What happened After the company updated investors on its second-quarter financials and the progress it's making in its clinical-stage drug pipeline, shares in Achillion Pharmaceuticals (NASDAQ: ACHN) are soaring 24% higher at 11:45 a.m. EDT today. So what Since licensing its hepatitis C clinical-drug pipeline to Johnson & Johnson (NYSE: JNJ) in 2015, Achillion Pharmaceuticals has been knee-deep in developing new therapies for other indications. Yesterday afternoon, the company shared with investors its second-quarter performance and its clinical-stage pipeline progress. IMAGE SOURCE: GETTY IMAGES. In the second quarter of 2017, Achillion Pharmaceuticals lost $22.5 million, which was an increase from the $18.5 million it lost in Q2 2016. A slight increase in general and administrative spending and a larger increase in research and development spending were the culprits behind the bigger loss. Specifically, R&D expenses were $18.3 million in the quarter, up from $14.2 million for the same period in 2016. General and administrative expenses were $5.4 million, up slightly from $5.2 million last year. While the bigger loss isn't good news, management reported progress on ACH-4471 that suggests its increased spending may pay off someday. ACH-4471 is a Factor D inhibitor oral drug that may help patients with a rare disease called paroxysmal nocturnal hemoglobinuria, or PNH, a disease in which the immune system attacks and destroys red blood cells. According to management, four patients given ACH-4471 showed "meaningful improvements" in LDH, hemoglobin, fatigue score, and other markers of response. These findings have Achillion Pharmaceuticals planning to expand its ACH-4471 trial to include more patients. Now what PNH is a life-threatening disease affecting fewer than 10,000 people in the U.S. and Europe combined, but it's a meaningful market for Achillion Pharmaceuticals' to be targeting. There are few treatment options, but one of them is Alexion Pharmaceuticals' (NASDAQ: ALXN) Soliris, a medicine that costs hundreds of thousands of dollars per year. Soliris is approved for multiple indications, including PNH, and last quarter, sales totaled $814 million, up 16% year over year. Tapping into the PNH market via ACH-4471 could eventually be profit-friendly, but we have a ways to go before we see this drug commercialized. Its efficacy needs to be confirmed in more trials before we know for certain that Achillion Pharmaceuticals has a winner on its hands, and those studies won't be cheap to conduct. For example, management expects to spend between $75 million to $78 million on R&D this year alone. Overall, ACH-4471 may indicate that Achillion Pharmaceuticals could one day benefit from something other than its relationship with J&J, but this is still a risky stock that's likely to post losses for the foreseeable future, so investors should approach it cautiously. 10 stocks we like better than Achillion PharmaceuticalsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the 10 best stocks for investors to buy right now... and Achillion Pharmaceuticals wasn't one of them! That's right -- they think these 10 stocks are even better buys. Click here to learn about these picks! *Stock Advisor returns as of August 1, 2017 Todd Campbell has no position in any stocks mentioned. His clients may have positions in the companies mentioned. The Motley Fool owns shares of and recommends Johnson & Johnson. The Motley Fool has a disclosure policy.