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Mogamulizumab vs. investigator's choice in ATL
Discussion
In this randomized phase II trial, the first of ATL outside Japan, mogamulizumab monotherapy demonstrated responses and predictable safety in patients with relapsed/refractory ATL, whereas the comparator arm (investigator’s choice of chemotherapy) showed almost no activity. cORR was higher in those randomized to moga- mulizumab versus the investigator’s choice arm by blinded Independent Review for the ITT population: 11% vs. 0%.
This rate of response was less than that seen in the previ- ous phase II study of mogamulizumab monotherapy in 26 evaluable (not in the ITT population) Japanese patients with relapsed CCR4+ ATL, which showed a 50% ORR.22
Several key differences may account for the discrepancy in activity. The Japanese study only included relapsed, not refractory patients, and confirmation of response (although not required) was evaluated after 4 weeks (com- pared to 8 weeks in our study). In addition, randomized patients in this study had a higher incidence of poor prog-
Figure 2. Kaplan-Meier analysis of progression-free survival during the randomized period.
Figure 3. Forest plot of progression-free survival during randomization adjusted for baseline characteristics. Age group = (i) < versus ≥40 years; age group (ii) = ≤65 versus ≥65 years; baseline Eastern Cooperative Oncology Group (ECOG): 0/1 versus 2; bone marrow in current sites: yes versus no; ATL subtype at consent: acute versus chronic versus lymphoma; best response to last ATL therapy: CR+PR versus SD+PD+unknown. ATL: adult T-cell leukemia/lymphoma; CI: confidence interval; CR: complete response; HR: hazard ratio; IC: investigator choice; PFS: progression-free survival; PD: progressive disease; PR: partial response; SD: stable disease.
haematologica | 2019; 104(5)
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