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Alemtuzumab Too Toxic for CLL Therapy

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – After induction chemoimmunotherapy in previously untreated symptomatic patients with chronic lymphocytic leukemia (CLL), consolidation therapy with the monoclonal anti-CD52 antibody alemtuzumab (Campath-1H) improved complete response rates and reduced minimal residual disease — but led to a high risk of fatal infections.

The research group reporting these results, the Cancer and Leukemia Group B, has consequently decided not to conduct any more studies of alemtuzumab consolidation.

Dr. John C. Byrd of The Ohio State University, Columbus and colleagues note in the Journal of Clinical Oncology online August 9th that patients with CLL invariably relapse even with a complete response to induction therapy. “An important clinical question concerns the value of eliminating minimal residual disease (MRD)”

Alemtuzumab is approved for CLL, and preliminary studies showed it could eliminate residual disease after different induction therapies. The team studied the effect of consolidation therapy with alemtuzumab given 3 months after induction therapy with fludarabine and rituximab in 102 patients with CLL, with the hope that the 3-month interval would reduce toxicity.

After induction, the complete response rate was 29% and the partial response rate was 61%, for an overall response rate of 90%. The MDR-negative rate was 15%.

Fifty-eight of the patients received alemtuzumab. In this group, after alemtuzumab the overall response rate was 91% although the complete response rate increased to 66%, and 50% of the patients were MDR-negative.

However, five patients who had a complete response to induction therapy and received alemtuzumab consolidation died of infectious diseases, the first one 7 months after completing alemtuzumab therapy.

Furthermore, 2-year progression-free survival and overall survival were similar for patients who did and did not receive alemtuzumab.

“Given the toxicity and absence of clear survival benefit, CALGB will not pursue additional studies of alemtuzumab consolidation,” the authors state. They do point out that other novel therapeutic agents “are active in CLL and warrant clinical study as potential CLL consolidation therapies.”

Reference:

Consolidation Therapy With Subcutaneous Alemtuzumab After Fludarabine and Rituximab Induction Therapy for Previously Untreated Chronic Lymphocytic Leukemia: Final Analysis of CALGB 10101

Clin Oncol 2010;28.