* Humira growth signals importance of biotech medicines
* Lipitor, Plavix patent expiries upturn rankings in 2012
* Q1 results will show how Big Pharma is coping
* Roche kicks off earnings season April 12
LONDON, April 11 (Reuters) - Abbott Laboratories' $9-billion arthritis drug Humira is set to take the crown as the world's top-selling medicine this year, highlighting the dominance of costly biotechnology products as revenues from old-style pills decline.
Neither of last year's biggest sellers - Pfizer's cholesterol fighter Lipitor or blood thinner Plavix from Sanofi and Bristol-Myers Squibb - will even make it into the top 10 in 2012, according to consensus forecasts compiled by Thomson Reuters Pharma.
The dramatic shift in the sales landscape, triggered by a record wave of patent expiries, will be centre-stage during the forthcoming quarterly results season as investors weigh up how leading pharmaceutical companies are adapting.
"They've all seen this coming but their ability to manoeuvre is limited," said Simon Friend, global pharmaceutical leader at PricewaterhouseCoopers.
"It's a tale of two worlds ... there is certainly a rush to streamline costs and step up looking for new products."
Roche, the first Big Pharma to report sales figures on April 12, is relatively well-placed in the new era, given its leading position in biotech and cancer drugs, which it hopes to consolidate by buying gene sequencing firm Illumina.
Roche has three anti-cancer drugs in the global top 10 with Rituxan, Avastin and Herceptin. Others are less fortunate.
Pfizer is already feeling the loss of Lipitor, after the U.S. patent ran out in November, while for Sanofi and Bristol the first three months of 2012 were the last full quarter of U.S. Plavix sales before cheap generics hit.
Bottom of the pack is AstraZeneca, trading on just 7 times this year's expected earnings. It has already warned that earnings will fall by more than 10 percent in 2012 as its antipsychotic Seroquel and other drugs face generic competition.
ON A ROLL
Abbott's Humira, by contrast, is on a roll.
Analysts expect the U.S. firm to report first-quarter revenue from the injectable medicine up 11 percent from a year ago and worldwide sales, including those booked by Japan's Eisai , are forecast to reach $9.3 billion this year.
Although best known as a treatment for rheumatoid arthritis, Humira is also used for a range of other inflammatory diseases. On Wednesday, it was approved in Europe for a seventh indication against ulcerative colitis.
The medicine is expected to retain its market-leading position through 2016, by which time it will rack up sales of $11.75 billion - still short of the $13 billion achieved by Lipitor at its peak.
Two other biologic rheumatoid arthritis drugs - Johnson & Johnson and Merck & Co's Remicade and Amgen and Pfizer's Enbrel - are set to take second and third place behind Humira this year, but they are growing more slowly.
Humira will be the key asset when Abbott spins off its pharma business from the wider diversified healthcare company later this year. Competition, however, is looming.
A U.S. advisory panel will meet on May 9 to consider whether to approve a novel arthritis pill from Pfizer called tofacitnib, challenging so-called anti-TNF drugs like Humira.
Mark Schoenebaum, an analyst at ISI Group, expects a vote for approval but believes tofacitnib may be restricted to patients for whom anti-TNFs do not work, given the outstanding questions about its safety record in clinical trials.
With a growing emphasis on drugs to treat conditions like cancer and inflammatory conditions, which are typically prescribed by specialists for relatively limited numbers of patients, some analysts doubt if any single drug will ever match Lipitor's sales peak.
The one area where sales above $13 billion a year seem plausible is Alzheimer's disease - but expectations for an effective treatment remain low, despite ongoing late-stage clinical trials with experimental products from Eli Lilly and Pfizer and J&J.