The Food and Drug Administration approved a drug Friday for leukemia patients who develop allergies to chemotherapy treatments.

EUSA Pharma, a privately-held trans-Atlantic company, developed the drug named Erwinaze designed for acute lymphoblastic leukemia patients who become sensitive to the commonly used class of chemotherapy treatments derived from E. coli bacteria.

The orphan drug works to combat a disease that affects fewer than 200,000 people a year and is injected into muscle three times a week into patients.

Acute lymphoblastic leukemia causes the body to produce too many white blood cells that typically help fight off infections and form bone marrow.

The drug breaks down an amino acid, asparagine, essential for cells with leukemia, according to a company statement released Friday. Two other FDA-approved drugs, Elspar from Merck and Co. and Oncaspar from Sigma-Tau Pharmaceuticals, Inc., function in a similar manner, but are derived from E. coli.

Researchers estimate that 15 percent to 20 percent of patients develop allergies to the E. coli-derived drugs, approximately 450 to 600 children in the U.S. per year.

The approval of Erwinaze is an important advance because it is the only treatment option that can enable these patients to continue and complete their full course of therapy, Stephen Sallan, chief of staff at the Dana-Farber Cancer Institute, said in a press statement released by EUSA Pharma.

Though the drug treats only a handful of patients, the FDA came out with a statement touting the approval.

The approval of Erwinaze underscores the FDA's commitment to the approval of drugs for conditions with limited patient populations with unmet medical needs using novel trial endpoints Richard Pazdur, director of hematology and oncology products in the FDA's Center for Drug Evaluation and Research, said in a press release.

Side effects associated with Erwinaze include blood clotting, bleeding, nausea, vomiting and high blood sugar, allergic reactions, pancreatic inflammation, according to a company press release.