Multinational randomized phase 2 trial of resminostat versus placebo maintenance in patients with advanced mycosis fungoides or Sézary syndrome

The multinational, double-blind, randomized phase 2 RESMAIN trial evaluated resminostat (HDAC inhibitor) maintenance treatment after disease control in patients with advanced-stage mycosis fungoides or Sézary syndrome (MF/SS). Adult patients with controlled stage IIB-IVB MF/SS and an ECOG performance status 0-2 were randomized to oral resminostat 600 mg (n=100) or placebo (n=101) once daily on the first 5 days of 14-day treatment cycles. Treatment was continued until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). The median PFS was 8.3 months (95% CI 4.2-15.7) in the resminostat group and 4.2 months (2.8-6.4) in the placebo group (HR 0.62; p=0.015). Adverse events were reported in 96% of patients in the resminostat group and 80% of patients in the placebo group, with grade ≥ 3 adverse events in 38% and 15%, respectively, and serious treatment-related adverse events in 11% and 1%, respectively. There were no treatment-related deaths. The authors conclude that these findings support the beneficial effect of resminostat maintenance therapy in patients with advanced MF/SS.