Clinical trial results can move biotech stocks significantly higher or lower, so investors need to pay particularly close attention to companies that are expected to report trial data soon. These three companies are expected to report results from studies by the end of this year that could cause their shares to pop or drop. Read on to find out if you might want to take on the risk of owning any of these stocks in your portfolio.

No. 1: Achillion Pharmaceuticals (NASDAQ:ACHN)

When Johnson & Johnson (NYSE:JNJ) licensed Achillion Pharmaceuticals' hepatitis C pipeline last year, investors hoping for an outright acquisition were disappointed. However, that disappointment could shift to enthusiasm if midstage trial results show that Johnson & Johnson has a best-in-class hepatitis C therapy in the wings.

Last year, Johnson & Johnson initiated a midstage study that combines Achillion Pharmaceuticals' odalasvir with AL-335 and Olysio, two other drugs in Johnson & Johnson's pipeline. That triplet, which is being evaluated in newly diagnosed hepatitis C patients, could be game-changing because the treatment duration being evaluated is for periods of eight weeks or less.

Currently, most hepatitis C patients are treated for at least 12 weeks.

Achillion Pharmaceuticals expects that results from this study will be released in the third quarter, and if they're positive, it wouldn't be shocking if shares rally. Johnson & Johnson's licensing pact calls for Achillion Pharmaceuticals to receive up to $1.1 billion in milestones and royalties in the mid-teens to the 20s.

No. 2: Ophthotech Corp. (NASDAQ:ISEE)

Aging baby boomers mean that more people are requiring treatment for vision loss caused by age-related macular degeneration. As a result, Novartis' (NYSE:NVS) Lucentis and Regeneron's (NASDAQ:REGN) Eylea are each racking up more than $4 billion in annual sales.

Soon, those two drugs could be joined by a third blockbuster.

Ophthotech is developing Fovista for use alongside anti-VEGF therapies, including Lucentis and Eylea, and if late-stage trial results expected in the fourth quarter are positive, then an application for FDA approval of Fovista could hit regulators desks early next year.

While no one knows how the data will read out, midstage results were good enough to prompt Novartis to ink a $1 billion licensing deal with Ophthotech that secures it ex-U.S. rights to Fovista. In trials, patients receiving Fovista plus Lucentis saw their vision improve by 10.6 letters on a standard eye chart. For comparison, there was a 6.5-letter improvement in patients receiving Lucentis alone.

Ophthotech expects that in addition to having its Fovista-plus-Lucentis trial results by year's end, it will also have results from a separate study evaluating its use alongside Eylea in 2017. If both Lucentis and Eylea trials pan out, then Fovista could become an add-on therapy that's tied to $8 billion in global sales and growing. With a market opportunity that big, it's not hard to imagine that Ophthotech's shares could move dramatically depending on its upcoming data.

Image source: Kite Pharmaceuticals.

No. 3: Kite Pharmaceuticals (NASDAQ: KITE)

Patients diagnosed with aggressive non-Hodgkin lymphoma have few treatment options and a poor prognosis, but that could soon change if Kite Pharmaceuticals' KTE-C19 trial delivers the goods later this year.

KTE-C19 is a chimeric antigen receptor T-cell therapy (CAR-T) that re-engineers a patient's immune system to better find and destroy cancer cells. Research into CAR-T is occurring at several companies, but Kite Pharmaceuticals' program for B-cell cancers could be closest to commercialization.

Kite Pharmaceuticals' management expects that results will be available for KTE-C19 by the end of this year in patients who no longer respond to chemotherapy. In previous studies, KTE-C19 has delivered impressive efficacy that includes a 78% overall response rate in refractory B-cell cancers.

Because of the significant unmet need for new treatments in this indication, positive results could lead to the filing of KTE-C19 for accelerated approval. If all goes well, this drug could conceivably be on the market by the middle of next year. If so, I think it has billion-dollar blockbuster potential.

KTE-C19 could be reason alone to take the risk of owning Kite Pharmaceuticals, but I also think this company may deserve an M&A premium, too. Big biopharma has been aggressively buying up companies with de-risked cancer programs, and a win for KTE-C19 could spark the interest of any number of companies, including Amgen, Inc. (NASDAQ:AMGN). Amgen already collaborates with Kite Pharmaceuticals, and Kite's chief medical officer is the former head of Amgen's oncology program. Therefore, that combination could make sense. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.