Amgen Inc. on Monday reported higher third-quarter earnings that were fueled by double-digit increases in sales of its anemia drugs.

The Thousand Oaks-based biotech said after the market closed that it had net earnings of $1.1 billion, or 94 cents a share. That’s up from $967 million, or 77 cents, in the same period a year ago. Revenue increased 15 percent in the third quarter to $3.61 billion. Excluding stock option expenses and other items, Amgen posted adjusted earnings of $1.04 per share, beating the Wall Street consensus by 6 cents.

The company also increased its earnings-per-share guidance for the fiscal year to $3.85 to $3.95, up from $3.75 to $3.85.

Amgen, which last month won U.S. approval for its first direct cancer treatment, Vectibix, continued to see substantial growth in its top product lines. Worldwide sales of the extended-release anemia treatment Aranesp increased 27 percent to $1.07 billion. Sales of the older Epogen, which is marketed only in the United States, grew 6 percent to $633 million, in part due to demand among free-standing dialysis clinics, which have annual patient population growth of 3 to 4 percent. Aranesp continued to replace Epogen sales to hospitals.

Combined worldwide sales of Neulasta and the older Neupogen, both of which fight infection primarily among chemotherapy patients, increased 13 percent to $998 million.

North American sales of Enbrel grew 6 percent to $705 million, primarily in its core rheumatoid arthritis market. Growth in its use for psoriasis and other dermatological conditions has not met expectations, said the company, which plans to increase its patient and physician education programs.

Shares closed down 58 cents Monday to $73.37 but in after-hours trading climbed nearly 2 percent ($1.38) to $74.75 after the earnings were announced.