Results from a European multicenter phase-II mogamulizumab trial

Pier Luigi Zinzani from the University of Bologna, Italy, and colleagues recently published data from a phase-II study of mogamulizumab in R/R PTCL in a Letter to the Editor of Haematologica in October 2016. Mogamulizumab is approved in Japan for the treatment of CCR4-positive PTCL patients. The authors’ study aimed to primarily assess the ORR of R/R PTCL patients treated with the anti-CCR4 monoclonal antibody, mogamulizumab, in a 15 center, European, phase-II trial. Their secondary outcomes were duration of response, PFS, OS, and safety, and their study enrolled 38 patients of which 35 were included in their analysis.

Highlights:

• Mogamulizumab dose = 1 mg/kg weekly for 4 weeks, then every two weeks until PD, toxicity, death, or withdrawal
• Evaluated every 8 weeks from first treatment by investigators
• ORR = 11.5% (95% CI: 3.2–26.7%), mPFS = 2.1 months (95% CI: 1.3–3.9 months)
• 1pt CR, 3pts PR at 8 weeks (after two cycles)
• Median duration of SD = 2.8 months
• Treatment related AE ≥ grade 3 = 36.8%. AEs included thrombocytopenia, (13.2%) and anemia (7.9%)

Zinzani et al. noted that their reported ORR was much lower than a previous study of 29 patients with relapsed CCR4-positive PTCL by Ogura et al. within a Japanese population (11.5% vs 34%). There were many potential reasons given for this difference including that Zinzani et al. included refractory PTCL patients, which are known to have a poorer outcome than relapsed patients. Additionally, the dose in the Ogura et al. study was higher, with 68% of patients receiving the maximum eight doses in eight weeks.

In conclusion, despite a low ORR of 11.4%, there was an SD or better rate of 45.7%. For the future, the authors suggested exploring combination therapies with mogamulizumab in the treatment of R/R PTCL.