Amgen has reported a decline in second-quarter earnings, but not by as much as some analysts had predicted, as the fall in sales of its flagship anaemia drugs Aranesp and Epogen was not so sharp.

Net income was down 8% to $941 million, while revenues sneaked up just 1% to $3.76 billion. Sales Aranesp (darbepoetin alfa) dropped 13% to $825 million as turnover in the USA of the erythropoiesis stimulating agent fell 26% to $427 million, on lower market demand caused by regulatory and reimbursement changes. However, sales of the older ESA, Epogen (epoetin alfa), were not affected by the aforementioned problems and were flat at $622 million.

On a more positive note, combined worldwide turnover of Amgen’s white blood cell stimulators Neulasta (pegfilgrastim) and Neupogen (filgrastim) climbed 15% to $1.20 billion. North American sales of the anti-inflammatory Enbrel (etanercept) were up 2% to $841 million, hit by competition and unfavorable changes in wholesaler inventory levels, while global revenues for Sensipar (cinacalcet), for the treatment of secondary hyperparathyroidism in dialysis patients, leapt 39% to $150 million. However sales of the anticancer antibody Vectibix (panitumumab) fell to $32 million compared with $45 million in the like, year-earlier period.

Chief executive Kevin Sharer said that “our business showed good stability through the first half of the year”, giving us confidence to increase our previously issued guidance on a full year basis” to $4.25-$4.45 per share from $4.00-$4.30. Amgen’s revenue forecast for 2008 is now $14.6-$14.9 billion, up from $14.2-$14.6 billion.

The results went down well with analysts, and Deutsche Bank said that Amgen had put in a “stellar quarter” with all its major products beating estimates. The figures were released after the markets closed but by the end of trading, the firm’s shares had risen 12.2% to $60.48 on the back of the firm posting promising late-stage data on its investigational compound denosumab.

That data shows that the monoclonal antibody reduced the incidence of fractures in postmenopausal women. Full data from the study will not be released until September but most analysts are suggesting that an approval from the US Food and Drug Administration is looking very likely.