Inhibrx Biosciences, Inc. reports Phase 1/2 data showing 20% ORR and 5.5-month PFS for ozekibart plus FOLFIRI in heavily pretreated colorectal cancer.
Written By: Sana Khan, BPharm
Reviewed By: Pharmacally Editorial Team
Inhibrx Biosciences, Inc. reported updated interim results from its ongoing Phase 1/2 study evaluating ozekibart (INBRX-109) in combination with FOLFIRI in patients with locally advanced or metastatic, unresectable colorectal cancer (CRC), based on data as of April 10, 2026.
The analysis included 45 evaluable patients from a heavily pretreated population, with approximately 70% receiving treatment in the fourth-line setting and 80% previously progressing on irinotecan-based regimens.
The combination demonstrated an objective response rate of 20% per RECIST v1.1 criteria, notably higher than historical response rates of 1–6% with current standard therapies in similar settings, with nearly half of responses lasting longer than six months and observed irrespective of RAS or RAF mutation status.
Median progression-free survival was 5.5 months, with 42% of patients remaining progression-free at six months and nine patients continuing on therapy, indicating durable benefit in a subset of patients, while the disease control rate reached 87%.
The safety profile of ozekibart in combination with FOLFIRI was consistent with known chemotherapy-related effects, with the most common treatment-related adverse events being diarrhea, fatigue, and nausea, primarily Grade 1 or 2, and no significant liver toxicity observed despite a high prevalence of baseline liver metastases.
Ozekibart is a tetravalent death receptor 5 (DR5) agonist antibody designed to induce tumor cell death and has previously received Fast Track and orphan drug designations from the U.S. Food and Drug Administration for chondrosarcoma.
In a separate registrational study in advanced or metastatic conventional chondrosarcoma, the therapy demonstrated a significant progression-free survival benefit, reducing the risk of disease progression or death by 52% compared to placebo and more than doubling median PFS.
The company plans to meet with the U.S. Food and Drug Administration in the second half of 2026 to discuss initiating a first-line registrational trial in colorectal cancer and to explore potential accelerated regulatory pathways in later-line CRC and refractory Ewing sarcoma, while a Biologics License Application for chondrosarcoma was submitted in April 2026.
According to CEO Mark Lappe, the observed efficacy and manageable safety profile support further clinical development, including evaluation in earlier lines of treatment and additional indications.
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About the Writer
Sana Jamil Khan is a BPharm graduate with a strong interest in medical writing and scientific communication. Her work focuses on interpreting clinical research, exploring developments in pharmaceutical science, and presenting complex medical information in a clear and accessible manner. She is particularly interested in topics related to human clinical studies, drug safety observations, and emerging therapeutic research.