– Event to be webcast live on Tuesday, September 8 ^th at 5:00 a.m. PT –

SAN DIEGO, Sept. 4, 2026 /PRNewswire/ -- Inhibrx Biosciences, Inc. (Nasdaq: INBX) ("Inhibrx" or the "Company"), a clinical-stage biopharmaceutical company focused on developing a broad pipeline of novel biologic therapeutic candidates, today announced that it will host a live webcast presentation on Tuesday, September 8, 2026 at 5:00 a.m. Pacific Time, to provide primary endpoint results from the randomized and controlled Phase 2 portion of the HexAgon study, which is evaluating the safety and efficacy of INBRX-106, a hexavalent OX40 agonist, in combination with pembrolizumab (the combination arm) versus pembrolizumab monotherapy (the control arm) in first-line patients with treatment-naïve, PD-L1 positive (CPS = 20) metastatic or unresectable recurrent Head and Neck Squamous Cell Carcinoma (HNSCC).

Investors may join via the web: https://app.webinar.net/4712m15mpwW or may listen to the call by dialing (1-888-880-3330). Please refer to Inhibrx Biosciences, Inc. or the conference ID 6981384 when calling in. The webcast will also include a slide presentation of the data, which is also incorporated into the Company's investor deck accessible at https://inhibrx.com/inhibrx-biosciences-inc-investors/. Following the webcast, the presentation may be accessed through a link on the "Events and Presentations" section of Inhibrx's website. The webcast will be available for 60 days following the event. Inhibrx will also update its corporate presentation within the "Investors" section of its website at www.inhibrx.com.

About INBRX-106

INBRX-106 is a hexavalent agonist targeting OX40 (CD134), a costimulatory receptor on T-cells. Utilizing Inhibrx's proprietary single-domain antibody (sdAb) platform, INBRX-106 is designed to achieve the high-order receptor clustering necessary for robust T-cell activation and survival, a feat that has eluded traditional bivalent antibody approaches.

About Inhibrx Biosciences, Inc.

Inhibrx Biosciences is a clinical-stage biopharmaceutical company focused on developing a broad pipeline of novel biologic therapeutic candidates. Inhibrx Biosciences utilizes diverse methods of protein engineering to address the specific requirements of complex target and disease biology, including its proprietary protein engineering platforms. Inhibrx Biosciences was incorporated in January 2024 as a direct, wholly-owned subsidiary of Inhibrx, Inc. Prior to the sale of Inhibrx, Inc. and the INBRX-101 program to Sanofi S.A., Inhibrx Biosciences acquired certain corporate infrastructure and other assets and liabilities through a series of internal restructuring transactions effected by Inhibrx, Inc. Inhibrx, Inc. also completed a distribution to holders of its shares of common stock of 92% of the issued and outstanding shares of Inhibrx Biosciences. Following such transactions, Inhibrx Biosciences' current clinical pipeline of therapeutic candidates includes ozekibart (INBRX-109) and INBRX-106, both of which utilize multivalent formats where the precise valency can be optimized in a target-centric way to mediate what we believe to be the most appropriate agonist function. For more information, please visit www.inhibrx.com.

Investor and Media Contact:

Kelly Deck, CFO
ir@inhibrx.com
858-795-4260

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SOURCE Inhibrx Biosciences, Inc.