Source: Gilead Sciences.

Investors anxiously awaiting Gilead Sciences' (NASDAQ:GILD) fourth-quarter financial results can now take a deep breath. The biotech announced those results after the market close on Tuesday. Gilead's shares initially climbed slightly in after-hours trading but then fell by 5%. Here are the key details from Gilead's fourth quarter and a look further into 2015. 

By the numbers

Gilead reported fourth-quarter revenue of $7.3 billion, a whopping 135% year-over-year increase from the $3.1 billion in revenue from the same period in 2013. This figure easily beat the average analysts' estimate of $6.72 billion. Full-year revenue for 2014 came in at $24.9 billion, compared with $11.2 billion in the previous year.

GAAP fourth-quarter earnings were $3.5 billion, or $2.18 per diluted share -- a huge jump over the $791 million, or $0.47 per diluted share, reported for the fourth quarter of 2013. Gilead reported non-GAAP earnings for the quarter of $3.9 billion, or $2.43 per diluted share, compared with $930 million, or $0.55 per diluted share, in the same period last year. This earnings result beat the consensus analyst expectation of $2.22 per share.

For the full year of 2014, Gilead announced GAAP earnings of $12.1 billion, or $7.35 per diluted share, compared with $3.1 billion, or $1.81 per diluted share in the previous year. Non-GAAP earnings for full-year 2014 came in at $13.3 billion, or $8.09 per diluted share, reflecting a large increase from the $3.5 billion, or $2.04 per diluted share, reported for 2013.

Behind the numbers

All eyes were definitely on Gilead's hepatitis C franchise. Harvoni racked up sales of $2.107 billion in the fourth quarter, while Sovaldi generated sales of $1.732 billion. The two drugs combined for $10.283 billion in 2014 and by themselves accounted for most of Gilead's year-over-year revenue growth.

Harvoni. Source: Gilead Sciences.

Gilead also benefited from growth in several of its HIV/AIDS drugs. Stribild and Complera/Eplivera were the big winners, with 88% and 33% year-over-year sales increases, respectively. Truvada and Viread also saw solid growth.

The only bad news on the HIV/AIDS front was a slight decline in sales for Atripla compared with the fourth quarter of 2013. That decrease was expected, though, as Gilead's other drugs take center stage. All of the company's antiviral drugs (excluding Harvoni and Sovalid) combined for fourth-quarter sales of $2.887 billion, compared with $2.502 billion in the same period for 2013.

Many investors might tend to overlook Gilead's other drugs, but they also performed well. Other drugs, including Letairis, Ranexa, and AmBisome, generated sales of $496 million during the fourth quarter, compared with $402 million in the fourth quarter of 2013.

Looking ahead

With Gilead reporting strong results for the fourth quarter, why would shares drop in after-hours trading? The answer lies in the company's outlook for this year.

The biotech projects net product sales of $26 billion to $27 billion. That reflects an increase over the $24.474 in product sales reported for 2014. However, Wall Street was expecting revenue (which includes both product sales and other sources such as royalties) of $28.65 billion. Gilead might have leaned toward a conservative outlook, but investors hoped for stronger growth.

The big challenge is competition. AbbVie (NYSE:ABBV) kicked off a pricing battle after gaining FDA approval for its hepatitis C drug, Viekira Pak. That move forced Gilead to respond by lowering prices to counteract AbbVie's scoring of an exclusive deal with the nation's largest pharmacy benefits manager, Express Scripts (NASDAQ:ESRX)

Despite the disappointment over a lower-than-desired outlook for 2015, investors do have cause to celebrate, as Gilead announced the initiation of a quarterly dividend program. The company plans to pay a dividend of $0.43 per share, which represents a yield of around 1.6%. Gilead's board also approved a new five-year, $15 billion share-repurchase program. 

Some will probably fret about Gilead's forecast for hepatitis C franchise sales growth. Long-term investors, though, will focus on the generally positive business fundamentals for the company, combined with its attractive valuation -- and breathe easy.