Malaria Drug Tafenoquine May Combat Babesiosis

A recent study suggests that tafenoquine, a drug typically used for malaria, might be an effective treatment for immune-compromised individuals suffering from babesiosis, a tick-borne parasitic infection. The findings were published in the journal Clinical Infectious Diseases and indicate that tafenoquine successfully treated four patients in New England who had not responded to standard therapies.

Dr. Peter Krause, the study’s first author and a senior research scientist at the Yale School of Public Health’s Department of Epidemiology of Microbial Diseases, expressed optimism about the potential impact of tafenoquine. "Tafenoquine is going to make a huge difference, I think, in people who are severely immunocompromised," he stated.

Babesiosis is a widespread tick-borne disease, particularly prevalent in the northeastern and upper midwestern United States. The disease is caused by parasitic microorganisms that invade red blood cells, similar to how malaria parasites operate. The first human case was reported in 1957. Symptoms of babesiosis include fever, sweats, chills, headache, fatigue, weakness, and joint and muscle pain.

The standard treatment for babesiosis involves a two-drug regimen of the antibiotics atovaquone and azithromycin. According to Dr. Edouard Vannier, a co-author of the study and an assistant professor at Tufts Medical Center’s Division of Geographic Medicine and Infectious Diseases, this combination is effective for most patients with mild disease. However, the babesiosis parasite has been showing signs of developing resistance to this treatment. “In patients who are severely ill and severely immunocompromised, because resolution does not happen fast enough, the parasite has a chance to mutate,” Vannier explained. This often results in atovaquone resistance.

When resistance occurs, patients are at risk of relapse, which can lead to severe babesiosis. Up to 20% of those who relapse may die from the infection. The patients in the study had compromised immune systems and experienced dangerous relapses after the standard two-drug therapy failed.

Out of the five patients in the study, four were cured after being treated with tafenoquine. In these successful cases, tafenoquine was used in combination with other antibiotics or malaria treatments like atovaquone, proguanil, azithromycin, and clindamycin. The fifth patient, who received tafenoquine alone, did not see a resolution of their infection.

Nevertheless, the study demonstrated that tafenoquine could overcome the babesiosis parasite’s resistance. Vannier suggested that future treatment could involve testing babesiosis patients to determine the specific resistances their parasites have developed and then selecting the appropriate medications. “Testing for mutations is the future of treating these patients and opens the door to personalized medicine,” he noted. “The whole idea is to tailor the therapy to the patient.”

This tailored approach could lead to more effective treatments for babesiosis, particularly in patients with compromised immune systems, providing hope for those who do not respond to current standard therapies.