FDA likely to delay decision on Genzyme MS drug

Lemtrada was once seen as key to the future of Genzyme.
Lemtrada was once seen as key to the future of Genzyme.(Bloomberg/File)

An inconclusive series of votes by a medical advisory panel could prompt US regulators to delay deliberations and demand further work from Genzyme before deciding whether to approve the Cambridge biotech’s multiple sclerosis drug, Lemtrada, once seen as key to its future.

That was the view of some analysts briefing investors late this week after an all-day meeting of a Food and Drug Administration advisory committee Wednesday left many in the biomedical field scratching their heads. The panel concluded that the drug worked, but posed risks ranging from rashes and bleeding to thyroid cancer. At the same time, it concluded that Genzyme’s clinical trials were not adequate.


“More likely than not, I would bet the FDA would want to see more details from Genzyme on safety precautions,” said pharmaceutical analyst Seamus Fernandez, managing director at Boston health care investment bank Leerink Swann. “We’ve seen instances when the FDA delays approval of a product until a company presents a risk evaluation and mitigation strategy.”

In a research report titled “Yes Probably Means No for Lemtrada,” analyst Jeffrey Holford at the securities firm Jefferies LLC in New York, wrote that the panel’s “gut feeling” was that the MS drug helps patients despite safety concerns. But he warned that findings of clinical study design flaws reduced the probability of approval to 20 to 30 percent. Even if the FDA signs off on Lemtrada, he said, it will probably restrict use to patients who have tried other medicines.

Genzyme executives, working to evaluate data from the advisory meeting in Silver Spring, Md., said testimony from patients and medical specialists confirmed that the company’s experimental treatment works well for many patients suffering from MS. The autoimmune disease affects the brain and central nervous system of an estimated 400,000 people in the United States and about 2.5 million worldwide.


“The one thing that was absolutely clear at the meeting was that there is a very strong unmet need in MS,” said Genzyme senior vice president Bill Sibold, who heads its MS business. “We believe Lemtrada offers real benefits to patients. It’s certainly not without risks. But we believe they can be managed. MS patients in this country should have the right to make that choice.”

In a series of votes at the end of the advisory committee meeting, the panel sent mixed signals to FDA officials who will rule on whether Genzyme, owned by French drug maker Sanofi SA, will be permitted to sell Lemtrada in the United States.

The agency has not said when it will make a decision, but analysts had been anticipating one by the end of the year.

The advisers, in an 11-to-6 vote, accepted the view of FDA staff that there was “bias” in the clinical trials because Genzyme didn’t keep patients from knowing whether they were taking Lemtrada or a rival drug, Rebif, which is marketed by EMD Serono of Rockland.

But the committee, on a 12-to-6 vote, said Genzyme nonetheless provided substantial evidence that Lemtrada worked for patients with relapsing MS. And by a 17-to-0 vote, the panel concluded that Lemtrada’s safety concerns shouldn’t preclude its approval for patients for whom other drugs aren’t effective. At the same time, it voted 16-to-0 to recommend that Genzyme’s drug should not be allowed for sale in the United States for use by newly diagnosed MS patients. (Some panel members abstained from a number of the votes.)


“While the trials were not ideal in design, they’re all we have right now,” said Richard P. Hoffman, a drug information consultant from Hernando, Fla., who was on the advisory panel. “Hopefully, [Lemtrada] will provide some new treatment options for multiple sclerosis patients.”

Lemtrada was approved in September for sale in Europe for both newly diagnosed patients and for those who have tried other MS treatments. In the United States, however, analysts said it is now unlikely that Lemtrada will be OK’d as a “first-line” therapy for new MS patients, limiting the drug’s potential market.

Robert Weisman can be reached at Follow him on Twitter @GlobeRobW.