Eli Lilly saw global revenue fall by 4% in the first quarter of 2012 after sales of its atypical antipsychotic drug Zyprexa decreased by more than half due to generic exposure.

Revenues totalled $5.6 billion as sales increased by 41% in China but flat lined in the US and decreased outside America by 9% after Zyprexa lost exclusivity in all major markets bar Japan.

John C. Lechleiter, Lilly’s Chairman, President and CEO, says the Q1 figures represent a “solid start” to the year and despite the Zyprexa losses “demonstrated strong underlying growth in other products and key regions”.

Lilly expects to lose in the region of more than $3bn in Zyprexa sales but still record revenue this year between $21.8bn and 22.8bn.

It hopes the reduction in revenue generated by Zyprexa will be offset by growth in other key brands such as Cymbalta, Humalog, Humulin and newer products including Effient and Axiron.

In the first three months of the year, Cymbalta generated sales of $1.1 billion, an increase of 23% on the same period in 2011. Alimta sales were up 5% to $606.8m, Humalog generated $590.3m and revenue for Cialis, Humulin, Forteo, Strattera and Effient also increased.

But it was the 56% loss of sales on Zyprexa which saw global revenue fall as the former blockbuster totalled $562.7m in Q1. Sales of Evista also dropped 4% to $256.2m in the quarter.

The Indianapolis-based company’s total operating expenses increased by 3% compared with the 2011 Q1 after it continued its R&D-based strategy.

“We strongly believe that our innovation-based strategy will enable Lilly to return to steady growth following a period of multiple patent expirations,” said John C. Lechleiter.

Global revenue increased 5% in 2011 at Eli Lilly to $24.2 billion after the company saw demand increase but net income fall 14% to $4.3bn.

Agreements to supply generic versions of Zyprexa and Gemzar helped reduce the impact after the two lost patent exclusivity and saw revenue in the US increase by one per cent to $12.9bn. Revenue outside the US increased 11% to $11bn.

Lilly says total revenue was reduced by approximately $410 million due to the impact of the US healthcare reforms and now predicts to lose billions of dollars in 2012 due to generic competition for Zyprexa.

In 2011, total operating expenses increased 8% and R&D expenses were up 3% to just over $5bn. Lilly also paid $316.4m in relation to severance costs after its restructuring.

Its operating income was down 15% to $5.5bn compared to 2010 after an increase in R&D charges as part of its diabetes collaboration with Boehringer Ingelheim, coupled with clinical trial costs, restructuring and lower gross margin per cent.

The loss of patent exclusivity on antipsychotic treatment Zyprexa saw global sales drop 8% to $4.6bn. Zyprexa lost its patent protection in the US in October, resulting in sales decreasing by 13%. Outside the US, where exclusivity was also lost in the majority of markets, sales fell 3% to $2.45bn. But in Japan, where its patent still stands, sales reached $540m.

Gemzar also suffered at the hands of generic competition for the first time as sales decreased by 61% to $452.1m. But the news was better for Alimta, Humalog, Cialis, Humulin, Evista, Forteo and Strattera, which all recorded improved sales in 2011.

Lilly also received royalties of $409.2 million from Erbitux, an increase of 6% on 2010; $422.7m from Byetta, a 2% loss compared with 2010; and $302.5m from sales of Effient.

But Lilly now anticipates that revenue will fall to between $21.8bn and $22.8bn next year after an expected decline of more than $3bn in Zyprexa sales due to its exposure to generic competition. It hopes the loss in revenue will be partially offset by growth in Cymbalta, Cialis, Humalog, Humulin and Forteo, as well as continued improvement in its newer products such as Effient, Axiron and Tradjenta.

Japan and Emerging Markets are expected to continue to post strong underlying growth. But overall revenue in these markets is also expected to be hit by pricing actions in Japan and the impact of patent expirations, including Zyprexa, in a number of countries in these regions.