Amgen-Backed AMUNDSEN Trial Shows Early Repatha Drives LDL Targets but No One-Year Outcome Benefit

Starting Repatha (evolocumab) before percutaneous coronary intervention in patients hospitalized with high-risk acute myocardial infarction sharply improved LDL cholesterol control in the AMUNDSEN trial, but the intensive strategy did not significantly reduce death or unplanned cardiovascular hospitalization during the first year. At 12 months, 81.6% of evaluable patients assigned to early evolocumab reached the trial’s LDL-C target, compared with 39.6% under standard care, while the main clinical endpoint occurred in 14.6% and 15.4% of patients, respectively.

AMUNDSEN tested a question that matters beyond the cholesterol number itself: whether moving a PCSK9 inhibitor to the catheterization laboratory, before urgent or primary PCI, could improve both lipid control and near-term outcomes after a heart attack. The randomized phase 4 study enrolled 2,161 patients at 48 sites in six countries. It was supported by an unrestricted grant from Amgen and by the ACTION Study Group; the investigators reported that the funders had no role in the trial’s design, conduct, analysis, manuscript preparation, or publication decision.

Early Repatha More Than Doubled LDL Target Attainment

Patients were randomized to evolocumab 140 mg every two weeks for one year, with the first injection given before PCI, or to standard care alone. Standard care included high-intensity oral lipid-lowering treatment and allowed a PCSK9 inhibitor later when indicated. The AMUNDSEN results published in JAMA on August 29 showed that 792 of 970 evaluable patients in the evolocumab group met the primary lipid endpoint at one year, compared with 370 of 934 in the control group. That endpoint required both an LDL-C level below 55 mg/dL and at least a 50% reduction from baseline. The adjusted odds ratio was 5.54, with a 95% confidence interval of 4.50 to 6.82 and a P value below .001.

The separation appeared quickly. Six weeks after the acute event, median LDL-C was 16 mg/dL with early evolocumab and 56 mg/dL with standard care. At that point, 91% of the evolocumab group had already reached the combined LDL target, versus 34% of the control group. By 12 months, 76.5% of evaluable patients receiving evolocumab also had LDL-C below 40 mg/dL, compared with 20.6% under standard care.

The trial population was designed to capture patients at elevated risk after acute MI. Mean age was 67 years, 79% of participants were men, 58% presented with ST-elevation MI and 42% with non-ST-elevation MI. Mean LDL-C at admission was 116 mg/dL. Almost all participants, 96%, underwent primary or urgent PCI. On the day of randomization, 94% were receiving statins and 28% were receiving ezetimibe, so the comparison was not against an untreated control group.

Only 41 patients in the standard-care arm, or 3.8%, received a PCSK9 inhibitor during follow-up even though the protocol allowed later use under guideline indications. That gap helps explain why the study produced such a large difference in LDL target attainment. It also illustrates the practical issue AMUNDSEN was built to test: a stepwise approach can leave many post-MI patients above recommended LDL levels for weeks or months before therapy is intensified.

Clinical Outcomes Were Nearly Identical at One Year

The lipid result did not translate into a statistically significant one-year advantage on the main clinical endpoint. Death from any cause or an unplanned cardiovascular hospitalization occurred in 159 of 1,087 patients assigned to evolocumab and 165 of 1,074 assigned to standard care. The adjusted odds ratio was 0.94, with a 95% confidence interval from 0.73 to 1.19 and a P value of .59. The absolute difference was less than one percentage point.

Other event measures pointed in the same direction. A secondary composite of death, myocardial infarction, stroke or transient ischemic attack, or unplanned revascularization occurred in 10.0% of the evolocumab group and 10.9% of the standard-care group. Serious adverse events also did not differ between the groups. Those findings argue against the idea that giving evolocumab immediately before PCI produces an additional short-term clinical effect, beyond its LDL-lowering action, that can be detected within one year in a trial of this size.

A prespecified per-protocol analysis did show fewer deaths or unplanned cardiovascular hospitalizations among patients who adhered to the assigned strategy, 10.2% with evolocumab versus 14.3% with standard care. The trial authors treated that result cautiously and said likely selection bias means it needs confirmation. The intention-to-treat analysis remained the principal result, and it found no significant clinical benefit at one year.

That distinction is important when interpreting the headline. AMUNDSEN did not show that aggressive LDL lowering lacks cardiovascular value. Instead, it showed that immediate evolocumab produced much deeper and faster LDL reduction without demonstrating a measurable improvement in the prespecified clinical endpoint over the first 12 months. The study’s open-label design also creates potential for bias, although clinical events were adjudicated by an independent committee blinded to treatment assignment.

AMUNDSEN Tests a Faster Path for a Growing Repatha Franchise

For Amgen, the result lands as Repatha continues to grow commercially. The company reported that Repatha sales reached $953 million in the second quarter of 2026, up 37% from a year earlier, with the increase driven by volume growth. First-half sales were $1.83 billion, 35% higher year over year. AMUNDSEN does not change the central commercial fact that Repatha is already an established cardiovascular product, but it provides new evidence about how early the drug might be deployed after acute MI and what physicians can reasonably expect during the first year.

The study also sharpens the difference between achieving a biological target and proving a clinical outcome benefit on the same timetable. PCSK9 inhibition can reduce LDL-C rapidly, yet cardiovascular benefit from sustained lipid lowering may take longer to emerge. AMUNDSEN was powered for its one-year clinical composite, but it was not a multi-year outcomes study. Its authors said the absence of an early benefit argues against a clinically meaningful acute non-LDL effect of PCSK9 inhibition rather than against longer-term benefit from lower LDL exposure.

A larger Amgen-sponsored study is positioned to address that longer horizon. EVOLVE-MI has enrolled 6,019 patients hospitalized with acute MI and is comparing very early evolocumab plus routine lipid management with routine lipid management alone. Its primary outcome tracks total myocardial infarctions, ischemic strokes, arterial revascularizations, and all-cause deaths over roughly 3.5 years. ClinicalTrials.gov lists May 29, 2027 as the estimated primary completion date.

Until longer-term data arrive, AMUNDSEN leaves physicians and investors with a split result. Starting Repatha in the catheterization laboratory was far more effective than the usual stepwise strategy at getting high-risk post-MI patients to recommended LDL levels, and the difference appeared within weeks. What it did not do was establish a one-year reduction in death or unplanned cardiovascular hospitalization. The next test is whether maintaining that much lower LDL exposure for several years changes the clinical outcome curve that remained essentially flat during AMUNDSEN’s first year.