Biotechnology's mind-numbing share price volatility means that only the most risk-tolerant investors should consider owning them -- but for investors with a penchant for risk and a stomach tough enough to handle the inevitable pops and drops, there may be opportunities to discover emerging biotech companies with promising pipelines that could send their shares significantly higher in 2015. Ophthotech Corporation (ISEE), Achillion Pharmaceuticals (ACHN), and Portola Pharmaceuticals (PTLA) could be among that select group of companies next year. Let's take a closer look and learn a bit more about them.

Source: Flickr user All T

Eyes are on you
Ophthotech is an intriguing company that is developing a treatment for vision loss tied to age-related macular degeneration -- but instead of developing a drug to replace the market-leading therapies already available, Ophthotech is evaluating Fovista as a therapy to be used alongside them.

That decision means that Ophthotech only needs to show that a therapy that includes Fovista is better than using Novartis' (NVS 3.19%) Lucentis and Regeneron's (REGN 0.98%) Eylea alone, a critical distinction that could allow Ophthotech to piggy back on these wildly successful drugs.

Lucentis generates roughly $4 billion a year in sales for Novartis' and Roche, its partner on the drug, and Regeneron's Eylea is on track to deliver sales of $2.8 billion in the next 12 months. Those blockbuster revenue run rates suggest that Ophthotech could have a big opportunity ahead of it.

Novartis seems to agree. Earlier this summer, Novartis agreed to pay Ophthotech up to $1 billion, plus royalties, to partner with it on Fovista overseas. Novartis' interest stems from Ophthotech's phase 2 trials, in which patients dosed with both Fovista and Lucentis saw their vision improve by 10.6 letters on a standard eye chart, which was better than the 6.5 letters for patients only taking Lucentis.

If Fovista can duplicate that performance in phase 3 trials and match that benefit in trials that are studying its use alongside Eylea, then investors may decide that Ophthotech is worth far more than its current $1.5 billion market cap.

Source: Achillion

Faster is better
Few stories captured financial headlines more often this year than Gilead Sciences' (GILD 0.82%) new class of hepatitis C treatments. After winning FDA approval last December, Gilead Sciences' Sovaldi notched more than $8.5 billion in sales through the first nine months of 2014. The game-changing drug, which boasts cure rates in the low 90% range, is a substantial improvement over prior generation therapies, though admittedly Sovaldi isn't perfect -- in many cases, patients still need to take side-effect laden drugs peginterferon and ribavirin. As a result, in October Gilead Sciences launched its second-generation hepatitis C drug Harvoni, which boasts a cure rate in the high 90% range, eliminates the use of those drugs, and reduces treatment duration to eight weeks for 40% of hepatitis 1 patients.

Although Harvoni is better than Sovaldi, Achillion Pharmaceuticals thinks it can do even better. It's developing ACH-3102, which can be used alongside Sovaldi to potentially cut the number of weeks patients require treatment even more. In a small phase 2 trial, 100% of patients taking Achillion's ACH-3102 alongside Sovaldi were able to achieve a functional cure in eight weeks. That could mean a big advance for treatment given that 60% of patients still need to take Harvoni for 12 weeks; however, Achillion is also studying whether or not ACH-3102 can deliver a cure in six weeks instead. 

So far, results from the six week study are encouraging. 100% of the patients receiving ACH-3102 and Sovaldi were clear of the disease four weeks after completing treatment. If that 100% clearance rate holds up for 12 weeks, then Achillion could have a best in class treatment regimen, and since Gilead Sciences paid $11 billion in 2012 to get its hands on Sovaldi and Merck paid $3.8 billion to acquire hepatitis C competitor Idenix last summer, Achillion may prove to be worth more than its $1.5 billion market cap.

Life saving advancement
Ask anyone who suffers from heart disease or who has had a hip or knee replacement and you'll learn that most of them are familiar with the anticoagulant warfarin, which is sold under the brand name Coumadin. That drug has been the go-to drug used to keep blood flowing for decades, but increasingly warfarin is taking a back-seat to a new class of drugs known as Factor Xa inhibitors.

Those Factor Xa inhibitors work differently than warfarin. Instead of targeting the body's ability to use vitamin K to clot blood, they target the Factor Xa enzyme that produces thrombin, a key cog in blood coagulation. That difference means that Factor Xa drugs have some important advantages over warfarin, including less monitoring and less chance of brain hemorrhages. As a result, sales of J&J and Bayer's Factor Xa drug Xarelto are racking up billions of dollars in sales per year. Another Factor Xa drug made by Bristol-Myers (BMY 0.38%) and Pfizer (PFE 0.46%) sold as Eliquis is also growing quickly, with sales of $216 million last quarter, up from $41 million a year ago.

Despite that sales growth, Factor Xa drugs do have one big disadvantage: there's no antidote to reverse their effect. That means that doctors have few options to stop the bleeding in patients who suffer injuries or require emergency surgery. As a result, many doctors shy away from using Factor Xa drugs in elderly patients who are frail, which is weighing down potential sales.

In a bid to address that problem, Portola Pharmaceuticals is developing andexanet alfa, a Factor Xa reversal agent that has shown considerable success in phase 2 and phases 3 trials. In fact, the drug has been so successful that J&J, Pfizer, and Bristol-Myers are helping fund Portola's trial costs. Importantly, Portola hasn't given up any of its commercialization rights to andexanet alfa, which means that potential sales could make the company worth more than its current $1.5 billion valuation.

Checking enthusiasm
Ophthotech, Achillion, and Portola all have promising drugs that offer catalysts that could send shares higher, but all three are clinical stage companies without any approved products or revenue. That means that any failure in trials could result in shares of these companies falling sharply. As a result, investors should remember that these are interesting, but speculative companies.