A Phase I Study of the Anti-CC Chemokine Receptor 4 Antibody, Mogamulizumab, in Combination with Nivolumab in Patients with Advanced or Metastatic Solid Tumors.

Purpose: Regulatory T cells (Tregs) expressing CC chemokine receptor 4 (CCR4) can suppress antitumor immune responses and are associated with poor prognoses in several cancers. We assessed the safety and efficacy of combined mogamulizumab (anti-CCR4 antibody) and nivolumab [anti-programmed death-1 (PD-1) antibody] in immunotherapy-naïve patients with advanced/metastatic solid tumors.

Patients And Methods: This study (NCT02476123) comprised dose-escalation (3+3 design) and expansion parts. Patients received nivolumab (3.0 mg/kg) every 2 weeks, with mogamulizumab (0.3 or 1.0 mg/kg in dose escalation, 1.0 mg/kg in expansion) once weekly for 4 weeks, then every 2 weeks, until progression or unacceptable toxicity. Primary objective was safety; secondary objectives were antitumor effects, pharmacokinetics, and immunogenicity. Exploratory biomarker analyses were conducted.

Results: Ninety-six patients were enrolled (July 2015-November 2016): six patients in the dose-escalation part and 90 in the expansion part. No dose-limiting toxicities were observed in the dose-escalation part. Grade 3/4 treatment-related adverse events (TRAEs) occurred in 29% of patients in the expansion part (no grade 5 TRAEs). The most frequent TRAEs were rash (39%), rash maculopapular (20%), diarrhea (13%), stomatitis (12%), and pruritus (11%). There were four (27%) confirmed tumor responses among 15 patients with hepatocellular carcinoma, and one confirmed and two unconfirmed responses among 15 patients with pancreatic adenocarcinoma. During treatment, populations of effector Tregs (CD4CD45RAFoxP3) decreased and CD8 T cells in tumor-infiltrating lymphocytes increased.

Conclusions: Combining an anti-PD-1 antibody, nivolumab, with a Treg-depleting anti-CCR4 antibody, mogamulizumab, provides an acceptable safety profile, antitumor activity, and a potentially effective option in cancer immunotherapy.