Abstract 1446P
Background
Bavituximab, an investigational, chimeric monoclonal antibody designed to inhibit the immunosuppressive effects of phosphatidylserine, is being evaluated in combination with pembrolizumab in patients with advanced gastric and gastroesophageal junction (GEJ) cancer. Post-hoc analyses from the phase III Sunrise second-line lung cancer study indicated that patients who progressed on study treatment with bavituximab plus docetaxel and continued with a checkpoint inhibitor as the next line of therapy showed significantly improved overall survival. Cumulative data suggest that bavituximab may potentiate pembrolizumab-mediated checkpoint inhibition, possibly increasing overall clinical benefit.
Methods
ONCG100 is a phase II, multicenter, open-label, single-arm global study designed to assess the safety, tolerability and efficacy of bavituximab (3 mg/kg, QW) and pembrolizumab (200 mg, Q3W) when administered in combination to advanced gastric or GEJ adenocarcinoma patients, regardless of PD-L1 status, who have progressed on ≥1 prior standard therapy (NCT04099641).
Results
As of 23Apr2020, 24 out of 80 patients were enrolled with the number of prior treatments ranging from 1 to 4; 18 patients remain on study. A total of 154 treatment emergent adverse events (TEAEs) were reported in 20 patients (83.3%) with 15 events reported as related to the combination. All TEAEs were reported as grade 1 or 2 with the exception of anemia and dehydration (both grade 3, related to bavituximab). The only TEAE reported in >2 patients included fatigue (related to the combination). Sixteen serious adverse events were reported in 5 patients (20.8%) all of which were reported as treatment-unrelated; an exception was 1 event of dehydration (grade 3, related to bavituximab). Five patients have at least 1 post-baseline scan evaluable for anti-tumor activity: there were 2 partial responses, 2 stable disease, and 1 progressive disease. One patient discontinued due to an unrelated advese event.
Conclusions
The 3 mg/kg dose of bavituximab was readily combined with pembrolizumab with manageable adverse events and early preliminary activity. Updated data from the study will be presented.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Oncologie, Inc.
Funding
Oncologie, Inc.
Disclosure
I. Chau: Research grant/Funding (self): Janssen-Cilag (Inst); Lilly (Inst); Merck Serono (Inst); Sanofi (Inst); Advisory/Consultancy: AstraZeneca; Bayer; Bristol-Myers Squibb; Lilly; Merck Serono; MSD Oncology; Oncologie International; Pierre Fabre; Roche/Genentech; Honoraria (self): Lilly. H. Park: Research grant/Funding (self): Ambrx (Inst); Amgen (Inst); Array BioPharma (Inst); AstraZeneca (Inst); Bayer (Inst); BeiGene (Inst); Bristol-Myers Squibb (Inst); Daiichi Sankyo (Inst); EMD Serono (Inst); Genentech (Inst); Gilead Sciences (Inst); GlaxoSmithKline (Inst); Incyte (Inst); . J. Lee: Advisory/Consultancy: Oncologie; Seattle Genetics; Research grant/Funding (self): AstraZeneca; Lilly; Merck Sharp & Dohme. S. MacIntyre: Shareholder/Stockholder/Stock options, Full/Part-time employment: Oncologie. K. Culm-Merdek: Shareholder/Stockholder/Stock options, Full/Part-time employment: Oncologie; Shareholder/Stockholder/Stock options: BMS, ImmunoGen. J.C. Bendell: Advisory/Consultancy: Amgen (Inst); Apexigen (Inst); Arch Oncology (Inst); ARMO BioSciences (Inst); Array BioPharma (Inst); AstraZeneca (Inst); Bayer (Inst); Beigene (Inst); Bicycle Therapeutics (Inst); Boehringer Ingelheim (Inst); Bristol-Myers Squibb (Inst); Celgene (Inst); ; Research grant/Funding (institution): Abbott/AbbVie (Inst); Acerta Pharma (Inst); ADC Therapeutics (Inst); Agios (Inst); Amgen (Inst); Apexigen (Inst); Arch Oncology (Inst); Arcus Biosciences (Inst); ARMO BioSciences (Inst); Array BioPharma (Inst); Arrys (Inst); AstraZeneca/MedImmune (Inst).