During the 1990s, with the introduction of industry user payments for regulatory submissions (a practice also applied at the newly formed EMEA), the criticism of excessive caution faded. New incentives for accelerated review were also introduced to encourage drug companies to develop “orphan” drugs for rare diseases.
 

However, the renewed enthusiasm came under fresh attack in late 2004, after Merck voluntarily withdrew its painkiller Vioxx after fears it could increase heart attacks. That sparked an explosive debate about whether the FDA should have been more sceptical and cautious in its scrutiny, and pushed the agency back on the defensive.
 

Peter Pitts, a commentator and former FDA official, says: “In the late Bush era, all applications were given a ‘complete response’,” the agency’s letter -deferring a decision as it seeks more information. “When the political heat was on, there was greater reluctance to make a judgment that was not clear cut. Career staff were scared of their own shadow, and would not take decisions.”
 

For example, only this autumn did the FDA approve GlaxoSmithKline’s Cervarix, a vaccine to prevent cervical cancer – the first time in more than half a century that it had approved a novel “adjuvant”, an additive designed to boost the human immune response.
 

It has yet to authorise any flu vaccines with new adjuvants, although the EMEA has approved such products for years, and despite the public health gains of using the additives as a way to spread scarce supplies of vaccine more broadly.
 

Andrew Baum, pharmaceutical analyst at Morgan Stanley in London, says: “The EMEA goes at a good, steady pace, like a mountain goat. The FDA is like a bipolar rabbit, sometimes in a stupor and at other times bolting forwards very fast. Now we are starting to see the -science take precedence over the politics again.”
 

Yet such transatlantic comparisons are fraught with difficulty. Vioxx was approved by regulators in both regions, for instance, but it was subsequently marketed much more aggressively by Merck in the US. That resulted in more widespread use among patients who, along with relatives, responded aggressively in a more litigious culture by suing as side effects emerged.