Low‐dose alemtuzumab in refractory/relapsed chronic lymphocytic leukemia: Genetic profile and long‐term outcome from a single center experience

Relapsed/refractory chronic lymphocytic leukemia (CLL) represents a clinical challenge, in particular when high risk gene mutations occur. In this setting, alemtuzumab was recognized to be effective. This retrospective study evaluates long‐term efficacy and tolerability of low‐dose alemtuzumab in relapsed/refractory CLL and correlates clinical outcome with biological feature. Sixty‐two consecutive patients (median age 68 years) were evaluated; alemtuzumab was administered 30 mg weekly for up to 18 weeks. Among the patients included in the analysis, 37% were fludarabine‐refractory, 33.3% carried a TP53 disruption, 14.8% a NOTCH1 mutation and 9% a SF3B1 mutation. Overall response rate (ORR) was 61.3% (complete remission 25.8%). After a median follow‐up of 43 months, overall survival (OS) and progression free survival (PFS) were 43.1 and 15 months, respectively; while ORR was 77.8% for patients carrying TP53 disruptions (OS 33.8 months) and 43.5% for fludarabine‐refractory patients (OS 30 months). Noteworthy, long‐term survivors (OS ≥ 36 months) were 54.8%. None of the biological poor risk factors negatively impacted on ORR, PFS and OS. Grade ≥3 cytopenia occurred in 24.2% patients, 6.5% experienced a grade ≥3 non‐CMV infection and no grade ≥3 CMV‐event occurred. In conclusion, low dose‐alemtuzumab is safe and effective in relapsed/refractory CLL, also in a long‐term follow‐up and high‐risk genetic subgroups. Am. J. Hematol. 90:970–974, 2015. © 2015 Wiley Periodicals, Inc.