Inhibrx Biosciences Presents INBRX-109 Data Update at ESMO Sarcoma and Rare Cancers Congress 2026

Phase 1 Study of Ozekibart (INBRX-109) Combined With Irinotecan and Temozolomide Shows Robust Antitumor Activity in Relapsed/Refractory Ewing Sarcoma

Mar. 12, 2026 at 10:50am

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Inhibrx Biosciences presented updated findings from a phase 1 study evaluating the tetravalent death receptor 5 (DR5) agonist ozekibart (INBRX-109) in combination with irinotecan and temozolomide (IRI/TMZ) in patients with relapsed/refractory Ewing sarcoma. The combination demonstrated robust antitumor activity, with an objective response rate of 64.5% and a disease control rate of 87.1%. The safety profile was consistent with IRI/TMZ, with no new safety signals observed.

Why it matters

Ewing sarcoma is a rare, aggressive tumor with poor outcomes, especially in the relapsed/refractory setting. The combination of ozekibart and IRI/TMZ represents a potential new treatment option that could significantly improve outcomes for these patients, including those who have progressed on prior IRI/TMZ regimens.

The details

In the ongoing phase 1 study, 39 patients with advanced or metastatic Ewing sarcoma received ozekibart at the recommended phase 2 dose of 3 mg/kg every 3 weeks in combination with IRI (50 mg/m2/day on days 1-5) and TMZ (100 mg/m2/day on days 1-5). The most common treatment-emergent adverse events were diarrhea, nausea, anemia, and vomiting, which were consistent with the known safety profile of IRI/TMZ. Four patients (10.3%) discontinued treatment due to adverse events.

  • The data cutoff for this analysis was January 15, 2026.
  • Median follow-up at the time of data cutoff was 6.01 months (range, 0-27.2 months).

The players

Inhibrx Biosciences, Inc.

An American biopharmaceutical company focused on developing novel biologics, including the tetravalent DR5 agonist ozekibart (INBRX-109).

Ana Sebio

The presenter of the data at the ESMO Sarcoma and Rare Cancers Congress 2026.

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What they’re saying

“These findings support further evaluation of ozekibart + IRI/TMZ in relapsed/refractory Ewing sarcoma.”

— Ana Sebio

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

The combination of ozekibart and IRI/TMZ demonstrated robust antitumor activity and a manageable safety profile in patients with relapsed/refractory Ewing sarcoma, including those who had progressed on prior IRI/TMZ regimens. These results support further development of this combination as a potential new treatment option for this patient population with high unmet medical need.