Background: Mantle cell lymphoma (MCL) is an unfavorable subtype of B-cell non-Hodgkin lymphoma characterized by median progression-free survival (PFS) and median overall survival (OS) of only 1.5 and 3–4 years respectively. Although high-dose therapy and an autotransplant may prolong OS, it does not result in a long-term disease free survival. Therefore, there is a need for novel therapeutic approaches for this entity.
Methods: We conducted a single-arm phase II study in subjects with newly-diagnosed MCL to assess efficacy and safety of a novel intensive regimen R-MACLO-IVAM-T, a modification of a protocol designed by Magrath et al (
Results: Accrual started in 4/2004 and ended in 3/2008 when the planned 22 subjects were enrolled. All subjects were evaluable for toxicity and 21 were evaluable for response. Median age was 56.5 years (range 39–73). All subjects had at least stage 3 disease with bone marrow involvement in 19 and gastrointestinal involvement in 10. Distribution according to IPI: 0–1 factor, 3; 2 factors, 8; 3 factors, 8; and 4 factors, 3. Twenty subjects had diffuse variant and 2 had blastic variant. Nineteen subjects completed all 4 cycles of therapy; treatment was stopped in 2 subjects after 2 and 3 cycles respectively, and one subject died during the first cycle. Of the 21 subjects completing 2 cycles of therapy, 20 achieved CR and one PR. Two subjects relapsed at 9 and 33 months respectively, while 19 remain relapse free after median follow-up of 25 months (range 5–51). With a total follow-up of 545 months, the estimated relapse rate is 4.4 per 100 patients per year. There were two deaths: 1 from sepsis on cycle 1 day 8 and the other in CR at 38 months from non-small cell lung cancer diagnosed 19 months after MCL. Common severe toxicities were grade 3–4 neutropenia, thrombocytopenia and anemia in 33%, 19% and 17% of R-MACLO cycles and in 50%, 88% and 68% of R-IVAM cycles respectively. There were 14 bacteremias in 82 cycles, 12 of which were after R-IVAM therapy. Six episodes of reversible grade 1–2 renal toxicity occurred after methotrexate. The thalidomide maintenance dose was reduced in 6 subjects due to grade 3–4 neutropenia and reduced or stopped in 8 subjects because of grade 3–4 peripheral neuropathy. Patients remain under follow-up for relapse and survival.
Conclusions: R-MACLO-IVAM-T results in a high overall response rate of 100% (95% CR and 5% PR) and a low relapse rate. At a median follow-up of 25 months, median PFS and OS were not reached. The 2-year actuarial PFS of 94% compares favorably with previously reported 2-year actuarial PFS of 40% and 67% for CHOP-like regimens without and with upfront bone marrow transplantation (