EMA investigates Allergan blockbuster hopeful Esmya on reports of liver damage

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The EMA has recorded four cases of liver damage among patients taking Allergan's Esmya.

As Allergan chases a U.S. approval for uterine fibroids drug Esmya, across the pond, regulators are investigating the treatment for liver damage.

The European Medicines Agency’s (EMA) Pharmacovigilance Risk Assessment Committee (PRAC) has launched a review of the product after four cases of serious liver damage turned up among patients, Bernstein’s Ronny Gal wrote in a note to clients. Three of those cases ended in liver transplantation, the EMA noted.

While “our immediate reaction to the news was concern about risk to the FDA approval,” Gal wrote, investors should rest assured that there’s no reason to panic. 670,000 patients have received Esmya, and “this appears to be a standard review procedure ... with no alerts to the public,” he said. Plus, a high dose of the compound is already approved in the U.S. as an emergency contraceptive.

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Allergan, for its part, does not expect the investigation will have an impact on its New Drug Application, a company spokesman said by email, adding that "we do not believe there is a causal relationship between Esmya and liver transplantation." No cases of liver transplantation came up in any of the controlled clinical trials for Esmya in the EU, Canada or the U.S., he said.

Still, it’s “something to watch,” Gal figures, as Allergan’s going after a label for chronic use “without time limits.” And the product’s ability to reach blockbuster heights—as Allergan insists it can—depends on the label’s breadth.

Analysts, for their part, aren’t quite as optimistic about Esmya’s sales potential, PRAC investigation aside. RBC Capital Markets’ Randall Stanicky forecasts $829 million in 2023 sales, while Barclays analyst Doug Tsao has cited a peak sales estimate from First Order Analytics that hits as low as $286 million.

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One reason for their caution? Forthcoming competition from AbbVie and Neurocrine Biosciences in the form of elagolix, a prospect currently in phase 3 trials. Allergan marketing chief Bill Meury, though, isn’t worried about the market crowding.

“Pharmacologically and clinically, elagolix and Esmya are different,” he said in an October interview. “I believe they’ll be used in different populations, and I believe that the two compounds can coexist in the market.”

Meanwhile, RBC’s Stanicky figures the Dublin drugmaker should hive off women’s health altogether. The way he sees it, it’s a chance to drum up $6 billion in deal proceeds, with companies such as Impax, Lupin and CooperSurgical making likely suitors.