What happened

Progenics Pharmaceuticals (NASDAQ:PGNX) was up as much as 23% this morning after announcing that the FDA accepted the marketing application for its cancer drug Azedra.

Investors have since come to their senses, with shares trading up 4.2% at 12:09 p.m. EST.

Accepted stamp

Image source: Getty Images.

So what

The FDA does a cursory review when it accepts the application and can refuse to file the application if it doesn't meet the agency's standards; getting a refuse to file ruling would typically send shares down, but meeting the low bar of getting the application accepted doesn't justify a double-digit increase.

That goes double for Progenics since the FDA had already signed off on the clinical trial design under a Special Protocol Assessment (SPA). Essentially, an SPA says the FDA agrees the trial will meet its standards if the study meets its primary endpoint, which Azedra did when it produced a 50% or greater reduction of all antihypertensive medication for at least six months in patients with pheochromocytoma and paraganglioma, which are rare neuroendocrine tumors.

The FDA gave the marketing application a priority review, shaving four months off the standard review time, which is good news, but again, should have been widely expected since the drug already had Breakthrough Therapy designation. There aren't any drugs approved for patients with malignant pheochromocytoma and paraganglioma, which is exactly the type of medication the priority review program is supposed to support.

Now what

It's now just a waiting game for Progenics Pharmaceuticals' investors. The FDA's goal is to make a decision by April 30, but it's not bound to honor that date.

Recently, though, companies -- especially those being reviewed by the FDA's oncology division -- have seen their applications approved earlier than expected. A couple of weeks early, on tax day perhaps, would certainly brighten up the day, but a decision a month or so earlier isn't out of the question.

Brian Orelli and The Motley Fool have no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.