Michael Unterhalt

There is no generally established prognostic index for patients with mantle cell lymphoma (MCL), because the International Prognostic Index (IPI) and Follicular Lymphoma International Prognostic Index (FLIPI) have been developed for diffuse large cell and follicular lymphoma patients, respectively. Using data of 455 advanced stage MCL patients treated within 3 clinical trials, we examined the prognostic relevance of IPI and FLIPI and derived a new prognostic index (MCL international prognostic index, MIPI) of overall survival (OS). Statistical methods included Kaplan-Meier estimates and the log-rank test for evaluating IPI and FLIPI and multiple Cox regression for developing the MIPI. IPI and FLIPI showed poor separation of survival curves. According to the MIPI, patients were classified into low risk (44% of patients, median OS not reached), intermediate risk (35%, 51 months), and high risk groups (21%, 29 months), based on the 4 independent prognostic factors: age, performance status, lactate dehydrogenase (LDH), and leukocyte count. Cell proliferation (Ki-67) was exploratively analyzed as an important biologic marker and showed strong additional prognostic relevance. The MIPI is the first prognostic index particularly suited for MCL patients and may serve as an important tool to facilitate risk-adapted treatment decisions in patients with advanced stage MCL.

PURPOSE: Mantle cell lymphoma (MCL) is characterized by a poor prognosis with a low to moderate sensitivity to chemotherapy and a median survival of only 3 to 4 years. In an attempt to improve outcome, the German Low Grade Lymphoma Study Group (GLSG) initiated a randomized trial comparing the combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) and rituximab (R-CHOP) with CHOP alone as first-line therapy for advanced-stage MCL. PATIENTS AND METHODS: One hundred twenty-two previously untreated patients with advanced-stage MCL were randomly assigned to six cycles of CHOP (n = 60) or R-CHOP (n = 62). Patients up to 65 years of age achieving a partial or complete remission underwent a second randomization to either myeloablative radiochemotherapy followed by autologous stem-cell transplantation or interferon alfa maintenance (IFNalpha). All patients older than 65 years received IFNalpha maintenance. RESULTS: R-CHOP was significantly superior to CHOP in terms of overall response rate (94% v 75%; P = .0054), complete remission rate (34% v 7%; P = .00024), and time to treatment failure (TTF; median, 21 v 14 months; P = .0131). No differences were observed for progression-free survival. Toxicity was acceptable, with no major differences between the two therapeutic groups. CONCLUSION: The combined immunochemotherapy with R-CHOP resulted in a significantly higher response rate and a prolongation of the TTF as compared with chemotherapy alone. Hence, R-CHOP may serve as a new baseline regimen for advanced stage MCL, but needs to be further improved by novel strategies in remission.

BACKGROUND: The long-term prognosis for older patients with mantle-cell lymphoma is poor. Chemoimmunotherapy results in low rates of complete remission, and most patients have a relapse. We investigated whether a fludarabine-containing induction regimen improved the complete-remission rate and whether maintenance therapy with rituximab prolonged remission. METHODS: We randomly assigned patients 60 years of age or older with mantle-cell lymphoma, stage II to IV, who were not eligible for high-dose therapy to six cycles of rituximab, fludarabine, and cyclophosphamide (R-FC) every 28 days or to eight cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) every 21 days. Patients who had a response underwent a second randomization to maintenance therapy with rituximab or interferon alfa, each given until progression. RESULTS: Of the 560 patients enrolled, 532 were included in the intention-to-treat analysis for response, and 485 in the primary analysis for response. The median age was 70 years. Although complete-remission rates were similar with R-FC and R-CHOP (40% and 34%, respectively; P=0.10), progressive disease was more frequent with R-FC (14%, vs. 5% with R-CHOP). Overall survival was significantly shorter with R-FC than with R-CHOP (4-year survival rate, 47% vs. 62%; P=0.005), and more patients in the R-FC group died during the first remission (10% vs. 4%). Hematologic toxic effects occurred more frequently in the R-FC group than in the R-CHOP group, but the frequency of grade 3 or 4 infections was balanced (17% and 14%, respectively). In 274 of the 316 patients who were randomly assigned to maintenance therapy, rituximab reduced the risk of progression or death by 45% (in remission after 4 years, 58%, vs. 29% with interferon alfa; hazard ratio for progression or death, 0.55; 95% confidence interval, 0.36 to 0.87; P=0.01). Among patients who had a response to R-CHOP, maintenance therapy with rituximab significantly improved overall survival (4-year survival rate, 87%, vs. 63% with interferon alfa; P=0.005). CONCLUSIONS: R-CHOP induction followed by maintenance therapy with rituximab is effective for older patients with mantle-cell lymphoma. (Funded by the European Commission and others; ClinicalTrials.gov number, NCT00209209.).

In follicular lymphoma (FL) and mantle cell lymphoma (MCL) the monoclonal antibody rituximab (R) improves the prognosis when combined with chemotherapy. The present study investigated R-maintenance after R-chemotherapy. Patients with recurring or refractory FL and MCL were randomized to 4 courses of fludarabine, cyclophosphamide, and mitoxantrone (FCM) alone or combined with R (R-FCM). Responding patients underwent a second randomization for R-maintenance comprising 2 further courses of 4-times-weekly doses of R after 3 and 9 months. The first randomization was stopped after 147 patients, when R-FCM revealed a significantly better outcome. All subsequent patients received R-FCM. Of the 176 patients who are currently evaluable (as of October 2005), 138 received R-FCM for remission induction. Response duration was significantly prolonged by R-maintenance after R-FCM, with the median not being reached in this evaluation versus an estimated median of 16 months (P = .001). This beneficial effect was also observed when analyzing FL (P = .035) and MCL (P = .049) separately. Hence, R-maintenance is effective after salvage with R-chemotherapy and significantly prolongs response duration in patients with recurring or refractory FL or MCL.