お知らせ • Oct 24
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
On October 23, 2025, Inhibrx announced (i) positive topline results from its registrational ChonDRAgon study (n= 206) investigating ozekibart (INBRX-109) as a single agent versus placebo in patients with advanced or metastatic, unresectable chondrosarcoma and (ii) updates on the ongoing expansion cohorts investigating ozekibart in combination with FOLFIRI in late-line colorectal cancer and in combination with irinotecan and temozolomide in refractory Ewing sarcoma. Inhibrx also announced that it plans to submit to the U.S. Food and Drug Administration a biologics license application in the second quarter of 2026. The ChonDRAgon study met its primary endpoint of a statistically significant and clinically meaningful median progression-free survival (“PFS”) for patients with advanced or metastatic chondrosarcoma treated with ozekibart compared to placebo. Ozekibart achieved a 52% reduction in the risk of disease progression or death compared to 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 versus 2.66 months for placebo. Importantly, ozekibart is the first investigational therapy to demonstrate a significant PFS benefit in a randomized trial for chondrosarcoma, a disease with no approved systemic options. The benefit of ozekibart was consistent across all pre-specified subgroups, including patients with isocitrate dehydrogenase (“IDH”)-wild-type and IDH-mutant tumors. Other key secondary endpoints, including disease control rate (54% vs 27.5%), and delay to deterioration in pain and physical function, further supported the clinical benefit observed with ozekibart. Ozekibart was generally well tolerated, with a manageable safety profile. The most common treatment-related adverse events were fatigue, constipation, and nausea. Hepatotoxicity, a known risk for this mechanism of action, occurs during the first treatment cycle and is in patients with underlying hepatic impairment. One hepatotoxicity-related fatal event occurred early in the study, prior to the implementation of mitigation measures. Over the course of the ChonDRAgon study, this risk was effectively mitigated by excluding patients with severe liver impairment and by implementing close monitoring during early treatment cycles, allowing for prompt management of liver enzyme elevations. This approach resulted in a low overall incidence of treatment-related hepatic adverse events, 11.8% compared to 4.5% in the placebo arm, the majority of which were Grade 1 or 2 in severity. Based on initial results from the Phase 1 trial of ozekibart in combination with FOLFIRI for the treatment of advanced or metastatic, unresectable colorectal cancer (“CRC”), Inhibrx initiated an expansion cohort enrolling 44 patients, as a fourth line of therapy for approximately 70% of patients and as a third line of therapy for approximately 30% of patients. 80% of patients had been previously treated with regimens containing irinotecan. Efficacy, based on RECIST v1.1 criteria, was assessed in 26 evaluable patients to date who had at least one post-baseline scan. The results show a 23% overall response rate (“ORR”) and an overall disease control rate of 92%. These outcomes are highly encouraging in a heavily pretreated CRC population, where responses are rare (5-6%) and outcomes are generally poor with the current standard of care. Ozekibart, in combination with FOLFIRI, was well tolerated. The most common treatment-emergent adverse events included anemia, diarrhea, nausea, and fatigue, with the majority being low-grade and consistent with the known safety profile of FOLFIRI. Based on initial results from the Phase 1 trial of ozekibart in combination with irinotecan and temozolomide (“IRI/TMZ”) for advanced or metastatic, unresectable, relapsed, or refractory Ewing sarcoma, Inhibrx initiated an expansion cohort which is expected to enroll up to 50 patients. Of the 33 patients recruited to date, more than half were third or fourth line patients. Among the 25 evaluable patients to date, Inhibrx observed a 64% ORR, and a disease control rate of 92%, with the majority of patients experiencing measurable tumor reduction. These outcomes are highly encouraging in this difficult-to-treat patient population as compared to the response rate typically observed with standard IRI/TMZ (15-30%). Ozekibart in combination with IRI/TMZ was well tolerated. The most common adverse events were diarrhea, nausea, anemia, and fatigue, all consistent with the known safety profile of IRI/TMZ.