33% investigator-assessed objective response rate and 90% disease control rate at 10 mg/kg every three weeks in patients with PD-(L)1-resistant/refractory NSCLC —

— Preliminary efficacy and safety results support further development of cesalatamig monotherapy —

- OncoC4 Inc., a late clinical-stage biopharmaceutical company developing novel medicines for cancer, neurological and immunological diseases, reported encouraging Phase 1/2 results for cesalatamig (AI-081), its investigational PD-1/VEGF bispecific antibody, as monotherapy in patients with PD-(L)1-resistant/refractory non-small cell lung cancer (NSCLC). The findings will be presented in a late-breaking oral presentation at the Society for Immunotherapy of Cancer (SITC) 2026 Annual Meeting in Phoenix, Arizona.

Results reported in the SITC abstract were derived from a pooled analysis of the global, multicenter, open-label BiPAVE-001 and BiPAVE-001 CN Phase 1/2 studies. As of July 31, 2026, the safety population included 103 patients with NSCLC who had received at least one dose of cesalatamig monotherapy at 1, 3, 10 or 20 mg/kg Q3W. Of these patients, 77 (75%) had non-squamous histology, 25 (24%) had squamous histology and one had unknown histology. 77% of patients had a baseline ECOG performance status of 1. The median number of prior therapy lines was two, and 42% of patients had received three or more prior lines.  The safety profile was comparable between patients with squamous and non-squamous histology. The cesalatamig monotherapy is well tolerated at all dose levels.

Among 55 efficacy-evaluable patients with PD-(L)1 resistant/refractory NSCLC, cesalatamig monotherapy demonstrated dose-dependent antitumor activity. At 1 mg/kg (10 patients), 3 mg/kg (24 patients) and 10 mg/kg (21 patients) Q3W, investigator-assessed objective response rates (ORR) were 10%, 21% and 33%, respectively; disease control rates (DCR) were 40%, 67% and 90%, respectively.  Responses to cesalatamig monotherapy were observed across PD-L1 expression levels. Exposure-response analyses support selection of 10 mg/kg Q3W as the dose for further development.

"Patients whose NSCLC progresses after immunotherapy and chemotherapy have limited effective treatment options," said Kai He, MD, PhD, principal investigator of the US BiPAVE-001 trial and the presenter of this study. "The responses and disease control observed with cesalatamig monotherapy are encouraging. Together with the manageable safety profile observed in these studies, these findings support further clinical evaluation in this setting."

"These findings strengthen the rationale for advancing cesalatamig monotherapy in previously treated NSCLC," said Yang Liu, PhD, Co-founder, Chief Executive Officer and Chief Scientific Officer of OncoC4. "The clinical results and exposure-response analyses support the selection of 10 mg/kg every three weeks as the dose for our planned pivotal study and provide a clear path forward for the continued development of cesalatamig in this setting."