FDA OKs Cresemba, Astellas drug for rare but serious fungal infections, after priority review

The Food and Drug Administration has approved a new antifungal drug, Cresemba, to treat two rare but serious infections that typically strike people with weakened immune systems.

The drug was approved under the FDA's designation as a Qualified Infectious Disease Product. Drugs for treating fungal and bacterial infections that receive the designation get expedited review and five years of extra market exclusivity under a provision of the recent FDA Safety and Innovation Act meant to spur drugmakers to develop needed medicines for such infections.

Cresemba is the sixth medicine approved by the FDA as a result.

It was approved to treat aspergillosis, which is caused by the Aspergillus fungus, and mucormycosis, which is caused by the Mucorales fungus. The drug is sold in both pill and injectable forms.

Cresemba, known chemically as isavuconazonium, is made by Astellas Pharma US Inc. of Northbrook, Illinois, a unit of Astellas Pharma Inc., one of Japan's biggest drugmakers.

The most common side effects of Cresemba are nausea, vomiting, diarrhea, headache, abnormal liver blood tests, low potassium levels in the blood, constipation, shortness of breath, coughing and tissue swelling, according to the FDA. More serious, but rarer side effects include liver problems and severe allergic and skin reactions.

Roughly 50,000 patients were hospitalized in 2010 for treatment of aspergillosis, which most often strikes patients receiving chemotherapy, stem cell transplants, high doses of steroid medications and immune-suppressing drugs needed after organ transplants. The infection can kill up to 30 percent of them.

Mucormycosis is rarer, striking about 1.2 people per million residents in 2006, but that's nearly double the U.S. rate a decade earlier. It's believed the increase is due to more people living with HIV or receiving immune-suppressing drugs due to various diseases. Studies indicate mucormycosis kills 44 percent of patients with diabetes who get the fungal infection, and far more with blood cancers and other life-threatening diseases.