It was a headline-grabbing conclusion. Only half of the cancer drugs authorised by the European Medicines Agency (EMA) showed a significant improvement in overall survival or quality of life when they were approved or in follow-up studies, according to a study published in the British Medical Journal.

The research has prompted a lot of discussion about how new drugs should be assessed, what constitutes sufficient evidence for approval, and how we balance a robust decision-making process with the need for speedy access to the latest treatments.

It’s a topic of great interest to us here at The Institute of Cancer Research in London – given our critical role in the discovery and development of many new cancer treatments.

The authors of the study looked at 48 drugs approved for 68 uses by the EMA from 2009-2013, and assessed whether they improved survival or quality of life for patients.

There are a number of ways you can measure the effectiveness of a new treatment in a trial – from long-term measures such as how long people on the treatment survive (overall survival), to shorter-term measures, like the length of time before somebody’s cancer begins to get worse (progression-free survival). These outcomes are called endpoints, and the primary endpoint of a study is the one the researchers decide at the outset of the study should be used to decide if a new treatment is more effective when compared with another treatment or a placebo.

Another possible endpoint for a study is the patient’s quality of life, where a patient’s overall wellbeing and ability to continue living a normal life are assessed during treatment.

The study found that at the time of approval, while all the drugs will have shown evidence that they were effective in some way, only just over a third of the approved drug uses showed evidence of increasing survival. And only 1 in 10 had evidence that they improved quality of life.

A further eight drugs were found to increase survival or improve quality of life in studies performed after approval.

Overall survival was used in only a quarter of trials as the primary endpoint, with the others approved on so-called ‘surrogate’ end points including progression-free survival and various laboratory measures of a patient's response to the treatment.

None of the approvals had used quality of life as a primary endpoint, and only just over half of the trials had measured it at all. The writers of the study suggest that using surrogate endpoints as the basis of approval, rather than overall survival, leads to ineffective drugs making it to market.

However, surrogate endpoints such as progression-free survival can also be valuable outcomes in their own right. Many drugs may offer limited increases in overall survival, but can improve the quality of life of patients significantly in the time they have left by temporarily stalling the progression of the disease.

And overall survival data tends to be collected in large, phase III clinical trials, which are very expensive to run, and take a long time. The ICR and many other organisations have been arguing that we need to be flexible in the way drugs are assessed, in order to speed up the approval process and get the best new treatments to patients more quickly.

It is of course vital that new drugs are shown to be effective, but with high-quality, innovative clinical trial design, it is possible to provide good evidence of effectiveness from smaller, earlier studies.