"This is the breakout. This is the all-time move," said CNBC's Jim Cramer. "I've been waiting for this drug to be revealed. It was better than I thought."
The results provide the first evidence that targeting a protein known as PCSK9 could slash cardiovascular risks for millions of patients.
The injectable drug, alirocumab, lowers "bad" LDL cholesterol in a new way and are widely expected to reap multi-billion dollar sales.
"This could be a multi-, multi-, multi-billion drug because there's 12 million people who could be helped by this immediately," Cramer said on "Squawk on the Street."
The findings are "a very big win" for Regeneron's stock, too, Cramer said. Though Cramer said he first recommended the stock when it was trading at roughly $5 a share in 2005, he now agrees with Credit Suisse's current $400 price target.
—By CNBC's Drew Sandholm. Reuters contributed to this report.
DISCLOSURE: When this story was published, Cramer's charitable trust did not own Regeneron Pharmaceuticals and Sanofi.