FDA likely to delay decision on Genzyme MS drug

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.

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