Rituximab useful for advanced indolent lymphoma

A new study has found for the first time that maintenance therapy with the novel antibody, rituximab (MR) following cyclophosphamide, vincristine and prednisone (CVP) therapy improves progression-free survival in patients with stage III-IV indolent lymphoma, according to Howard S. Hochster, M.D. of NYU Langone Medical Center, lead author of a recent study published online ahead of print in the Journal of Clinical Oncology.

In a study, sponsored by the National Institutes of Health and conducted by the Eastern Cooperative Oncology Group (ECOG) titled, "Maintenance Rituximab After Cyclophosphamide, Vincristine, and Prednisone Prolongs Progression-Free Survival in Advanced Indolent Lymphoma: Results of the Randomized Phase III ECOG1496 Study," researchers looked at 311 patients with stable or responding disease after CVP therapy. The patients were randomly assigned to observation only or a maintenance rituximab (MR) 375 mg/square meter once per week for 4 weeks every 6 months for 2 years. Results are the first phase III data showing patients with untreated indolent lymphoma can be given (MR) after chemotherapy with minimal toxicity to prevent relapse.

"Low grade lymphoma is very treatable, with patients living many years on the average," says Howard Hochster, M.D. professor of medicine and clinical pharmacology at NYU School of Medicine and director of gastrointestinal oncology and early drug development at the NYU Cancer Institute. "But no one treatment to date has been able to show benefit on long term survival. This reasonably non-toxic antibody can improve disease free survival by several years and possibly effect overall survival. In this group of patients, even 10 years of observation is a little too soon to show survival benefits, but the trend is present."

An improved disease response was seen in 22% of rituximab-treated patients versus just 7% of control subjects. Toxic effects were minimal in both groups. Three year progression-free survival was also higher in the MR group: 68% vs. 33% in controls. In the sub group of 282 patients with follicular lymphoma, the corresponding rates were 64% and 33%. With more than ten years follow-up, the patients receiving MR went nearly 5 years on average before relapse, compared with 1.9 years without .

According to the National Cancer Institute, lymphoma is a disease in which malignant cancer cells form in the lymph system. Indolent lymphoma includes several sub-types of lymphoma that tend to grow and spread slowly, and has few symptoms. It's also called low-grade lymphoma.

The anti-CD20 monoclonal antibody, rituximab was approved for use in follicular lymphoma and indolent lymphoma in 1997 for those no longer responding to chemotherapy. In this setting, the objective response rate was 48% and the agent had rare serious adverse effects, generally limited to infusional toxicity. On the basis of earlier trials, the E1496 study, is the first to test rituximab to maintain response to chemotherapy in indolent lymphoma. Observations from this most recent study add to a substantial body of evidence that the combination of rituximab with chemotherapy is a new standard for patients with indolent lymphoma who require treatment.

The National Cancer Institute funded this multi-center, national trial through ECOG, which began in 1997. Trial centers included the NYU Langone Medical Center in New York City, the Dana Farber Cancer Institute in Boston, Columbia Cancer Agency in Vancouver, the Mayo Clinic in Rochester, Northwestern University in Chicago, Stanford University in Stanford and the University of Maryland in Baltimore.

"This study has led to a new FDA indication for the use of rituximab as maintenance therapy in patients with indolent lymphoma," states Dr. Hochster.