Abstract
Introduction Mogamulizumab is approved in the United States (US) for the treatment of adults with relapsed/refractory (r/r) mycosis fungoides/Sézary syndrome (MF/SS) following ≥1 prior systemic treatment. This retrospective, observational cohort study investigated adult patients (pts) treated with mogamulizumab as monotherapy (MT) or combination therapy (CT) in the US.
Methods ConcertAI de-identified electronic medical records from academic and community oncology practices were analyzed. Eligible pts were diagnosed with r/r MF/SS and had initiated mogamulizumab treatment between 10/1/2018–08/12/2022. CT was defined as mogamulizumab usage concomitant with another systemic or skin-directed treatment (excluding topical steroids) for ≥28 days. Duration was calculated from the start of mogamulizumab until the last treatment (+14 days). Response was assessed after Day 27 of treatment until the start of the next systemic treatment or the last available medical record (response assessment period). Time to next treatment (TTNT) and progression-free survival (PFS) were estimated by Kaplan-Meier methods. Selected safety events (infusion reactions, rash, severe skin reactions, infection, immune-related reactions, and cardiac events) were also extracted.
Results We identified 110 pts with MF/SS treated with mogamulizumab; 6 with <28 days of treatment were excluded from efficacy analyses. Seventy-five (72.1%) and 29 (27.9%) pts had MT and CT, respectively. Median (Q1, Q3) time from diagnosis to mogamulizumab treatment was 26.6 (10.3, 80.1) months (mo) in the MT group and 53.3 (18.0, 86.1) mo in the CT group. Mogamulizumab was used in MF and SS as MT in 64.0% and 79.6%; and CT in 36.0% and 20.4% of pts, 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. Thirty-two pts (30.8%) were diagnosed with blood involvement (data missing for 60 pts); 24 had MT and 8 had CT. Mogamulizumab was given as MT in 45.3% and 46.7% of pts and CT in 58.6% and 37.9% of pts in academic and community settings, respectively. Fourteen CT pts (48.3%) had mogamulizumab added to pre-existing treatment, 8 (27.6%) had another treatment added to mogamulizumab, and 7 (24.1%) initiated mogamulizumab concurrently with CT. The most common systemic CT options were bexarotene (8 pts [27.6%]), extracorporeal photopheresis ([ECP] 7 pts [24.1%]), and methotrexate (5 pts [17.2%]) with some differences between MF and SS.
Of 99 pts with results in the response assessment period, physician-reported response was documented in 47/70 pts (67.1%) on MT and 21/29 pts (72.4%) on CT. Median (Q1, Q3) time from initiation to initial response was 1.5 (0.9, 2.5) mo for MT and 2.3 (1.8, 4.7) mo for CT. Overall response rate for pts 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% CI) PFS was 8.3 mo (4.4, 13.5) for MT and 9.2 mo (2.8, 14.8) for CT. Median (95% CI) TTNT was 12.3 mo (7.2, 22.3) (MT: 10.7 mo [6.5, 22.6]; CT: 12.3 mo [5.6, 23.8]).
In 110 pts in the safety analysis, 72/81 pts (88.9%) on MT and 22/29 pts (75.9%) on CT had ≥1 safety event. Infections included cellulitis (MT: 7 pts [8.6%], CT: 1 pt [3.4%]), pneumonia (MT: 4 pts [4.9%], CT: 0 pts), and sepsis (MT: 2 pts [2.6%], CT: 0 pts). Infusion reactions occurred in 23 pts (28.4%) on MT and 5 (17.2%) on CT. Skin conditions (due to disease or adverse events) were reported by 60 pts (74.1%) on MT and 19 (65.5%) on CT, most commonly pruritus (MT: 47 pts [58.0%]; CT: 16 pts [55.2%]) and rash (MT: 39 pts [48.1%]; CT: 11 pts [37.9%]). Rash was documented before mogamulizumab in 65/110 pts (59.1%). In the 45/110 pts (40.9%) without a history of rash, 13/32 pts (40.6%) on MT and 5/13 pts (38.5%) on CT reported treatment-emergent rash after mogamulizumab.
Conclusions These data show relatively frequent CT with mogamulizumab, most often with ECP, bexarotene, or methotrexate with mogamulizumab, often added to another systemic treatment for CTCL. In this cohort, the risk of selected safety events was not significantly different with mogamulizumab CT. Response rate, TTNT, and PFS were numerically higher with CT. Study limitations include potential for incomplete or incorrect documentation in medical records and lack of standardized response assessment criteria; however, this analysis demonstrates safety and a potential benefit of mogamulizumab in CT for pts with MF/SS.
