Esperion shares yo-yo as NEJM papers downplay cancer death data

An NEJM paper and editorial on bempedoic acid have countered concerns that safety problems will derail Esperion Therapeutics’ efforts to bring the cholesterol drug to market. The publications side with Esperion’s interpretation that the imbalance in cancer deaths is a chance finding.

When Esperion posted phase 3 data on ATP citrate lyase inhibitor bempedoic acid last year, investors looked past the efficacy data and zeroed in on a safety signal. Specifically, 13 people in the treatment arm died, compared with two people in the smaller control arm. The imbalance raised concerns that regulators would request another trial or ultimately block Esperion’s path to market altogether.

Esperion was more sanguine, noting that only 15 of the 2,230 patients enrolled in the study died and arguing that the imbalance—including details such as the divergent rates of cancer deaths—were chance findings, rather than red flags about the safety of bempedoic acid.

Publications in NEJM have reached similar conclusions. The write up of the trial, which lists Esperion’s director of clinical development among its authors, stated that “observed imbalances in deaths from cancer are likely to be a chance finding.” That conclusion is underpinned by the fact that deaths from cancer occurred throughout the trial and the balance in nonfatal neoplasms between the arms.

In an accompanying editorial, the University of Oxford’s Michael Holmes argued that while the death imbalance is “potentially alarming,” the 95% confidence intervals renders “the relative risk values virtually meaningless.” If FDA reaches a similar conclusion, bempedoic acid could win approval early next year. 

The interpretations provided in NEJM offered succour to observers who fear the death imbalance will block Esperion’s path to market. Jefferies analyst Michael Yee wrote that the publications “should refute any lingering arguments” about the safety of the drug. 

Esperion shares initially rose 7% on the back of the publications, although the stock remains well down on the levels it hit before the phase 3 data dropped. Later Thursday morning, shares were in the red by around 7%.