Amgen says that fourth-quarter revenues increased 11% to $4.42 billion, helped by strong sales growth for Enbrel, Prolia and Xgeva.

However, the world's largest biotech noted that net income fell 16% to $788 million. The fall was due primarily to acquisition charges and legal-related expenses.

Sales of the anaemia drug Aranesp (darbepoetin alfa) were down 9% to $489 million and its older erythropoiesis stimulating agent, Epogen (epoetin alfa) slipped 1% to $479 million. Combined turnover of Amgen’s white blood cell stimulators Neulasta (pegfilgrastim) and Neupogen (filgrastim) were also down 1% to $1.31 billion.

The anti-inflammatory Enbrel (etanercept), partnered with Pfizer and sold by Amgen in North America, leapt 23% to $1.16 billion, while Sensipar/Mimpara (cinacalcet), for the treatment of secondary hyperparathyroidism in dialysis patients, rose 19% to $256 million.

The colorectal cancer drug Vectibix (panitumumab) increased 5% to $91 million, while Nplate (romiplostim), for the treatment of chronic immune thrombocytopenic purpura, increased 26% to $101 million.

Sales of Prolia (denosumab) for the treatment of postmenopausal women at increased risk of osteoporotic fractures, reached $154 million, up 90%, while Xgeva (also denosumab) for the treatment of bone metastases to reduce skeletal related events in patients with cancer, climbed 60% to $215 million.

Chief executive Robert Bradway said that "we enter 2013 with good momentum, a broad late-stage pipeline and a continued focus on building our business internationally". Last month, the company agreed to buy Iceland's deCode Genetics for $415 million and in April acquired Turkey's Mustafa Nevzat Pharmaceuticals in a deal valued at $700 million.

In terms of pipeline, the company announced that it has initiated Phase III studies for AMG 145 in subjects with high levels of low-density lipoprotein cholesterol. Also Amgen noted that enrolment has resumed for a Phase III study of trebananib in recurrent ovarian cancer that was previously suspended due to supply issues with Johnson & Johnson's chemotherapy Doxil/Caelyx (doxorubicin).