RESMAIN: Resminostat maintenance in advanced-stage mycosis fungoides or Sézary syndrome

Results from the phase II, multicenter, double-blind, randomized, placebo-controlled RESMAIN trial (NCT02953301), evaluating resminostat, a histone deacetylase inhibitor, as maintenance therapy in adults with advanced-stage mycosis fungoides or Sézary syndrome (N = 201), were published in The Lancet Haematology by Stadler et al. The study enrolled patients with histologically confirmed Stage IIB–IVB mycosis fungoides or Sézary syndrome, who had disease control after ≥1 prior systemic therapy or total skin electron beam (TSEB). The primary endpoint was progression-free survival (PFS).

Key data: In total, 100 patients were randomized to resminostat maintenance, and 101 were randomized to placebo. At data cutoff, median PFS was 8.3 months (95% confidence interval [CI], 4.2–15.7) with resminostat vs 4.2 months (95% CI, 2.8–6.4) with placebo (hazard ratio [HR], 0.62; 95% CI, 0.42–0.92; p = 0.015). The overall response rate (ORR) was 17% (95% CI, 10–27) with resminostat, including a partial response (PR) in 14% and complete response (CR) in 4%, vs 10% (95% CI, 5–18) with placebo, including a PR in 10% and no CRs. Grade ≥3 treatment-emergent adverse events (TEAEs) occurred in 38% of patients with resminostat vs 15% with placebo, and serious adverse events in 19% vs 12%. The most common any grade TEAEs with resminostat included nausea (68%), diarrhea (44%), vomiting (32%), and fatigue (29%).

Key learning: Resminostat maintenance therapy significantly extended PFS vs placebo in patients with advanced-stage mycosis fungoides or Sézary syndrome and prior disease control, with a manageable safety profile, supporting its consideration as a treatment option in this challenging clinical setting.