The U.S. Food and Drug Administration (FDA) has approved Xolair (omalizumab) for the treatment of a type of chronic hives, Genetech, a part of the Roche Group, announced in a statement released Friday.

Xolair is approved for treatment of chronic idiopathic urticaria (CIU). The drug is for people age 12 and above who have stopped responding to treatment with H1-antihistamine therapy. The drug is an injectable prescription medicine.

CIU are hives with no known cause. People with the condition experience severe itching, pain and discomfort. CIU may last for a few weeks to months and even years. Nearly 1.5 million people in the U.S. suffer from CIU.

"This approval from the FDA is great news for patients in the US suffering from CIU, a skin disease known as CSU in other parts of the world," said David Epstein, Division Head of Novartis Pharmaceuticals in a statement. "Up to 50% of patients do not respond to approved doses of H1-antihistamines, which up until now have been the only licensed treatment for CIU in the US."

The newly approved drug is jointly developed by Genentech and Novartis Pharma AG.

"Chronic idiopathic urticaria can be difficult to manage because its causes are unknown, and other approved medicines aren't effective enough for many patients," said Sandra Horning, M.D., chief medical officer and head of Global Product Development, according to a press release. "We are pleased to have Xolair as a new option for people with this serious skin condition."

Xolair's efficacy and safety was evaluated in two clinical trials called ASTERIA I and ASTERIA II. The studies included 641 patients aged between 12 and 75 years. Participants were given different doses of the test drug or placebo once every four weeks for 24 weeks in the (ASTERIA I) study. In the (ASTERIA II), the same trial was conducted over a 12-week period.

Researchers found that Xolair was better than placebo in reducing itching in people with CIU.

Nausea, headaches, throat or sinuses, cough, joint pain, and upper respiratory tract infection were the most common side-effects of using the drug, Novartis said in a statement. People using the drug might also experience a serious allergic reaction called anaphylaxis

Novartis added that the drug should not be used to treat any other allergic condition or be used in children under 12 years.