Esperion and Daiichi Sankyo square up on Nexletol milestone

Shares in Esperion Therapeutics lost more than half of their value after it disclosed a dispute with Daiichi Sankyo on a $300 million milestone payment relating to cholesterol drug Nexletol.

The disagreement revolves around the results of the CLEAR study of Nexletol (bempedoic acid) reported earlier this month, which backed use of the drug for patients with elevated cholesterol and at risk of a heart attack who don’t respond to statin drugs.

It’s a case of how you interpret the results. Esperion maintains that a 13% reduction in the overall risk of major cardiovascular adverse events (MACE), plus a 23% reduction in heart attack and a 19% drop in coronary revascularisation procedures, means that the conditions for payment have been met.

On the other hand, Daiichi Sankyo – which licenses rights to Nexletol in some markets – disagrees. It is on the hook for the milestone payment once the CLEAR results are added into the drug’s label in Europe, with its size tied to the magnitude of the drug’s effect on cardiovascular outcomes.

At issue is the 20% threshold for payment in their licensing agreement. Esperion insists that the heart attack reduction means it has satisfied the requirement, but Daiichi Sankyo begs to differ, saying it should only apply to the 13% MACE readout, and that means it does not have to make any milestone payment.

In a filing with the Securities & Exchange Commission (SEC), Esperion has indicated that it “strongly disagrees” with Daiichi Sankyo’s stance, adding that if necessary it will “enforce its contractual rights and seek the milestone payments it believes it is entitled to.”

Nexletol has been approved as an alternative to statins since 2020, becoming the first drug in the ATP citrate lyase (ACL) inhibitor class to reach the market, and was once tipped as a future blockbuster. Sales growth has been sluggish, however, at just $56 million in the US last year, and Esperion had been looking at the CLEAR results to accelerate take-up.

Arguably just as important was the expected cash injection from Daiichi Sankyo, given that Esperion ended 2022 with around $167 million in cash and has said it expects full-year 2023 operating expenses to be between $225 million and $245 million.

Any resolution of the dispute with Daiichi Sankyo could be months or even years away, and in any event will only come into play once the CLEAR results are added to Nexletol’s label. And Esperion has yet to file the cardiovascular risk reduction data for approval in the US and Europe.

There have been reports that Esperion plans to file a lawsuit over the matter within the next few days, in the hope of getting a judgment ahead of the outcome of the regulatory reviews.

Image by Benoît DE HAAS from Pixabay