentation of positive Phase 1b combination data for givastomig, in combination with nivolumab and mFOLFOX6, at the *European Society for Medical Oncology Gastrointestinal Cancers Congress 2025 (ESMO GI 2025)* in Barcelona (abstract #388MO)*.* Givastomig is a bispecific antibody targeting Claudin 18.2 and 4-1BB. I-Mab plans to host a virtual investor event on Tuesday, July 8<sup>th</sup> (register here) to review these data.

The Phase 1b data (NCT04900818) show a confirmed objective response rate (ORR) of 71% across all doses (12/17), and 83% (10/12) at doses selected for the ongoing dose expansion study (8 mg/kg and 12 mg/kg). Responses occurred in tumors with low levels of PD-L1 expression and/or Claudin 18.2 (CLDN18.2) expression, with favorable overall tolerability. There were no Grade 3 or greater events for nausea and vomiting, and only one Grade 3 TRAE for increased liver enzymes. The data are based on the results of the dose escalation part of a Phase 1b study evaluating the givastomig combination as first line therapy (1L) in patients with Claudin 18.2-positive gastric cancers (≥1+ IHC staining intensity in ≥1% of tumor cells). The primary endpoint is safety. The study enrolled only patients in the U.S.

"The positive Phase 1b combination data presented at ESMO GI bolster our confidence in givastomig's potential to be a best-in-class Claudin 18.2 directed therapy. Givastomig has been well tolerated when combined with immuno-oncology and chemotherapy, has shown a high objective response rate, with rapid onset and durable responses that have deepened over time, supported by consistent pharmacokinetic data and soluble 4-1BB induction," **said Phillip Dennis, MD, PhD, Chief Medical Officer of I-Mab.** "In addition, we are optimistic about the results from the 8 mg/kg and 12 mg/kg doses. These doses showed an ORR of 83%, with consistent responses across PD-L1 and Claudin 18.2 expression levels, and a favorable overall safety profile. These data further our conviction in the ongoing Phase 1b dose expansion study. We believe givastomig has broad potential in a number of gastric cancer settings and look forward to continued advancement of the program."

"I am encouraged by the response rates, as well as the deepening of responses over time, demonstrated by the givastomig combination regimen in the Phase 1b dose escalation study that we presented today at ESMO GI. Despite approved therapies, targeted treatment options for gastric cancers continue to be limited. While the data are early, givastomig combination therapy demonstrates a high response rate across Claudin18.2 and PD-L1 expression levels," said **Samuel J Klempner, MD, Associate Professor of Medicine at Massachusetts General Hospital**. "In addition, I have been pleased to observe that givastomig has a favorable overall tolerability profile with a low level of gastrointestinal side effects -- especially important for patients with gastric cancer. I look forward to participating in the ongoing givastomig clinical development program, and hope we may be able to expand the population of patients who may benefit from Claudin 18.2 directed agents."

**Virtual Investor Event:** 

Register (here) for the Post-ESMO GI 2025 Investor Event to be held on Tuesday, July 8<sup>th</sup> at 2:00 PM EDT. A replay of the webinar will be accessible on the Events page of the I-Mab website for 90 days.

**Fireside Chat Event with Lucid Capital Markets to Recap the Presentation:** 

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Tune in (here) for a fireside chat sponsored by Christopher Liu, PharmD, Managing Director at Lucid Capital Markets that will be accessible today at 2:00pm EDT on the Events page of the I-Mab website. A replay of the fireside chat will be available for 90 days.

**ESMO GI Presentation Details:**

A full copy of the ESMO GI presentation is available on the Publications and Presentations page of the I-Mab website here.

**Givastomig Phase 1b Dose Escalation Data Summary in 1L Gastric Cancers** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•17 advanced metastatic gastric cancer patients were treated with givastomig across the 5 mg/kg (n=5), 8 mg/kg (n=6), and 12 mg/kg (n=6) dose levels as of the May 15, 2025 data cutoff. All patients were efficacy evaluable

**Patient Characteristics:**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•The 17 patients enrolled in the study were treatment naïve metastatic gastric, esophageal or gastroesophageal adenocarcinomas

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Patients were HER2-negative, Claudin 18.2-positive (defined as ≥1+ IHC staining intensity in ≥1% of tumor cells), regardless of PD-L1 expression levels

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•All patients were enrolled at sites within the United States

**Efficacy Results:**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Confirmed Objective Response Rates (ORRs):

o71% of patients (12/17) achieved a partial response (PR) per RECIST v1.1

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;▪5 mg/kg (2/5)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;▪8 mg/kg (5/6)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;▪12 mg/kg (5/6)

oAt the doses selected for dose expansion (8 and 12 mg/kg), 83% (10/12) of patients achieved PRs

o80% of patients (4/5) with CLDN18.2 expression below 75% (CLDN-Low) achieved a PR. The CLDN-Low response rate increased to 100% of patients (3/3) in the doses selected for expansion (8 and 12 mg/kg)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•The disease control rate (DCR) was 100% across the three dose levels

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Dose-dependent pharmacokinetics (PK) were observed, similar to monotherapy PK

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Patients also experienced a dose dependent induction of soluble 4-1BB, a positive indicator of T cell activation and engagement

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| | | |
|:---|:---|:---|
| &nbsp;&nbsp;**ORR: % (n)** | &nbsp;&nbsp;**All**<br>**(n=17)** | &nbsp;&nbsp;**Cohorts Chosen for Expansion**<br>**(8 and 12 mg/kg)**<br>**(n=12)** |
| &nbsp;&nbsp;**PD-L1** |  |  |
| &nbsp;&nbsp;Any  | &nbsp;&nbsp;71 (12/17) | &nbsp;&nbsp;83 (10/12) |
| &nbsp;&nbsp;≥5  | &nbsp;&nbsp;82 (9/11) | &nbsp;&nbsp;89 (8/9) |
| &nbsp;&nbsp;<5 | &nbsp;&nbsp;50 (3/6) | &nbsp;&nbsp;67 (2/3) |
| &nbsp;&nbsp;≥1  | &nbsp;&nbsp;73 (11/15) | &nbsp;&nbsp;82 (9/11) |
| &nbsp;&nbsp;<1  | &nbsp;&nbsp;50 (1/2) | &nbsp;&nbsp;100 (1/1) |
| &nbsp;&nbsp;**CLDN18.2** |  |  |
| &nbsp;&nbsp;≥75 | &nbsp;&nbsp;67 (8/12) | &nbsp;&nbsp;78 (7/9) |
| &nbsp;&nbsp;<75  | &nbsp;&nbsp;80 (4/5) | &nbsp;&nbsp;100 (3/3) |

---

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| | | |
|:---|:---|:---|
| &nbsp;&nbsp;**ORR: % (n)** | &nbsp;&nbsp;**PD-L1 ≥ 5** | &nbsp;&nbsp;**PD-L1 < 5** |
| &nbsp;&nbsp;CLDN18.2 ≥ 75 | &nbsp;&nbsp;80 (8/10) | &nbsp;&nbsp;0 (0/2) |
| &nbsp;&nbsp;CLDN18.2 < 75 | &nbsp;&nbsp;100 (1/1) | &nbsp;&nbsp;75 (3/4) |

---

**Durability:** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•8 of 17 patients remained on study treatment and the longest treatment duration was 13.3 months as of the data cutoff

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Median follow-up was 9.0 months across all dose levels as of the data cutoff

**Safety:**

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Treatment-related adverse events (TRAEs) leading to discontinuation of any treatment were 12% (two patients), five patients had progressive disease, two patients withdrew from the study for social reasons

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•No dose limiting toxicities (DLT) were observed and a maximum tolerated dose (MTD) was not reached

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Common TRAEs (≥10% of patients) were generally Grade 1 or Grade 2 including nausea, vomiting, infusion related reaction, fatigue, decreased appetite, diarrhea, abdominal pain, chills, dyspepsia and gastritis

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Grade 3 TRAEs attributed to givastomig were rare, with single cases of abdominal pain, ALT/AST increases, gastritis, and infusion related reaction

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•Four cases of Grade 3 and two cases of Grade 4 treatment-related neutropenia were observed driven by an early restriction on prophylaxis use of G-CSF, which has been subsequently lifted. The neutropenia cases were primarily attributed to mFOLFOX6 in the 8 mg/kg cohorts

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•No Grade 5 TRAEs were reported

**About Givastomig**

Givastomig (TJ033721 / ABL111) is a bispecific antibody targeting Claudin 18.2 (CLDN18.2)-positive tumor cells. It conditionally activates T cells through the 4-1BB signaling pathway in the tumor microenvironment where CLDN18.2 is expressed. Givastomig is being developed for first line (1L) metastatic gastric cancers, with further potential in other solid tumors. In Phase 1 trials, givastomig has shown promising anti-tumor activity attributable to a potential synergistic effect of proximal interaction between CLDN18.2 on tumor cells and 4-1BB on T cells in the tumor microenvironment, while minimizing toxicities commonly seen with other 4-1BB agents.

An ongoing Phase 1b study is evaluating givastomig for the treatment of gastric cancer in the 1L setting in combination with standard of care, nivolumab (an anti-PD-1 checkpoint inhibitor) plus chemotherapy, in dose escalation and dose expansion cohorts. Dose escalation is complete, and enrollment in the first dose expansion cohort (n=20) finished ahead of schedule. Enrollment continues to progress ahead of schedule in the second dose expansion cohort (n=20). The study builds on positive Phase 1 monotherapy data.

Givastomig is being jointly developed through a global partnership with ABL Bio, in which I-Mab is the lead party and shares worldwide rights, excluding Greater China and South Korea, equally with ABL Bio.

**About I-Mab**

I-Mab (NASDAQ: IMAB) is a U.S.-based, global biotech company, focused on the development of precision immuno-oncology agents for the treatment of cancer. The Company's differentiated pipeline is led by givastomig, a potential best-in-class, bispecific antibody (Claudin 18.2 x 4-1BB) designed to treat Claudin 18.2-positive gastric cancers. Givastomig conditionally activates T cells via the 4-1BB signaling pathway in the tumor microenvironment where Claudin 18.2 is expressed. Givastomig is being developed for first-line metastatic gastric cancers, with additional potential in other solid tumors. In Phase 1 trials, givastomig was observed to maintain strong tumor-binding and anti-tumor activity, attributable to a potential synergistic effect of proximal interaction with Claudin 18.2 and 4-1BB, while minimizing toxicities commonly seen with other 4-1BB agents.

For more information, please visit www.i-mabbiopharma.com and follow us on LinkedIn and X.

**I-Mab Forward Looking Statements**

This announcement contains forward-looking statements. These statements are made under the "safe harbor" provisions of the U.S. Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified by terminology such as "will", "expects", "believes", "designed to", "anticipates", "future", "intends", "plans", "potential", "estimates", "confident", and similar terms or the negative thereof. I-Mab may also make written or oral forward-looking statements in its periodic reports to the U.S. Securities and Exchange Commission (the SEC), in its annual report to shareholders, in press releases and other written materials and in oral statements made by its officers, directors or employees to third parties. Statements that are not historical facts, including statements about I-Mab's beliefs and expectations, are forward-looking statements. Forward-looking statements in this press release include, without limitation, statements regarding: the Company's pipeline and clinical development of I-Mab's drug candidates, including givastomig; the projected advancement of the Company's portfolio and anticipated milestones and related timing; the Company's expectations regarding the impact of data from ongoing and future clinical trials; the timing and progress of studies and trials (including with respect to patient enrollment); the potential benefits of givastomig; and the availability of data and information from ongoing studies and trials. Forward-looking statements involve inherent risks and uncertainties that may cause actual results to differ materially from those contained in these forward-looking statements, including but not limited to the following: I-Mab's ability

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to demonstrate the safety and efficacy of its drug candidates; the clinical results for its drug candidates, which may or may not support further development or New Drug Application/Biologics License Application (NDA/BLA) approval; the content and timing of decisions made by the relevant regulatory authorities regarding regulatory approval of I-Mab's drug candidates; I-Mab's ability to achieve commercial success for its drug candidates, if approved; I-Mab's ability to obtain and maintain protection of intellectual property for its technology and drugs; I-Mab's reliance on third parties to conduct drug development, manufacturing and other services; and I-Mab's limited operating history and I-Mab's ability to obtain additional funding for operations and to complete the development and commercialization of its drug candidates, as well as those risks more fully discussed in the "Risk Factors" section in I-Mab's annual report on Form 20-F filed with the SEC on April 3, 2025, as well as the discussions of potential risks, uncertainties, and other important factors in I-Mab's subsequent filings with the SEC. All forward-looking statements are based on information currently available to I-Mab. I-Mab undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as may be required by law.

**I-Mab Investor & Media Contacts**

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| |
|:---|
| PJ Kelleher |
| LifeSci Advisors |
| +1-617-430-7579 |
| pkelleher@lifesciadvisors.com  |
| IR@imabbio.com |

---

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## Exhibit 99.2

![Slide 1](imab-ex99_2s1.jpg)

A Phase Ib dose escalation study of givastomig, a CLDN18.2 x 4-1BB bispecific antibody, in combination with immunochemotherapy in HER2-negative, CLDN18.2-positive gastric, esophageal or gastro-esophageal junction adenocarcinoma Samuel J. Klempner, Farshid Dayyani, Jeremy Kratz, Sunnie Kim, Claire (Cong) Xu, Christoph M. Ahlers, Xuejun Liu, Jou-Ku Chung, Peter Sabbatini, Phillip A. Dennis, Sangmi Lee, Juyeun Jeon, Geoffrey Ku 02 July 2025

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![Slide 2](imab-ex99_2s2.jpg)

DECLARATION OF INTERESTS SJK has served as a consultant and/or in an advisory role for Bristol-Myers Squibb, Merck, Astellas, Daiichi-Sankyo, Natera, Novartis, AstraZeneca, Mersana, Sanofi-Aventis, Amgen, Boehringer-Ingelheim, Taiho Oncology, Eisai, BeiGene, Elevation Oncology, EsoBiotec, and Gilead. SJK reports prior stock/equity in Turning Point Therapeutics and Nuvalent. SJK is currently participating as an investigator on the study being presented.

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![Slide 3](imab-ex99_2s3.jpg)

Background Ku ESMO 2024 Shen JITC 2024 Givastomig, a CLDN18.2 x 4-1BB bispecific antibody, was well tolerated as monotherapy and showed activity in heavily pretreated CLDN18.2-positive gastric cancer patients.1 Givastomig exerts anti-tumor activity through CLDN18.2-based, tumor-directed T-cell activation.2 Dose-dependent pharmacokinetics and induction of soluble 4-1BB were observed. Here we present the preliminary data from the dose escalation of givastomig combined with nivolumab and FOLFOX. Highly potent CLDN18.2 mAb Higher affinity than zolbetuximab Binds to tumor cells with a wide range of CLDN18.2 expression Silenced Fc: IgG1 No ADCC or CDC Minimize unintended systemic immune activation driven by FcgR-mediated 4-1BB clustering Conditional 4-1BB agonist Localized T cell activation in TME leading to potent tumor killing and minimal 4-1BB-mediated liver toxicity or systemic immune response Anti-CLDN18.2 IgG1 Anti-4-1BB scFv Givastomig

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![Slide 4](imab-ex99_2s4.jpg)

Notes: GC = gastric cancer; GEJ = gastroesophageal junction; EAC = esophageal adenocarcinoma; mFOLFOX6 = standard of care chemotherapy regimen; Q2W = every two weeks; giva = givastomig; ORR = objective response rate; PK = pharmacokinetic; PD = pharmacodynamic; BoR = best overall response; DoR = duration of response; PFS = progression free survival; OS = overall survival; 1L = first line Phase Ib Study Design of Givastomig Combined with Immunochemotherapy Study Design: Multi-center, dose-escalation and expansion phase Ib study Enrolled only US patients Bayesian optimal interval design with at least four subjects per dose Eligibility: 1L unresectable or metastatic GC/GEJ/EAC (GEA) HER2-negative CLDN18.2 ≥1+ on ≥1% of tumor cells All comers PD-L1 Dose Level 1 (n=5) Giva 5 mg/kg + nivolumab 240 mg + mFOLFOX6 Q2W Dose Escalation (n=17) Dose Level 2 (n=6) Giva 8 mg/kg + nivolumab 240 mg + mFOLFOX6 Q2W Dose Level 3 (n=6) Giva 12 mg/kg + nivolumab 240 mg + mFOLFOX6 Q2W Endpoints: Primary: Safety Secondary: Response rate: ORR, BoR, DoR Survival: PFS, OS PK/PD Dose Expansion (n=40) Dose Level 3 (n=20) Giva 12 mg/kg + nivolumab 240 mg + mFOLFOX6 Q2W Dose Level 2 (n=20) Giva 8 mg/kg + nivolumab 240 mg + mFOLFOX6 Q2W Fully Enrolled Enrollment Ongoing

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![Slide 5](imab-ex99_2s5.jpg)

Feature(s) 5 mg/kg (n=5) 8 mg/kg (n=6) 12 mg/kg (n=6) Total (n=17) Age Median (range) 45 54 57 56 (41, 65) (35, 69) (43, 79) (35, 79) Gender Female 3 (60%) 4 (67%) 5 (83%) 12 (71%) Male 2 (40%) 2 (33%) 1 (17%) 5 (29%) Race White 5 (100%) 3 (50%) 3 (50%) 11 (65%) Asian 0 2 (33%) 2 (33%) 4 (23%) Black 0 1 (17%) 0 1 (6%) NR 0 0 1 (17%) 1 (6%) ECOG PS 0 4 (80%) 4 (67%) 1 (17%) 9 (53%) 1 1 (20%) 2 (33%) 5 (83%) 8 (47%) Tumor Location Gastric 3 (60%) 5 (83%) 6 (100%) 14 (82%) GEJ 1 (20%) 1 (17%) 0 2 (12%) Esophageal 1 (20%) 0 0 1 (6%) CLDN18.2 ≥ 75% 3 (60%) 5 (83%) 4 (67%) 12 (71%) < 75% 2 (40%) 1 (17%) 2 (33%) 5 (29%) ≥ 40% 4 (80%) 5 (83%) 5 (83%) 14 (82%) < 40% 1 (20%) 1 (17%) 1 (17%) 3 (18%) PD-L1 CPS ≥ 1 4 (80%) 5 (83%) 6 (100%) 15 (88%) < 1 1 (20%) 1 (17%) 0 2 (12%) MSI MSI-H 0 0 0 0 MSS 5 (100%) 6 (100%) 6 (100%) 17 (100%) Baseline Patient Characteristics Notes: DCO May 15, 2025 ECOG PS = Eastern Cooperative Oncology Group performance status; GEJ = gastroesophageal junction; CPS = combined positive score; MSI = microsatellite instability; MSI-H = microsatellite instability-high; MSS = microsatellite stable; NR = not reported

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![Slide 6](imab-ex99_2s6.jpg)

Key Adverse Events Related to Any Drug in ≥ 10% Adverse Event (n=17) Grades ≤ 2 Grade 3 Grade 4 All Grades Neutropenia 6 (35%) 4 (24%) 2 (12%) 12 (71%) Peripheral neuropathy 10 (59%) 0 0 10 (59%) Nausea 9 (53%) 0 0 9 (53%) Vomiting 6 (35%) 0 0 6 (35%) Infusion related reaction 6 (35%) 1 (6%) 0 7 (41%) Diarrhea 5 (29%) 0 0 5 (29%) Abdominal pain 2 (12%) 1 (6%) 0 3 (18%) Gastritis 1 (6%) 1 (6%) 0 2 (12%) ALT increased 1 (6%) 1 (6%) 0 2 (12%) AST increased 1 (6%) 1 (6%) 0 2 (12%) 5 mg/kg (n=5) (%) 8 mg/kg (n=6)(%) 12 mg/kg (n=6) (%) Total (n=17) (%) TEAE 100% 100% 100% 100% TRAE giva 80% 83% 100% 88% TRAE any drug 100% 100% 100% 100% SAE 60% 67% 17% 47% Related SAE giva 20% 0 17% 12% Related SAE any drug 40% 17% 17% 24% Grade ≥3 TEAE 80% 67% 50% 65% Grade ≥3 TRAE giva 20% 17% 33% 24% Grade ≥3 TRAE any drug 60% 67% 33% 53% TRAE  interruption 0 50% 17% 24% TRAE  treatment DC 20% 0 17% 12% Disease progression 0 33% 0 12% TRAE any drug  death 0 0 0 0 Notes: DCO May 15, 2025 TEAE = treatment emergent adverse event; TRAE = treatment related adverse event; SAE = serious adverse event; DC = discontinuation; giva = givastomig Immune Related Adverse Events Adverse Event (n=17) Grades ≤ 2 Grade 3 Grade 4 All Grades Pneumonitis 1 (6%) 0 0 1 (6%) Immune nephritis 0 1 (6%) 0 1 (6%) Rash maculo-popular 2 (12%) 0 0 2 (12%) No Dose Limiting Toxicity was observed Givastomig Was Well Tolerated in Combination with Immunochemotherapy

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![Slide 7](imab-ex99_2s7.jpg)

Biomarker Confirmed ORR: % (n) All Escalation (n=17) Cohorts Chosen for Expansion (8 & 12 mg/kg) (n=12) Total 71 (12/17) 83 (10/12) PD-L1 ≥ 5 82 (9/11) 89 (8/9) < 5 50 (3/6) 67 (2/3) ≥ 1 73 (11/15) 82 (9/11) < 1 50 (1/2) 100 (1/1) CLDN18.2 ≥ 75 67 (8/12) 78 (7/9) < 75 80 (4/5) 100 (3/3) Confirmed ORR: % (n) PD-L1 ≥ 5 PD-L1 < 5 CLDN18.2 ≥ 75 80 (8/10) 0 (0/2) CLDN18.2 < 75 100 (1/1) 75 (3/4) Notes: DCO May 15, 2025; PD-L1 assays:22C3 pharmDX, or local test; CLDN: Ventana SP455 or 43-14A SD = stable disease; PR = confirmed partial response; ORR = objective response rate; CPS = combined positive score; CLDN = Claudin 18.2 Objective Response Rate of 71% Across Range of PD-L1 & CLDN18.2 Expression

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![Slide 8](imab-ex99_2s8.jpg)

8 and 12 mg/kg (n=12) All (n=17) Median follow up (months) (95% CI) 7.8 (5.7, 10.2) 9.0 (6.1, 11.5) Median duration of response (months) (95% CI) NE (4.5, NE) NE (4.8, NE) PFS median (months) (95% CI) NE (4.5, NE) NE (4.8, NE) PFS 6 months (%) (95% CI) 81.5 (43.5, 95.1) 72.9 (42.6, 89.0) Notes: DCO May 15, 2025 PFS = progression free survival; CI = confidence interval; PD = progressive disease; PR = partial response; SD = stable disease; NE = not evaluable Responses are Rapid, Deep, and Sustained CPS CLDN

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Givastomig appears to be well tolerated at 5 mg/kg, 8 mg/kg, and 12 mg/kg in combination with nivolumab and FOLFOX, without significant GI, hepatic, or immune-related toxicities. Dose-dependent pharmacokinetics and induction of soluble 4-1BB were observed with the combination, similar to monotherapy (data not shown). Promising preliminary efficacy of the combination with overall ORR of 71% and 83% at doses being explored in expansion (8 mg/kg and 12 mg/kg). Anti-tumor activity was observed in patients with a wide range of CLDN18.2 expression (e.g. 3/3 PRs < 40%) as well as low PD-L1 expression (CPS < 5%). Enrollment of dose expansion cohort at 8 mg/kg is completed and ongoing at 12 mg/kg (NCT04900818). Conclusions Notes: DCO May 15, 2025 GI = gastrointestinal; ORR = objective response rate; PR = confirmed partial response; CPS = combined positive score

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I-Mab and the authors would like to thank all the patients and their families, as well as all the investigators, clinical trial researchers, personnel and staff who contributed to or participated in the trial ESMO GI 2025 Copies of this presentation obtained through QR (Quick Response) and/or text key codes are for personal use only and may not be reproduced without written permission of the authors.