Key Takeaways
- Shares of Inhibrx Biosciences climbed 17% Monday following encouraging Phase 2 data for INBRX-106 in head and neck cancer treatment.
- Combination therapy with pembrolizumab delivered a 44% objective response rate compared to 21.4% for pembrolizumab monotherapy.
- Among evaluable patients, 11 of 25 responded in the combination group versus 6 of 28 in the monotherapy group; combination therapy produced three complete responses compared to zero in the control.
- Patients receiving combination treatment demonstrated T-cell proliferation levels up to 15 times greater than those on pembrolizumab alone.
- The Phase 3 segment of the trial is scheduled to commence in Q3 2026, with progression-free survival outcomes anticipated in Q4 2026.
Shares of Inhibrx Biosciences (INBX) advanced 17% Monday following the biotechnology company’s announcement of encouraging preliminary findings from the Phase 2 HexAgon clinical trial evaluating INBRX-106 in head and neck cancer patients.
Inhibrx Biosciences, Inc., INBX
The equity has already delivered exceptional returns exceeding 1,000% over the trailing 12-month period, propelled by favorable trial outcomes for another oncology candidate, INBRX-109, announced last October.
The clinical study evaluated INBRX-106 — characterized as a hexavalent OX40 agonist — administered alongside pembrolizumab versus pembrolizumab monotherapy. Trial participants 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 confirmed objective response rate of 44%. The control cohort receiving pembrolizumab alone recorded 21.4% — representing a substantial 22.6 percentage point advantage.
Total enrollment reached 68 participants, with 33 assigned to the combination regimen and 35 to the control group. The evaluable patient population consisted of 53 individuals.
Within that cohort, 11 of 25 patients receiving the combination treatment demonstrated responses. In contrast, 6 of 28 patients on pembrolizumab monotherapy responded.
The INBRX-106 combination arm documented three complete responses. The control arm recorded zero complete responses.
Immune Cell Activity Reinforces Clinical Findings
Beyond objective response metrics, the immunological data proved particularly noteworthy. Patients administered the combination regimen exhibited up to a 15-fold mean elevation in CD8+ and CD4+ T-cell proliferation. Patients receiving pembrolizumab alone demonstrated increases reaching only 2.5-fold.
Inhibrx stated this biological evidence provides mechanistic validation for the clinical outcomes — essentially confirming the underlying immunology correlates with observed patient responses.
CEO Mark Lappe expressed that the organization was “greatly encouraged by these early clinical results,” emphasizing specifically the quality and depth of responses already documented in participants.
Tolerability Profile Deemed Acceptable
The combination regimen exhibited a safety profile characterized by the company as manageable and aligned with anticipated outcomes for combined immunotherapy approaches.
The most frequently reported treatment-emergent adverse events included rash, diarrhea, fatigue, and infusion-related reactions. The majority presented as low-grade events.
No treatment-related fatalities occurred in either study arm.
Inhibrx indicated that progression-free survival data from the Phase 2 component is projected for release in Q4 2026.
The Phase 3 segment of the HexAgon clinical program is planned to initiate in Q3 2026.
