FDA Approval Summary: Mogamulizumab-kpkc for Mycosis Fungoides and Sézary Syndrome

The FDA approved mogamulizumab-kpkc, a CC chemokine receptor type 4 (CCR4)- directed monoclonal antibody, in August 2018 for treatment of adult patients with relapsed or refractory mycosis fungoides or Sezary syndrome after at least one prior systemic therapy. Regular approval was based on a randomized, open-label trial that randomized 372 such patients, with a median of 3 prior systemic therapies, to either mogamulizumab-kpkc or vorinostat. Investigator-assessed progression-free survival (PFS) was statistically significantly longer in the mogamulizumab-kpkc arm, which had an estimated median PFS of 7.6 months (95% confidence interval [CI], 5.6-10.2) compared to 3.1 months (95% CI, 2.8-4.0) in the vorinostat arm (hazard ratio 0.53; 95% CI, 0.41-0.69). The confirmed overall response rate was 28% and 5%, respectively (p