By Joseph Walker
The U.S. Food and Drug Administration has become aware of
cognitive adverse events related to a closely watched group of
experimental anti-cholesterol drugs being developed by large drug
firms, Sanofi SA said in a regulatory filing Friday.
The FDA has asked Sanofi and Regeneron Inc., which are
codeveloping one of the drugs, known as PCSK9 inhibitors, to assess
the potential for their drug to cause neurocognitive adverse
events, Sanofi said, reiterating a similar disclosure Regeneron
made in a February filing.
Several other companies, including Amgen Inc. and Pfizer Inc.,
are also developing PCSK9 inhibitors. Analysts and investors have
watched development of the drugs closely because of their potential
to treat millions of patients whose high cholesterol isn't well
controlled with statins.
Shares of Regeneron fell as much 11% on Friday, underscoring the
high expectations that many investors have placed on Regeneron and
Sanofi's drug. Regeneron shares won back some of their losses by
the end of the day, and were down 3% to $329.11 at the close of
regular trading. Shares of Amgen fell 1.55% to $122.26. American
depository shares of Sanofi fell 1.1% to $51.93.
In a phone interview Friday, Regeneron Chief Executive Leonard
Schleifer said the FDA made the request of Sanofi and Regeneron in
February. The FDA also asked that the companies inform regulators
of the feasibility of including neurocognitive testing in at least
a subset of patients in one or more of their clinical trials,
according to the filings.
Dr. Schleifer said Regeneron and Sanofi haven't been informed of
the specific adverse events the FDA has observed. He said the
companies haven't seen any indication of such events in their
clinical studies. The drug Sanofi and Regeneron are developing,
alirocumab, is currently in late-stage clinical studies.
"We're not aware of any safety concern right now," Dr. Schleifer
said.
In an email, Sanofi spokesman Jack Cox said the company has "not
seen a neurocognitive adverse event (safety) signal in the
alirocumab data."
Currently approved treatments for high cholesterol called
statins include warnings about the potential for cognitive
impairment, including memory loss, amnesia and confusion. Dr.
Schleifer said he thought these were the types of adverse events
the FDA might be concerned about.
Kristen Davis, an Amgen spokeswoman, said in an emailed
statement that Amgen has been communicating with the FDA regarding
reports of neurocognitive adverse events related to PCSK9 drugs.
Amgen had previously reported amnesia and memory or mental
impairment in less than or equal to 1% of patients in a 52-week
clinical study, she said. "We will continue to monitor for these
events carefully," Ms. Davis said.
In a statement, Pfizer said that it wasn't aware of any
neurocognitive safety signals with its drug, bococizumab. "The FDA
has not sent us any request," a Pfizer spokeswoman said in an
email.
Regeneron first disclosed the FDA's interest in neurocognitive
adverse events in a February regulatory filing, but the disclosure
wasn't widely noticed at the time.
An FDA spokeswoman said the agency was aware of neurocognitive
adverse events tied to cholesterol drugs and was carefully
monitoring these events as part of its oversight of new drug
development. The agency said it couldn't discuss specific drug
development programs.
Jonathan D. Rockoff contributed to this article.
Write to Joseph Walker at joseph.walker@wsj.com
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