Benlysta (belimumab) is expected to gain US approval this week by the Food and Drug Administration (FDA), USA, for the treatment of lupus (systemic lupus erythematosus). This is the first drug approval with benefits for lupus patients in half-a-century. Pharmaceutical experts believe Benlysta will become a huge blockbuster, with potentially $3 billion plus global annual sales within the next four years. They also add that approval is highly likely this coming Thursday.

Human Genome Sciences, the makers of Benlysta, is currently a biotech company running at a loss. Benlysta's approval will change everything, and most likely it will become ripe for takeovers overnight. The new medication's long-term sales estimates are high, with possibly annual sales of over $5 billion by 2019 (Wall Street Journal).

Early on, Human Genome Sciences' future looked bleak when initial trial data disappointed. However, during the Spring of 2009 things started to look more encouraging. The company's future took a massive turn for the better when an FDA Advisory Panel recommended approval in a 13-2 vote in November 2010.

There is still some concern over whether regulatory authorities might insist on some limits when the drug is approved. Experts say it does not help all lupus patients, while others have described its benefits as "mild". Most expect the approval to cover a fairly broad population with moderate to severe lupus symptoms.

Following the FDA Advisory Panel's positive response, the regulatory agency has asked for some additional information, which Human Genome Sciences says it submitted. In a communiqué, Human Genome Sciences wrote:

"In December 2010, the FDA extended the Prescription Drug User Fee Act (PDUFA) target date for priority review of the BENLYSTA application to March 10, 2011. If approved, BENLYSTA would be the first new approved drug for lupus in more than 50 years. HGS and GSK expect a regulatory decision in Europe in the second half of 2011."

Lupus, also known as systemic lupus erythematosus, or SLE is an autoimmune disease - the patient's immune system becomes hyperactive and attacks healthy, normal tissue, resulting in inflammation, swelling, and damage to the skin, lungs, kidneys and heart.

The immune systems of individuals without lupus produce antibodies, types of proteins, to protect and fight against antigens. An antigen is a substance that can trigger the body to produce antibodies, such as bacteria and viruses. In patients with lupus, their immune systems cannot distinguish between antigens and healthy tissue properly. Antibodies are consequently directed against healthy tissue, and not just antigens - resulting in damage.

Human Genome Sciences together with GlaxoSmithKline are jointly seeking approval of Benlysta. Both companies say they expect a regulatory decision in Europe later on this year.

Sources: Human Genome Sciences, GlaxoSmithKline, Wall Street Journal

Written by Christian Nordqvist