For the first time in more than 50 years, the U.S. Food and Drug Administration (FDA) approved a new drug in 2011 to treat lupus, an autoimmune disease affecting as many as 1.5 million Americans.

Benlysta, or belimumab, is a biologic – the first to be approved and used for lupus. It’s an intravenous infusion that works to reduce the number of B cells that appear to be overactive in lupus patients.

The drug’s maker, Human Genome Sciences Inc., says the medication will be available by the end of March to patients with the painful and often difficult-to-treat disease.

Benlysta, when used with existing therapies, may be an important new treatment approach for health care professionals and patients looking to manage symptoms associated with this disease,” says Erica V. Jefferson, an FDA spokesperson. “The disease can be debilitating, negatively impacting a patient's everyday life and can also be fatal.”

The FDA says it based its approval on two clinical studies of more than 1,600 lupus patients. An FDA press release says those studies show patients taking Benlysta and standard therapies had less disease activity than those not getting the medication, and there were some signs the medicine may also have reduced severe lupus flares.

“The first study wasn’t impressive in terms of any significant improvement. A second study showed it was effective. I don’t think anyone thinks it’s curing lupus, but it gives you something in your arsenal of drugs to try,” says Robert Katz, MD, a rheumatologist at Rush University Medical Center in Chicago and chairman of the medical advisory board for the Illinois chapter of the Lupus Foundation.

“I think it will be effective and I think it’s nice to have it available. But I don’t think it will be that helpful for the most challenging patients. I base that on the first trials, which weren’t that positive,” Dr. Katz says.

The last drug the FDA approved to treat lupus is the antimalarial Plaquenil, or hydroxychloroquine, in 1955. Lupus patients may take corticosteroids, such as prednisone, other antimalarials, immunosuppressive drugs and nonsteroidal anti-inflammatory drugs. But these medications don’t always help lupus patients, and they can cause serious or unpleasant side effects. Dr. Katz says Benlysta won’t necessarily replace these medications, but it might reduce the amount patients have to take.

“You might still have to take prednisone every day, but maybe you can take less of it,” Dr. Katz explains.

Side effects of Benlysta include nausea, diarrhea and fever. Because 17 percent of the trial participants had reactions to the infusion including headache and skin reactions – not uncommon with biologic infusions – the FDA recommends that patients first get treated with an antihistamine.

There were indications that African-American patients didn’t respond as well to Benlysta as other patients, though the numbers weren’t definitive, so the drug maker will conduct a study to evaluate Benlysta’s effectiveness for African-Americans. The FDA estimates that lupus occurs three times as often in African-American women as Caucasian women.

There will be other studies on the drug as well. “Human Genome Sciences will be conducting an additional controlled trial to further evaluate safety concerns such as serious infections, death and depression. The (FDA) is also requiring Human Genome Sciences to conduct additional studies including a pregnancy registry, a study in children with lupus and a study of the effect of Benlysta on vaccinations,” Jefferson adds.

Dr. Katz says now that the drug is approved, there’s an opportunity to see it used in a wider spectrum of patients than were involved in the clinical trial and that will shed more light on its effectiveness as well. “All kinds of lupus patients will be given it, so we’ll have a better way of gauging it with sicker patients,” Dr. Katz explains.

Benlysta is expected to come with an average yearly price tag of $35,000 without insurance – which is similar to other biologic medications used to treat autoimmune diseases.