Inhibrx to Present INBRX-106 Phase 2 HNSCC Results

San Diego, California, USA, September 4, 2026

Inhibrx Advances Phase 2 HNSCC Clinical Program

The upcoming presentation will focus on data from the randomized and controlled Phase 2 portion of the HexAgon study, which is designed to evaluate the safety and efficacy of INBRX-106 plus pembrolizumab compared with pembrolizumab alone. The trial is enrolling patients with treatment-naïve, PD-L1-positive HNSCC whose tumors have a combined positive score (CPS) of at least 20. The first-line setting and defined biomarker population make the study particularly relevant to the development of new immunotherapy combinations for patients with metastatic or unresectable recurrent disease. By incorporating a control arm receiving pembrolizumab monotherapy, the study is intended to assess the potential contribution of INBRX-106 to the treatment regimen. The webcast is scheduled for September 8, 2026, at 5:00 a.m. Pacific Time and will include a slide presentation of the clinical data. Inhibrx stated that the presentation will also be incorporated into its investor materials following the event. The company has previously provided interim Phase 2 information on INBRX-106, making the forthcoming primary endpoint analysis an important next step in evaluating the candidate’s development potential in first-line HNSCC.

INBRX-106 Uses Hexavalent OX40 Agonist Approach

INBRX-106 is an investigational hexavalent agonist targeting OX40 (CD134), a costimulatory receptor expressed on T cells. Inhibrx is developing the molecule using its proprietary single-domain antibody (sdAb) platform, with the candidate designed to achieve high-order receptor clustering that the company believes is necessary for robust T-cell activation and survival. This approach is intended to stimulate the immune system through the OX40 pathway and potentially complement the activity of pembrolizumab, an immune checkpoint inhibitor targeting the PD-1 pathway. The scientific rationale for the combination centers on using two complementary mechanisms of immune modulation. Pembrolizumab blocks PD-1-mediated inhibitory signaling, while INBRX-106 is designed to activate the OX40 costimulatory pathway on T cells. Inhibrx’s multivalent protein-engineering strategy is intended to address the receptor-clustering requirements associated with OX40 activation. The company is therefore investigating whether adding targeted immune costimulation to PD-1 blockade can improve therapeutic activity in a biomarker-selected HNSCC population. However, INBRX-106 remains investigational, and its potential clinical benefit must be determined through clinical data and subsequent regulatory evaluation.

Primary Endpoint Data Could Guide Further Development

The forthcoming primary endpoint results could provide important information about the clinical performance of INBRX-106 in combination with pembrolizumab and help determine the future direction of the HexAgon program. In May 2026, Inhibrx reported interim Phase 2 data for INBRX-106 in first-line HNSCC and said the initial results demonstrated a potential costimulatory benefit over PD-1 monotherapy. The September presentation is expected to provide the primary endpoint analysis from the randomized portion of the study, offering a more comprehensive assessment of the investigational combination. For the broader biopharmaceutical and oncology research sector, the program highlights continued efforts to develop next-generation immune agonists and multivalent biologics that can complement established checkpoint inhibitors. If supported by the forthcoming data, the findings could inform subsequent clinical development of INBRX-106 in HNSCC. Nevertheless, the September 4 announcement does not establish efficacy, safety superiority, regulatory approval, or a future treatment recommendation. The significance of the program will depend on the detailed clinical results and subsequent scientific and regulatory assessment.

Source: Inhibrx Biosciences press release