PCSK9 inhibitor combined with a statin may help reduce LDL cholesterol after heart transplant

The cholesterol medication alirocumab, a PCSK9 inhibitor, combined with a statin appeared to reduce LDL cholesterol levels by more than 50% among patients after a heart transplant, according to a late-breaking science presentation today at the American Heart Association's Scientific Sessions 2025. The meeting, Nov. 7-10, in New Orleans, is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science.

Our study found treating patients who have had a heart transplant with a more aggressive cholesterol management regimen was safe and lowered their LDL-cholesterol levels significantly. These results support PCSK9 inhibitors for patients who have high LDL cholesterol levels in conjunction with statin therapy, however, we need more studies testing treatment with PCSK9 inhibitors with longer term follow-up with more participants to confirm if PCSK9s can reduce the development of cardiac allograft vasculopathy."

William F. Fearon, M.D., FAHA, study author, professor of medicine and chief of interventional cardiology at Stanford University School of Medicine in Stanford, California

According to the American Heart Association, high LDL (low-density lipoprotein) cholesterol, known as "bad" cholesterol, has no symptoms, but it can increase risk for cardiovascular issues because it can cause plaque to build up in the arteries. This buildup may block blood flow or break loose and cause a heart attack or stroke.

In this clinical trial, called CAVIAR (Cardiac Allograft Vasculopathy Inhibition with AliRocumab), researchers tested the safety and effectiveness of adding the PCSK9 inhibitor alirocumab to a statin regimen among patients soon after a heart transplant to prevent the development of cardiac allograft vasculopathy (CAV). CAV is common and the primary cause of death for many patients after a heart transplant. The study, which included more than 100 adults after a heart transplant, also evaluated the change in coronary artery plaque volume soon after the heart transplant through one year later. Participants were assigned to take either alirocumab or a placebo, together with rosuvastatin, a commonly prescribed cholesterol-lowering medication.

The trial results showed that one-year post-transplant, alirocumab plus rosuvastatin was safe and effectively lowered LDL cholesterol. The cholesterol-lowering impact of taking both medications was beyond what was achieved with rosuvastatin alone. Coronary plaque reduction was not significant in either group though, and there was no statistically significant difference between the plaque progression in the groups.

After one year, the study found:

• The average LDL cholesterol levels decreased by more than 50% among participants in the alirocumab group-from 72.7 mg/dL at enrollment to 31.5 mg/dL. The average LDL cholesterol levels among participants in the placebo group did not statistically change from the average 69.0 mg/dL at enrollment.
• Although the coronary artery plaque volume increased numerically in both groups from baseline to 12 months, there was no change in plaque volume between the alirocumab and placebo group.
• Plaque progression was minimal in both the alirocumab groups and the placebo group.
• There were no significant side effects in either group.

The study had some limitations, with researchers noting that because there was less plaque progression than expected between both groups and because the LDL levels were low at baseline in the rosuvastatin alone (placebo) arm, the study power to detect a difference when adding alirocumab was reduced. Based on various research studies, the American Heart Association recommends a "lower is better" approach for cholesterol, especially LDL-C, rather than a single ideal number for everyone. For healthy adults, an LDL-C level below 100 mg/dl is considered ideal. For those with pre-existing conditions like atherosclerotic cardiovascular disease or diabetes, target levels are more stringent and the guidelines focus on reducing LDL-C to 70 mg/dL or lower.

Study details, background and design:

• The study group included 114 adults who had heart transplants; their mean age was 58 years old.
• Stanford University conducted the trial, starting in 2019. Transplant patients were identified at two health care centers: Stanford Medical Center and Kaiser Permanente in Santa Clara, California.
• Participants were enrolled in the trial within eight weeks after the heart transplant and randomly assigned to one of two groups: group one (57 adults) was prescribed 150 mg of alirocumab with rosuvastatin; group two (57 adults) was assigned to take a placebo with rosuvastatin.
• At time of enrollment in the trial and one year after the heart transplant, all participants underwent additional screening procedures to evaluate the blood flow and plaque buildup in their coronary arteries.

CAV, which causes narrowing and blockage of vessels supplying blood to the heart, is a common complication after a heart transplant and a primary cause of death after a transplant. High LDL cholesterol is a contributing factor to CAV, and it is usually treated with statins. Treatment with statins alone, however, often falls short in achieving the target levels for low cholesterol.