NEW YORK (Reuters Health) – Results of two phase II trials investigating the addition of bortezomib to combination treatments of follicular lymphoma suggest that the strategy is feasible and effective, and the authors of the two reports in the Journal of Clinical Oncology online August 1 call for randomized studies.

However, “one may ask whether this is worthwhile,” writes Dr. Gilles Salles in a related editorial.

Dr. Salles, with Hospices Civils de Lyon and Universite Claude Bernard de Lyon, France, notes that survival with follicular lymphoma has been extended considerably over the last decade but new treatment options are needed. Proteasome inhibitors such as bortezomib have demonstrated broad anti-cancer activity but have shown variable effects in follicular lymphoma in numerous phase II studies.

In one of the two phase II trials currently reported in JCO, a multicenter team added bortezomib to bendamustine and rituximab (B-R) in the treatment of 73 patients with relapsed or refractory follicular lymphoma. Dr. Nathan Fowler, with MD Anderson Cancer Center in Houston, Texas, and his associates found that the overall response rate was 88%, including a complete response rate of 53%.

Still, notes Dr. Salles, “the estimated median response duration (12 months) and median progression-free survival (15 months) do not seem to have improved as compared with results achieved with B-R alone (21 months response duration and 23 months PFS, respectively).”

The second phase II trial being reported included 94 patients with previously untreated follicular lymphoma. Dr. Laurie Sehn with the BC Cancer Agency in Vancouver, British Columbia, Canada, and colleagues added bortezomib to a regimen of rituximab, cyclophosphamide, vincristine, and prednisone (R-CVP) and found this produced an overall response rate of 86%, including a 51% complete response.

Regarding this result, Dr. Gilles points out that it “does not seem to differ from that observed in 272 patients receiving R-CVP in the PRIMA (Primary Rituximab and Maintenance) study (53%).”

He suggests that response rates should have been better if bortezomib had in fact sensitized lymphoma cells to cytotoxic drugs. In the absence of more convincing indications that these combination regimens have potential benefit in follicular lymphoma, he concludes, “Other therapeutic options (eg, new antibodies, immunomodulatory agents, kinase inhibitors, and so on) may be considered higher priorities for clinical trials in the field.”

Reference:
Is There a Role for Bortezomib Combinations in the Management of Patients With Follicular Lymphoma?
J Clin Oncol 2011:29.