Roche will be pleased with news that its experimental leukaemia drug GA101 significantly improved progression free survival in patients in late-stage clinical trials, raising hopes of a follow-up to is flagship drug MabThera/Rituxan.

The Swiss drug giant's biotech arm Genentech has unveiled Phase III data showing that GA101 (obinutuzumab) hit its primary goal by reducing the risk of disease worsening and death in patients with chronic lymphocytic leukaemia (CLL) compared with those treated with just the chemotherapy chlorambucil.

It is hoped that the success of GA101 could help cushion the blow facing the drugmaker from biosimilar versions of its biggest selling drug MabThera/Rituxan, which could take large bites out of the drug's current $7 billion annual sales as a treatment for cancer and arthritis.

GA101 has been specifically designed as the first glycoengineered, type 2 anti-CD20 monoclonal antibody in development for B-cell malignancies. In preclinical trials, the drug has shown evidence of increased direct cell killing and antibody-dependent cellular cytotoxicity, the firm said.

According to Roche, there are indications that GA101 may even outperform its predecessor as a first-line treatment for CLL, but all should become clear when its two drugs go head-to-head in a trial in the next stage of the clinical development programme.

A full set of data from the trial will be submitted for presentation at an upcoming medical meeting, as well as European and US authorities for potential approval.