Merck’s enlicitide slashes LDL-C by 55.8%: Could this daily pill replace PCSK9 injections?

Enlicitide decanoate, Merck & Co., Inc.’s (NYSE: MRK) investigational oral PCSK9 inhibitor, achieved a 55.8 percent reduction in LDL-C at 24 weeks in the Phase 3 CORALreef Lipids trial, with results showing sustained efficacy and a safety profile comparable to placebo. The full data were presented at the American Heart Association Scientific Sessions 2025, positioning enlicitide as a potential first-in-class oral alternative to injectable PCSK9 therapies for patients with atherosclerotic cardiovascular disease (ASCVD).

Merck & Co., Inc. is aiming to make enlicitide the first oral PCSK9 inhibitor to receive regulatory approval. Designed as a once-daily pill, the therapy is intended to offer an accessible, high-efficacy option for patients with elevated cholesterol levels who are either statin-intolerant or unable to meet LDL-C goals through existing treatments. The Phase 3 findings highlight enlicitide’s promise in reshaping the lipid-lowering landscape.

How effective was enlicitide in reducing LDL-C and other atherogenic lipids in the CORALreef trial?

The Phase 3 CORALreef Lipids trial enrolled 2,912 adults with either established ASCVD or high risk for a first cardiovascular event. Participants received either 20 milligrams of oral enlicitide daily or a placebo, while continuing background lipid-lowering therapy or reporting documented statin intolerance. At week 24, the primary endpoint was met, with LDL-C levels falling 55.8 percent in the enlicitide group compared to placebo. A post-hoc reanalysis that removed five biologically implausible baseline values revised this to a 59.7 percent reduction.

Beyond LDL-C, the treatment demonstrated substantial reductions in other lipid metrics. At week 24, enlicitide lowered non-high-density lipoprotein cholesterol by 53.4 percent, apolipoprotein B by 50.3 percent, and lipoprotein(a) by 28.2 percent. By week 52, LDL-C reduction remained significant at 47.6 percent in the primary analysis and 52.4 percent in the post-hoc reanalysis, supporting enlicitide’s durability as a lipid-lowering agent.

Crucially, 67.5 percent of enlicitide-treated patients met the dual target of a minimum 50 percent LDL-C reduction and achieving LDL-C below 55 milligrams per deciliter, compared to just 1.2 percent in the placebo group.

What does the CORALreef Lipids trial design reveal about clinical rigor and patient diversity?

The CORALreef Lipids study was a randomized, double-blind, placebo-controlled trial designed to reflect real-world diversity. Participants were already on statins or had demonstrated intolerance, ensuring inclusion of a wide range of patient profiles. High adherence was reported across treatment groups, with 97 percent compliance to protocol and dosing schedules, reinforcing the viability of daily oral administration in long-term outpatient care.

The trial’s rigorous safety assessments showed no significant differences in adverse event incidence between enlicitide and placebo. Serious adverse events and deaths were balanced between arms. Discontinuations due to adverse events were minimal and similar, reported at 3.1 percent for enlicitide and 4.1 percent for placebo. These results support enlicitide’s tolerability, which is crucial for long-term cardiovascular risk management.

How does enlicitide differ from injectable PCSK9 inhibitors currently used in clinical practice?

Current PCSK9 inhibitors, such as alirocumab and evolocumab, are injectable monoclonal antibodies that lower cholesterol by blocking PCSK9’s interaction with LDL receptors, which results in increased cholesterol clearance. Enlicitide operates through the same biological mechanism but is formulated as a small molecule macrocyclic peptide designed for oral administration.

The advantage lies in ease of use. Injections often require cold-chain logistics, trained administration, and are associated with treatment inertia. Enlicitide eliminates these barriers by offering once-daily oral dosing without sacrificing potency. According to Dr. Dean Y. Li, president of Merck Research Laboratories, enlicitide was developed to deliver antibody-like efficacy and specificity in a patient-friendly pill format. Its ability to mimic injectable efficacy in a more accessible form may shift treatment preferences for both patients and physicians.

Why does enlicitide matter for ASCVD patients and global cardiovascular outcomes?

Atherosclerotic cardiovascular disease is the leading cause of death worldwide, responsible for approximately 85 percent of cardiovascular deaths. In the United States alone, hypercholesterolemia affects roughly 86 million adults, and a majority of treated patients still fail to meet LDL-C targets. These statistics underscore the need for novel therapeutics that improve access, adherence, and long-term risk reduction.

Dr. Ann Marie Navar of UT Southwestern Medical Center, a lead author of the study, stated that despite existing therapies, a large percentage of ASCVD patients fail to reach optimal lipid goals. Enlicitide, with its strong efficacy and placebo-comparable safety, offers a compelling new option to bridge this gap and address a critical public health challenge.

By lowering the treatment burden associated with injections and expanding options for statin-intolerant patients, enlicitide could significantly broaden the population of patients who successfully manage their cholesterol.

How does the broader CORALreef clinical program support Merck’s cardiovascular ambitions?

CORALreef Lipids is one of several trials evaluating enlicitide in different ASCVD populations. The broader CORALreef program includes CORALreef HeFH, focused on heterozygous familial hypercholesterolemia; CORALreef AddOn, for patients already on lipid-lowering therapy; and CORALreef Outcomes, a large-scale cardiovascular outcomes trial with more than 14,500 participants.

Merck & Co., Inc. is also conducting complementary trials such as CORALreef Extension, CORALreef Pediatric, and CORALreef Combination. In total, over 19,000 patients are being evaluated across this clinical program, reinforcing the company’s commitment to establishing enlicitide as a foundational therapy in lipid management.

The breadth and depth of this program indicate that Merck & Co., Inc. is not treating enlicitide as a niche offering but as a cornerstone of its revived cardiovascular portfolio.

What does investor sentiment and market positioning look like for Merck after these results?

Investor response to the CORALreef Lipids data has been measured but positive. Analysts view enlicitide as a strategic expansion beyond Merck & Co., Inc.’s oncology-heavy portfolio, led by Keytruda. While the company’s share price saw only a modest lift following the AHA presentation, the broader financial outlook hinges on successful regulatory filings and eventual commercialization.

Institutional investors are closely watching how enlicitide will be priced and reimbursed, particularly in markets where existing PCSK9 injectables face cost-related headwinds. Analysts expect enlicitide to be priced competitively and to benefit from its oral formulation when it comes to payer negotiations and patient uptake.

Should the drug secure approval and demonstrate strong real-world adherence advantages, enlicitide could capture substantial market share from Regeneron Pharmaceuticals and Amgen. However, analysts caution that Merck & Co., Inc.’s long-term success in this space will depend on execution, including outcomes trial readouts and global health system partnerships.

What happens next in Merck’s regulatory journey for enlicitide?

Merck & Co., Inc. plans to submit results from the CORALreef Lipids, CORALreef HeFH, and CORALreef AddOn trials to regulatory authorities worldwide. These filings will seek to establish enlicitide as the first oral PCSK9 inhibitor approved for use in reducing LDL-C levels in patients with ASCVD or high cardiovascular risk.

The upcoming results from CORALreef Outcomes will be especially significant, as cardiovascular endpoint data could reinforce enlicitide’s place in treatment guidelines and payer coverage frameworks. Pending these outcomes and regulatory approvals, Merck & Co., Inc. aims to bring enlicitide to market within the next two years.

This strategy aligns with the company’s long history in cardiovascular innovation, dating back nearly 70 years. With enlicitide, Merck & Co., Inc. is once again seeking to lead in one of the most consequential categories in global health.

What are the key takeaways from Merck’s enlicitide Phase 3 trial and its potential impact on ASCVD care?

• Enlicitide decanoate, Merck & Co., Inc.’s oral PCSK9 inhibitor, reduced LDL-C by 55.8 percent at week 24 in the Phase 3 CORALreef Lipids trial.
• The post-hoc reanalysis showed an even greater LDL-C reduction of 59.7 percent, excluding biologically implausible baseline values.
• Sustained LDL-C lowering was observed through 52 weeks, with reductions of up to 52.4 percent.
• Secondary lipid markers also improved significantly, including a 53.4 percent drop in non-HDL-C, a 50.3 percent decrease in apolipoprotein B, and a 28.2 percent reduction in lipoprotein(a).
• 67.5 percent of patients on enlicitide achieved both a 50 percent LDL-C reduction and LDL-C levels under 55 mg/dL, compared to only 1.2 percent in the placebo group.
• The safety profile of enlicitide matched that of placebo, with low adverse event discontinuation rates.
• Enlicitide is formulated as a once-daily pill and could become the first oral PCSK9 inhibitor approved for ASCVD treatment.
• Merck & Co., Inc. plans to file regulatory submissions based on CORALreef Lipids, HeFH, and AddOn trials, and awaits outcomes data from CORALreef Outcomes.
• Analysts see enlicitide as a potential game-changer in lipid management, offering a scalable, adherence-friendly alternative to injectable PCSK9 therapies.
• The CORALreef clinical program spans over 19,000 participants and reflects Merck & Co., Inc.’s strategic push to re-establish leadership in cardiovascular care.