European drug regulators have tightened up the prescribing rules for Crestor, AstraZeneca’s cholesterol lowering treatment, following problems with side effects.
Doctors have been told they should start with low doses of the drug and must seek specialist advice before prescribing the highest, 40mg, dose after a small number of patients suffered a potentially dangerous muscle wasting syndrome.
The move comes less than a month after AstraZeneca was forced to write to doctors in the UK and Netherlands following reports of kidney problems and will heighten fears over the safety of Crestor.
Crestor is the most potent member of a class of powerful cholesterol-lowering treatments called statins that have saved millions of lives. Bayer was forced to withdraw its statin Baycol two years ago, after it was linked with over 100 deaths.
AstraZeneca said more patients reached their target cholesterol level with Crestor than any other treatment, while side effects were extremely rare and nobody had died from taking it.
The side effects appear to have occurred after doctors transferred patients from other cholesterol lowering drugs, without taking account of the fact that Crestor is more effective at lower doses than its rivals. “”This should be viewed against a background of caution towards statins in general,” the company said.
Crestor has been winning market share from Lipitor, the $9.3bn-a-year market leader made by Pfizer of the US. Any serious doubts about its safety would have devastating consequences for AstraZeneca, which analysts predict could achieve peak sales of more than $4bn (Â£2.2bn) a year with the drug.
However, the shares fell only 15p to Â£25.94 as investors took the view that the warning would not seriously affect sales. James Culverwell, analyst at Merrill Lynch, said the new prescribing rules would have “minimal impact” on the sales prospects of Crestor.
However, rival companies in the $26bn-a-year statin market are likely to seize on the new prescribing rules, and dangers of doctors making mistakes, when promoting their statins to the medical community.
Public Citizen, a US consumer group, has advised patients to take other available statins because of Crestor’s alleged “unique kidney toxicity”.
An editorial last year in The Lancet, the UK medical journal, said the drug had less safety data than rivals and accused AstraZeneca of using “blatant marketing dressed up as research”.
However, AstraZeneca said it was one of the most closely studied medicines on the market. “We’ve had no deaths. We’ve had 2m patients and 5m prescriptions. We’ve had some cases of myopathy and rhabdomyolysis but it’s very rare. Less than 0.01 per cent,” the company said.