Ionis, Novartis heart drug fails in late-stage trial

• Pelacarsen did not reduce the risk of major cardiovascular events including heart disease death, heart attack, stroke, or urgent procedures to restore blood flow compared to placebo
• The drug successfully lowered lipoprotein(a) cholesterol levels as in previous studies, but this did not translate to cardiovascular risk reduction
• Pelacarsen was one of three experimental drugs representing more than $10 billion in potential peak annual sales for Novartis and a driver of the Swiss drugmaker's long-term growth plans

Summary: Ionis-Novartis Heart Drug Fails Late-Stage Trial

Ionis Pharmaceuticals and partner Novartis announced on September 4 that their experimental heart drug pelacarsen failed to meet primary endpoints in a late-stage clinical trial. The drug, designed to lower lipoprotein(a)—a cholesterol-carrying particle—did not reduce the risk of major cardiovascular events including heart disease death, heart attack, stroke, or urgent cardiac procedures compared to placebo.

While pelacarsen successfully lowered lipoprotein(a) levels consistent with earlier studies, this biochemical effect did not translate into meaningful cardiovascular risk reduction for patients. Ionis CEO Brett Monia expressed disappointment that the positive impact on lipoprotein(a) levels failed to deliver clinical benefits.

Market Implications:

The failure represents a significant setback for both companies, particularly Novartis. Pelacarsen was one of three key experimental drugs—along with multiple sclerosis treatment remibrutinib and genetic therapy elu-desiran—that collectively represent over $10 billion in potential peak annual sales. These drugs are critical drivers of Novartis' long-term growth strategy, making this outcome particularly consequential for investors.

The failed trial highlights ongoing challenges in cardiovascular drug development, where reducing biomarkers doesn't always correlate with improved patient outcomes. This setback may pressure Novartis to rely more heavily on its other pipeline candidates to meet growth expectations and could impact both companies' stock valuations in the near term.

For the broader pharmaceutical sector, this serves as another reminder of late-stage clinical trial risks, even when earlier-phase data appears promising.