TCL-127: Impact of Concomitant Steroids on Mogamulizumab Efficacy in MAVORIC

Abstract

Context: Topical steroids are a mainstay of treatment for patients with mycosis fungoides (MF) and Sezary syndrome (SS). Because patients undergoing mogamulizumab treatment likely also receive steroids, a thorough understanding of the safety/efficacy of their concomitant use is beneficial for physician decision-making. This post hoc analysis was designed to determine how many MAVORIC patients were treated with steroids and their impact on the safety/efficacy of mogamulizumab therapy. Design: MAVORIC ( NCT01728805 ) was an open-label, phase 3 trial in which patients with previously treated MF/SS were randomized 1:1 to mogamulizumab (1.0 mg/kg weekly for the first 28-day cycle, then Days 1 and 15 of subsequent cycles) or vorinostat (400 mg daily). Patients on a stable, low dose of corticosteroids could continue use, and investigators attempted tapering to the lowest tolerable dosage. Results: Steroid use occurred in the majority of patients (intent-to-treat [ITT] population: 67%, 249/372; mogamulizumab arm: 68%, 127/186; vorinostat arm: 66%, 122/186). Similar numbers of patients were treated with low-/intermediate-potency and high-potency steroids in each arm (mogamulizumab: 24% and 44%; vorinostat: 23% and 43%). Patients receiving mogamulizumab with concomitant steroids had longer median progression-free survival (PFS) relative to the ITT population (9.4 vs 7.7 months); however, in the vorinostat group, PFS was similar between groups (3.1 vs 3.1 months). Mogamulizumab also resulted in a higher overall response rate (ORR, confirmed complete response + partial response) in patients receiving concomitant steroids relative to those in the ITT population (37% vs 28%), whereas vorinostat ORR was similar between groups (3% vs 5%). For most disease stages, ORR was better in mogamulizumab-treated patients receiving concomitant steroids relative to those in the ITT population. Differences were also noted between mogamulizumab-treated patients receiving concomitant steroids and the ITT population within the skin (54% vs 42%) and blood compartments (73% vs 68%). No unexpected differences were reported in the AE profiles of patients with steroid use vs patients without steroid use and the ITT population. Conclusions: Concomitant steroid therapy, which likely mirrors regular clinical practice for patients with MF/SS, may be associated with increased patient benefit for mogamulizumab-treated but not vorinostat-treated patients. Funding: Kyowa Kirin.