US-based Gilead Sciences has received marketing authorisation from the European Commission for its Zydelig (idelalisib) 150mg tablets to treat two incurable blood cancers, chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL).

Zydelig is an oral inhibitor of phosphoinositide 3-kinase (PI3K) delta, which plays a key role in the activation, proliferation and viability of B cells, a critical component of the immune system.

Used in combination with rituximab, Zydelig is to be used to treat CLL patients, who have received at least one prior therapy or as first-line treatment in the presence of 17p deletion or TP53 mutation in patients unsuitable for chemo-immunotherapy.

It has received approval as a monotherapy to treat FL patients, who are refractory to two prior lines of treatment.

Gilead Sciences chairman and CEO John C. Martin said: "Zydelig represents an important therapeutic advance for patients living with CLL and FL.

"Gilead is pleased to be making a difference in the lives of people living with these blood cancers and we are committed to helping ensure timely access to the treatment for patients who may benefit from therapy."

The approval was based on data from a randomised, placebo-controlled Phase III trial (study 116) of Zydelig in combination with rituximab in 220 patients with relapsed CLL who were not able to tolerate standard chemotherapy.

In October 2013, the study 116 was stopped due to a highly statistically significant benefit in progression-free survival (PFS) in the Zydelig plus rituximab arm compared with the rituximab only treatment arm.