Phase 2 Study Design and New Data from the Phase 1 SAD/MAD Trial of LHP588, A Second‐Generation Gingipain Inhibitor for the Treatment of P. Gingivalis ‐ Positive Alzheimer Dementia

Abstract

AbstractBackgroundGingipains, toxic protease virulence factors from the bacterial pathogen P. gingivalis (Pg), were discovered in postmortem brains of patients with Alzheimer’s disease. Gingipain levels correlated with tau and ubiquitin pathology, and oral infection of wild‐type mice with Pg resulted in brain inflammation and neurodegeneration that was blocked by gingipain inhibitors.LHP588 is a second‐generation orally bioavailable and brain‐penetrant lysine gingipain inhibitor that reduces the toxicity of Pg and the bacterial load. A first‐generation molecule (COR388/atuzaginstat) previously showed reduction of cognitive decline in prespecified cohorts defined by their infection load, but it was discontinued due to a hepatic safety signal. We will review new data from the LHP588 SAD/MAD, and the design of the Phase 2b study planned for initiation later this year.MethodThe Phase 1 study of LHP588 enrolled 32 individuals in the SAD component with 4 cohorts and concurrent placebo (25 mg, 50 mg, 100 mg, 200 mg) and 24 healthy subjects in the 10‐day MAD portion, with 3 cohorts and concurrent placebo (50, 100 mg, and 200 mg).ResultIn the study of atuzaginstat, significance was not observed in the full intent‐to‐treat population, however, prespecified subgroup analyses indicated efficacy in patients with Pg‐positive saliva (Pg+), slowing cognitive decline compared with placebo on the ADAS‐Cog11 by approximately 50% (p = 0.02). Changes in Pg DNA in saliva correlated significantly with changes on the ADAS‐Cog, CDR‐SB, and MMSE.The second‐generation lysine gingipain inhibitor LHP588 was well‐tolerated in the SAD and 10‐day MAD study; adverse events in the active arms were mild and sporadic. PK with once‐daily dosing achieved target concentrations sufficient for reduction of systemic Pg infection at doses >25 mg of LHP588, and exposures equivalent or greater than those achieved with the high dose of atuzaginstat. LHP588 was also detected in the CSF.ConclusionLHP588 was well‐tolerated in healthy volunteers without evidence of hepatic safety signals to date, and its PK profile was supportive of once daily dosing. The Phase 2 trial of LHP588 proposed to start in late 2023 will be similar in design to the prior atuzaginstat study but will be restricted to subjects with Pg+ saliva.