Orbus Therapeutics has now shared results from their global Phase 3 STELLAR trial, which tested a combination of eflornithine and lomustine in patients with recurrent anaplastic astrocytoma. Eflornithine is a drug that slows tumor growth by blocking ornithine decarboxylase, an enzyme that helps cancer cells grow and divide.
The primary efficacy endpoint for the study, overall survival in the intent-to-treat population of 343 patients, did not achieve statistical significance. However, the company noted promising and clinically meaningful improvement for a subset of 194 patients in the study who had recurrent grade 3 IDH mutant astrocytoma. In this subset, patients receiving the combination therapy had a median OS of 34.9 months, compared to 23.5 months with lomustine alone. Median PFS was 15.8 months versus 7.2 months with lomustine alone. The treatment was generally well-tolerated although, consistent with prior eflornithine studies, there were some Grade 3+ adverse events related to myelosuppression and hearing impairment.