Evaluating lenalidomide-rituximab treatment for follicular lymphoma

This study looked at the effectiveness of rituxumab (Rituxan) with lenalidomide (Revlimid) for untreated follicular lymphoma (FL). It found that this treatment was more effective than rituxumab with chemotherapy. They also found that blood tests of trace FL can predict outcomes.

Follicular lymphoma (FL) is a slow-growing type of non-Hodgkin lymphoma. FL cannot be cured, and will repeatedly relapse after treatment. However, FL can be managed for years.

The relapse of FL is related to a small number of cancerous FL cells remaining after treatment, which eventually move into the bloodstream. For FL with certain mutations (abnormal genes), scientists can measure this residual FL. To do this, they use polymerase chain reaction (PCR). This technology can locate a specific segment of DNA (genetic material) and copy it repeatedly. Using PCR, a blood or bone marrow sample can be tested for a genetic mutation of the FL. If it comes back positive, this is known as minimal residual disease (MRD). MRD is an indication that a small amount of FL is remaining after treatment. However, even when there is no detectable MRD it is still possible that not all of the FL is gone.

Rituximab is an antibody therapy. Rituximab with chemotherapy (R-chemo) is a standard initial treatment for FL. Lenalidomide is an immunotherapy drug used in several blood cancers, including FL. The combination of rituximab and lenalidomide (R-len) can avoid chemotherapy-related side effects. It is not clear whether R-len is as effective as R-chemo in patients with untreated FL.

This study included 222 patients with previously untreated FL. Almost all (96%) patients had advanced disease (stage III or IV). 122 patients received R-len for 18 cycles. The other 100 patients received R-chemo as a comparison. Almost all (99) of these patients received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). All patients received maintenance with rituximab. All of the FL had a known mutation, and MRD was tested initially and after treatment at 24 weeks. Patients were followed for 3 years.

After 24 weeks, 98% of patients had no MRD in the blood and 78% had no MRD in the bone marrow. Patients without MRD in the blood at 24 weeks were significantly less likely to have the cancer return within 3 years. 84% of patients without MRD had no signs of cancer, compared to 55% of those with MRD. The results for bone marrow MRD were similar.

Patients taking R-len achieved no detectable MRD more often than those taking R-chemo (90% vs. 77%).

This study concluded that R-len is at least as effective as R-chemo. It also found that MRD is a useful prognosis test for patients with FL with a detectable mutation.

The mutation used in this study, BCL2-JH, is more easily detected in the blood for patients with advanced disease. MRD testing may not be useful for patients with less advanced FL.