The IV formulation of fludarabine phosphate is an effective treatment in patients with B-cell chronic lymphocytic leukemia (B-CLL), yielding overall response rates of 60% to 80%. An oral formulation of fludarabine phosphate has been developed. In a previously published multicenter, open-label, phase II clinical trial, 81 previously untreated B-CLL patients received 10-mg tablets of fludarabine phosphate (Fludara® oral) 40 mg/m2/day for 5 days, repeated every 4 weeks. The primary endpoint of the trial was response rate, and secondary endpoints included safety and quality of life assessments. Of 81 patients (mean age, 61.2 years; range, 30–75 years) with previously untreated B-CLL, 81.5% were classified as Binet stage B or C. The overall response rate (complete response [CR] + partial response [PR]) using National Cancer Institute (NCI) criteria was 80.2% (12.3% CR and 67.9% PR) and the median time to progression was 841 days (range, 28–1,146 days) (
Rossi JF, et al. J Clin Oncol 2004;22:1260–1267
). The most frequently reported grade 3/4 adverse event was myelosuppression: WHO grade 3/4 hematologic toxicities included granulocytopenia (32.1%), anemia (9.9%), and thrombocytopenia (4.9%). This analysis reports on the long-term follow-up of this cohort during the period from November 2001 to November 2004. Of the 74 patients eligible for the survival analysis, 61 were also assessed for duration of response using NCI criteria: 9 CR (14.8%) and 52 PR (82.2%). During the 3-year follow-up period, 22 (29.7%) patients did not progress. For those who progressed, median time to progression was 29.7 months, and median duration of response was 22.9 months. In 41 (80.4%) of these patients, an increase in circulating lymphocytes was reported as evidence of disease progression. In 23 patients (45.1%), an increase in the sum of the products of at least 2 lymph nodes and/or appearance of new palpable nodes was reported as evidence of disease progression. During the indicated follow-up period, 37 patients (50%) received subsequent treatment. Twelve patients (16.2%) died during the follow-up period: 7 patients (58.3%) due to disease progression, 3 patients (25.0%) due to adverse events, and 2 patients (16.7%) due to other causes. Results from this study suggest that oral fludarabine phosphate is clinically effective and well tolerated by patients with previously untreated B-CLL. Moreover, these data demonstrate that oral fludarabine phosphate achieves response rates and duration of response comparable to those achieved with first-line fludarabine phosphate IV therapy.
