INBRX-106 with Keytruda (pembrolizumab)

Sept. 8, 2026: Inhibrx Biosciences, Inc. (NASDAQ: INBX) reported primary endpoint results from the randomized Phase 2 portion of the HexAgon study of INBRX-106 plus pembrolizumab versus pembrolizumab alone in first-line, treatment-naïve, PD-L1 positive (CPS ≥20) metastatic or unresectable recurrent HNSCC. In 63 evaluable patients, confirmed ORR was 48.3% with the combination versus 26.5% with pembrolizumab alone; complete responses were 13.8% versus 0%. Median PFS was 9.6 months versus 4.9 months, with 6-month PFS rates of 72.4% versus 42.8%.

Results were stronger in HPV+ disease: cORR was 80.0% versus 33.3%, CR rate 30.0% versus 0%, and 6-month PFS 90.0% versus 33.0%; median PFS was not reached with the combination versus 4.6 months for pembrolizumab alone. The combination was described as generally manageable, with mostly low-grade rash, fatigue, and diarrhea.

Based on these data, the company plans to expand Phase 2 by about 50 additional HPV+ OPSCC patients (CPS ≥1) to support a potential accelerated regulatory pathway, then align with FDA and start the Phase 3 confirmatory portion. Separately, INBRX-106 is in a Phase 1/2 perioperative NSCLC study, with initial results targeted by mid-2027.