FDA Accepts BLA for Ozekibart in Unresectable or Metastatic Chondrosarcoma

The FDA has accepted a biologics license application (BLA) for ozekibart (INBRX-109) for patients with unresectable or metastatic conventional chondrosarcoma, according to a press release from Inhibrx Biosciences.¹ 

A Prescription Drug User Fee Act date of April 14, 2027, has been set. If approved, ozekibart would become the first systemic therapy ever approved for this indication.

The BLA is supported by the primary efficacy results from the phase 2 ChonDRAgon (NCT04950075), in which ozekibart, a precision-engineered, tetravalent death receptor 5 (DR5) agonist antibody, achieved a 52% reduction in the risk of disease progression or death vs placebo (stratified HR, 0.479; 95% CI, 0.33-0.68; P <.0001), more than doubling median progression-free survival (PFS) by central investigator radiology review (CIRR) to 5.52 months vs 2.66 months for placebo. The PFS benefit was consistent across all prespecified subgroups, including patients with IDH wild-type and IDH-mutant tumors.

The randomized, blinded, placebo-controlled ChonDRAgon study enrolled 206 patients across 67 sites worldwide and stands as the largest randomized trial ever conducted in conventional chondrosarcoma. Secondary efficacy end point data from that trial were presented by Hans Gelderblom, MD, PhD, chair of the Department of Medical Oncology at Leiden University Medical Center, at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.²

Secondary efficacy data presented at the 2026 ASCO Annual Meeting further supported the findings. Investigator-assessed PFS aligned closely with the CIRR-assessed primary end point, with a median PFS of 4.20 months vs 2.33 months (HR, 0.48; 95.02% CI, 0.33-0.68; P <.0001).

Tumor response data showed that ozekibart demonstrated a confirmed objective response rate (ORR) of 5.8% (95% CI, 2.6%-11.2%) by CIRR vs 0% (95% CI, 0.0%-5.2%) with placebo. Stable disease was achieved in 71.5% of patients receiving ozekibart vs 52.2% receiving placebo, and the disease control rate (DCR) favored ozekibart at 54.0% (95% CI, 45.3%-62.6%) vs 27.5% (95% CI, 17.5%-39.6%). Among the 8 confirmed partial responders in the ozekibart arm, the median duration of response was 11.1 months (95% CI, 2.8–not evaluable).

Quality-of-life data from the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) added clinically meaningful context to the efficacy findings. Patients receiving ozekibart experienced a significantly longer time to deterioration in pain compared with those receiving placebo (median, 2.76 vs 1.41 months; stratified HR, 0.61; 95% CI, 0.43-0.85; P = .0033). Similarly, time to deterioration in physical functioning was prolonged with ozekibart vs placebo (median, 2.56 vs 1.41 months; stratified HR, 0.56; 95% CI, 0.40-0.78; P = .0007). These delays in functional decline further support the clinical relevance of the disease control observed with ozekibart in this population.

Inhibrx is also exploring ozekibart in combination with irinotecan-based regimens across expansion cohorts in Ewing sarcoma and colorectal cancer. Updated data from a phase 1/2 study (NCT03715933) evaluating ozekibart plus folinic acid, fluorouracil, and irinotecan in pretreated advanced colorectal cancer previously demonstrated a 20% ORR and 87% DCR in that population.³

References

1. Inhibrx Announces U.S. FDA acceptance of BLA for ozekibart in patients with conventional chondrosarcoma. News release. Inhibrx Biosciences, Inc. June 15, 2026. Accessed June 16, 2026. https://tinyurl.com/yc6pjtrk
2. Gelderblom H, Wang V, Doherty M, et al. The tetravalent death receptor 5 (DR5) agonist ozekibart (INBRX-109) in conventional chondrosarcoma: secondary efficacy endpoints from the randomized, registrational, phase 2 ChonDRAgon study. J Clin Oncol. 2026;44(suppl 16):11504. doi:10.1200/JCO.2026.44.16_suppl.11504
3. Inhibrx provides clinical update on ozekibart (INBRX-109) in late line colorectal cancer. News release. Inhibrx Biosciences, Inc. April 21, 2026. Accessed June 16, 2026. https://tinyurl.com/ydjjy3xm