The FDA has accepted a biologics license application (BLA) for ozekibart (INBRX-109), a tetravalent death receptor 5 (DR5) agonist antibody, for the treatment of adult patients with unresectable or metastatic conventional chondrosarcoma.1
The agency identified no filing review issues and assigned a Prescription Drug User Fee Act (PDUFA) goal date of April 14, 2027.
Ozekibart previously received fast track designation in January 2021 and orphan drug designation in November 2021 from the FDA for this indication.¹ If approved, ozekibart would represent the first systemic therapy ever cleared for a patient population that has historically had no approved treatment options beyond surgical resection.
"The FDA's acceptance of our BLA for ozekibart is a monumental milestone for Inhibrx and, more importantly, for the chondrosarcoma community," Mark Lappe, chief executive officer of Inhibrx, stated in a news release. "Chondrosarcoma is an aggressive and devastating bone cancer and there are currently no approved therapies for patients suffering from this disease. We look forward to working closely with the FDA during this review process to potentially bring this first-in-class targeted therapy to patients as quickly as possible."
Ozekibart Meets Another Regulatory Milestone in Rare Sarcoma Subtype
- The FDA accepted the BLA for ozekibart for unresectable or metastatic conventional chondrosarcoma with a PDUFA goal date of April 14, 2027.
- In the ChonDRAgon trial, ozekibart more than doubled median PFS vs placebo (5.52 vs 2.66 months; HR, 0.479; 95% CI, 0.33-0.68; P <.0001), marking the first significant PFS benefit demonstrated in a randomized trial for this disease.
- Ozekibart holds both FDA fast track and orphan drug designation for conventional chondrosarcoma and, if approved, would be the first-ever systemic therapy cleared for this indication.
What data supported this BLA?
In the registrational phase 2/3 ChonDRAgon trial (NCT04950075), ozekibart resulted in a 52% reduction in the risk of disease progression or death compared with placebo (stratified HR, 0.479; 95% CI, 0.33-0.68; P < .0001). The median progression-free survival (PFS) increased from 2.66 months on placebo to 5.52 months on ozekibart, meeting the study’s primary end point.¹ This represents the first statistically significant PFS benefit demonstrated for any investigational agent in a blinded, randomized trial in conventional chondrosarcoma.
This benefit with ozekibart was consistent across prespecified subgroups, including patients with IDH wild-type and -mutant tumors.2 The disease control rate was 54% with ozekibart vs 27.5% with placebo. Ozekibart also demonstrated a delay in deterioration of pain and physical function compared with placebo, a patient-centered outcome of particular relevance given the high symptom burden associated with locally advanced and metastatic chondrosarcoma.
Regarding safety, ozekibart was generally well tolerated. The most frequent treatment-related adverse effects (AEs) were fatigue, constipation, and nausea. The incidence of treatment-related hepatic AEs was 11.8% with ozekibart compared with 4.5% in the placebo arm, and the majority of these AEs were low grade.
How was the ChonDRAgon trial designed?
The ChonDRAgon study is a randomized, blinded, placebo-controlled, registrational trial enrolling patients with grade 2 or 3 unresectable or metastatic conventional chondrosarcoma.1 The study was initiated in June 2021 and enrolled a total of 206 patients across 67 sites worldwide.
Eligible patients were randomly assigned 2:1 to receive ozekibart or placebo administered intravenously every 3 weeks. Stratification factors included line of therapy, tumor grade, and IDH1/2 mutation status. Of note, patients assigned to the placebo arm were permitted to cross over to receive ozekibart upon confirmed disease progression by central independent radiology review.
The study’s primary end point was PFS assessed by blinded central independent radiology review per RECIST 1.1 criteria. Secondary end points included overall survival, investigator-assessed PFS, objective response rate, duration of response, DCR, delay to deterioration in pain and physical function, quality of life, safety and tolerability, pharmacokinetics, and antidrug antibody assessment.
What’s next for ozekibart in clinical development?
Beyond the pending BLA in chondrosarcoma, ozekibart is being evaluated in ongoing expansion cohorts in combination with irinotecan-based regimens for Ewing sarcoma and colorectal cancer. According to the news release, encouraging early signals have been observed in these cohorts, supporting further exploration.
References
- Inhibrx Biosciences, Inc. Inhibrx announces U.S. FDA acceptance of BLA for ozekibart in patients with conventional chondrosarcoma. News Release. Inhibrx. June 15, 2026. Accessed June 15, 2026. https://inhibrxbiosciences.investorroom.com/2026-06-15-Inhibrx-Announces-U-S-FDA-Acceptance-of-BLA-for-Ozekibart-in-Patients-with-Conventional-Chondrosarcoma
- Inhibrx Biosciences reports positive topline results from its registrational trial of ozekibart (INBRX-109) in chondrosarcoma and provides updates on colorectal cancer and Ewing sarcoma expansion cohorts. News Release. Inhibrx. October 23, 2025. Accessed June 15, 2026. https://inhibrxbiosciences.investorroom.com/2025-10-23-Inhibrx-Biosciences-Reports-Positive-Topline-Results-from-its-Registrational-Trial-of-Ozekibart-INBRX-109-in-Chondrosarcoma-and-Provides-Updates-on-Colorectal-Cancer-and-Ewing-Sarcoma-Expansion-Cohorts
