experimental medication
In Phase III randomized controlled trials, an experimental medication is tested against the current treatments in large patient groups. (Photo: iStock)

For more than 50 years, all new medications have been tested in patients using a similar approach, consisting of three consecutive phases of clinical trials. Each phase of testing produces data that helps to establish the new medication's effectiveness and safety.

Subsequently, these data are used by regulatory agencies – such as Health Canada and the Food and Drug Administration (FDA) in the United States – to decide whether the new medication should be made available to all patients diagnosed with a particular disease.

In the past 15 years, the FDA and Health Canada have accelerated their approval process in an attempt to make new drugs to treat serious illnesses available faster. As a result, some anticancer drugs have been approved without being tested in Phase III randomized controlled trials (RCT).

The repercussions of approving drugs without supporting RCTs have not been examined thoroughly.

"Many researchers are concerned by the rapid approval process," said Dr. Eitan Amir, a Clinical Researcher at the Princess Margaret Cancer Centre. "They are not convinced that a drug's benefit and potential toxicities in routine clinical practice can be predicted accurately without RCTs."

​To address this, Dr. Amir led a study evaluating the effect of RCTs on changes to drug labels. Because drug labels contain important safety information – such as dosage, side effects and other warnings – the changes made to labels can act as an indicator of potential problems with the approval process.

The study examined 59 anticancer drugs that were approved by the FDA between 2006 and 2016 and found that common side effects listed on drug labels were more likely to change for drugs that had not been tested in RCTs.

"Our findings suggest that rapid approval of drugs without supporting RCTs help patients receive new drugs faster at the expense of complete safety data," Dr. Amir says. "Healthcare professionals should be aware of this and should practice increased vigilance when prescribing such drugs."

This work was supported by The Princess Margaret Cancer Foundation.​

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