July 20, 2009

Human Genome Reports Success Of Late-Stage Lupus Drug Trial

Human Genome Sciences Inc. reported on Monday that a late-stage clinical trial of its experimental lupus drug Benlysta had shown success in reducing symptoms of the disease.

The news, which was reported just after midnight, shocked many who had dismissed the product, and caused shares of the company's stock to soar 274 percent.

Results of the 52-week, 867-person trial showed that patients taking a high dose of Benlysta, which is administered once a month by IV infusion, had a 57.6 percent improvement in their symptoms compared with 43.6 percent improvement among those taking a placebo.

The results were statistically significant and met the primary objective of the clinical trial, the company said.

"Benlysta could be the first true disease-modifying therapy for lupus patients -- a blockbuster opportunity," Leerink Swann analyst Joseph Schwartz told Reuters.

Among patients taking a low dose of Benlysta, 51.7 percent showed improvement in their symptoms, a figure that was also statistically significant.

The trial's primary goal was to demonstrate a four-point or greater improvement in disease symptoms as measured by a scale known as Selena Sledai.  

A four-point reduction on the 10-point scale equates to a positive, or meaningful response.  All of the patients taking part in the trial had a score of six or higher, with higher scores indicating more disease activity.

The trial also required that patients did not experience a worsening of their disease in any organ beyond one originally affected, a goal the trial met at both the high and low doses of Benlysta.

The trial's success boosted shares of other companies trying to develop lupus drugs, such as Immunomedics Inc. and ZymoGenetics Inc., which are developing a drug in collaboration with Merck Serono, a unit of Germany's Merck KGaA.  Shares of Immunomedics rose 3.6 percent to $3.16, while shares of ZymoGenetics, were up more than 12 percent to $4.90.

Lupus is a complex disease in which the immune system attacks the body's own organs and tissues, including the joints, heart, kidneys, lungs, brain, blood or skin.   Symptoms include skin rash, fever, arthritis, kidney damage, achy joints and chest pain.  Lupus affects an estimated 1.5 million people in the U.S. and 5 million worldwide, according to figures from the Lupus Foundation of America.

The success of the trial, known as BLISS-52, takes Human Genome one step closer to being the first company to have a new lupus drug approved in five decades.   Although a number of drugs approved for other indications are often used to treat lupus, none have been approved specifically as lupus treatments in decades.

However, Benlysta is not expected to treat all patients, but will be targeted to a subset of lupus sufferers with mild to moderate disease.   That is because an earlier trial failed to meet its primary goal, but researchers noticed that a subset of patients responded very well to the drug. 

The late-stage, or Phase III, trials were designed in conjunction with the U.S. Food and Drug Administration (FDA) to test those patients most likely to benefit from the drug.

As a result, the initial market for Benlysta consists of roughly 300,000 patients, according to a Reuters report citing Human Genome CEO Thomas Watkins.   If the drug is approved, roughly 150,000 U.S. patients stand to benefit.

Although that is only a small portion of the total number affected by lupus, it is nevertheless a significant advance, Watkins told Reuters, adding that from a corporate perspective the drug represents a substantial revenue opportunity.

"A drug like this, with this kind of promise, has the potential to be a blockbuster drug," he said.

Drugs are typically considered blockbusters when they generate $1 billion or more in revenue.  Profits from sales of Benlysta would be split between Human Genome and its partner, GlaxoSmithKline Plc.

The company is set to report results of the second, confirmatory trial in November.  Human Genome said there are no substantive differences between the two trials, the first of which was conducted in Asia, Latin America and Eastern Europe, while the second was conducted in Europe and North America.

If the findings of the second trial replicate those of the first, Human Genome and GlaxoSmithKline would seek to file for approval of the drug by early 2010, said David Stump, Human Genome's head of research and development.

If the FDA grants it a priority review, Benlysta could hit the market by the end of next year.  Without a priority review, the drug could be on the market by early 2011.  Priority review is typically given to drugs that meet unmet medical needs.  

Benlysta is designed to inhibit BLyS, a naturally occurring protein in the body that keeps B-cells, which make antibodies that prevent infection, functioning normally.   In patients with lupus, B-cells are over stimulated, and produce antibodies known as auto-antibodies that attack the body.

Given the disappointing results from a prior trial, some analysts had all but dismissed any hope for the drug.

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