HGSI and GSK post strong Ph III results with Benlysta in lupus

UK drug giant GlaxoSmithKline and the USA's Human Genome Sciences Inc (HGSI) say that their developmental drug Benlysta (belimumab) met the primary endpoint in BLISS-76, the second of two pivotal Phase III trials in seropositive patients with systemic lupus erythematosus (SLE).

Analysts believe that Benlysta - which could be the first new drug to come to market for this condition in 50 years - could generate peak sales of $3 billion a year, and the news comes at a time that HSGI suffered a disappointment with its anthrax treatment ABthrax (raxibacumab; see separate story today). Marketing authorization filings for the lupus drug are expected during the first half of next year.

Earlier this year, suggestions that GSK is planning a takeover HGSI at $30/share - or some $4 billion - pushed the latter's stock up $2.03 to $19.21 per share in afternoon trading on August 25, with a gain of 11.8% (The Pharma Letter August 26)

BLISS-76 study results through 52 weeks showed that belimumab 10mg/kg plus standard of care achieved a statistically-significant improvement in patient response rate as measured by the SLE Responder Index at Week 52, compared with placebo plus standard of care. Study results also showed that belimumab was generally well tolerated, as demonstrated by a similar rate of discontinuations due to adverse events across treatment groups, with overall adverse event rates comparable between the drug and placebo treatment groups.

'The BLISS-76 results confirm our view that Benlysta has the potential to become the first new approved drug in decades for people living with systemic lupus,' said Thomas Watkins, president and chief executive of HGSI. 'We plan to submit marketing applications in the first half of 2010, following discussions with regulatory authorities in the USA, Europe and other regions. We will continue to work with GSK to advance this drug to the market where it may benefit patients with significant need.'

Carlo Russo, senior vice president, Biopharm Development, at GSK, said: 'The results from this second pivotal Phase III trial reinforce our belief that belimumab could deliver a significant therapeutic option for patients with lupus who have had no new treatment in 50 years.'

The data from the BLISS-76 study were analyzed after 52 weeks, in accord with the study protocol, in support of a potential Biologics License Application in the USA and Marketing Authorization Applications in Europe and other regions. However, the BLISS-76 study is ongoing and will continue for 24 more weeks. Additional data will be available following completion of the full 76-week study period. Belimumab is the first in a new class of drugs called BLyS-specific inhibitors, and is being developed by HGSI and GSK under a co-development and commercialization agreement signed in August 2006.

Key Findings from BLISS-76

'We are delighted that the efficacy of treatment with belimumab plus standard of care was superior to placebo plus standard of care in both BLISS-52 and BLISS-76, with overall adverse event rates comparable to placebo plus standard of care,' said David C. Stump, M.D., Executive Vice President, Research and Development, HGS. 'Belimumab met the primary endpoint in both pivotal Phase 3 trials, as specified by the Special Protocol Assessment Agreement with FDA. We look forward to the full presentation of the BLISS-76 52-week results at an appropriate scientific meeting, hopefully in the first half of 2010.'