GlaxoSmithKline shares have taken a fresh hit following news that the share of the market for newly prescribed oral antidiabetics held by its drug Avandia® (rosiglitazone) has sunk without trace, after a study published recently which linked the drug to cardiovascular events.
According to early prescription data published by the market intelligence group Impact RX, the share of the market enjoyed by Avandia for newly prescribed OADs fell to approximately zero from around 10% in the two days after the 21 May article in the New England Journal of Medicine. The study, criticised by GSK, concluded that the drug increased the risk of heart attack by 43% and cardiac-related death by 64%.
The Impact Rx data was cited in a note issued by Deutsche Bank analysts who said that new and switch prescription data from 1,900 US primary-care physicians showed Avandia’s average share of the newly written OAD prescription market on 21, 22 and 23 May was 10%, 8% and 6% respectively, which suggests its share dropped to almost zero on 22 and 23 May. “This reaction is far worse than we had anticipated and suggests that there could be as much as 22% downside risk to GSK’s near term earnings, suggesting that there is still further downside to the firm’s share price,” Deutsche Bank said.
The data also notes that the rate of patients switching from one drug to another was three times the usual level, with Takeda’s Actos® (pioglitazone) increasing its share of the new prescription market from 10% to 22%.
Alas for GSK, the furore around the NEJM study shows no sign of abating, and it is feared that the company’s major ongoing RECORD study may be affected by patients dropping out of the trial. GSK chief medical officer Ronald Krall told the New York Times that independent research committees overseeing the RECORD study were concerned about the ability of the study to continue and were considering what to do to prevent people from dropping out of the trial.
The 4,450-patient study is scheduled to continue until the end of 2008, and GSK has been hoping that a successful outcome will serve to dispel concerns surrounding Avandia.