“It was a very large randomized study and it was particularly good. It showed better quality of life and it is quite promising,” said study investigator Steven Horwitz, MD, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York, New York. “Is it likely that mogamulizumab is going to be an important addition for a particularly hard-to-treat subset of patients.”
Patients with CTCL suffer reduced quality of life often due to intractable itching and recurrent infections, and advanced stages have a poor prognosis. In early studies, mogamulizumab, a monoclonal antibody directed against CCR4, was found to be safe with a 37% ORR. The current trial was an open-label, multinational, randomized, phase III study comparing mogamulizumab to vorinostat in previously treated patients with CTCL.
In this study, patients randomized to vorinostat could crossover to mogamulizumab upon disease progression or intolerable toxicity. The primary endpoint was investigator-assessed PFS in the randomized population using the global composite response, which was based on skin, blood, nodes, and viscera.
The study included 372 patients (median age, 63.5 years), and the median number of prior systemic treatments for both arms was 3. The researchers found that patients treated with mogamulizumab experienced a greater improvement in PFS compared with patients treated with vorinostat (hazard ratio [HR], 0.53; 95% CI: 0.41-0.69; P < .0001). The median PFS for the mogamulizumab arm was 7.7 months (95% CI: 5.7-10.3) compared with 3.1 months (95% CI: 2.9-4.1) for the vorinostat arm.
A secondary assessment by an independent review showed improvement in PFS (HR, 0.64; 95% CI: 0.49-0.84; P = .0007); the median PFS was 6.7 months for mogamulizumab and 3.8 months for vorinostat. The global ORR was significantly improved in the patients receiving mogamulizumab at 28% compared with 4.8% for patients receiving vorinostat (P < .0001). Among patients who crossed over from vorinostat, there was an ORR of 30.1%.