With hundreds of companies having already reported quarterly results, we're now in the heart of earnings season. The key to making smart investment decisions with stocks releasing their quarterly reports is to anticipate how they'll do before they announce results, leaving you fully prepared to respond quickly to whatever inevitable surprises arise. That way, you'll be less likely to make an uninformed kneejerk reaction to news that turns out to be exactly the wrong move.

Let's turn to Gilead Sciences (NASDAQ:GILD). The biotech giant has pioneered work in fighting HIV/AIDS, and its shares have rocketed higher throughout the past year. Let's take an early look at what's been happening with Gilead Sciences over the past quarter and what we're likely to see in its quarterly report Monday.

Stats on Gilead Sciences

Analyst EPS Estimate


Change from Year-Ago EPS


Revenue Estimate

$2.43 billion

Change from Year-Ago Revenue


Earnings Beats in Past 4 Quarters


Source: Yahoo! Finance.

Will Gilead Sciences keep investors healthy?
Analysts expect solid results from Gilead this quarter, having raised their estimates on earnings per share by a penny over the past three months. The stock price also reflects that enthusiasm, with shares up more than 18% since late October.

Gilead is best known for its HIV treatments, and the company launched two new HIV-fighting products last year, Complera and Stribild. But Gilead has also been working on diversifying its base of drugs, with the company boosting its exposure to oncology.

Perhaps most promising, though, is Gilead's hepatitis-C pipeline, which it made a priority after its big $11 billion acquisition of Pharmasset a year ago. As Fool health-care analyst David Williamson sees it, Gilead is winning the hep-C race, as its sofosbuvir has continued to show amazing results in eradicating the hep-C virus. Competitors are still lining up to fight back, with Idenix (NASDAQ:IDIX) having made a deal with Johnson & Johnson (NYSE:JNJ) earlier this week in an attempt to create an all-oral combination of hepatitis-C treatments. But Gilead has the inside track to an all-oral treatment, and that could spell disaster for intravenous treatment options that Vertex Pharmaceuticals (NASDAQ:VRTX) and Merck (NYSE:MRK) offer. Vertex and Merck would have considerable trouble competing against a treatment with fewer side effects.

With drug companies, earnings are often less important that approvals and trial results. But you should still look at adoption rates of approved treatments as well as any progress Gilead announces on its trials to assess the company's future prospects. With Gilead running on all cylinders, it'd take a bad report to derail enthusiasm about the stock.

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Fool contributor Dan Caplinger has no position in any stocks mentioned. You can follow him on Twitter @DanCaplinger. The Motley Fool recommends Gilead Sciences, Johnson & Johnson, and Vertex Pharmaceuticals. The Motley Fool owns shares of Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.