Key Highlights
- Shares of Inhibrx Biosciences climbed 17% Monday following encouraging Phase 2 clinical trial data for INBRX-106 in head-and-neck cancer treatment.
- INBRX-106 paired with pembrolizumab delivered a 44% objective response rate compared to 21.4% for pembrolizumab monotherapy.
- Among evaluable patients, 11 of 25 in the combination therapy group responded, while 6 of 28 in the single-agent group showed response; the combination arm recorded three complete responses versus zero in the control group.
- Patients receiving combination therapy experienced T-cell proliferation levels up to 15 times greater than those treated with pembrolizumab alone.
- The Phase 3 segment of the trial will launch in Q3 2026, with progression-free survival results anticipated in Q4 2026.
Shares of Inhibrx Biosciences (INBX) advanced 17% Monday after the biotechnology firm disclosed encouraging preliminary findings from its Phase 2 HexAgon clinical study evaluating INBRX-106 for head and neck cancer.
Inhibrx Biosciences, Inc., INBX
The equity has already gained over 1,000% during the past year, propelled by favorable data from another oncology candidate, INBRX-109, released in October.
The clinical study evaluated INBRX-106 — a hexavalent OX40 agonist — administered alongside pembrolizumab versus pembrolizumab as a single agent. Enrolled patients were first-line, treatment-naïve individuals with PD-L1 positive metastatic or unresectable recurrent head and neck squamous cell carcinoma.
The combination therapy arm achieved a 44% confirmed objective response rate. Pembrolizumab monotherapy produced a 21.4% response rate — representing a 22.6 percentage point advantage for the combination approach.
The trial enrolled 68 participants overall, with 33 assigned to combination therapy and 35 to the control group. The evaluable patient population consisted of 53 individuals.
Within this evaluable cohort, 11 of 25 patients receiving combination treatment responded. Among those on pembrolizumab alone, 6 of 28 demonstrated response.
The INBRX-106 combination arm produced three complete responses. The control arm recorded zero complete responses.
Immune Cell Activity Reinforces Clinical Findings
Beyond tumor response metrics, the immunological data proved particularly noteworthy. Patients treated with the combination demonstrated up to a 15-fold mean elevation in CD8+ and CD4+ T-cell proliferation. Pembrolizumab monotherapy patients showed increases reaching only 2.5-fold.
Inhibrx indicated this offers mechanistic validation for the clinical outcomes — essentially, the underlying biological mechanisms align with the patient responses observed.
CEO Mark Lappe expressed that the company was “greatly encouraged by these early clinical results,” highlighting specifically the quality and depth of responses documented thus far.
Safety Data Deemed Acceptable
The combination regimen exhibited a safety profile characterized by the company as manageable and aligned with expectations for immunotherapy combinations.
The most frequently reported treatment-related adverse events included rash, diarrhea, fatigue, and infusion-related reactions. The majority were classified as low-grade.
Neither study arm reported any treatment-related fatalities.
Inhibrx announced that progression-free survival data from the Phase 2 segment will be available in Q4 2026.
The Phase 3 component of the HexAgon study will commence in Q3 2026.
