Lighthouse Pharmaceuticals has obtained the US Food and Drug Administration (FDA) clearance for its investigational new drug (IND) application to commence a Phase II clinical trial of LHP588 for P. gingivalis-positive Alzheimer’s disease.

The regulatory agency provided a ‘Study May Proceed’ letter to the company following its review of a complete IND package. 

Chronic toxicology, safety, production, Phase I human trial data as well as the protocol for the prospective Phase II SPRING trial were part of the package. 

The double-blind, randomised, placebo-controlled trial will evaluate the safety and efficacy of a once-daily dose of LHP588 to treat P. gingivalis-positive mild to moderate Alzheimer's disease. 

It will enrol 300 subjects who will be randomised into three arms to receive 25 or 50mg LHP588 or placebo for 48 weeks. 

A next-generation, brain-penetrant small-molecule inhibitor of gingipain, LHP588 showed safety and tolerability in a previously concluded Phase I trial.

Data from the GAIN trial in mild to moderate AD patients with a positive P. gingivalis showed that another gingipain inhibitor, atuzaginstat, offered a dose-dependent 57% reduction in cognitive decline versus a placebo.

Lighthouse Pharmaceuticals CEO Casey Lynch said: “The clinical efficacy and safety data provided by the GAIN trial has enabled us to significantly de-risk the mechanism of action, maximise target engagement with higher exposures of LHP588, and implement the optimal clinical study design. 

“LHP588 is a next-generation gingipain inhibitor that has been optimised for selectivity and metabolism, demonstrating an excellent safety profile in both human and toxicology studies.”