There's no nice way to put this: The current hepatitis C drugs stink. They're only able to cure half the patients treated with them, and they have horrible side effects to boot.

The poor efficacy and safety profile is the reason why Merck's (NYSE: MRK) PegIntron and Roche's Pegasys have never sold all that well, especially considering the large number of patients infected with hepatitis C -- an estimated 3.2 million in the U.S. alone.

If you're thinking this might be a potential goldmine, you're not alone.

The frontrunners
Merck and Vertex Pharmaceuticals (Nasdaq: VRTX) are far in front, having already submitted their marketing applications to the Food and Drug Administration.

An FDA advisory panel will review both Merck's boceprevir and Vertex's telaprevir on successive days next month. I expect both will get positive recommendations from the committees considering the unmet need, high efficacy -- cure rates in the 70% range -- and reasonable safety record.

The drugs haven't been tested head-to-head against each other, but based on their individual trials, Vertex and marketing partner Johnson & Johnson (NYSE: JNJ) seem to have the upper hand.

Watch your back
While both drugs work better than current treatments and are even able to cure patients that failed previous treatments, they still require PegIntron or Pegasys to be taken alongside the oral medications. The treatment time can be shortened from 48 weeks down to 24 weeks, but that still means patients are injecting themselves and dealing with nasty side effects for six months.

We're headed toward an all-oral cocktail of drugs that doesn't require the current injectable drugs. Which drugs will be part of that cocktail remains to be seen.

The potentials are presenting plenty of data at the European Association for the Study of the Liver this week as they vie for a spot in the cocktail.

Novartis (NYSE: NVS) and Debiopharm's DEB025 looked good in a phase 2 trial combined with Pegasys and has recently started enrolling patients in a late-stage trial.

Achillion Pharmaceuticals (Nasdaq: ACHN) also presented data from a phase 2 trial at the meeting. ACH-1625 looks promising, but we'll have to wait to make sure that the initial patient responses are sustained. Vertex saw its combination of VX-222 and telaprevir initially help patients, but the virus was able to find a way around the treatment, and patients rebounded.

Bristol-Myers Squibb (NYSE: BMY) might take the cake with the highest sustained response rate -- a whopping 92% of patients taking its BMS-790052. But the dose was only tested on 12 patients, so I wouldn't read much into the actual number beyond that it means the drug is worthy of a larger trial.

Pharmasset (Nasdaq: VRUS) released its data a little early by sticking it in one of the abstracts that were published ahead of the meeting. A combination of two of its drugs dropped virus levels in 94% of patients, but it was only results from 14 days of treatment in 16 patients.

Which one?
It's really too early to tell. Hepatitis C drugs seem to have a bigger issue with side effects than they do with efficacy, so investors shouldn't start jumping for joy just because the drug appears to be working.

How much of a threat the up and comers are to Merck and Vertex also isn't very clear. It's possible that they might try to latch on, combining their drugs with the front runners, rather than trying to take them head-on. Vertex has the clear advantage when combined with the current standard of care, which could mean a preferred seat at the combination table.

Johnson & Johnson is a Motley Fool Inside Value pick. Vertex Pharmaceuticals is a Motley Fool Rule Breakers recommendation. Novartis is a Motley Fool Global Gains pick. Johnson & Johnson is a Motley Fool Income Investor selection. Motley Fool Options has recommended a diagonal call position on Johnson & Johnson. The Fool owns shares of Johnson & Johnson. Motley Fool Alpha LLC owns shares of Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.`