Cholesteryl ester transfer protein (CETP) inhibition reduces low density lipoprotein-cholesterol (LDL-C) while simultaneously increasing high density lipoprotein-cholesterol (HDL-C) levels and improving HDL-particle functionality. These lipoprotein modifications may provide a novel pathway for Alzheimer disease (AD) prevention through effects on lipid modulation, antioxidant activity, and neuro-inflammation. This approach could prove particularly beneficial for APOE4 carriers, who face elevated risks for both AD and atherosclerotic cardiovascular disease (ASCVD).

To examine the effects of obicetrapib, an oral CETP inhibitor, on biomarker changes indicative of AD pathology among patients with ASCVD

This was a pre-specified substudy of the BROADWAY trial, a phase 3, double-blind, placebo-controlled pivotal registration trial to evaluate the LDL-C lowering efficacy of obicetrapib in adult patients with established ASCVD and/or heterozygous familial hypercholesterolemia (HeFH), whose LDL-C was not adequately controlled, despite being on maximally tolerated lipid-lowering therapy.

The trial was conducted across 188 sites in China, Europe, Japan, and the United States. Participants were recruited from cardiology clinics and lipid specialty centers from 2021 to 2024.

Participants with ASCVD in BROADWAY who had known ApoE status and phosphorylated tau-217 (p-tau217) measured at baseline and 12 months.

Participants in BROADWAY were randomized 2:1 to receive oral obicetrapib 10 mg daily or placebo for 12 months.

AD plasma biomarkers were measured at baseline and 12 months using standardized SIMOA assays. The key outcome measure of interest was change in plasma p-tau217 from baseline to 12 months. Other outcome measures included changes in p-tau217/(Aβ42:40), p-tau181, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL).

The analysis population consisted of 1535 (61 %) of the 2530 BROADWAY participants. Median age was 67 years and 67.0 % were male. Baseline p-tau217 levels varied significantly by ApoE subgroup s , with ApoE4 carriers generally having higher concentrations and ApoE4/E4 participants exhibiting the highest median concentration (0.56 pg/mL). Obicetrapib significantly attenuated p-tau217 increases compared to placebo (adjusted mean 2.09 % vs 4.94 %; P = 0.025). Treatment differences were most pronounced in ApoE4 carriers, where adjusted mean increases were 1.92 % and 6.91 %, for obicetrapib and placebo, respectively ( P = 0.041). Furthermore, among ApoE4/E4 participants, there was a 7.81 % adjusted mean decrease in p-tau217 with obicetrapib compared to a 12.67 % increase with placebo, representing a 20.48 % treatment difference ( P = 0.010). Positive trends were observed across secondary biomarkers, with obicetrapib also significantly limiting increases in the p-tau217/Aβ42:40 ratio compared to placebo (2.51 % vs 6.55 %; P = 0.004). In addition, among ApoE4/E4 participants, obicetrapib demonstrated significant effects on GFAP (-6.39 % vs +8.85 %; P = 0.006) and NfL (-10.49 % vs +6.82 %; P = 0.020). Strong correlations were observed between end-of-study obicetrapib plasma concentrations and biomarker improvements ( r =-0.64), suggesting CETP inhibition as a potential mechanism, although other drug effects may also contribute to these changes.

Obicetrapib significantly slowed AD biomarker progression over 12 months in participants with ASCVD, with the greatest effects in ApoE4 carriers. Among ApoE4/E4 participants, obicetrapib reduced p-tau217 levels by a placebo-adjusted 20.48 % and demonstrated consistent effects across multiple AD biomarkers. These findings represent the first demonstration of an oral intervention capable of reducing both beta-amyloid and tau pathology biomarkers in ApoE4 carriers, offering a potential preventive strategy for this high-risk population who currently have no effective prevention options. Future research will need to establish whether these biomarker changes translate to clinical benefits in dedicated AD prevention trials.

ClinicalTrials.gov Identifier: NCT05142722.