In what has been described as the first lupus drug in decades to show effectiveness in phase 3 clinical trials, the announcement that Benlysta (belimumab) outperformed placebo has surprised Wall Street, where many had assumed the drug was going nowhere.

Earlier today, the Lupus Research Institute (LRI) and its National Coalition of state and local organizations congratulated Human Genome Sciences Inc (HGS) and GlaxoSmithKline (GSK) on what they described as the “highly promising results” of the late stage trial of their experimental drug to treat people with systemic lupus.

Benlysta (belimumab) is the first investigational human monoclonal antibody in a class called “BLyS-specific inhibitors” and is being developed by HGS and GSK under a co-development and commercialization agreement that they signed in August 2006.

BLyS-specific inhibitors recognize and inhibit the biological activity of B-lymphocyte stimulators.

Systemic lupus erythematosus (SLE) or lupus, is a chronic and sometimes fatal autoimmune disorder that not many people know about, although it affects more than 1.5 million Americans, mostly women of childbearing age. It is a leading cause of premature cardiovascular disease, kidney disease and stroke among young women, says the LRI.

The disease causes production of antibodies that attack nearly every healthy organ and tissue of the body, including kidneys, brain, heart, lungs, skin, blood and joints.

The last time a treatment was approved was nearly 50 years ago, and many of the drugs currently used are nearly as toxic as the disease itself.

LRI President, Margaret G Dowd said:

“We are very hopeful that we now are strongly on our way to the first new treatment for lupus in 50 years.”

“The lupus community commends HGS and GlaxoSmithKline for their commitment and perseverance in finally bringing this potential new lupus treatment to trial,” said Dowd.

“And we thank the hundreds of people with lupus who enrolled and took part in this important trial. Participation like theirs is critical to finding answers to this illness,” she added.

The results that have been announced are of BLISS-52, the first of two double-blind, placebo-controlled phase 3 trials. It involved a total of 867 participants at 90 clinical sites in 13 countries, primarily in Asia, South America and Eastern Europe.

The trial showed that two doses of Benlysta (formerly known as LymphoStat-B), given together with standard of care, were more effective than placebo with standard of care in people with serologically active systemic lupus.

According to an HGS statement, Benlysta:

“Achieved a clinically and statistically significant improvement in patient response rate at Week 52, compared with standard of care alone.”

The drug was also shown to be well tolerated, with adverse event rates comparable between placebo and active drug groups, they said.

Specifically, the topline result of the BLISS-52 trial was that based on an an intention-to-treat (ITT) analysis, both trial doses of the drug plus standard of care showed a clinically and statistically significant improvement versus placebo plus standard of care: 57.6 per cent for 10 mg/kg, 51.7 per cent for 1 mg/kg versus 43.6 per cent for placebo (p=0.0006 and 0.011 for the two doses versus placebo respectively).

“Patient response was defined by an improvement in SELENA SLEDAI score of 4 points or greater, no clinically significant BILAG worsening, and no clinically significant worsening in Physician’s Global Assessment,” said HGS.

SELENA SLEDAI is a disease activity scale that indicates a clinically important reduction in SLE disease activity. The Physician’s Global Assessment defines worsening as an increase of 0.30 points or more from baseline, and BILAG measures severity of flares as they affect organs.

The results for the each individual element of the patient respose rate were “consistent with the overall improvement shown for the primary endpoint,” they added.

Results of a second Phase 3 trial, BLISS-76, involving 826 participants at 133 clinical sites in 19 countries, primarily in North America and Europe, are expected later this year.

BLISS-52 and BLISS-76 are the largest clinical trials ever conducted in people with lupus. The design of the two trials is similar, but the duration of therapy in the two studies is different — 52 weeks for BLISS-52 and 76 weeks for BLISS-76.

President and CEO of HGS, H Thomas Watkins, told the press that:

“Given the limited treatment options currently available, patients would benefit greatly from potential new treatments.”

He said if the second trial shows positive results in November this year:

“We and GSK plan to submit marketing applications in the United States, Europe and other regions in the first half of 2010.”

Chief of the division of rheumatology and allergy-clinical rheumatology at North Shore-LIJ Health System in New York, Dr Richard Furie said:

“This is a major advance for patients, families, and physicians–the entire lupus community!”

“There is no doubt that a drug approval will foster further drug development and additional discoveries,” he added.

Dr Daniel J Wallace, clinical professor of medicine at the David Geffen School of Medicine at UCLA, said the promising results represent:

“A breakthrough for finally utilizing a methodology that enables researchers to demonstrate disease improvement.”

Dr Tammy O Utset, an associate professor of medicine at the University of Chicago, praised the drug companies, and described their approach as ambitious in that they conducted “huge international concurrent trials which represent a large investment in systemic lupus therapy”.

Dr Carlo Russo, Senior Vice President, Biopharm Development at GSK said that:

“Lupus is a chronic, often debilitating, and sometimes fatal illness that affects an estimated five million people worldwide and can have a devastating effect on both patients living with the disease and their families.”

He said both companies were looking forward to successfully completing the trials so they can bring “this potentially important therapeutic advance to patients suffering from SLE”.

Professor Sandra V Navarra, a principal investigator on the trials and Head of Rheumatology at the University of Santo Tomas, Manila, The Philippines, said:

“We are very encouraged by the findings of BLISS-52, and look forward to presenting these results later in the year. We also look forward to the results of BLISS-76 later this year.”

According to Reuters news agency,Wall Street analysts had dismissed belimumab because an earlier trial had produced disappointing results.

But in an interview given after announcing these latest findings, Watkins said the drug had “blockbuster” potential.

Sources: HGS, Lupus Research Institute, Reuters.

Written by: Catharine Paddock, PhD