Time to raise the bar of proof for cancer drugs


By Mardi Chapman

5 Oct 2017

Cancer drugs are coming onto the market without clear evidence they improve the quality or quantity of patients’ lives, according to an evaluation of drug approvals by the European Medicines Agency.

The study of 48 cancer drugs approved for 68 indications between 2009 and 2013 found a significant survival benefit had been demonstrated in only 35% of the indications. The overall survival benefit was a median of 2.7 months (range 1.0-5.8 months).

An improvement in quality of life was demonstrated in only 10% of indications.

The study found that the lack of evidence continued into the post-market period with only an additional three indications (7%) shown to extend life and five (11%) to improve quality of life after more than three years follow-up.

“When survival gains over existing treatment options or placebo were shown, they were often marginal and judged to be clinically meaningful in less than half (11/23, 48%) of all cases,” the study said.

The researchers said none of the pivotal trials supporting the drug approvals included quality of life as a primary outcome.

“These are particularly troubling findings as many of the drugs in our sample were approved to treat advanced metastatic disease, when the purpose of treatment is palliative – that is, to improve quality of life – or to extend life while ensuring that any survival gains are not outweighed by a deterioration in quality of life from adverse events or other negative factors related to treatment.”

An accompanying editorial said the findings were consistent with those from similar research on cancer drugs approved by the FDA in the US.

The author said the regulatory system was ‘broken’ given ‘huge expenditures on cancer drugs with certain toxicity and uncertain benefit’.

“The expense and toxicity of cancer drugs means we have an obligation to expose patients to treatment only when they can reasonable expect an improvement in survival or quality of life.”

He said the use of uncontrolled study designs or surrogate endpoints should be the exception not the rule, and when surrogate measures were used, post-marketing studies must be started, completed and published.

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