Roche's new blood cancer drug Gazyva has failed to show significant improvements versus veteran therapy MabThera/Rituxan in patients with previously untreated diffuse large B-cell lymphoma, marking a setback in plans to protect sales from biosimilar competition.

The Swiss drugmaker announced that the Phase III GOYA study assessing Gazyva/Gazyvaro (obinutuzumab) plus CHOP chemotherapy in people with previously untreated diffuse large B-cell lymphoma failed to meet its primary endpoint of significantly cutting the risk of progression-free survival (PFS) compared to MabThera/Rituxan (rituximab) plus CHOP chemotherapy.

Gazyva is an engineered monoclonal antibody designed to attach to CD20, a protein expressed on certain B cells, but not on stem cells or plasma cells. The drug is designed to attack and destroy targeted B-cells both directly and together with the body's immune system.

The firm was hoping to replicate findings from two previous studies showing that the drug boosted PFS in patients with previously untreated follicular lymphoma or chronic lymphocytic leukaemia compared to MabThera/Rituxan, when each was combined with chemotherapy.

"We will continue to analyse the GOYA data to better understand the results, and to study other investigational treatments in this disease with the goal of further helping these patients," said Sandra Horning, chief medical officer and head of Global Product Development at Roche.

The findings are a blow as showing that Gazyva is significantly better than MabThera/Rituxan would have given the drug a competitive edge over cheaper biosimilars of the latter drug.

Gazyva/Gazyvaro is currently approved in more than 70 countries in combination with chlorambucil, for people with previously untreated chronic lymphocytic leukaemia, and also in combination with combination with bendamustine to treat follicular lymphoma.

The firm said data it would present data from the GOYA study at an upcoming medical meeting.