Olutasidenib showed disease control in IDH1-mutated chondrosarcoma

What the study found: Olutasidenib, an inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), was well tolerated in patients with recurrent/relapsed locally advanced or metastatic IDH1-mutated chondrosarcoma. In the conventional chondrosarcoma subgroup, the study reported disease control.
Why the authors say this matters: The authors conclude that chondrosarcoma has limited treatment options and that their findings indicate olutasidenib may have activity in conventional chondrosarcoma.
What the researchers tested: This was a phase 1b/2 clinical trial (NCT03684811) in patients with locally advanced or metastatic mIDH1 chondrosarcoma. Patients received olutasidenib 150 mg twice daily, and the study assessed objective response rate, adverse events, progression-free survival, and overall survival.
What worked and what didn't: Twenty-three patients were enrolled, including 16 with conventional chondrosarcoma. Among 21 response-evaluable patients, 11 had stable disease, 8 had progressive disease, and 2 were not evaluable. Median progression-free survival was 2.0 months overall and 3.5 months in conventional chondrosarcoma; median overall survival was 16.0 months overall and 19.0 months in conventional chondrosarcoma. No dose-limiting toxicities were reported.
What to keep in mind: The abstract notes an open-label design and a low patient sample because conventional chondrosarcoma is rare. It also does not report an objective response rate in the provided summary.

Key points

• Olutasidenib was studied in recurrent/relapsed locally advanced or metastatic IDH1-mutated chondrosarcoma.
• The trial enrolled 23 patients, including 16 with conventional chondrosarcoma.
• Among response-evaluable patients, stable disease was more common than progressive disease.
• Median progression-free survival was 2.0 months overall and 3.5 months in conventional chondrosarcoma.
• No dose-limiting toxicities were reported.
• The study was open-label and had a small sample size.