Exelixis Inc. (EXEL - Get Report)  reported fourth-quarter earnings above analysts' forecasts amid strong revenue from collaboration agreements and royalty payments to distribute its drugs.

Alameda, Calif.-based Exelixis posted adjusted earnings of $115.97 million, or 37 cents a share, for the fourth quarter vs. $38.4 million, or 12 cents a share, in the comparable year-earlier period. Analysts surveyed by FactSet had expected the drug discovery company to earn 24 cents a share.

On a GAAP basis, per-share earnings jumped to $1.15 from 13 cents in the year-earlier period. Revenue more than doubled, rising to $228.6 million from $120.1 million in the comparable year-earlier period.

Shares of Exelixis gained more than 5% in early trading on Wednesday, rising $1.22 to $22.90 on the Nasdaq Stock Exchange.

"Exelixis achieved strong financial performance in 2018, with solid growth in cabozantinib net product revenue, total revenue, and importantly, earnings per share and cash on hand," CEO Michael Morrissey said in a statement.

Exelixis last month announced Food and Drug Administration approval of its cancer drug CABOMETYX for treatment of patients with certain types of liver cancer. Also last month, the company's Japanese partner, Daiichi Sankyo Co., received approval from the Japanese health ministry for MINNEBRO tablets, which treat hypertension.

For 2019, Exelixis is expecting R&D expenses of between $285 million and $315 million, including non-cash expenses related to stock-based compensation of $20 million, the company said.