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Lighthouse announces FDA approval to proceed with Phase 2 SPRING Trial of LHP588, a next-generation treatment in development for P. gingivalis-positive Alzheimer's disease

Phase 1 single ascending and multiple ascending dose studies previously completed demonstrate safety, tolerability and dosing to reach optimal target engagement


SAN FRANCISCO, NOV. 16, 2023 - Lighthouse Pharmaceuticals, a clinical-stage biopharmaceutical company pioneering precision medicine for the treatment of Alzheimer’s and other diseases of aging, today announced clearance by the U.S. Food and Drug Administration (FDA) of the Investigational New Drug (IND) application for LHP588, the company's next-generation gingipain inhibitor, for the treatment of P. gingivalis-positive Alzheimer’s disease.

The “Study May Proceed” notification from the FDA was based on review of the comprehensive IND package including safety, chronic toxicology, manufacturing, Phase 1 human data, and the planned Phase 2 SPRING (Stopping PRogression of P. gINGivalis-positive Alzheimer’s disease) trial protocol. LHP588 is a next-generation, brain penetrant small-molecule gingipain inhibitor that demonstrated safety and tolerability in the completed Phase 1 study, along with plasma levels predicted to be sufficient to engage the target with just once-daily oral dosing.

The planned Phase 2 SPRING clinical trial is a randomized, double-blind, placebo-controlled study to assess the efficacy and safety of once-a-day dosing of LHP588 for the treatment of P. gingivalis-positive mild to moderate Alzheimer’s disease. 300 patients will be enrolled in the trial and randomized into three arms (placebo, 25 and 50 mg) for 48 weeks of treatment. Patients must have mild to moderate Alzheimer’s disease and evidence of P. gingivalis infection, based on a saliva test.  The GAIN trial of the first-generation gingipain inhibitor, atuzaginstat, demonstrated that patients with mild to moderate AD and a positive P. gingivalis saliva test had a dose-dependent, 57% slowing of cognitive decline on the pre-specified proof of concept endpoint, ADAS-Cog11, compared to the placebo group (p = 0.02).

“We are very pleased to have FDA clearance to initiate the SPRING Phase 2 clinical trial. Previous studies of this mechanism indicated promise of the precision medicine approach being leveraged by Lighthouse going forward. The clinical efficacy and safety data provided by the GAIN trial has enabled us to significantly de-risk the mechanism of action, maximize target engagement with higher exposures of LHP588, and implement the optimal clinical study design,” said Casey Lynch, CEO of Lighthouse Pharmaceuticals. “LHP588 is a next-generation gingipain inhibitor that has been optimized for selectivity and metabolism, demonstrating an excellent safety profile in both human and toxicology studies.  With FDA clearance in hand, we look forward to working with our clinical advisors and investors to move this important clinical study forward.”

About Lighthouse Pharmaceuticals

Lighthouse Pharma is a clinical stage private biopharmaceutical company pioneering precision medicine approaches to major unmet medical needs based on expertise in small molecule protease inhibition. Lighthouse's lead program, LHP588, a Phase 2 ready orally bioavailable small molecule, targets a specific, infectious pathogen, Porphyromonas gingivalis, which is associated with chronic degenerative and inflammatory disorders including dementia, periodontal disease, atherosclerosis, and orodigestive cancers. For more information, visit


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