Phase I summary of the HB0025 efficacy and safety to the heavily pretreated non-small cell lung cancer (NSCLC) population.

e14600 Background: HB0025 is a recombinant humanized bispecific molecule built on IgG1 that targets the human programmed death ligand 1 (PD-L1) and vascular endothelial growth factor (VEGF, VEGF-A, VEGF165). Here we present the NSCLC results in Phase 1 study. Methods: This ongoing, open-label, multicenter, dose escalation and dose expansion, phase 1 trial to evaluate the safety and efficacy of HB0025 for pts with advanced solid tumors. HB0025 is administered intravenously every 14 days (Q2W). Response was evaluated by RECIST v.1.1 every 8 weeks. Results: As of Dec 25, 2023, 12 (7M/5F) NSCLC pts have received HB0025 at doses of 3mg/kg (n=1), 6mg/kg (n=2), 10mg/kg (n=2), 12mg/kg (n=1), 20mg/kg (n=5), 30mg/kg (n=1). Overall, the median age was 61.5 years, the median number of prior treatment lines was 4. The histologic types include squamous cell (Sq)-NSCLC (2 pts) without EGFR/ALK mutation and non- squamous cell (Nonsq)-NSCLC (10 pts), among of Nonsq-NSCLC 9 pts carrying EGFR/ALK mutation. The 3 pts with EGFR/ALK wild-type gene fail to prior anti-PD-1 treatment, 9 pts with EGFR/ALK gene mutation fail to prior TKI therapy. Among the 12 pts having imaging tumor assessment, the ORR was 25% and DCR was 66.7%, which included 3 partial responses (PR) ,5 stable disease (SD), and 4 progressive disease (PD) according to RECIST v1.1.For the 2 Sq-NSCLC pts, one pt achieved PR with 3mg/kg HB0025 treatment, the other pt achieved SD. For the10 Nonsq-NSCLC pts, there were 2 PR (20mg/kg and 30mg/kg treatment, respectively), 4 SD and 4 PD. Till the report date, the PR status and HB0025 treatment are ongoing to 3 PR pts, which includes 1 Sq-NSCLC pt, and 2 Nonsq-NSCLC pts which one pt doesn’t carry EGFR/ALK mutation. The Sq-NSCLC pt whose maximum tumor regression is 60% achieves PR after 4 cycles of treatment, and the duration of response (DOR) is more than 22 months. The one Nonsq-NSCLC pt whose maximum tumor regression is 74% achieves PR after 2 cycles of treatment, and the DOR is more than 11 months. The other Nonsq-NSCLC pt whose tumor regression is 32% achieves PR after 4 cycles of treatment, and the DOR is more than 2 months. Among the 5 SD pts, 1 Sq-NSCLC pt’s progression-free survival (PFS) is more than 14 months and continusous, 2 Nonsq-NSCLC pts’ PFS is more than 6 months and ongoing. For the 12 pts, 11 pts (91.7%) experienced a treatment related adverse events (TRAEs). The most common TRAEs included proteinuria (50%, 6/12), lymphocyte count decrease (50%, 6/12), blood bilirubin increased (33.3%, 4/12), and blood pressure increased (33.3%, 4/12). TRAEs ≥ grade 3 occurred in 2 (16.7%) pts. No TRAE leading to discontinuation and death. Conclusions: HB0025 monotherapy showed an acceptable safety profile and promising anti-tumor activity for prior heavily treated NSCLC, no matter in TKI-resistant population with EGFR/ALK mutation or population failed to anti-PD-1 treatment. Now Phase II studies of combination chemotherapy are ongoing. Clinical trial information: NCT04678908 .