French drugmaker Sanofi forecast 2012 earnings would fall less than expected as cost cuts and demand for diabetes and rare disease drugs cushion the blow from patent expiries.

Sanofi said on Thursday full-year earnings could fall 12%, compared with its previous guidance for a decline of up to 15%, helped also by demand from emerging markets.

"We are seeing the light at the end of the tunnel," chief executive Chris Viehbacher told reporters after third-quarter income dropped less than expected.

"As our growth platforms continue to build steam, we believe this will put Sanofi back on a growth trajectory," he added.

Sanofi has seen sales of blockbusters such as blood clot preventer Plavix nearly wiped out by the loss of patent protection. Plavix was the world's second-biggest-selling medicine until its U.S. patent lapsed in May.

It expects to return to growth from next year thanks to emerging markets, diabetes, vaccines, animal health, biotech drugs and new products such bowel cancer drug Zaltrap and multiple sclerosis pill Aubagio.

Sanofi's better than expected third quarter and improved guidance contrast with bleak quarterly earnings from European rivals, which are also facing headwinds from a wave of patent expiries sweeping through the global pharmaceutical industry.

Switzerland's Novartis reported lower-than-expected third-quarter sales on Thursday, dragged down by a patent loss on top-selling blood pressure drug Diovan and lower sales at its generics unit.

Sales at AstraZeneca slumped by a bigger-than-expected 19% in the third quarter.

"Sanofi should be capable of returning to very consistent revenue and EPS growth over the long-term, which makes it unique among its peers," said Bernstein analyst Tim Anderson.

Double-digit growth

In the three months to Sept. 30, Sanofi's business net income, which excludes items such as amortisation and legal costs, fell 7.4% to €2.22 billion ($2.9 billion), beating the average forecast of 1.97 billion in a Reuters poll.

Double-digit percentage growth in diabetes treatment Lantus and rare disease unit Genzyme as well as the weaker euro lifted sales to 9.04 billion, up 3.3%, offsetting the slump in Plavix and cancer treatment Eloxatin due to generic competition.

Sales in emerging markets, one area Sanofi is betting on for future growth, provided a cushion to the overall results, though they grew slower than in the previous quarter - up 6.8% compared with 9.8% in the second quarter - due to a lower contribution from Asia and Latin America.

The shares have risen around 17% since the start of 2012, giving the company a market capitalization of over €87 billion, close to toppling its former parent, oil company Total, as the largest company on the CAC 40.