I-Mab Publishes First-in-Human Data For Givastomig Monotherapy In 'Clinical Cancer Research', Showing Up To 18% Response Rate In Heavily Pretreated Gastric Cancer Patients; Safety And Efficacy Support Ongoing 1L Combination Trials With Nivolumab And Chemotherapy

Monotherapy efficacy and safety profile provided backbone for clinical development strategy in 1L combination with nivolumab plus chemotherapy

ROCKVILLE, MD, June 30, 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 publication of the first-in-human monotherapy data for givastomig, a bispecific Claudin 18.2 x 4-1BB antibody, in Clinical Cancer Research, a journal of the American Association for Cancer Research (CCR), and a highly-ranked clinical oncology publication. The CCR paper1 details promising clinical data showing that givastomig monotherapy achieved an objective response rate (ORR) of 16% in heavily pretreated Claudin 18.2-positive gastric cancer patients. The publication can be accessed HERE.

The CCR paper represents the first peer-reviewed manuscript publication of the Phase 1 monotherapy study of givastomig in heavily pre-treated solid tumor patients, after initial presentation of these data in poster form at the European Society of Medical Oncology (ESMO) Congresses in 2023 and 2024. The study evaluated a total of 75 patients with gastric cancers or other solid tumors, including 43 efficacy-evaluable patients with CLDN18.2-positive advanced or metastatic gastroesophageal carcinoma (GEC). Claudin 18.2 expression in responders ranged from 11% to 100%, demonstrating the activity of givastomig in tumors with low levels of Claudin 18.2 (CLDN18.2) expression. After the data cutoff, two additional patients were enrolled in the monotherapy study, resulting in an additional confirmed partial response (PR), leading to an increased ORR of 18% (8/45 patients). The Company anticipates sharing an updated monotherapy data set on the 45 patients in the fourth quarter of 2025 at a major medical meeting.

Monotherapy data indicate that givastomig is well tolerated and demonstrates single-agent activity in heavily pretreated patients. These findings support its development in combination with standard immunochemotherapy (nivolumab plus mFOLFOX6) as a first line (1L) treatment for gastric cancers. Data from the ongoing dose escalation combination study will be presented at a Mini Oral presentation at the ESMO Gastrointestinal (ESMO GI) Cancers Congress 2025 on July 2, 2025 in Barcelona, Spain.