Eflornithine and lomustine improved survival compared with lomustine alone in patients with grade 3 IDH-mutant astrocytoma whose disease progressed after radiation and adjuvant temozolomide treatment, according to a press release from Orbus Therapeutics, the manufacturer of eflornithine.
Findings from this subpopulation of the STELLAR study were also recently presented at the Society for Neuro-Oncology Annual Meeting.
According to the National Cancer Institute, astrocytoma is a type of glioma (or brain tumor) that forms in star-shaped cells — astrocytes — in the brain and spinal cord. Although they can be either noncancerous or cancerous, those considered grade 3 are malignant, meaning they can grow and spread quickly. An IDH mutation can make tumor cells grow more quickly and aggressively.
“For patients with recurrent grade 3 astrocytoma, a rare and fatal disease, there are very few available treatment options,” Bob Myers, Chief Executive Officer of Orbus, said in the release. “The last FDA approval of a chemotherapeutic agent for these patients was 25 years ago.”
In the STELLAR study, researchers compared the safety and efficacy of eflornithine plus lomustine with lomustine alone in patients with anaplastic astrocytoma whose disease recurred after radiation, surgery and adjuvant temozolomide chemotherapy, according to the release. In particular, researchers enrolled 343 patients, of whom 194 had grade 3 IDH-mutant astrocytoma.
The survival improvements with the combination treatment were clinically more meaningful in patients with IDH-mutant astrocytoma than with the overall study population, according to the release. For all patients in the STELLAR study, 343 patients treated with eflornithine and lomustine were 94% as likely to die as those who received the standard treatment with lomustine.
In contrast, in the 194 patients with recurrent grade 3 IDH-mutant astrocytoma, eflornithine plus lomustine contributed to clinically meaningful improvements in progression-free survival (PFS) and overall survival (OS). The median OS was 34.9 months in patients treated with eflornithine plus lomustine compared with 23.5 months in those treated with lomustine alone. Regarding PFS, the median was 15.8 months in the combination group compared with 7.2 months in the lomustine-alone group.
“The subset results for the patients with recurrent grade 3 astrocytoma in the STELLAR study represent the first positive outcome to show significant increases in overall survival and progression-free survival in a very difficult-to-treat form of malignant glioma,” Dr. Howard Colman, the Jon M. Huntsman Presidential Chair in Neuro-Oncology at the Huntsman Cancer Institute at the University of Utah in Salt Lake City, said in the release. “These findings from the STELLAR study are very impressive and provide caregivers and patients with hope for a new treatment option for this fatal disease.”
The release also noted that treatment with eflornithine plus lomustine was well-tolerated, with no unexpected safety signals observed throughout the trial. The most common grade 3 (severe) or worse side effects from treatment were related to hearing impairment and myelosuppression. The patients with grade 3 or worse blood-related side effects or organ function-related side effects were to the extent of what researchers expected, the release explained.
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