Chronic Lymphocytic Leukemia Coverage from Every Angle

Chemoimmunotherapy vs Chemotherapy in CLL: 5-Year Follow-up of Complement 1 Trial

By: Celeste L. Dixon
Posted: Monday, May 11, 2020

Chlorambucil is the preferred treatment of elderly patients with chronic lymphocytic leukemia (CLL) who cannot tolerate fludarabine, cyclophosphamide, and rituximab. In the phase III Complement 1 trial, Fritz Offner, MD, PhD, of University Hospital Ghent, Belgium, and colleagues have been investigating the benefit of adding the monoclonal antibody ofatumumab to the front-line chlorambucil treatment in this population. The trial’s 5-year results, published in the British Journal of Haematology, support the primary analysis findings: Compared with chlorambucil monotherapy, the combination demonstrates clinical benefit and tolerability, with no new safety concerns.

The overall and progression-free survival final analyses were similar to the earlier findings. “On long‐term follow‐up in the chemoimmunotherapy arm versus the chemotherapy arm, there was an estimated 12% (not significant) and 39% risk reduction overall and progression-free survival, respectively,” declared the authors. However, “a high rate (61%) of treatment with next‐line therapies in both treatment arms may dilute any potential overall survival difference and confound the interpretation of the overall survival results.”

Of note, however, is that of the study’s original 447 patients, split about evenly between the arms, just 19 patients (4%) completed the 5-year follow-up. Three-quarters of patients completed the initial treatment phase; ultimately, 183 patients (41%) died, and 245 (55%) withdrew from the study. However, other reports with small sample sizes, Dr. Offner and co-investigators reminded, “also support the overall efficacy for use of chemoimmunotherapy regimens.”

In the final analysis, overall survival for the chemoimmunotherapy versus chemotherapy arms was 38% versus 44%, respectively (12% reduction in the risk of death; P = .363). Estimated overall survival at 5 years was 68.5% versus 65.7%, respectively. The median progression-free survival was 23.39 months versus 14.72 months in the chemoimmunotherapy and chemotherapy arms, respectively (estimated 39% risk reduction; P < .001).

Disclosure: The study authors’ disclosure information can be found at

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