Peter Attia hosts this special episode of The Drive Podcast, diving deep into obicetrapib, a CETP inhibitor that has captured his attention for both cardiovascular and potential Alzheimer's disease applications.

The discussion covers the complex history of CETP inhibitors, explaining why four previous drugs in this class failed spectacularly, from torcetrapib's blood pressure toxicity to dalcetrapib's lack of efficacy. Attia walks through the biology of reverse cholesterol transport and how CETP mediates the exchange between HDL and LDL particles.

The episode focuses heavily on the Broadway biomarker study, which examined Alzheimer's-related blood markers in patients taking obicetrapib. The most compelling findings emerged in APOE4 carriers, particularly those with two copies of the E4 allele, where the drug showed dramatic improvements in tau and neuroinflammation markers.

Attia explains the connection between lipid biology and brain health, detailing how APOE4 carriers have impaired cholesterol transport in the brain and why increasing functional HDL particles through CETP inhibition might compensate for this genetic disadvantage.

The Graveyard of CETP Inhibitors: Four Failed Attempts

Torcetrapib was terminated in 2006 due to increased mortality from blood pressure elevation, an off-target toxicity unrelated to CETP inhibition that hasn't affected subsequent drugs in the class.

Dalcetrapib raised HDL cholesterol by 30-40% but didn't meaningfully lower LDL or APOB, leading to no cardiovascular benefit and abandonment by Roche in 2012.

Evacetrapib doubled HDL cholesterol and reduced LDL by 30%, but APOB only fell 12 mg/dL - insufficient to show benefit over two years, causing Eli Lilly to terminate the program in 2015.

Anacetrapib showed 9-10% reduction in coronary events over four years, proving CETP inhibitors could work, but Merck pulled it due to concerns about long half-life and fat cell retention.

Obicetrapib's Breakthrough Lipid Results

In the Phase II ROSE trial, obicetrapib added to high-intensity statin therapy produced an additional 50% LDL cholesterol reduction and 30% APOB reduction.

The ROSE II trial combining high-intensity statin, ezetimibe, and obicetrapib achieved over 60% LDL cholesterol reduction, demonstrating unprecedented lipid-lowering power.

Broadway Phase III trial enrolled 2,500 patients with established atherosclerotic disease or familial hypercholesterolemia on maximum therapy, showing 30% additional LDL reduction and 16% APOB reduction.

LP(a) fell by one-third across trials, likely through decreased synthesis of apolipoprotein(a), addressing a genetically determined risk factor affecting one in eight to twelve people.

Brain Biology and APOE4: The Lipid Connection

The brain operates its own cholesterol economy behind the blood-brain barrier, using APOE proteins instead of APOA1 to shuttle lipids between astrocytes, microglia, and neurons.

APOE4 carriers produce less efficiently lipidated proteins that form unstable lipoprotein particles, leading to impaired cholesterol transport and lipid droplet accumulation in brain cells.

The dysfunction stems from a single amino acid substitution - cysteine to arginine at position 112 - that alters protein shape and downstream behaviors, similar to sickle cell disease.

Small, lipid-poor HDL particles containing APOA1 can cross the blood-brain barrier in limited amounts, potentially augmenting cholesterol efflux where APOE4 function is impaired.

Broadway Biomarker Study: Alzheimer's Signals

The pre-specified biomarker analysis included over 1,500 participants (median age 67, two-thirds male) with cardiovascular disease but no cognitive impairment, stratified by APOE genotype.

Primary endpoint pTau217 increased 5% in placebo versus 2% in obicetrapib across all participants, with stronger effects in APOE4 carriers (7% vs 1.5% increase).

In APOE4/4 carriers over 70 (29 people), placebo showed 12.7% pTau217 increase while obicetrapib showed 7.8% decrease - a statistically significant 20% difference.

All secondary biomarkers moved favorably in APOE4/4 carriers: NFL (17% difference), GFAP (15%), pTau181 (14%), and pTau217/Aβ42:40 ratio (23% difference).

Clinical Implications and Future Directions

"I haven't been as excited about any drug in the market or a drug that's about to enter the market as I am with respect to this drug" - Peter, emphasizing his cautious optimism.

European approval expected Q4 2026 based on biomarker data, while US approval awaits PREVAIL cardiovascular outcome trial results showing hard endpoints.

An ideal prevention trial would enrich for APOE4 carriers, track cognitively intact individuals in their 60s-70s for several years with longitudinal cognitive endpoints and serial biomarkers.

The drug shows metabolic neutrality or potential benefit, contrasting with statins' small but real increase in type 2 diabetes risk, suggesting cholesterol reduction itself isn't the culprit.