Imatinib and pegylated IFN-α2b discontinuation in first-line chronic myeloid leukemia patients following a major molecular response.

OBJECTIVES: Previous studies indicate that 40-50% of patients with chronic myeloid leukemia in prolonged complete molecular remission may discontinue imatinib therapy without imminent relapse. The combination of pegylated interferon-alpha (Peg-IFN-α2b) and imatinib may increase the rate of successful discontinuation. METHODS: In this pilot study, we prospectively stopped imatinib from patients (n = 12) who had achieved major molecular response (MMR) after ≥12 months of treatment with either imatinib or imatinib+Peg-IFN-α2b. Molecular monitoring was carried out monthly for BCR-ABL1. In addition, analyses of lymphocyte immunophenotype, function, and plasma cytokines were performed. RESULTS: In the monotherapy group, 5/6 patients lost MMR within 4 months. One patient remains to date in MR(4.0) 61 months after discontinuation. In the combination therapy group, 2/6 patients relapsed within 4 months while still receiving Peg-IFN-α2b. Four of six patients were able to discontinue both treatments, but three of these patients relapsed after 3 months. One patient is still in sustained MR(4.0) at 58 months off all treatment. All relapsed patients re-responded to imatinib. The two successfully discontinued patients had either an increased number of NK-cells or functionally active T-cells. CONCLUSIONS: A higher frequency of relapsed patients in our study in comparison with other studies may be due to the shorter duration of imatinib treatment prior to discontinuation. However, in selected patients with an active immune system, even a short duration of TKI therapy (<2 yr) may allow for therapy discontinuation but this needs to be confirmed in larger prospective studies.

Prolonged immunochemotherapy with rituximab, cytarabine and fludarabine added to cyclophosphamide, doxorubicin, vincristine and prednisolone and followed by rituximab maintenance in untreated elderly patients with mantle cell lymphoma: a prospective study by the Finnish Lymphoma Group.

There is no consensus on treatment strategies for elderly patients with mantle cell lymphoma (MCL). In this prospective phase II study we investigated whether the poor outcome could be improved, with reasonable toxicity, by prolonging the immunochemotherapy. Ten cycles of alternating cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP)/cytarabine (AraC) with eight doses of rituximab (R) were given as induction. The potential synergism of intermediate-dose AraC and fludarabine was tested in cycles 6-8. Induction was followed by bimonthly rituximab maintenance for 2 years. The median age of the 60 included patients was 74 years, and the Mantle Cell Lymphoma International Prognostic Index (MIPI) was intermediate or high risk in 98% of the patients. The overall response rate was 95% (complete response/complete response unconfirmed 87%). The response of 11 patients improved with cycles 6-8 (R-fludarabine-AraC). Progression-free survival was 70% and overall survival 72% at 4 years, respectively. Treatment related mortality was 2%. Severe infections were rare, with only one grade 4 infection. More dose reductions were needed during fludarabine-containing courses as compared to R-AraC. In 20 patients a transient grade 4 neutropenia without severe infections was recorded during maintenance. In conclusion, elderly patients with MCL can be treated relatively intensively with acceptable toxicity.