For the past 20 years, nifurtimox for the treatment of American trypanosomiasis (Chagas disease), a parasitic infection caused by Trypanosoma cruzi, had only been available through the Centers for Disease Control and Prevention (CDC) under the Institutional Review Board-approved Investigational New Drug (IND) protocol. In August of 2020, the US Food and Drug Administration (FDA) approved the medication for the treatment of Chagas disease. The safety report from the CDC on nifurtimox was reviewed in an analysis, with findings published in the Morbidity and Mortality Weekly Report.
Between 2001 and 2021, 336 patients in the United States requested nifurtimox treatment through the CDC. These patients had a median age of 37 (range, 1-78) years, 58.9% were women, 93.2% were Hispanic, and 34.2% and 8.6% resided in California and New York, respectively.
As Chagas disease is endemic to rural areas in Latin America, few patients were exposed in the US (5.1%). Most exposures occurred in El Salvador (34.6%), Mexico (31.4%), and Bolivia (11.7%).
Among patients who received nifurtimox, 91.4% reported an adverse event. Stratified by symptoms, patients experienced gastrointestinal (68.7%), neurologic (60.5%), constitutional (46.5%), psychiatric (34.6%), musculoskeletal (28.0%), dermatologic (14.4%), cardiovascular (3.3%), and miscellaneous (8.2%) adverse events.
Compared with results of previously conducted clinical trials on the use of nifurtimox, the CDC observed an increased rate of adverse events among children and adolescents with Chagas disease who received nifurtimox (90% vs 64.5%).
Among all reported adverse events, 20.5% were severe. Severe adverse events reported by at least 5 patients included nausea (n=11), headache (n=9), anorexia (n=7), anxiety (n=7), depression (n=7), insomnia (n=6), abdominal pain (n=6), dizziness or vertigo (n=5), paresthesia (n=5), peripheral neuropathy (n=5), and weight loss (n=5).
There was no significant associations between either age or sex and an increased risk for adverse events among patients who received nifurtimox.
This study was limited as 23% of patient reports did not include data on adverse events, and 10% of the reported adverse events did not include information on severity.
In regard to the FDA’s approval of nifurtimox, the researchers concluded that “physicians should be aware of the frequency of adverse events when prescribing nifurtimox.”
Abbott A, Montgomery SP, Chancey RJ. Characteristics and adverse events of patients for whom nifutimox was released through the CDC-sponsored investigational new drug program for treatment of Chagas disease-United States, 2001-2021. MMWR Morb Mortal Wkly Rep. 2022;71(10):371-374. doi:10.15585/mmwr.mm7110a2