Merck shares battered after it shutters vorapaxar trial

Just days after newly named Merck CEO Ken Frazier (photo) singled out the anti-clotting drug vorapaxar as a star in the company's late-stage pipeline, the company slammed the brakes on one of the two major studies it's conducting for the therapy and curtailed treatment in the second. Billed as a potential megablockbuster with estimates of $3 billion to $5 billion in peak revenue, investors responded by taking a 6.6 percent bite out of the company's stock.

The savage response on Wall Street may be in part due to uncertainty. Merck didn't explain why it was taking the dramatic action, leaving everyone to speculate why a heart drug study would be shelved just months ahead of an expected regulatory filing. And there may be no quick answers.

"We do not yet know the safety and efficacy results of the trials," Dr. Peter Kim, head of Merck Research Laboratories, told analysts. "We really want to take the time to evaluate everything" before revising the company's regulatory schedule. Many investors looked at the information void, however, and assumed the worst.

"No one, including Merck, knows why they wanted these changes,'' Barbara Ryan, an analyst with Deutsche Bank, told the Star-Ledger. "In the absence of the information, the market wiped out the value of the drug.''

The one late-stage study that will continue will proceed without patients who have experienced a stroke. Vorapaxar is a selective PAR-1 Thrombin Receptor Antagonist designed to diminish clot formation.

- here's the Merck release
- read the story from the Wall Street Journal
- check out the Star-Ledger story