Competition in the lucrative cholesterol treatment market, the biggest drug market in the world, is heating up before a crucial US patent expiry this week.
With Merck's blockbuster cholesterol drug, Zocor, losing patent protection on Friday, the Anglo-Swedish drug maker AstraZeneca and its US rivals, Merck and Schering- Plough, are locked in a fierce battle to prove their medicines are better at lowering high cholesterol levels, blamed for heart attacks and strokes.
New clinical evidence presented at the International Symposium on Atherosclerosis in Rome showed Merck and Schering's Vytorin treatment is more effective in reducing bad cholesterol than AstraZeneca's top-selling Crestor medicine.
However, AstraZeneca hit back yesterday with the publication of a separate study showing a combination of Crestor and another cholesterol drug, ezetimibe, lowered bad cholesterol - low-density lipoprotein (LDL) - by an unprecedented 70 per cent.
With health authorities around the world adopting a "lower is better" approach to cholesterol in the fight against cardiovascular disease, anti-cholesterol medicines have become the world's biggest-selling drug class. Sales in the 13 main markets were $29bn (£16bn) in the year to the April.
When Merck's patent on Zocor, also known as simvastatin, runs out on Friday, its $4.4bn annual sales are set to shrivel as cheaper, generic versions of it come on to the market. The patent expiry has far-reaching implications for other companies that make cholesterol drugs in the statin category, putting them under huge pressure to prove the efficacy of their drugs.
Pfizer's Lipitor is the world's leading cholesterol drug and controls more than half the $16bn US market. The US drug maker risks losing a sizeable portion of Lipitor's $12bn annual sales and is developing a follow-up, but the product will not be on the market until 2008 at the earliest.
Vytorin, made by a joint venture of Merck and Schering, cut cholesterol levels by an average of 56 per cent across all doses against 52 per cent for Crestor, according to the latest study. Vytorin, a two-in-one pill, combines the ingredients ezetimibe, which blocks the absorption of cholesterol in the intestine, and simvastatin, which inhibits production of cholesterol in the liver.
But AstraZeneca's new study elicited positive responses from experts. Analysts at Morgan Stanley said the high efficacy of Crestor combined with ezetimibe indicated Crestor combinations could become the new "gold standard" of care in the long run.Reuse content