After nine years as the world’s biggest drugmaker, Pfizer is going to be knocked off its perch in 2012 by Sanofi.

That is the conclusion from consensus sales forecasts made by research company EvaluatePharma. Its report claims that the French firm will retain top spot until at least 2016, with Pfizer slipping to third place, behind Novartis, following patent expiries on its cholesterol blockbuster Lipitor (atorvastatin).

Sanofi's growth-by-acquisition strategy, culminating in its $20 billion purchase of Genzyme Corp, has pushed the firm to the top of the tree. EP notes that the latter takeover "was an aggressive cross-border move that revealed just how much the culture of Sanofi has changed in the last few years". The report says that sales of Genzyme’s Cerezyme (imiglucerase) for Gaucher disease and Lumizyme/Myozyme (alglucosidase alfa) for Pompe disease will help offset the effects of generics on bloodthinner Plavix (clopidogrel), the antithrombotic Lovenox (enoxaparin) and cancer drug Taxotere (docetaxel).

Novartis is expected to be Sanofi's closest challenger over the next few years, boosted by the multiple sclerosis pill Gilenya (fingolimod), Tasigna (nilotinib) for chronic myeloid leukaemia and the contribution of recently-acquired eye specialist Alcon.

As for Pfizer, EP says that Pfizer’s $68 billion acquisition of Wyeth in 2009 "went a long way to alleviate the pain of the impending loss of Lipitor" but the latter is "a huge product to replace". Loss of US patent protection in November means sales could shrink to $2 billion by 2016.

Still, "a couple of recent pipeline successes", including the rheumatoid arthritis pill tofacitinib and Eliquis (apixaban), the blood thinner partnered with Bristol-Myers Squibb, should see top-line drug sales start growing again by 2016.

Further down the table come GlaxoSmithKline and Roche, followed by Merck & Co and Johnson & Johnson, with AstraZeneca coming in eighth. EP notes that "a notable entrant to the top ten next year will be Teva", in 9th, while Takeda, "the only non-western contender in the top 15", will be 12th biggest in sales, helped by its recent acquisition of Nycomed.

EP concludes by noting that diabetes specialist Novo Nordisk "stands out with the predicted fastest growing drug sales over the period, 9% a year until 2016". These will be driven by demand for its once-daily GLP-1 agonist Victoza (liraglutide) and its new long acting insulin degludec.