BOSTON (

TheStreet

) --It's been a big year for hepatitis C. New drugs from

Vertex Pharmaceuticals

(VRTX) - Get Report

and

Merck

(MRK) - Get Report

, respectively, were approved and launched commercially that dramatically shorten treatment and improve cure rates for hepatitis C patients.

Meantime, investor interest in the "next" big hepatitis C treatments -- especially the potential for an all-oral combination therapy -- remains red hot. Just take a look at Pharmasset with shares up an astounding 260% this year, the best-performing drug and biotech stock this year.

The end of the year will be a busy time for Hep C drug developers. Investors will be paying close attention to the third-quarter results from Vertex, watching to see if Incivek can maintain the scorching-fast start to its commercial launch.

On the research side, the annual meeting of the

American Association for the Study of Liver Disease

(AASLD) convenes in San Francisco Nov. 4-7. This is one of two research meetings focused largely on Hep C held each year, which of course makes it a must-attend event for investors.

Research abstracts for the AASLD meeting will be posted online on Sept. 30, which gives investors a sneak peek at what to expect at this year's event.

The following

10 stocks

are all involved in Hep C drug development and will be either presenting new clinical data at AASLD this year or are expected to announce results from closely watched clinical trials before the end of the year.

Pharmasset

(VRUS)

Stock price/Market cap: $78.08/$5.9 billion

Year-to-date return: 258%

Key Hep C drugs: PSI-7977, PSI-938, RG7128 (co-developed with Roche)

PSI-7977 is a "nucleotide" inhibitor of the Hep C virus

and one of the most exciting oral hepatitis C drugs in development today. Investors can thank PSI-7977 for fueling a monster run in Pharmasset's share price (see above) that is tops among biotech and drug stocks this year.

PSI-7977 is generating a ton of buzz because data presented to date have demonstrated the experimental drug's strong potency against the Hep C virus, an ability to prevent the virus from mutating, and a relatively clean safety profile. As such, PSI-7977 has the potential to become a backbone in an all-oral therapy against Hep C.

At AASLD this year, researchers will be presenting data from a phase II study dubbed "Proton" which pairs once-daily '7977 with what is becoming (but not yet) the out-dated standard of care therapy -- a weekly injection of pegylated interferon and daily doses of oral ribavirin. Earlier this month, Pharmasset announced that 91% of genotype 1 patients achieved a cure at 12 weeks, which bodes well for the final analysis of cure rates at 24 weeks. Previously from the same study, genotype 2/3 patients (easier to treat) were able to achieve a cure rate of 100% at 24 weeks.

Pharmasset is also conducting a phase II study dubbed "Electron" exploring treatment with '7977 and ribavirin that both includes and excludes injectable interferon. In other words, this study is testing an all-oral Pharmasset drug regimen for the first time. A third phase II study, known as "Quantum," is also investigating all-oral Hep C therapies with various combinations of '7977, PSI-938 and ribavirin.

Idenix Pharmaceuticals

(IDIX)

Stock price/Market cap: $6/$577 million

Return year to date: 19%

Key Hep C drugs: IDX-184

Idenix, like Pharmasset, is developing a "nucleotide" drug against Hep C known as IDX184. The FDA has a partial clinical hold on IDX184 due to liver toxicity that cropped up in a study that combined '184 with another Idenix Hep C drug known as IDX320. Idenix believes that this safety signal was caused by '320 and development of that drug was shelved.

Importantly, Idenix believes that '184's safety profile, alone, is fine. The company is conducting a short phase IIb study of '184 right now, with interim data expected in the fourth quarter (not necessarily at AASLD.) If the safety profile of '184 comes back clean, FDA should be persuaded to lift the partial clinical hold.

If that happens and '184's safety is exonerated, investors are going to look more favorably at the drug's potential. That should narrow the valuation gap between Pharmasset and Idenix -- the two leading developers of Hep C nuc drugs. Idenix's valuation is likely to rise.

Vertex Pharmaceuticals

(VRTX) - Get Report

Stock price/market cap: $50.21/$10.5 billion

Year to date return: 43%

Key Hep C drugs: Incivek (approved), VX-222

Vertex launched Incivek in the spring (and quite strongly) so this year's AASLD, while technically Incivek's first as an approved Hep C drug, lacks a bit of drama. With that said, investors will get a chance to witness Vertex's Incivek marketing push up close and quiz Hep C experts on their views of the drug now that it's widely available.

One of the major themes of this year's AASLD from a research perspective will be what's next after Incivek, so Vertex can't rest on its laurels. Towards that end, Vertex will be presenting more data from a mid-stage study of a four-drug regimen that includes Incivek, the experimental VX-222 coupled with interferon/ribavirin.

Saddled with the need for interferon injections, Vertex's "Quad" regimen may not compete with all-oral combinations already under development from rivals. That means Vertex could also use AASLD to hunt for a new, potent oral drug with which it can partner.

The current analyst consensus estimate for third quarter sales of Incivek is $257 million, according to Bloomberg. Vertex is expected to lose 16 cents a share in the third quarter on total revenue of $297 million.

Inhibitex

( INHX)

Stock price/Market cap: $3.20/$250 million

Year to date return: 23%

Key Hep C drugs: INX-189

INX-189 is another nucleotide inhibitor of Hep C, similar to the drugs being developed separately by Pharmasset and Idenix Pharmaceuticals, although in still earlier stages of clinical trials.

At AASLD, researchers will present updated antiviral and safety data from a phase I study of INX-189 dosed for 7 days in genotype 1 patients.

More significant and new data on INX-189 will come early next year (likely first quarter) from a study just started that combines '189 with interferon and ribavirin in genotype 2 and 3 patients.

Achillion Pharmaceuticals

(ACHN) - Get Report

Stock price/Market cap: $6.05/$422 million

Year to date return: 46%

Key Hep C drugs: ACH-1625, ACH-2684, ACH-2928

Achillion expects to release proof-of-concept data from studies of three different experimental hepatitis C drugs before the end of the year. Among the expected results are 12-week, early virologic response data from a mid-stage study of Achillion's experimental once-daily protease inhibitor ACH-1625 combined with interferon and ribavirin.

At AASLD, Achillion will present a poster describing early efficacy results from a 28-day phase IIa study of '1625 plus standard of care.

Johnson & Johnson

(JNJ) - Get Report

and

Medivir

Stock price/Market cap (for JNJ): $63.61/$174.3 billion

Year to date return: 3%

Key Hep C drugs: TMC435

TMC435, a once-daily oral protease inhibitor, is the most significant near-term commercial threat to the three times-daily protease inhibitors Incivek and Victrelis, recently approved and launched by Vertex and Merck, respectively.

Three phase III studies of TMC435 completed patient enrollment in August so results aren't likely until late 2012 or early 2013.

At AASLD, researchers will present final results from the phase IIb "Pillar" study of TMC435 plus interferon/ribavirin in treatment naive, genotype 1 patients. Cure rates for the TMC435 regimens were in the low to mid 80% range with final cure rates from the control arm not yet disclosed.

Johnson & Johnson and Pharmasset have also teamed up to conduct a study combining TMC435 and PSI-7977.

Merck

(MRK) - Get Report

Stock price/market cap: $31.74/$98 billion

Year to date return: -12%

Key Hep C drugs: Victrelis, Vaniprevir (MK-7009), MK-5172

Like Vertex, Merck will have a commercial presence at AASLD for the first time with its protease inhibitor Victrelis. On the research side, Merck will present early-stage data on MK-5172, a second-generation protease inhibitor.

Bristol-Myers Squibb

(BMY) - Get Report

Stock price/market cap: $29.55/$50 billion

Year to date return: 12%

Key Hep C drugs: BMS-791325, BMS-790052

Most of the focus at AASLD will be on clinical updates on mid-stage studies of BMS-790052 in combination with interferon and ribavirin. Bristol and Pharmasset are also collaborating on a phase II study with a treatment regimen that combines BMS-790052 and PSI-7977.

Gilead Sciences

(GILD) - Get Report

Stock price/market cap: $38.21/$29.5 billion

Year to date return: 5%

Key Hep C drugs: GS 9190, GS 9256, GS 5885, GS 9451

Gilead, late to the Hep C drug development race, is playing catch up with a strategy of leapfrogging ahead to create an all-oral regimen from among a relatively large pipeline of experimental drugs.

This year's AASLD will likely feature incremental updates from early and mid-stage clinical trials involving Gilead's various Hep C drug candidates. Earlier this month, Gilead amended studies involving GS 9190 and interferon due to toxicity. The changes did not affect studies of all-oral regimens.

Anadys Pharmaceuticals

( ANDS)

Stock price/Market cap: .71/$40.5 million

Year to date return: -50%

Key Hep C drugs: Setrobuvir (ANA598)

Woe is the experimental oral Hep C drug that needs to be dosed twice daily. Setrobuvir, unfortunately, is just such a drug, which has made it hard for Anadys to remain competitive with its Hep C rivals.

Anadys recently completed patient recruitment for a 12-week phase II study of setrobuvir plus interferon/ribavirin in genotype 1 patients, with the first antiviral efficacy data expected in the fourth quarter.

>>To see these stocks in action, visit the

10 Hep C Stocks

portfolio on Stockpickr.

--Written by Adam Feuerstein in Boston.

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Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

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