Esperion Gets No FDA Clarity on Cholesterol Drug’s Approval Path

(Bloomberg) -- Esperion Therapeutics Inc. said its experimental drug may not be able to win U.S. Food and Drug Administration approval based solely on its ability to cut cholesterol, the requirement used to clear previous medicines, because the agency may change the way it views treating people with elevated levels of bad cholesterol.

The company said Tuesday it plans to begin the third round of studies typically needed for approval of a new medicine by the fourth quarter, with the results showing whether bempedoic acid significantly reduces bad cholesterol by 2019. The shares slumped 23 percent after the markets closed.

Esperion also will start a longer study by the end of this year to assess whether the pill reduces heart complications in high-risk patients who aren't able to take statin medications, the current standard of care. The result of that trial, expected by 2022, may be necessary to get approval in the U.S., the Plymouth, Michigan-based company said in a statement.

The drugmaker said the FDA wouldn't provide it with clarity on whether proof that the drug lowers bad cholesterol, known as low-density lipoprotein, or LDL, will be enough to get access to the U.S. market. While the agency granted limited approval to drugs from Sanofi, Regeneron Pharmaceuticals Inc. and Amgen Inc. based on their potent cholesterol-lowering abilities, definitive studies showing whether that translates into fewer heart attacks, strokes and deaths are still pending.

FDA officials “aren't willing to give advice on whether an LDL lowering indication will be available years from now,” Esperion Chief Executive Officer Tim Mayleben said. “It's not that the rules are different, but the FDA is saying that they don't know if it will be different.”

Any time a drug's benefit is measured by its effect on a surrogate marker, such as LDL cholesterol, its true ability to improve health remains somewhat uncertain, said Theresa Eisenman, an FDA spokeswoman. The agency approved the injected cholesterol lowering drugs for specific groups of patients because the benefit was expected to outweigh the risks, even before the final studies were complete, she said.

For future decisions, the drug's mechanism of action, magnitude of benefit, potential for side effects or other harm, and the target population could all affect the likelihood that the agency would approve a drug that works in an entirely new way based on its cholesterol-lowering effects, she said.

--With assistance from Anna Edney To contact the reporter on this story: Michelle Fay Cortez in Minneapolis at mcortez@bloomberg.net. To contact the editors responsible for this story: Drew Armstrong at darmstrong17@bloomberg.net, Cecile Daurat, John Lauerman