The Food and Drug Administration (FDA) has granted Orphan Drug designation to ATX01 (proprietary topical amitriptyline; AlgoTherapeutix) for the treatment of erythromelalgia.

Erythromelalgia is a rare condition typically associated with intense burning pain, severe redness and swelling primarily affecting the feet, and to a lesser extent, the hands. The pain associated with the disorder is believed to be due to sodium channel dysfunction.

ATX01 is a topical gel formulation of a proprietary high-concentration amitriptyline that works by targeting damaged nerve fibers in the skin, while avoiding systemic adverse reactions. The designation is supported by preclinical studies of topical amitriptyline that showed antinociceptive activity on voltage-gated sodium-channels Nav1.7, Nav1.8 and Nav1.9 as well as peripheral sensory nerve fibers Aβ, A∂ and C.

The Company plans to begin phase 1 clinical development in late 2020. 

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“The opportunity to investigate ATX01 in erythromelalgia is an exciting medical pursuit as those patients have very few options to relieve considerable pain,” said Stéphane Thiroloix, Algo Therapeutics founder and CEO. “It provides us with an opportunity to further our understanding of ATX01’s activity on Nav1.7 in a preclinical and clinical setting.”

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