The filarial worms that cause river blindness are dependent on the worm-symbiont Wolbachia bacteria for growth, development, reproduction, and survival. An antibiotic drug that targets the symbiont would cause the filarial worms to die, offering a new and practical treatment for this deadly disease.

Flubentylosin is a derivative of tylosin, a veterinary antibiotic that targets Wolbachia. The compound was identified through screening of anti-infective compounds led by AbbVie and the anti-Wolbachia consortium A-WOL at the Liverpool School of Tropical Medicine. Flubentylosin is currently in clinical development for the treatment of filarial diseases. Flubentylosin is orally available, induces a robust anti-Wolbachia effect in several in vivo models, demonstrates clear superiority over the current treatment doxycycline, and is effective after a shorter dosing regimen.

First-in-human Phase I studies for flubentylosin in healthy volunteers, including a single ascending dose study, a multiple ascending dose study, and a food effect study, were successfully completed by AbbVie’s Clinical Pharmacology Research Unit. These studies showed that flubentylosin is safe and well tolerated. In 2021, DNDi initiated a Phase II proof-of-concept study at two recently upgraded clinical trial sites in the Democratic Republic of the Congo.

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