No filing review issues identified by FDA with PDUFA goal date set for April 14, 2027
If Approved, Ozekibart Would Be the First and Only FDA-Approved Treatment for Unresectable or Metastatic Conventional Chondrosarcoma

, /PRNewswire/ -- Inhibrx Biosciences, Inc. (Nasdaq: INBX) ("Inhibrx" or the "Company"), a clinical-stage biopharmaceutical firm dedicated to creating innovative biologic treatments, today revealed that the U.S. Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) for review seeking clearance of ozekibart (INBRX-109) to treat individuals with unresectable or metastatic conventional chondrosarcoma. The FDA noted no filing review issues currently and set a Prescription Drug User Fee Act (PDUFA) target date of April 14, 2027. "The FDA's acceptance of our BLA for ozekibart marks a major achievement for Inhibrx and especially for those affected by chondrosarcoma," stated Mark Lappe, Chief Executive Officer of Inhibrx. "This aggressive bone cancer lacks any approved therapies at present. We anticipate close collaboration with the FDA throughout the review to deliver this pioneering targeted option to patients promptly."

The BLA draws on favorable outcomes from the ChonDRAgon trial, a randomized, blinded, placebo-controlled registrational study of ozekibart in metastatic or unresectable conventional chondrosarcoma cases. It achieved the main goal of statistically significant and clinically relevant median progression-free survival (PFS) for ozekibart recipients versus placebo. Ozekibart delivered a 52% decrease in progression or death risk relative to placebo (stratified Hazard Ratio [HR] 0.479; 95% CI: 0.33, 0.68; P<0.0001), extending median PFS beyond double to 5.52 months from 2.66 months on placebo. Notably, ozekibart stands as the initial investigational agent showing meaningful PFS gains in a blinded randomized chondrosarcoma trial, where no systemic treatments exist yet.

Upon approval, ozekibart would mark Inhibrx's debut commercial product and the first systemic therapy authorized for unresectable or metastatic conventional chondrosarcoma patients.

About Chondrosarcoma
Chondrosarcoma represents a rare malignancy arising mainly in cartilage cells within bones, frequently impacting the pelvis, hip, and shoulder areas. It ranks as the second most prevalent primary bone cancer. In unresectable or metastatic stages, outcomes remain poor historically since tumors resist standard oncology approaches, with surgery as the sole viable option for localized cases.

About ozekibart (INBRX-109)

Ozekibart functions as a precision-designed tetravalent death receptor 5 (DR5) agonist antibody that leverages DR5-driven tumor cell death. The FDA awarded Fast Track status to ozekibart in January 2021 for metastatic or unresectable conventional chondrosarcoma, followed by orphan drug designation in November 2021 for chondrosarcoma.

Inhibrx launched the ChonDRAgon study in June 2021 as a randomized, blinded, placebo-controlled registrational evaluation of ozekibart in metastatic unresectable conventional chondrosarcoma. It included 206 participants at 67 global sites. The core aim assessed ozekibart efficacy via median PFS determined by central independent radiology review under RECIST 1.1. Additional aims covered overall survival, investigator-assessed median PFS, quality of life metrics, objective response rate, response duration, disease control rate, safety, tolerability, pharmacokinetics, and anti-drug antibodies.

Eligibility required grade 2 or 3 unresectable or metastatic conventional chondrosarcoma. Participants received ozekibart or placebo every three weeks in a 2:1 ratio, stratified by therapy line, grade, and IDH1/2 mutation status.

Placebo-arm patients could switch to ozekibart after central review confirmed progression.

The ChonDRAgon trial succeeded on its primary endpoint with statistically significant clinically meaningful median PFS improvement for advanced or metastatic chondrosarcoma patients on ozekibart over placebo. Ozekibart produced a 52% risk reduction for progression or death versus placebo (stratified Hazard Ratio [HR] 0.479; 95% CI: 0.33, 0.68; P<0.0001), more than doubling median PFS to 5.52 months from 2.66 months on placebo. This positions ozekibart as the first agent with proven PFS benefit in a randomized chondrosarcoma study lacking approved systemic therapies.

Benefits held steady across all predefined subgroups, encompassing IDH-wild-type and IDH-mutant tumors. Further secondary measures such as disease control rate (54% vs 27.5%) and postponed worsening in pain and physical function reinforced the observed advantages.

Ozekibart showed general tolerability with a manageable safety profile. Frequent treatment-linked adverse events included fatigue, constipation, and nausea. Hepatotoxicity, an established mechanism risk, arises in the initial cycle mainly among those with preexisting liver issues. One early fatal hepatotoxicity event preceded mitigation steps. Subsequent monitoring excluded severe liver impairment cases and enabled prompt enzyme elevation management, yielding low treatment-related hepatic event rates at 11.8% versus 4.5% on placebo, mostly Grade 1 or 2.

Beyond the chondrosarcoma registrational trial, Inhibrx pursues expansion cohorts combining ozekibart with irinotecan regimens for Ewing sarcoma and colorectal cancer. Promising initial data encourage further study in these challenging tumor settings with substantial unmet needs.

About Inhibrx Biosciences, Inc.

Inhibrx Biosciences operates as a clinical-stage biopharmaceutical entity developing a diverse array of novel biologic candidates. It applies varied protein engineering techniques to meet complex target and disease requirements via proprietary platforms. Formed in January 2024 as a wholly owned subsidiary of Inhibrx, Inc., it obtained select infrastructure and assets through internal restructurings before Inhibrx, Inc. transferred its shares and the INBRX-101 program to Sanofi S.A. Inhibrx Biosciences' pipeline now features ozekibart and INBRX-106, employing optimized multivalent formats for agonist activity. Visit www.inhibrx.com for details.

Forward-Looking Statements

Inhibrx notes that statements in this release concerning non-historical matters constitute forward-looking statements grounded in current beliefs and expectations. These encompass pipeline strength assessments, ozekibart safety and efficacy based on available data, potential applications in colorectal cancer, Ewing sarcoma and other solid tumors, clinical development timelines for submissions and readouts, commercial prospects including first-product status, and assumptions that early data predict later outcomes. Results may vary due to inherent risks such as data audit discrepancies, trial initiation and completion uncertainties, interpretation variances, unexpected side effects or limited efficacy, competitor developments, regulatory timing, commercialization challenges, unavailable accelerated pathways, orphan designation limitations, pricing and reimbursement factors, platform utilization for new candidates, and other risks detailed in SEC filings including Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, and Current Reports on Form 8-K. Readers should avoid undue reliance on these statements, which apply only as of this date, with no obligation for updates. All forward-looking statements are qualified by this caution under the Private Securities Litigation Reform Act of 1995 safe harbor.