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Sanofi-Regeneron Must Assess Risk in New Cholesterol Drug

Regeneron Pharmaceuticals Inc. and Sanofi and must assess how their experimental cholesterol drug affects brain function after U.S. regulators learned of adverse events associated with this new class of medicines.

The companies don’t know how the Food and Drug Administration learned of the side effect, Paris-based Sanofi said today in a regulatory filing. Sanofi, Regeneron and Amgen Inc. are among companies in late-stage testing of the therapies, which are designed to inhibit the PCSK9 protein associated with high levels of LDL, or “bad” cholesterol.

Sanofi and Regeneron’s experimental drug may generate $2.5 billion in peak sales, said Robyn Karnauskas, an analyst with Deutsche Bank. Amgen’s drug, evolocumab, may draw $1.96 billion, according to analysts’ estimates compiled by Bloomberg. Cholesterol-lowering medicines now on the market already advise about cognitive impairment.

“To date we haven’t seen this problem but we’re going to look for it carefully,” Regeneron Chief Executive Officer Len Schleifer said today by telephone. “Right now this shouldn’t change anything,” with the timing to complete the trials.

Pfizer Inc., Roche Holding AG, Alnylam Pharmaceuticals Inc., Merck & Co. and Eli Lilly & Co. also have PCSK9 inhibitors under development. Sanofi said in the filing that it wasn’t aware of any neurocognitive side effects with the drug, alirocumab. Amgen, based in Thousand Oaks, California, is the furthest along in development, completing a fifth late-stage study in January.

FDA Request

“The FDA has requested that Sanofi and Regeneron make an assessment of potential neurocognitive adverse events across the global development program for alirocumab, especially in the longer-term studies,” Sanofi said.

Regulators also asked the companies to assess the feasibility of incorporating new tests for the potential cognitive effects “into at least a subset of patients” in their late-stage trials of the experimental drug. Regeneron noted the FDA’s request in a Feb. 13 filing.

Chris Raymond, an analyst with Robert W. Baird & Co., called the safety concerns overdone.

“Of note, Regeneron does not anticipate new trials,” Raymond wrote today in a note to clients. “And while bears may conclude this means FDA will now require outcomes data pre-approval, we think this is far from a given. Indeed, with the stock off about 8 percent, one would think a clinical hold has been issued.”

Regeneron fell 3.1 percent to $328.11 at the close in New York, after declining as much as 10 percent in intraday trading. Amgen decreased 1.6 percent to $122.26.

High-Risk Patients

It’s unclear whether the information the FDA requested will derail early approval of PCSK9 drugs in high-risk patients, who may be younger and less prone to the side effects on the brain, Andrew Berens and Sam Fazeli, analysts with Bloomberg Industries, wrote in a report today. They had estimated limited approval of a drug in the class in 18 months.

Schleifer said Sanofi had reported continuing to buy Regeneron stock as recently as March 3. Sanofi is Regeneron’s largest shareholder, with about 17 percent of the shares.

“They obviously weren’t worried about this, because they were buying our stock this week,” Schleifer said.

The PCSK9 inhibitors are designed to help people who can’t tolerate statins, which are the standard treatment, or can’t get their cholesterol under control with other therapies. Schleifer said the market for the drugs is big enough for multiple medicines to succeed.

Competitive Area

“There are five statins on the market each doing gangbusters,” Schleifer said. “There’s plenty of room for more than one here.”

Pfizer, maker of the cholesterol-lowering statin Lipitor, advises that all statins are associated with rare reports of cognitive impairment, including memory loss, forgetfulness, amnesia and confusion. The side effects “are generally nonserious, and reversible upon statin discontinuation,” according to Lipitor’s label.

Pfizer said today the FDA hasn’t sent it any request on the PCSK9 program in this context.

“At this stage of our bococizumab development program, we are not aware of any neurocognitive safety signals,” Victoria Davis, a spokeswoman for New York-based Pfizer, said in an e-mail. “We are monitoring the safety of our patients as we as do for all of our Phase 3 programs.”

Amgen said it has communicated with the FDA and has been monitoring patients in its clinical trials for cognitive impairment given the previous association of things like forgetfulness and confusion with taking statins.

“We will continue to investigate the potential for cognitive impairment in our program,” Kristen Davis, an Amgen spokeswoman, said in an e-mail. “We do not anticipate any delay from this activity to our program.”

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