Commentary on Abstract #2804

Mantle cell lymphoma is one of the most challenging of the NHLs. It exhibits the worst features of both the indolent and aggressive lymphomas. With its short survival of 2 ½ to 3 years, mantle cell lymphoma resembles an aggressive NHL, but, like the follicular lymphomas, it is not curable. Many chemotherapeutic regimens can induce transient responses in patients with mantle cell histology. Encouraging results have been observed with the hyperCVAD (hyperfractionated cyclophosphamide, vincristine, Adriamycin, and dexamethasone) regimen followed by stem-cell transplantation (Khouri et al: J Clin Oncol 16:3803-3809, 1998). Nevertheless, additional approaches are needed.

In a phase I/II study published in 1998, about 32% of patients with mantle cell lymphoma responded to single-agent rituximab given in a schedule that was more intensive schedule than the standard program (Coiffier et al: Blood 92:1927-1932, 1998). More recently, the results of a European phase II trial of rituximab (Foran et al: J Clin Oncol 18:317, 2000) that included 34 newly diagnosed and 40 previously treated patients with mantle cell lymphoma showed response rates of 38% and 37%, respectively, including 10 CRs. The median duration of response was 1.2 years. Also using single-agent rituximab, Winkler et al (abstract #4419; see page 22) achieved two complete remissions in four patients with mantle cell lymphoma that lasted 8+ and 19+ months, respectively.

Howard and coworkers (abstract #2804) accrued 40 patients with newly diagnosed mantle cell lymphoma to a protocol employing CHOP plus rituximab as initial treatment. The complete remission rate was 33%, with unconfirmed complete responses (CRu) in 15% of patients, and PRs in 48%. In almost half of the patients, there was no detectable bcl-1 rearrangement after therapy. The median progression-free survival was 16.2 months. Unfortunately, even those patients who achieved a molecular response relapsed.

Therefore, whereas rituximab may play a therapeutic role in mantle cell lymphoma, successful treatment of this disease remains a difficult problem.