Researchers reported on Saturday that an experimental medication intended to prevent heart attacks and strokes has failed a critical clinical test. The drug, which targets a specific blood particle linked to cardiovascular events, did not protect the volunteers in the closely monitored study. This result marks a significant setback in the ongoing effort to find new therapies for a leading cause of death in developed nations.
Steven Nissen, a cardiologist at the Cleveland Clinic who led the research, described the outcome as shocking. He noted that despite high hopes for success, the study did not yield the expected reduction in risk. Nissen emphasized that cardiovascular disease remains the top killer in many countries, making the search for additional protective treatments a priority for the medical community.
The study focused on patients who maintain healthy lifestyles, including low cholesterol, controlled blood pressure, balanced diets, and regular exercise. Despite these precautions, many individuals still experience heart attacks and strokes. Nissen explained that these patients are frequently seen in clinics and often have elevated levels of lipoprotein(a), or Lp(a). This cholesterol-carrying protein has long been associated with an increased risk of heart disease.
According to Nissen, approximately 20% of the global population has elevated Lp(a) levels, affecting roughly one billion people. Until recently, physicians had limited options to lower these levels. However, several pharmaceutical companies have developed new experimental medications capable of significantly reducing Lp(a), leading to heightened expectations for clinical success.
The trial involved 8,350 adults who already had heart disease. Participants were randomly assigned to receive either a placebo or pelacarsen, a drug designed to cut Lp(a) levels. The researchers confirmed that the drug successfully suppressed Lp(a) by about 78%. However, after five years of treatment, this reduction did not translate into fewer cardiovascular complications for the patients.
Nissen presented the initial findings at an American Heart Association meeting in Chicago and published detailed results in the New England Journal of Medicine and NEJM Evidence. He called the results very disappointing. Novartis, the drugmaker that sponsored the study, had announced in the previous month that the results did not meet its goals, though it did not initially release specific data.
In a statement, Novartis said the study provides meaningful evidence regarding the relationship between Lp(a) and heart disease. The company stated that the findings may help inform future approaches to cardiovascular management and that such challenging studies play a crucial role in advancing the field, even when the results are not what was hoped for.
Experts are now analyzing why the drug failed to provide the expected benefits. Harlan Krumholz, a cardiologist at Yale University, noted that the high expectations made the negative result particularly jarring. Researchers are considering the possibility that high Lp(a) levels might be a marker for other underlying risks rather than a direct cause of heart attacks and strokes.
Other hypotheses include the need for longer or earlier treatment, such as before advanced hardening of the arteries occurs. Some experts suggest that the drug might only benefit patients with higher baseline Lp(a) levels or those with less well-controlled blood pressure and cholesterol. It is also possible that pelacarsen specifically has characteristics that limit its effectiveness, while other drugs in the same class might succeed.
Several other pharmaceutical companies, including Amgen and Eli Lilly, are currently testing different experimental Lp(a)-lowering drugs. Results from these trials are expected to emerge over the next few years. Karol Watson, a cardiologist at the University of California, Los Angeles, stated that the story is not over and that the research field is only just beginning to unfold.
