SAN DIEGO, June 15, 2026
Inhibrx Biosciences has achieved a major regulatory milestone with the U.S. Food and Drug Administration (FDA) accepting its Biologics License Application (BLA) for ozekibart (INBRX-109) for the treatment of patients with unresectable or metastatic conventional chondrosarcoma, a rare and aggressive bone cancer with no approved systemic therapies. The FDA confirmed that no filing review issues were identified and assigned a Prescription Drug User Fee Act (PDUFA) target action date of April 14, 2027. If approved, ozekibart would become the first FDA-approved treatment specifically indicated for unresectable or metastatic conventional chondrosarcoma, representing a potentially transformative advancement for patients who currently have limited therapeutic options beyond surgery. The acceptance underscores the growing momentum behind innovative targeted therapies designed to address rare cancers with significant unmet medical needs.
Pivotal ChonDRAgon Trial Demonstrates Significant Clinical Benefit
The BLA submission is supported by results from the pivotal ChonDRAgon Phase 3 registrational study, a randomized, blinded, placebo-controlled trial evaluating ozekibart in patients with advanced conventional chondrosarcoma. The study successfully achieved its primary endpoint by demonstrating a statistically significant and clinically meaningful improvement in progression-free survival (PFS). Patients treated with ozekibart experienced a 52% reduction in the risk of disease progression or death compared with placebo, with a hazard ratio of 0.479 and a highly significant p-value of less than 0.0001.
Median progression-free survival more than doubled, reaching 5.52 months compared with 2.66 months for placebo-treated patients. Importantly, ozekibart became the first investigational therapy to demonstrate a significant progression-free survival benefit in a randomized clinical trial for chondrosarcoma, a disease that has historically lacked effective systemic treatment options. Additional benefits included improved disease control rates and delayed deterioration in pain and physical functioning, further supporting the therapy’s potential clinical value.
Potential First-in-Class Therapy for Rare Bone Cancer
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Chondrosarcoma is the second most common primary bone malignancy and typically develops in the cartilage cells of bones, particularly in the pelvis, hip and shoulder. When the disease becomes metastatic or unresectable, prognosis is often poor because tumors generally respond poorly to conventional chemotherapy and other oncology treatments. Ozekibart is a precision-engineered tetravalent death receptor 5 (DR5) agonist antibody designed to selectively induce tumor cell death through activation of DR5 signaling pathways. The therapy previously received both FDA Fast Track Designation and Orphan Drug Designation, reflecting the urgent need for new treatment approaches in this rare cancer population. Clinical benefits observed in the ChonDRAgon study were consistent across predefined patient subgroups, including individuals with both IDH-mutant and IDH-wild-type tumors, suggesting broad applicability across diverse patient populations.
Inhibrx Expands Ozekibart Development Beyond Chondrosarcoma
In addition to the regulatory review for chondrosarcoma, Inhibrx is continuing to explore the broader therapeutic potential of ozekibart across other difficult-to-treat cancers. The company is currently evaluating the drug in expansion cohorts involving Ewing sarcoma and colorectal cancer, where early signals of activity have supported further clinical investigation. Safety findings from the registrational trial showed that ozekibart was generally well tolerated, with the most common treatment-related adverse events including fatigue, constipation and nausea. While hepatotoxicity remains a recognized risk associated with the mechanism of action, enhanced patient selection criteria and monitoring strategies successfully reduced the incidence of serious liver-related complications during the study. As regulatory review progresses toward the April 2027 decision date, Inhibrx Biosciences is positioned to potentially deliver the first approved systemic therapy for conventional chondrosarcoma, a breakthrough that could significantly change the treatment landscape for patients facing this rare and devastating disease.
Source: Inhibrx Biosciences press release
