Monday, December 20, 2010

Bendamustine Continues to Impress

This month, some new trial data came available that continues to illustrate the advantages of the "new" alkylating agent bendamustine (Treanda). Bendamustine is a nitrogen mustard agent that was developed in East Germany in the 1960s. Despite being a very old communist drug, it is now a very new capitalist drug, with the price tag and brand name to boot. It's effective enough that there are now a number of trials looking at whether bendamustine can stand in for the more conventional chemotherapy regimens like CHOP (in combination, of course, with new drugs of choice like rituximab).

In Canada, there are currently five ongoing clinical trials involving bendamustine that are looking for test subjects with lymphoma. These include an ofatumumab trial in refractory patients (bendamustine versus O-B), a GA101 study in refractory patients (bendamustine versus B-GA101) the major BRIGHT Study for new patients (B-R going head to head with the older standbys, R-CHOP and R-CVP). A sixth trial is looking at bendamustine in childhood leukemia patients.
In this month's issue of Clinical Lymphoma, Myeloma & Leukemia, Georgetown researcher Bruce Cheson et al. look at results from two recent American trials involving 161 patients with relapsed or refractory (resistant) indolent lymphoma following prior rituximab regimens. About two-thirds of the patients had follicular lymphoma. They were given 6-8 cycles of bendamustine monotherapy, which had a response rate of 76%, including 23% complete responses (remission). Unfortunately most of these were not long-lasting remissions: half lasted 10 months or less, and about one-quarter survived two years progression-free. Still, it does suggest the communists got something right.

The recent American Society of Hematology (ASH) Conference also featured a paper by Matthias Rummel et al., researchers in Germany, on the benefits of bendamustine in relapsed patients, this one involving combination bendamustine-rituximab therapy. They enrolled 219 patients with relapsed follicular and mantle cell lymphoma in 2003 (about 2/3 of whom had Stage IV disease), and randomized them to receive either rituximab and bendamustine, or rituximab and fludarabine (Fludara), a purine analog. The "B-R" regimen had a higher overall response rate (84%-52%), a higher complete remission rate (38%-16%), and a higher median progression-free survival (30 months-11 months).

I have only the abstract to work with at the moment, but some further comments on this study are necessary. This study reads as a straight-up comparison of bendamustine and fludarabine, with bendamustine winning (summary: the German drug wins, say the Germans). The abstract doesn't indicate whether the patients in this study had relapsed after rituximab; this would be the norm if a study started today, but in 2003, it would be reasonable to guess that at least some eligible patients would not have had rituximab before. Whether this might affect the results, and how, is difficult to say for certain.

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