OncoC4 Inc. 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 are being presented in a late-breaking oral presentation at the Society for Immunotherapy of Cancer (SITC) 2026 Annual Meeting in Phoenix, Arizona.

The company said the preliminary efficacy and safety results support further development of cesalatamig monotherapy.

Study Design and Patient Population

The results reported in the SITC abstract came 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 every three weeks (Q3W).

Among these patients:

  • 77 (75%) had non-squamous histology
  • 25 (24%) had squamous histology
  • One had unknown histology
  • 77% had a baseline ECOG performance status of 1
  • The median number of prior therapy lines was two
  • 42% had received three or more prior lines

OncoC4 said the safety profile was comparable between patients with squamous and non-squamous histology, and that cesalatamig monotherapy was well tolerated at all dose levels.

Efficacy Results

Among 55 efficacy-evaluable patients with PD-(L)1-resistant/refractory NSCLC, cesalatamig monotherapy demonstrated dose-dependent antitumor activity, according to the company.

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.

Investigator and Company Comment

“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."

Presentation Details

The presentation is titled "Safety and Efficacy of Cesalatamig, a Novel PD-1/VEGF Bispecific Antibody, as Monotherapy in PD-(L)1–Resistant/Refractory NSCLC: Results from Global, Multicenter, Open-Label Phase 1/2 Studies."

  • Abstract: #1187 (late-breaking oral presentation)
  • Presenter: Kai He, MD, PhD
  • Date: November 7, 2026
  • Meeting: 41st Annual Meeting of the Society for Immunotherapy of Cancer, Phoenix, Arizona
  • Session: Clinical Oral Abstract Session 2, beginning at 1:45 PM MST

About Cesalatamig

Cesalatamig (AI-081) is an investigational, tetravalent PD-1/VEGF bispecific antibody designed to promote cooperative interactions between PD-1 and VEGF blockade in the tumor microenvironment. It combines high-affinity binding with Fc-silencing modifications intended to avoid depletion of PD-1-positive effector T cells.

Cesalatamig is being evaluated as monotherapy and in combination with standard of care in the ongoing BiPAVE-001 clinical program. In September 2026, the U.S. FDA granted cesalatamig Fast Track designation for NSCLC that has progressed after concurrent or sequential PD-(L)1-targeted immunotherapy and platinum-based chemotherapy.

About the BiPAVE-001 Program

BiPAVE-001 (NCT06635785) and BiPAVE-001 CN (CTR20253261) are ongoing Phase 1/2 clinical trials evaluating the safety, pharmacokinetics, and efficacy of cesalatamig in patients with advanced solid tumors. OncoC4 is conducting these studies in the United States and China, respectively.

Part A is the first-in-human Phase 1 dose-escalation and dose-expansion portion in patients with advanced solid tumors. Part B is the Phase 2 portion and includes dose-optimization trials evaluating AI-081 as monotherapy or in combination with standard of care in selected indications.

About OncoC4

Headquartered in Rockville, Maryland, OncoC4 is a privately held, late clinical-stage biopharmaceutical company engaged in the discovery and development of novel biologics for the treatment of cancer, neurological and immunological diseases.

The company said its pipeline features assets with first-in-class and best-in-class potential targeting both novel and well-validated targets across oncology and immunological diseases. Cesalatamig is a wholly owned PD-1/VEGF bispecific antibody undergoing global clinical development in multiple oncology indications.

Tasafustobart (ONC-841) is a first-in-class anti-SIGLEC-10 antibody currently in a Phase 2 trial for oncology indications and a Phase 1 trial for neurodegenerative diseases. OncoC4 recently initiated a first-in-human trial of ONC-783, a first-in-class T cell engager targeting a novel CD24 epitope selectively expressed across a broad spectrum of human cancers, including solid tumors and hematological malignancies, in the United States.

OncoC4 has a strategic collaboration with BioNTech to co-develop gotistobart (BNT316/ONC-392), a tumor microenvironment-selective Treg depletion candidate targeting CTLA-4, in multiple solid tumor indications, including an ongoing pivotal clinical trial in squamous non-small cell lung cancer.