Analyst: Safety Worries Dog Merck & Co.’s Osteoporosis Drug

Published: Sep 16, 2014

Analyst: Safety Worries Dog Merck & Co.’s Osteoporosis Drug

September 16, 2014

By Riley McDermid, BioSpace.com Breaking News Sr. Editor

Drug giant Merck & Co. is facing increasing concern about the cardio safety of its osteoporosis drug odanacatib, which would could muddy its way as its seeks U.S. Food and Drug Administration approval, an analyst with ISI Group said today.

The company just announced its Phase III data for odanacatib at the American Society for Bone and Mineral Research conference earlier this week.

The info showed that the drug will build bone mineral density in patients, while demonstrating a significant reduction in fractures.

It found a 47 percent relative risk reduction of clinical hip fractures; a 54 percent relative risk reduction of new and worsening morphometricvertebral fractures; and a 23 percent relative risk reduction of clinical nonvertebral fractures. Most surprisingly, it could reduce clinical vertebral fractures by as much as 72 percent.

But Mark Schoenebaum, a biotech and pharmaceuticals analyst for ISI Group, cautioned that the drug still shows signs of being hard on the cardiovascular system,

“But on cardiovascular safety (recall, we learned at the analyst day even in May '14 that there were imbalance in atrial fibrillation and stroke events), we learned today there were numerical imbalances in afibrilliation, stroke, major adverse cardiac events and deaths,” he wrote in a note to investors.

Schoenebaum said that while none were statistically significant, with confidence intervals of the hazard ratios crossed one, many still trended the same way, which would have most data readers preferring a placebo over odanacatib.

“While not statistically significant, these safety issues will be analyzed closely by the FDA,” he wrote. “Merck reports that it continues to collect data from the blinded extension study and plans additional analyses including a re-adjudication of MACE events.”

As a result, the company told the conference it does not plan to file with the FDA until 2015. “Bottom line: The fracture data reported for odanacatib (an oral drug with a novel mechanism of action) are generally in line with bisphosphonates, the current standard of care,” wrote Schoenebaum.

While odanacatib did not result in osteonecrosis of the jaw and had a low rate of atypical femoral shaft fractures, the numerical imbalances of cardiovascular events will be analyzed closely by the FDA and "commercially could make detailing the drug to doctors more difficult.”

“Despite these concerns, as expectations for odanacatib had already come down meaningfully on the Street (we saw this more as an upside opportunity for MRK), we expect a modest impact to MRK's stock,” he concluded.

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