In a phase III trial (SWOG S9005) reported in the Journal of Clinical Oncology,1 YongLi Ji, MD, PhD, and Claire Verschraegen, MD, of the University of Vermont Cancer Center; and colleagues found no benefit of treatment with the antiprogestin agent mifepristone vs placebo in patients with unresectable meningioma. Progesterone receptors are expressed in approximately 70% of meningiomas.
In the double-blind trial, 164 evaluable patients were randomized between 1992 and 1998 to receive oral mifepristone at 200 mg daily (n = 80) or placebo (n = 84) for 2 years. Patients with response or stable disease could continue with the same blinded therapy. Patients progressing on placebo could cross over to receive mifepristone. The primary endpoint was failure-free survival.
Overall, 30% of the mifepristone group and 33% of the placebo group completed the 2-year study without disease progression, adverse events, or other reasons for treatment discontinuation. In analysis adjusting for sex, menopausal status, prior radiotherapy, and progressive/recurrent vs newly diagnosed disease, median failure-free survival was 10 months in the mifepristone group vs 11 months in the placebo group (hazard ratio [HR] = 1.02, P = .90). No overall survival benefit was observed (HR = 1.05, 95% confidence interval = 0.69–1.59).
Grade 3 and 4 adverse events occurred in 39% and 8% of patients in the mifepristone group and in 29% and 1% of patients in the placebo group (P = .03), respectively.
The investigators concluded: “Long-term administration of mifepristone was well tolerated but had no impact on patients with unresectable meningioma.”■
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit jco.ascopubs.org.
1. Ji Y, Rankin C, Grunberg S, et al: Double-blind phase III randomized trial of the antiprogestin agent mifepristone in the treatment of unresectable meningioma: SWOG S9005. J Clin Oncol 33:4093-4098, 2015.