Janssen's Imbruvica (ibrutinib) has been approved in Europe as a treatment for two rare blood cancers.

The European Commission gave the drug the green light for its use in adults with relapsed or refractory mantle cell lymphoma (MCL), or chronic lymphocytic leukaemia (CLL).

In the case of CLL, patients must have received at least one prior therapy, or for first-line use in patients unsuitable for chemo-immunotherapy they must have either the 17p deletion or TP53 mutation chromosomal abnormality.

Jane Griffiths, company group chairman for Janssen, Europe, Middle East and Africa (EMEA), said: "We are delighted the European Commission has approved Imbruvica as a new treatment approach, which could prolong the lives of patients with these complex blood cancers.

"This is a positive step forward for patients, and Janssen is committed to looking into further areas of unmet need in blood cancers where Imbruvica could improve outcomes."

The first-in-class once-daily pill is a Bruton's tyrosine kinase (BTK) inhibitor that woks by blocking BTK, a protein that helps certain cancer cells live and grow.

The approval of Imbruvica, which has orphan drug status in Europe, was based on the phase III RESONATE study in CLL, which compared oral Imbruvica to GlaxoSmithKline's Arzerra (ofatumumab) given intravenously.

Janssen said its drug saw progression-free survival (PFS) results that represented a 78% reduction in the risk of progression or death compared to Arzerra; and a 57% reduction in the risk of death in patients receiving Imbruvica versus those receiving Arzerra.

Meanwhile, in a phase II study in relapsed or refractory MCL, Imbruvica was associated with an overall response rate of 68%, a complete response rate of 21% and a partial response rate of 47%.

The drug's most common side effects include pneumonia, upper respiratory tract infection and sinusitis, and as part of Imbruvica's approval Janssen will implement a pharmacovigilance plan for the drug.

Imbruvica was co-developed by Janssen and Pharmacyclics Switzerland - which will have co-marketing rights to the drug in the US, where it is approved in both MCL and CLL.