New antibody giving Rituxan a run for the money?

Rituxan (rituximab), the anti-CD20 monoclonal antibody from Roche, has carried the market since it was approved in 1998, and significantly changed the lives of hundreds of thousands of lymphoma patients, contributing to substantially longer survival times in even some of the toughest B-cell subtypes.

But that's no reason to slack off, and according to an abstract presented at this year's ASH meeting, there could be a new player: Obinutuzumab (previously known as GA101), like Rituxan an anti-CD20 monoclonal antibody, currently in development. The difference between the two is that obinutuzumab has been engineered for increased antibody-dependent cell-mediated cytotoxicity.

In short, it's been designed to have higher cell-killing efficacy.

Obinutuzumab has become the first monoclonal antibody to take on Rituxan head-to-head in a clinical trial, an open-label phase II study of 175 patients with relapsed indolent non-Hodgkin's lymphoma (149 of them had follicular lymphoma).

Although these results are preliminary, researchers from the University of British Columbia in Vancouver reported at ASH that the FL patients on obinutuzumab had a response rate of 44.6%, compared with those on Rituxan, 33.3%. Complete remission rates were also higher in the obinutuzumab group.

While this is all promising, it should be noted that the study was funded by the pharmaceutical company developing obinutuzumab and that several of the researchers reported having financial links with many other such companies.

Source

Sehn LH, et al "Randomized phase II trial comparing GA101 (Obinutuzumab) with rituximab in patients with relapsed CD20+ indolent B-Cell non‑Hodgkin lymphoma: preliminary analysis of the GAUSS study" ASH 2011; Abstract 269.