It appears that Johnson & Johnson (NYSE:JNJ) may have just leapfrogged over Gilead Sciences (NASDAQ:GILD) in the quest to bring the first next-generation hepatitis C drug to market. Johnson & Johnson said Monday that the Food and Drug Administration accepted its application for simeprevir and will give the drug a priority review.

You'll recall, Gilead submitted sofosbuvir for approval in the beginning of April. The FDA typically takes two months to make sure everything is in order before accepting the application for the standard 10-month review or a six-month priority review. The latest PDUFA renewal calls for the clock to start after the applications are accepted; it used to start when they were submitted.

It looks like Gilead is about a month behind Johnson & Johnson and could be five months behind if sofosbuvir gets a standard review, although that seems extremely unlikely. If simeprevir received the faster review, I'd expect the FDA to give it to sofosbuvir, too.

Getting to the market first is usually a big advantage, but I'm not sure if it'll actually help simeprevir to beat sofosbuvir by a month. Johnson & Johnson is asking for approval of the drug in combination with pegylated interferon and ribavirin. Pegylated interferon drugs -- Merck's (NYSE:MRK) PegIntron and Roche's Pegasys -- both have to be injected and cause unpleasant side effects.

Hepatitis C is a slow-developing disease, so there's no immediate rush to treat newly diagnosed patients as witnessed by the drop off in sales of Vertex Pharmaceuticals' (NASDAQ:VRTX) Incivek. In the first quarter, sales of the drug, which also has to be used in combination with pegylated interferon, fell 42% year over year. It's hard to see how simeprevir plus pegylated interferon would make inroads with doctors with all-oral hepatitis C combinations in the works.

Likewise, it's hard to see initial blustery sales for Gilead's sofosbuvir, which will be used in combination with pegylated interferon and ribavirin in genotype 1 patients, the most common hepatitis C genotype in the U.S.

For both drugs, the approvals are just a means to the end -- the end being part of an all-oral drug cocktail. Interestingly, sofosbuvir and simeprevir worked really well together without pegylated interferon in a small clinical trial.

Once they're both approved, doctors could prescribe a combination of the two drugs off label to patients, but given the aforementioned slowly developing nature of the disease, it seems unlikely that they'd go that route without extra data. Depending on how Gilead and Johnson & Johnson price their drugs, there could be a cost issue as well; insurers may be unwilling to reimburse for the two drugs off label.