60 Degrees Pharmaceuticals Inc. (NASDAQ: SXTP) announced that three patients with relapsing babesiosis were cured after treatment with tafenoquine in an expanded use clinical trial.

The Washington-based pharmaceutical company conducted an open-label, multi-site study evaluating tafenoquine combined with atovaquone and other antimalarials in immunosuppressed patients who had previously failed conventional treatments. All three enrolled patients achieved cure status, as determined by negative RNA amplification tests following treatment completion.

The trial builds on a 2024 Yale School of Public Health study published in Clinical Infectious Diseases, which reported a 100% treatment success rate in four of five patients when tafenoquine was combined with standard care regimens. The fifth patient from the Yale study became the third patient in 60 Degrees' expanded access trial and was ultimately cured using a quadruple combination therapy.

Patients received tafenoquine treatment for up to one year until two consecutive negative PCR tests were recorded and symptoms resolved. Follow-up testing 60 to 90 days after treatment cessation used both RT-PCR and FDA-approved RNA amplification tests, with the latter being at least 1,000 times more sensitive than standard commercial RT-PCR tests.

Babesiosis is a tick-borne illness that can be life-threatening in elderly and immunosuppressed patients. No FDA-approved treatment currently exists for the disease. Tafenoquine is approved for malaria prophylaxis under the brand name ARAKODA but not for babesiosis treatment.

The company stated it believes treatment guidelines should be reviewed based on the combined data from seven patients across both studies.