Purpose: We conducted a randomized trial to evaluate the efficacy and safety of intravenous alemtuzumab compared with chlorambucil in first-line treatment of chronic lymphocytic leukemia (CLL).
Patients and methods: Patients received alemtuzumab (30 mg three times per week, for up to 12 weeks) or chlorambucil (40 mg/m(2) every 28 days, for up to 12 months). The primary end point was progression-free survival (PFS). Secondary end points included overall response rate (ORR), complete response (CR), time to alternative therapy, safety, and overall survival.
Results: We randomly assigned 297 patients, 149 to alemtuzumab and 148 to chlorambucil. Alemtuzumab had superior PFS, with a 42% reduction in risk of progression or death (hazard ratio [HR] = 0.58; P = .0001), and a median time to alternative treatment of 23.3 versus 14.7 months for chlorambucil (HR = 0.54; P = .0001). The ORR was 83% with alemtuzumab (24% CR) versus 55% with chlorambucil (2% CR); differences in ORR and CR were highly statistically significant (P < .0001). Elimination of minimal residual disease occurred in 11 of 36 complete responders to alemtuzumab versus none to chlorambucil. Adverse events profiles were similar, except for more infusion-related and cytomegalovirus (CMV) events with alemtuzumab and more nausea and vomiting with chlorambucil. CMV events had no apparent impact on efficacy.
Conclusion: As first-line treatment for patients with CLL, alemtuzumab demonstrated significantly improved PFS, time to alternative treatment, ORR and CR, and minimal residual disease-negative remissions compared with chlorambucil, with predictable and manageable toxicity.