ATLL: Results from phase II lenalidomide study appear promising for recurrent ATLL

Ishida, T. from the Nagoya City University Graduate Medical School, Japan, and colleagues reported the results of a multicenter phase II study on lenalidomide (25 mg/d) in 26 R/R Adult T-Cell Leukemia/Lymphoma (ATLL) patients. This was published in the Journal of Clinical Oncology online in September 2016. However, an accompanying editorial has raised some potential issues for the broad applicability of this study.

Highlights:

• Overall Response Rate (ORR) = 42% (95% CI, range 23–63%), Complete Response (CR) = 15%, CR unconfirmed (CRu) = 4%
• Median Progression Free Survival (mPFS) = 3.8 months (95% CI, range 1.9 months–not estimable), Median Overall Survival (mOS) = 20.3 months (95%, range 9.1 months–not estimable)
• Subtype response rate: acute = 33%, lymphoma = 57%, unfavorable chronic ATL = 50%
• Most common adverse events (AEs): neutropenia, lymphopenia, leukopenia, thrombocytopenia, and anemia
• Serious AEs occurred in 35% of patients and dose reduction/interruption due to AEs took place in 65% of patients

In an accompanying editorial by Mehta-Shah, N. and Horwitz, S.M. in the Journal of Clinical Oncology, the study by Ishida et al. was praised, however some issues were raised as to the study results applicability to other populations. These issues included the small trial size of the study, no data on the comparison between this condition in Japanese and American populations and highly selective eligibility criteria (4-week total washout).

Conclusions:

Taking both the editorial and study into consideration, Ishida et al. have shown data that indicates that lenalidomide is an effective and relatively safe treatment option for patients with ATLL in Japan. In order to elucidate the study’s applicability to the condition outside of Japan, further investigation will need to be conducted.

 Abstract:

Multicenter Phase II Study of Lenalidomide in Relapsed or Recurrent Adult T-Cell Leukemia/Lymphoma: ATLL-002

Takeshi Ishida et al.

Purpose: Few treatment options exist for adult T-cell leukemia/lymphoma (ATL), and the prognosis for this disease is poor. A phase I study of lenalidomide demonstrated preliminary antitumor activity in patients with relapsed ATL. The current phase II study evaluated the efficacy and safety of lenalidomide monotherapy in patients with relapsed or recurrent ATL.

Patients and Methods: Patients 20 years of age or older with acute, lymphoma, or unfavorable chronic subtype ATL, who had received one or more prior anti-ATL systemic chemotherapy and achieved stable disease or better on their last anti-ATL therapy with subsequent relapse or recurrence, were eligible. Patients received oral lenalidomide 25 mg/d continuously until disease progression or unacceptable toxicity. The primary end point was overall response rate; secondary end points included safety,  tumor control rate (stable disease or better), time to response, duration of response, time to progression, progression-free survival, and overall survival.

Results: Objective responses were noted in 11 of 26 patients (overall response rate, 42%; 95% CI, 23% to 63%), including four complete responses and one unconfirmed complete response. The tumor control rate was 73%. The median time to response and duration of response were 1.9 months and not estimable, respectively, and the median time to progression was 3.8 months. The median progression-free survival and overall survival were 3.8 and 20.3 months, respectively. The most frequent grade$ 3 adverse events were neutropenia (65%), leukopenia (38%), lymphopenia (38%), and thrombocytopenia (23%), which were all manageable and reversible.

Conclusion: Lenalidomide demonstrated clinically meaningful antitumor activity and an acceptable toxicity profile in patients with relapsed or recurrent aggressive ATL, hinting at its potential to become a treatment option. Further investigations of lenalidomide in ATL and other mature T-cell neoplasms are warranted.