Addition of rituximab to fludarabine may prolong progression-free survival and overall survival in patients with previously untreated chronic lymphocytic leukemia: an updated retrospective comparative analysis of CALGB 9712 and CALGB 9011.

Fludarabine and rituximab combination therapies in chronic lymphocytic leukemia (CLL) have yielded promising early results, but no comparative efficacy data relative to standard fludarabine treatment regimens have been reported. To assess the effect of the addition of rituximab to fludarabine therapy, we retrospectively compared the treatment outcome of patients with similar clinical characteristics enrolled on 2 multicenter clinical trials performed by the Cancer and Leukemia Group B and the US Intergroup that used fludarabine and rituximab (CALGB 9712, n = 104) or fludarabine (CALGB 9011, n = 178). In multivariate analyses controlling for pretreatment characteristics, the patients receiving fludarabine and rituximab had a significantly better progression-free survival (PFS; P < .0001) and overall survival (OS; P = .0006) than patients receiving fludarabine therapy. Two-year PFS probabilities were 0.67 versus 0.45, and 2-year OS probabilities were 0.93 versus 0.81. Infectious toxicity was similar between the 2 treatment approaches. These comparative data are retrospective and could be confounded by differences in supportive care or dissimilar enrollment of genetic subsets on each trial. Confirmation of these findings will require a prospective randomized trial comparing fludarabine and rituximab to fludarabine.

Phase II study of all-trans retinoic acid in the accelerated phase or early blastic phase of chronic myeloid leukemia: a study of the Eastern Cooperative Oncology Group (E1993).

The aims of this study were to evaluate the safety and efficacy of all-trans retinoic acid (ATRA) in the treatment of the accelerated and blastic phase of chronic myeloid leukemia (CML) and to evaluate in vitro correlates of biological activity. ATRA was administered in an intermittent schedule to patients with CML in the accelerated or blastic phases for a 6 week induction period, which was continued if there was evidence of clinical response or stable disease. If the patient was progressing at 6 weeks, interferon-alpha could be added to the ATRA. Laboratory correlative studies were performed prior to treatment and at intervals during treatment to evaluate effects on maturation and differentiation, and on CML progenitor cell growth by assessment of colony-forming cells (CFC). Eighteen patients were enrolled. There was 1 complete response, 1 partial response and 2 with hematological improvement. A fifth patient was stable on ATRA and interferon for several months. Laboratory data for the responders demonstrated high sensitivity of primary CFC to ATRA prior to treatment and low serial CFC counts on ATRA therapy. ATRA demonstrated clinical and hematological activity in 5 of 18 patients with the accelerated phase of CML, and there was evidence of a biological effect in laboratory studies of 3 of the 5 patients' progenitor cells. Combination therapy with other differentiating agents may be useful in this disease.

Therapy-related myeloid leukemias are observed in patients with chronic lymphocytic leukemia after treatment with fludarabine and chlorambucil: results of an intergroup study, cancer and leukemia group B 9011.

PURPOSE: Patients with chronic lymphocytic leukemia (CLL) may have disease transformation to non-Hodgkin's lymphoma or prolymphocytic leukemia; however, development of therapy-related acute myeloid leukemia (t-AML) is unusual. A series of patients enrolled onto an intergroup CLL trial were examined for this complication. PATIENTS AND METHODS: A total of 544 previously untreated B-cell CLL patients were enrolled onto a randomized intergroup study comparing treatment with chlorambucil, fludarabine, or fludarabine plus chlorambucil. Case report forms from 521 patients were reviewed for t-AML. RESULTS: With a median follow-up of 4.2 years, six patients (1.2%) to date have developed therapy-related myelodysplastic syndrome (t-MDS; n = 3), t-AML (n = 2), or t-MDS evolving to t-AML (n = 1), from 27 to 53 months (median, 34 months) after study entry. This included five (3.5%) of 142 patients treated with fludarabine plus chlorambucil and one (0.5%) of 188 receiving fludarabine; no chlorambucil-treated patients developed t-MDS or t-AML (P =.007). At study entry, the median age among these six patients was 56 years (range, 44 to 72 years); three were male; the CLL Rai stage was I/II (n = 4) or III/IV (n = 2). Response to CLL therapy was complete (n = 4) or partial remission (n = 1) and stable disease (n = 1). Marrow cytogenetics, obtained in three of six cases at diagnosis of t-MDS or t-AML, were complex, with abnormalities in either or both chromosomes 5 and 7. Other abnormalities involved chromosomes X, 1, 8, 12, 17, and 19. Median survival after diagnosis of t-MDS/AML was 3.5 months (range, 0.5 to 10.1 months). CONCLUSION: Our findings raise the possibility that alkylator-purine analog combination therapy may increase the risk of therapy-related myeloid malignancies, which is of particular relevance with regard to ongoing trials using these combination therapies.