When drug trials are stopped early, patients in need of such medications benefit; however, pharmaceutical companies could be pressuring researchers to exaggerate a drug’s benefits. A review of 25 cancer drug trials over 11 years found a trend in trials stopped early once a drug showed a strong benefit. Critics disagree saying drug benefits can be detected earlier because clinical trials are better designed and that it could be construed as unethical to continue a trial and denying a drug to ill patients.
Giovanni Apolone at the Mario Negri Institute for Pharmacological Research in Milan, Italy, looked at trials conducted between 1997 and 2007 which were stopped after interim data analysis. Trials analyzed averaged 30 months and over half were stopped within the last three years. Apolone also identified a trend wherein prematurely halted trials supported drug marketing: 12 were used to support a marketing application; 11 were published in the past three years. “This suggests a commercial component in stopping trials prematurely,” Apolone says; however, he stresses there is no proof this was any company’s intention. Apolone’s study did not cover if patients were harmed because of a drugs’ early approval. Rather, the study focused on if a drug’s benefits could have been exaggerated because the studies examined benefits such as long-term survival. “If a trial is evaluating the long-term efficacy of a treatment, short-term benefits, no matter how significant statistically, may not justify early stopping,” he said.
An Association of the British Pharmaceutical Industry spokesman said when a trial is stopped early, the regulatory authority is informed. “Assuming it is for a good reason they will be scrutinising the data especially carefully. It would not approve the drug unless the data was very robust. Patient safety is absolutely paramount, so we are not going to take any short cuts.” Overestimating a drug’s benefit could make it harder to review acceptability of its side effects, says Stuart Pocock at the London School of Hygiene and Tropical Medicine, UK. “Many cancer drugs are inevitably quite toxic, but I think patients are prepared to risk side effects if they are going to live longer,” adding, “The real problem is if a patient is being exposed to these side effects without getting a clinical benefit.”
According to Karol Sikora, professor of cancer medicine at Imperial College School of Medicine in London, trials might be stopped early because drug benefits are apparent earlier. “I suspect it is becoming more common because doctors are getting better at spotting which patients should be put into a clinical trial in the first place,” he says. For example, Herceptin—a breast cancer medication—targets a protein called HER2 and is only found on the surface of some breast cancer cells. Only those women with breast cancer who tested HER2-positive were given Herceptin during late-stage clinical trials.
Sikora noted independent committees generally scrutinize interim analysis before approving an early trial end. If they see a benefit, there can be strong ethical arguments to stop a trial saying, “If you didn’t stop the trial, it would mean that people in the control group would miss out.”