Exposure-Response Analysis for Mogamulizumab in Adults With Cutaneous T-Cell Lymphoma.

Mogamulizumab is a humanized monoclonal antibody against C-C chemokine receptor 4 approved in the United States for the treatment of patients with relapsed/refractory mycosis fungoides or Sézary syndrome, the most common forms of cutaneous T-cell lymphoma (CTCL). The exposure-response relationships for efficacy (progression-free survival [PFS] and overall response rate [ORR]) and safety (the 5 most common treatment-related adverse events by Medical Dictionary for Regulatory Activities [MedDRA] System Organ Class) for 184 patients with CTCL treated with mogamulizumab in a large, registrational clinical trial. Exposure metrics were area under the serum mogamulizumab concentration-time curve over the dose interval at steady state (AUC_ss ) and minimum serum mogamulizumab concentration after the first dose (C_min,1st ). PFS by investigator assessment, the primary efficacy objective, and PFS and ORR by independent review were not correlated with exposure metrics; however, there was a statistically significant positive relationship between a secondary objective, ORR by investigator assessment, and AUC_ss (P = .0168). The frequency of treatment-related adverse events was not related to exposure metrics (C_min,1st or AUC_ss ) for any of the MedDRA System Organ Classes examined. Of the covariates that were found to have a statistically significantly effect on the population PK model (ie, albumin, aspartate aminotransferase, body surface area, mild to moderate hepatic impairment, and sex), none was found to impact efficacy or safety, indicating that there is no need to modify dose on the basis of these parameters.