Eli Lilly has posted a healthy set of figures for the first quarter, despite flat sales of its antipsychotic Zyprexa and its profit growth beat analyst estimates.

Net income was up 23% to $1.31 billion, while sales reached $5.05 billion, a rise of 5%. The most striking performance came from the antidepressant and fibromyalgia blockbuster Cymbalta (duloxetine), which increased 17% to $709.3 million, though Lilly’s best-selling drug continues to be Zyprexa (olanzapine), which had turnover of $1.12 billion.

Of the firm’s other drugs, the insulin products Humalog and Humulin rose 11% and fell 7% respectively, to $450.6 million and $240.6 million. Gemzar (gemcitabine) was down 14% to $367.8 million, due to generic competition, though another cancer drug Alimta (pemetrexed) shot up 36% to $335.3 million. The erectile dysfunction drug Cialis (tadalafil) also impressed, bringing in $358.8 million, up 6%.

The osteoporosis drug Evista (raloxifene), which is also approved for the prevention of breast cancer for certain postmenopausal women, had revenues of $256.9 million, down 2%, while sales of Lilly’s other osteoporosis drug Forteo (teriparatide) edged up 1% to $187.5 million. The type 2 diabetes treatment Byetta (exenatide), which is sold in partnership with Amylin, had worldwide sales of $181.4 million, up 7%, and $97.5 million (+18%) of that was booked by Lilly.

Erbitux (cetuximab), the cancer agent that the company got hold of through its $6.5 billion acquisition of ImClone Systems last year, brought in $94.1 million.

Chief executive John Lechleiter said that despite the downturn in the economy, “Lilly delivered strong financial results, with good underlying operational performance, aided in part by movements in exchange rates". The figures, “in combination with prudent expense management, helped us to achieve operating leverage and robust earnings per share growth", he added.

The results failed to inspire analysts and Barbara Ryan at Deutsche Bank issued a note saying that near-term growth prospects will be tempered by the dilutive impact of the ImClone acquisition “and are vulnerable longer-term to patent expirations on important, profitable drugs, namely Zyprexa in 2011”. She and other analysts are now waiting to see how long it will take for the US Food and Drug Administration to approve the antiplatelet drug Effient (prasugrel), which was unanimously recommended for approval by an agency advisory panel earlier this year.

Chris Schott at JPMorgan said that "we continue to believe Lilly’s pipeline remains too early-stage...to convince us of its ability to meaningfully offset the loss of core franchises”, notably Zyprexa, Gemzar, Evista and Cymbalta.