By Joseph Walker
The U.S. Food and Drug Administration has become aware of
negative cognitive adverse events related to a closely watched
group of experimental anti-cholesterol drugs, Sanofi SA said in a
regulatory filing Friday.
The FDA asked Sanofi and Regeneron Inc., which are codeveloping
one of the drugs, known as PCSK9 inhibitors, to conduct an
assessment of the potential for their drug to cause neurocognitive
adverse events, Sanofi said, reiterating a similar disclosure
Regeneron made in a February filing.
In a phone interview Friday, Regeneron Chief Executive Leonard
Schleifer said the FDA made the request 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, and that the
companies haven't seen any indication of such events in their
clinical studies. The drug that 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.
Several companies, including Amgen Inc. and Pfizer Inc., are
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.
Kristen Davis, an Amgen spokeswoman, said in emailed statement
that Amgen had reported amnesia and memory or mental impairment in
less than or equal to 1% of patients in a 52-week clinical study.
"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.
The FDA didn't immediately respond to a request for comment.
Jonathan D. Rockoff contributed to this article.
Write to Joseph Walker at joseph.walker@wsj.com
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