The Long-Term Outlook for Mogamulizumab in Previously Treated Cutaneous T-Cell Lymphoma

Long-term mogamulizumab treatment provides significant clinical benefit to patients with previously treated cutaneous T-cell lymphoma (CTCL) who had blood involvement at baseline, regardless of C-C chemokine receptor 4 (CCR4) expression status. In addition, no increased safety risk was observed after 1 year of therapy. These are the findings of a follow-up analysis of the phase III MAVORIC study (abstract 2901), presented at the 2018 American Society of Hematology (ASH) Annual Meeting & Exposition in San Diego.

The MAVORIC study compared mogamulizumab to US Food and Drug Administration (FDA)–approved vorinostat in adults with relapsed/refractory mycosis fungoides or Sézary syndrome, two subtypes of CTCL. Patients who were previously treated with 1 or more systemic therapy were randomized 1:1 to receive mogamulizumab (1.0 mg/kg once weekly for the first 28-day cycle, then on days 1 and 15 of subsequent cycles) or oral vorinostat (400 mg daily). Researchers found that mogamulizumab significantly prolonged median progression-free survival (PFS) vs vorinostat (7.7 vs 3.1 months, respectively; P < .0001).

“This follow-up analysis assessed the safety and efficacy of mogamulizumab based on treatment exposure in order to characterize pts with MF/SS who were able to achieve long-term clinical benefit with mogamulizumab,” the authors wrote.

A total of 184 patients who received mogamulizumab were included in the analysis. Exposure quartiles were determined, and baseline demographics, confirmed global response rate, and safety were analyzed by exposure group. Frequencies were analyzed using Chi-square test, and continuous data were assessed by analysis of variance, in order to detect linear trends across exposure quartiles.

Significant trends were noted for the following: baseline Eastern Cooperative Oncology Group performance status (P = .04), disease type (P = .03), and blood involvement (defined as ≥ B1 per Olsen et al via J Clin Oncol 2011; P < .001); individuals receiving long-term treatment with mogamulizumab were more likely to have an ECOG PS grade of 0, Sézary syndrome, and/or blood involvement.

In addition, increasing exposure to mogamulizumab was associated with increased global response rates (P < .001 for mycosis fungoides, Sézary syndrome, or patients with both conditions). Of all patients randomized to receive mogamulizumab for longer than 351 days, 76% achieved a confirmed global complete or partial response.

Lastly, the percentage of patients reporting a treatment-emergent adverse event (TEAE) did not vary with longer exposure to mogamulizumab: at < 72 days exposure, 26% of patients reported TEAEs and 6% reported serious adverse events (SAEs); at 72 to 170 days, 18% reported TEAEs and 3% reported SAEs; at 171 to 350 day, 23% reported TEAEs and 6% reported SAEs; and at >351 days, 21% reported TEAEs and 4% reported SAEs). The most common TEAEs reported after > 351 days of exposure included drug eruption (9/45 [20%]), thrombocytopenia (5/45 [11%]), stomatitis (4/45 [9%]), and anemia (4/45 [9%]).

The FDA approved mogamulizumab in August of this year for the treatment of adult patients with relapsed or refractory mycosis fungoides or Sézary syndrome after at least one previous systemic therapy. “Mycosis fungoides and Sézary syndrome are rare, hard-to-treat types of non-Hodgkin lymphoma and this approval fills an unmet medical need for these patients,” wrote Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, following the approval.