What happened Shares of Epizyme (NASDAQ: EPZM) fell as much as 17.4% today after the company released fourth-quarter and full-year 2019 operating results. There wasn't much for investors to pick apart. The company is in the early stages of transitioning to commercial operations, which means it doesn't have much revenue. That also makes it difficult for Wall Street analysts to project quarterly revenue and earnings and makes misses or beats relatively meaningless. That said, investors might be a little nervous about full-year 2020 guidance. Epizyme expects to report operating expenses in the range of $300 million to $330 million. That marks a steep increase from 2019, when the business reported operating expenses of $200 million and an operating loss of $177 million. As of 11:36 a.m. EST, the pharma stock had settled to a 15% loss. Image source: Getty Images. So what There's a little nuance needed here. First, the fact that operating expenses and (very likely) operating losses are expected to grow isn't surprising. Epizyme needs to spend heavily to support the launch of Tazverik. The drug was approved as a treatment for epithelioid sarcoma earlier this year, while the company has filed a supplemental new drug application (sNDA) to use the product to treat follicular lymphoma. The U.S. Food and Drug Administration (FDA) is expected to make a decision on the sNDA by June 18. The two indications could support peak annual sales of as much as $500 million, although it will take years to ramp up to that level. Second, full-year 2020 operating expense guidance includes potential milestone payments Epizyme will need to make to partners if Tazverik earns additional marketing approvals. Third, Epizyme reported $381 million in cash and marketable securities at the end of 2019. It added another $50 million in January through a stock sale. The cash position is expected to be sufficient to fund operations into 2022. Now what All eyes are now focused on the market launch of Tazverik. It will take years to ramp up sales, but a slow start could make investors and Wall Street analysts begin to question the drug's potential. In other words, 2020 will be either a relatively boring year or one with plenty of volatility. 10 stocks we like better than EpizymeWhen 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 ten best stocks for investors to buy right now... and Epizyme wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Maxx Chatsko has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source