GlaxoSmithKline and Human Genome Sciences Benlysta (belimumab) has been awarded priority review status in the USA as a potential treatment for systemic lupus erythematosus. The target date for approval is 9 December 2010, six months after the biologic drug was filed.

The dossier includes the results of two pivotal Phase 3 clinical trials involving 1,684 patients with SLE. Benlysta is the first in a new class of drugs called BLyS-specific inhibitors to have completed Phase 3 trials with positive results, say the firms.

Indeed, the so-called BLISS-52 and BLISS-76 studies showed that the intravenous drug reduced disease activity when combined with current standard of care in patients with SLE and may make patients less vulnerable to flare-ups.

GSK submitted a Marketing Authorisation Application for belimumab to the European Medicines Agency (EMA) on 4 June 2010. In the USA, a priority review designation is granted to drugs that, if approved, offer major advances in treatment or provide a treatment where no adequate therapy exists. No new drug has been approved by regulatory authorities in more than 50 years.

SLE or lupus, is a chronic autoimmune disease of the connective tissue that can affect any part of the body, resulting in inflammation and tissue damage. It is estimated that 1.5 million people in the USA, and five million worldwide, suffer from various forms of lupus, including SLE.

Analysts have forecast Benlysta could reap in excess of $1 billion for its co-owners; GSK and HGS will share equally in both the late-stage development costs and profits.