Roche said final data from a late-stage trial continue to suggest that its Rituxan follow-up, GA101, could be a franchise-extender for the firm. When used with chlorambucil (a chemotherapy agent), GA101 helped people with chronic lymphocytic leukemia (CLL) live significantly longer without disease-worsening than did Rituxan plus chlorambucil. The full data are slated to be made available at a meeting later this year.

The sneak peek came from a pre-planned interim analysis of Roche’s Phase III trial dubbed CLL11, one of three Phase III head-to-head trials the company is running to show that the therapy has superior efficacy to older drug Rituxan.

It follows release of data from stage one of the same trial just two months ago. GA101 was fast-tracked by FDA for CLL after those data showed that GA101 plus chemotherapy reduced the risk of disease progress more than Rituxan plus chemotherapy, and that median progression-free survival (PFS) for GA101 with chlorambucil improved to 23 months vs. 10.9 months with chlorambucil alone.

Based on that earlier analysis, marketing applications for GA101 were submitted to regulatory bodies in the US and EU in April 2013. In addition to priority review, the FDA granted the GA101 application Breakthrough Therapy Designation. 

Today’s news came as another good sign. “These very strong results in CLL bode well for a potential efficacy in other types of blood cancer,” said Odile Rundquist, a Geneva-based analyst at Helvea AG, as reported by Bloomberg.

The other two Phase III trials are testing the drug in diffuse large B-cell lymphoma (DLBCL) and first-line, indolent non-Hodgkin’s lymphoma (iNHL).

Still, GA101 has big shoes to fill. Rituxan brought in approximately $7 billion for Roche last year and faces patent expiry in 2014. Both Novartis/Sandoz and Boehringer Ingelheim have biosimilars of Rituxan in the pipeline, with Phase III trials of each expected to end in 2014 and 2015, respectively.