FDA approves first U.S. treatment for Chagas disease

The U.S. Food and Drug Administration has granted accelerated approval to benznidazole for use in children ages 2 to 12 years old with Chagas disease. It is the first treatment approved in the United States for the treatment of Chagas disease. Chagas disease, or American trypanosomiasis, is a parasitic infection caused by Trypanosoma cruzi and can be transmitted through different routes, including contact with the feces of a certain insect, blood transfusions, or from a mother to her child during pregnancy. After years of infection, the disease can cause serious heart illness, and it also can affect swallowing and digestion. While Chagas disease primarily affects people living in rural parts of Latin America, recent estimates are that there may be approximately 300,000 persons in the United States with Chagas disease.

"The FDA is committed to making available safe and effective therapeutic options to treat tropical diseases," said Edward Cox, M.D., director of the Office of Antimicrobial Products in the FDA's Center for Drug Evaluation and Research.

The safety and efficacy of benznidazole were established in two placebo-controlled clinical trials in pediatric patients 6 to 12 years old. In the first trial, approximately 60 percent of children treated with benznidazole had an antibody test change from positive to negative compared with approximately 14 percent of children who received a placebo. Results in the second trial were similar: Approximately 55 percent of children treated with benznidazole had an antibody test change from positive to negative compared with 5 percent who received a placebo. An additional study of the safety and pharmacokinetics (how the body absorbs, distributes and clears the drug) of benznidazole in pediatric patients 2 to 12 years of age provided information for dosing recommendations down to 2 years of age.

The most common adverse reactions in patients taking benznidazole were stomach pain, rash, decreased weight, headache, nausea, vomiting, abnormal white blood cell count, urticaria (hives), pruritus (itching) and decreased appetite. Benznidazole is associated with serious risks including serious skin reactions, nervous system effects and bone marrow depression. Based on findings from animal studies, benznidazole could cause fetal harm when administered to a pregnant woman.

Benznidazole was approved using the Accelerated Approval pathway. The Accelerated Approval pathway allows the FDA to approve drugs for serious conditions where there is unmet medical need and adequate and well-controlled trials establish that the drug has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. Further study is required to verify and describe the anticipated clinical benefit of benznidazole.

The FDA granted benznidazole priority review and orphan product designation. These designations were granted because Chagas disease is a rare disease, and until now, there were no approved drugs for Chagas disease in the United States.

With this approval, benznidazole’s manufacturer, Chemo Research, S. L., is awarded a Tropical Disease Priority Review Voucher in accordance with a provision included in the Food and Drug Administration Amendments Act of 2007 that aims to encourage development of new drugs and biological products for the prevention and treatment of certain tropical diseases.