Antares has been less flinty with data from a couple of studies comparing Otrexup to methotrexate pills. These studies show patients can cross over from pills to Otrexup without significant problems and that Otrexup can maintain higher blood levels of methotrexate than pills. What's missing from these studies are data correlating higher blood levels of drug to better outcomes for patients. Antares has no efficacy data in rheumatoid arthritis comparing Otrexup to either oral or conventionally injected methotrexate. The company is assuming FDA will simply infer clinical efficacy of Otrexup from the precedent set by "regular" methotrexate.

The company has also conducted studies showing rheumatoid arthritis patients are capable of learning how to use the Otrexup self-injector device without significant problems.

The regulatory bar for Otrexup over which Antares needs to jump shouldn't be very high. Injectable methotrexate is approved already; the only thing Antares is doing is putting that methotrexate inside a fancy self-injector device. If Antares did its homework, Otrexup should be approved on Oct. 14. The risk for investors is having to trust Antares' clinical work without much independent verification.

Assuming Otrexup is approved, Antares intends to sell the drug in the U.S. on its own. Antares has no experience marketing a drug, nor does it have a commercial team in place. Covering the relatively small community of U.S. rheumatologists isn't hard, convincing them to prescribe your drug is. There are some theoretical cost advantages to using Otrexup (no price disclosed yet, but probably around $4,000 per year) because you'd be delaying the use of expensive biologic therapies that cost about $25,000 per year.

Antares is likely to face skepticism from all sides. Doctors won't have any efficacy data on Otrexup so may not rush to prescribe. Insurance companies could be slow to accept Otrexup because it will cost more than generic methotrexate, even if biologic therapy is delayed. (But for how long?)

And don't discount the opposition marketing that will rain down on Antares from Abbvie, Amgen and Johnson & Johnson if they feel like their blockbuster biologics are being threatened.

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