Heart Disease Clinical Trials 2026: Cardiovascular Studies and Recruiting Research

Cardiovascular disease remains the leading cause of death globally, and the research pace has not just kept up — it's accelerated. The most structurally interesting change in 2026 isn't a new drug molecule; it's the transformation of lipid management from a daily adherence problem into a twice-yearly injection. Inclisiran gives you 50% LDL-C reduction from two injections per year. Its cardiovascular outcomes trial is enrolling 22,000 patients. Meanwhile, Lp(a) — which until recently was a risk factor you could identify but couldn't treat — finally has multiple siRNA agents in Phase 3 outcomes trials. For a field that spent decades mostly refining statins, this is a genuinely different era.

GLP-1 Agonists: Cardiovascular Drugs That Also Cause Weight Loss

The framing matters here. Semaglutide and tirzepatide are not weight loss drugs that happen to have cardiovascular benefits — they are cardiovascular drugs with substantial metabolic effects. The SELECT trial (NCT03574597) enrolled patients with established cardiovascular disease but without diabetes and randomized them to semaglutide 2.4mg weekly versus placebo. The primary composite endpoint — non-fatal MI, non-fatal stroke, cardiovascular death — was reduced by 20% (HR 0.80, 95% CI 0.72–0.90) over ~3 years of follow-up. Weight loss contributed to some of the benefit, but analyses show the cardiovascular protection exceeds what weight change alone would predict, suggesting direct cardiac and vascular effects.

Semaglutide received expanded FDA approval for cardiovascular risk reduction in 2024, making it the first obesity drug with a labeled MACE indication. The SOUL trial confirmed the same 14% MACE reduction with oral semaglutide in T2D patients with high CV risk, validating cardiovascular benefit across delivery routes. Now the trials are pushing into new populations: FLOW-HF is examining semaglutide in HFpEF; tirzepatide's SURPASS-CVOT is fully enrolled; and EVOKE-2 is investigating GLP-1 cardiovascular and neurovascular protection in patients without current GLP-1 indications.

Lipid Lowering: RNA Therapies and the Lp(a) Problem

PCSK9 inhibitors (evolocumab/Repatha, alirocumab/Praluent) achieve 50–60% additional LDL-C reduction on top of statins, but require injections every 2–4 weeks and face cost and adherence barriers that have limited real-world uptake despite compelling trial data. Inclisiran (Leqvio) solves the adherence problem with a different mechanism: it's an siRNA that silences PCSK9 production in hepatocytes directly, requiring only two injections per year after an initial dose — at months 0 and 3, then every 6 months thereafter. The ORION program demonstrated 50% sustained LDL-C reduction. What remains unknown is whether this translates to MACE reduction; the ORION-4 Phase 3 outcomes trial (22,000 patients, primary MACE endpoint) is the pivotal study, with results expected 2026–2027.

Lp(a) reduction is the emerging frontier. Elevated Lp(a) affects approximately 20% of the global population and confers cardiovascular risk that statins don't touch — but until recently, no approved agent reduced it meaningfully. Pelacarsen (an antisense oligonucleotide targeting Lp(a) synthesis) is in the HORIZON Phase 3 outcomes trial. Olpasiran (siRNA, AMG 890) and lepodisiran (Eli Lilly) are in OCEAN(a)-OUTCOMES and ACCLAIM trials respectively. These are the first large randomized trials to test Lp(a) reduction as a cardiovascular endpoint — we don't yet know whether lowering Lp(a) reduces events, and these trials will answer that definitively.

HFpEF: Finally Getting Some Answers

Heart failure with preserved ejection fraction (HFpEF) — where the ventricles are stiff and don't fill normally despite normal contractility — accounts for roughly half of all heart failure and had essentially no proven pharmacological treatment until 2022. SGLT2 inhibitors empagliflozin and dapagliflozin changed that with EMPEROR-Preserved and DELIVER, demonstrating significant reductions in heart failure hospitalization. Modest reductions, to be clear — not the kind of mortality data that transformed HFrEF management — but real and guideline-recommended.

The SUMMIT trial (tirzepatide in HFpEF patients with obesity) produced something more striking: a 38% reduction in heart failure events and significant improvements in KCCQ score (symptom burden) and 6-minute walk distance. The effect was large enough that many HFpEF specialists consider tirzepatide the most promising new therapy in the phenotype, though the patient population (HFpEF with obesity) is specific. FINEARTS-HF is evaluating finerenone (non-steroidal mineralocorticoid receptor antagonist) in HFpEF with top-line results expected in 2026. Anti-inflammatory approaches — colchicine for post-MI cardioprotection, ziltivekimab (anti-IL-6 ligand) for HF with elevated inflammatory markers in ZEUS — are expanding the portfolio of mechanistically distinct approaches.

Gene Therapy: ATTR Cardiomyopathy and Beyond

Transthyretin amyloid cardiomyopathy (ATTR-CM) affects an estimated 500,000 Americans — predominantly older adults and those of West African descent carrying the Val122Ile variant — and was historically difficult to diagnose and impossible to cure. RNA interference therapies have changed the trajectory. Vutrisiran (HELIOS-B trial) demonstrated significant cardiovascular event reduction. Eplontersen (NEURO-TTRansform) showed deep TTR knockdown with meaningful cardiovascular and neurological benefits.

What makes the ATTR story particularly remarkable in 2026 is the gene editing data. NTLA-2001 (Intellia Therapeutics) is a CRISPR base editing construct that targets TTR-producing hepatocytes with a single IV infusion. Phase 1/2 data showed ~90% TTR knockdown that has persisted at 18+ months follow-up without any return of protein. A single treatment that durably eliminates the source of the misfolded protein — if this holds in larger trials, it would be a functional cure. Phase 2 enrollment is ongoing.

For AAV-based cardiac gene therapy, the PRECISION trial is evaluating SERCA2a gene delivery in heart failure with reduced ejection fraction — restoring calcium handling function to dysfunctional cardiomyocytes. This was a concept proposed in the 1990s based on understanding of cardiac physiology; it's taken this long to have a delivery vector safe enough and efficient enough to test clinically.

How to Access Cardiovascular Trials

Cardiovascular trials are more geographically distributed than most specialties — they're conducted at community cardiology practices, regional hospitals, and academic medical centers across the country, not only at NCI-designated centers. Key eligibility data to have ready before contacting any trial: most recent echocardiogram with ejection fraction documented, BNP or NT-proBNP level, LDL-C value on current therapy, eGFR, and a complete medication list including dose. For ATTR-CM trials specifically, TTR gene testing and a recent cardiac MRI are typically required. ClinicalTrials.gov searches by condition ("Heart Failure," "Coronary Artery Disease," "Transthyretin Amyloid") filtered to "Recruiting" reveal the full landscape; the American Heart Association's Patient Pages provide condition-specific context.

Key Trial Data Points

• SELECT trial: semaglutide 2.4mg reduced MACE by 20% (HR 0.80) in patients with CVD but no diabetes — GLP-1 agonists now carry a labeled cardiovascular risk reduction indication.
• SUMMIT trial: tirzepatide reduced HFpEF cardiovascular events by 38% in obese patients, with significant KCCQ and 6-minute walk improvements — strongest HFpEF signal since SGLT2 inhibitor data.
• ORION-4 (22,000 patients): the pivotal inclisiran cardiovascular outcomes trial; results expected 2026–2027 will determine whether twice-yearly siRNA LDL lowering reduces hard events.
• NTLA-2001 CRISPR base editing: ~90% TTR knockdown persisting 18+ months from a single dose in ATTR-CM Phase 1/2 — Phase 2 enrollment ongoing.
• Lp(a) outcomes trials (HORIZON, OCEAN(a)-OUTCOMES): first large randomized trials testing whether Lp(a) reduction prevents CV events — results will determine whether elevated Lp(a) is a treatable risk factor or merely a marker.