Mogamulizumab is approved in the United States (US) for the treatment of adults with relapsed/refractory mycosis fungoides/Sézary syndrome (MF/SS) following ≥1 prior systemic treatment. This retrospective, observational cohort study used ConcertAI electronic medical records to investigate effectiveness and safety in adult patients treated with mogamulizumab as monotherapy (MT) or combination therapy (CT) in the US. Of 104 patients with ≥28-day mogamulizumab treatment, seventy-five (72.1%) and 29 (27.9%) patients had MT and CT, respectively. Stage at diagnosis in the MT vs CT group included: 18.7% vs 20.7% I-IIA; 4.0% vs 17.2% IIB; 14.7% vs 10.3% III, and 22.7% vs 17.2% IV. Of 99 patients with results in the response assessment period, complete response (CR) and partial response (PR) were documented in 19/70 (27.1%) and 28/70 (40.0%) patients on MT, respectively, and 5/29 (17.2%) and 16/29 (55.2%) patient on CT. Overall response rate for patients with ≤3 and >3 prior therapies, respectively, was 75.0% and 53.8% in MT (n=70), and 73.9% and 66.7% in CT (n=29). Median (95% confidence interval) time to next systemic treatment was 12.3 months (95%CI: 7.2, 22.3) (MT: 10.7 months [95%CI: 6.5, 22.6]; CT: 12.3 months [95%CI: 5.6, 23.8]). In the assessment of selected safety events (N=110), no statistically significant differences were observed between MT and CT. Treatment-emergent rash was assessable in 45/110 patients (40.9%), 13/32 patients (40.6%) on MT and 5/13 patients (38.5%) on CT reported treatment-emergent rash. These data suggest CT is safe and has a role in treatment of MF/SS.This study was funded by Kyowa Kirin, Inc.
