Flexion shares rocket up on an FDA ‘endorsement’ for lead drug


Shares of Burlington, MA-based Flexion ($FLXN) soared 50% on Thursday after the biotech touted word from the FDA that its data on their lead drug were acceptable for filing an NDA.

Flexion and its investors have been on a roller-coaster ride for much of the past year, with shares plunging in the fall of 2015 with the news that its Phase IIb trial of FX006 (now dubbed Zilretta) for severe osteoarthritis pain had failed, then lurching upward in February when the late-stage trial scored the primary endpoint.

In the latest written exchange with the FDA, says Flexion, regulators noted that their data were “acceptable to support filing of an NDA submission.” So the biotech will now forgo the in-person pre-NDA meeting and move to a filing in the fourth quarter.

The injectable FX006 is based on one of the oldest treatment measures in place for osteoarthritis: a steroid shot right into a sore joint. The drug is a sustained-release corticosteroid mingled with a polymer designed to keep the steroid where it’s needed for some weeks. And the biotech's two late-stage studies both compared its action with that of a placebo rather than a steroid shot.

A 20-mg dose of their therapy failed to distinguish itself from a placebo at 12 weeks, but the 40-mg dose succeeded in the Phase III, which you can see in this detailed publication of the data.

“The endorsement from the FDA for the Zilretta NDA submission represents a major milestone in the development of this drug candidate and brings us one step closer to making it available to the many millions of knee osteoarthritis (OA) patients who lack good pain-relief options,” said CEO Michael Clayman in a statement.

Jumping from "acceptable to support filing" to an "endorsement" is quite a leap for a drug developer. But it seems to sit well with its backers this week.

- here's the release

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