Clinical trials have always been hampered by under-representation for certain key groups, and this is particularly a problem with children. A recent study published in the European Journal of Cancer  highlights how this has a devastating effect of access to drugs to treat paediatric cancers.
Childhood cancers are relatively rare – accounting for only 1% of cancers diagnosed in the UK. Despite this, according to staff at the Royal Marsden Hospital and the Institute of Cancer Research, only 7% of children who could benefit from recent precision cancer treatments were receiving them.
Most drugs prescribed for children have never been tested in children. About ten years ago, the figure was 50-75%. Things have improved since then, with paediatric trials being encouraged by the FDA and others but they are still relatively rare.
Unfortunately, children do not respond to drugs in the same way as tiny adults – not only are their diseases different, they metabolise, absorb, excrete and transform medicines differently. And these differences change as they develop towards adulthood.
Childhood cancers are often quite different from those in adults. In terms of “hard tumours” (i.e. excluding diseases like leukaemia), children are more likely to develop embryonal cancers, associated with growth and development. Also, their cancers are often caused by fewer mutations than those seen in adults – theoretically meaning they could respond better to modern treatments designed to target specific mutations.
So why are children not receiving precision cancer treatments?
There are many legitimate medical reasons for not using a precision treatment on a childhood cancer – the patient may already be too ill, be responding to chemotherapy or be enrolled on an immunological study. But the report authors believe that a reluctance to carry out paediatric trials is still a major barrier. They believe that the fear of something going wrong is a powerful motivator among those considering paediatric trials.
To make matters worse, a 2016 study  showed that many of the paediatric trials that do run, never produce meaningful results. Harvard University researchers examined the over 550 US paediatric clinical trials run between 2008 and 2011. They discovered that over 40% were never finished or were completed but were never published even five years after the trial finished.
Childhood cancers are rare – but don’t we owe the nearly 2,000 children diagnosed in the UK each year, access to at least the same, smarter safer drugs as adults?
Without a greater focus on paediatric trials, some of the most vulnerable in society will always have inferior treatment options.
 A tailored molecular profiling programme for children with cancer to identify clinically actionable genetic alterations – https://www.ejcancer.com/article/S0959-8049(19)30446-0/fulltext
 Many Pediatric Studies Are a Waste of Time - https://www.scientificamerican.com/article/many-pediatric-studies-are-a-waste-of-time/