AlgoTherapeutix is advancing its plan to unlock the power of amitriptyline through topical delivery. With the phase 1 trial meeting its objectives, AlgoTherapeutix is now gearing up for a pivotal study in chemotherapy-induced peripheral neuropathy (CIPN).
Oral amitriptyline is already used to treat some forms of pain but has failed to gain traction in CIPN, with a randomized clinical trial from more than a decade ago finding no significant efficacy. Later, two other groups tested topical prospects that co-formulated amitriptyline with ketamine, only to again find no significant effect on pain.
The failures raised the question of whether a higher dose of amitriptyline would be more effective. The oral study used a low dose to limit adverse events caused by systemic delivery, and the topical formulations also used a fairly small amount of the painkiller.
AlgoTherapeutix’s belief that a higher dose may be more effective is backed up by a scientific paper, coauthored by one of its employees, which describes the use of topical 10% amitriptyline in mice. Earlier topical formulations used topical amitriptyline doses of 5% or less. The research found topical 10% amitriptyline may provide pain relief to CIPN patients without the side effects of oral delivery.
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A phase 1 study has added to AlgoTherapeutix’s confidence in the safety of its approach. “We are delighted that ATX01’s innovative approach and formulation did not raise any safety concern, and its PK profile is consistent with our objectives,” AlgoTherapeutix CEO Stéphane Thiroloix said in a statement.
Buoyed by the data, AlgoTherapeutix plans to move into a pivotal phase 2 clinical trial next year. The study could position the topical drug candidate, ATX01, to address the unmet need in CIPN. Around half of patients on chemotherapy develop CIPN, in some cases driving physicians to reduce or stop dosing.