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What: Shares of Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY), a biopharmaceutical company developing novel therapeutics based on RNA interference, rose 10.8% last month, according to data from S&P Global Market Intelligence. Good news for its lead programs to begin the month, followed by positive results for an early clinical-stage hemophilia candidate, kept it rising into August.

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So what: To begin the month, Alnylam reported that patients receiving its lead candidate, patisiran, for treatment of nerve damage caused by a mutant transthyretin gene showed an average decrease of 6.7 points on the modified neuropathy impairment score after 24 months. The historical expected average for similar patients is an increase of between 26 and 30 points. This phase 2 data improves the outlook for patisiran's phase 3 trial, which is currently under way, with partner Sanofi (NASDAQ:SNY) sharing some of the costs.

Later in the month, Alnylam released stellar interim data from another Sanofi-partnered candidate: fitusiran for treatment of hemophilia. The antithrombin-targeting, once-monthly injection is intended for treatment of hemophilia A or B. Among 17 patients without inhibitors, it achieved an estimated annualized bleeding rate of zero. More importantly, it appears well-tolerated, with no serious adverse events reported among all 31 patients in the trial.

Now what: If patisiran's phase 3 results, expected in mid-2017, are consistent with recently released phase 2 data, its odds of earning approval look fairly solid. If given a green light, reaching peak annual sales near $1 billion isn't impossible, but Alnylam has yet to prove itself capable of commercializing anything.

The agreement with Sanofi leaves Alnylam responsible for potential sales in North America and Western Europe. Luckily, Alnylam's cash and securities pile of about $980 million at the end of March could be enough to hire a sales force to launch patisiran, if it succeeds. With Ionis Pharmaceuticals and its partner GlaxoSmithKline taking a breather with their transthyretin programs, Alnylam's commercial path for patisiran is likely to be much smoother.

In the meantime, early success with fitusiran provides a safety net if patisiran fizzles, and it should add a bit more cash to Alnylam's coffers. The company plans to begin phase 3 fitusiran studies early next year, triggering a $25 million milestone payment from Sanofi.

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