'Too many' trials stopped early before full risk evaluation
Research into new drugs is too often cut short, researchers warn
Wednesday, 09, Apr 2008 11:10
Too many trials of new cancer treatments are being stopped prematurely before their full risks and benefits can be evaluated, research warns today.
Italian scientists say the number of prematurely-stopped trials has increased dramatically in recent years.
They argue that without proper evaluation this could lead to a systematic over-statement of the effects of treatment and warn that patients could be harmed by new therapies being rushed prematurely into the clinic.
The team from Mario Negri Institute for Pharmacological Research studied 25 controlled clinical trials.
Writing in the journal Annals of Oncology, they say they found a consistent increase in prematurely stopped trials – more than half were stopped within the last three years.
They warn that it can take several years for the long-term benefits or adverse side-effects of a treatment to become apparent.
But the average study duration was 30 months among the 25 trials studied - with a range of between 12 and 64 months.
"We are aware that trials stopped early because they are showing benefit may result in the identification of promising new treatments for patients," said researcher Dr Giovanni Apolone.
"However, findings obtained following this strategy should be considered to be preliminary results that require subsequent confirmation."
He added: "We believe that only untruncated trials can provide the full level of evidence required to safely translate treatments into clinical practice.
"Without such evidence, unsafe and ineffective drugs could be marketed and prescribed, and patients' health could be jeopardised."
Professor Stuart Pocock, professor of medical statistics at the London School of Hygiene and Tropical Medicine, who was not involved in the study, commented: "Clinical trials need to stop early for superior benefit whenever there's proof beyond reasonable doubt that the new treatment really is superior.
"That would be an ethical obligation. However, too many trials are stopped early claiming efficacy without such strong evidence being available."