More teenagers and young adults need to be recruited into clinical trials of new treatments for cancer to improve drug development for these vulnerable groups, according to a Keynote Comment published in the April issue of The Lancet Oncology. People recruiting patients to clinical trials therefore need to specifically target young people, say Jeremy Whelan and Lorna Fern from University College, London, and authors of the Comment.
However, according to a Personal View article published in the same issue, trial recruitment of children in general is high, but the numbers of participants randomised can be low. This suggests there might be barriers to the understanding of patients and families of the randomisation process and to addressing their key concerns and highlights the need for more research.
“Clinical trials lie behind the story of remarkable scientific progress in the treatment of cancer in childhood”, explains Kathy Pritchard-Jones from the UK Institute of Cancer Research—lead author of the Personal View written with colleagues from the Netherlands and Italy. “For example, current survival from acute lymphoblastic leukaemia is associated with a successive series of collaborative clinical trials that spanned 35 years, during which 10-year survival increased from less than 10% to 80%.”
Phase III clinical trials of new treatments are needed before a new drug or intervention is approved for widespread use or to optimise current treatments, and they require large numbers of patients to provide sufficient evidence of efficacy and safety. However, because different age groups are likely to respond to treatments in different ways, findings from trials in adult populations cannot be directly applied to children and younger people. Furthermore, many cancers in paediatric and teenage populations are rare so to obtain evidence to support approval of a new drug in young people requires large-scale and coordinated efforts.
“For rare cancers of childhood or for specific subgroups, international cooperation is often the only way to produce sound evidence to improve clinical practice”, says Pritchard-Jones and colleagues. Just starting trials in rare cancers can improve survival, as shown by the example of International Society of Paediatric Oncology’s trials of treatment for hepatoblastoma—a very rare liver tumour with an average of 14 cases every year in Great Britain. Survival increased from below 40%, before the trials for this cancer started, to around 60% since participation began.
Although more than 70% of eligible children with cancer are recruited into phase III trials in Europe and the USA, there is discrepancy between different types of cancer in the numbers randomised: over 85% of eligible children with lymphoblastic leukaemia are recruited, with over 90% accepting randomisation, whereas only 39% of eligible patients accepted randomisation in a trial for Wilms’ tumour. The continued availability of clinical trials in an increasingly tight regulatory environment following the introduction of the EU Clinical Trials Directive is also a major concern, adds Pritchard-Jones.
Recruitment also varies between different age groups: in the Keynote Comment, Whelan and Fern highlight these differences. While participation among children less than 15 years of age might exceed 70%, less than 15% of eligible patients with cancer aged 15 to 19 years and as few as 2% of patients aged 20 to 30 years are recruited into clinical trials.
In the UK, the National Cancer Research Institute established a Teenage and Young Adult Clinical Studies Development Group in 2005 to investigate the shortfall in trial participation in this age group. Whelan and Fern suggest that the low numbers of trial participants are due to these patients falling in the gap between paediatric and adult oncology specialists. The recruitment of sufficient numbers of patients to trials will rely on “investigators who can overcome the constraints of traditional research communities arranged around patient age, which have for too long left teenagers and young adults forgotten in the middle”.
Low numbers of trial participants mean evidence to support changes to treatment for these under-represented age groups, even from international collaborative trials, is often poor. “Significant improvements in outcomes from cancer for teenagers and young adults will remain elusive without a coalition of forces including funders, policy makers, biologists, clinicians, and patients”, say Whelan and Fern.
Press contacts for Prof Kathy Pritchard-Jones:
Nadia Ramsey
The Institute of Cancer Research, Sutton, Surrey, UK
020 7153 5359 or, out of hours, the duty press officer on 07721 747900 nadia.ramsey@icr.ac.uk
Naomi Owen
The Royal Marsden Hospital, Sutton, Surrey, UK
020 7808 2107 or, out of hours, the duty press officer on 020 7352 8171 naomi.owen@rmh.nhs.uk
Dr Jeremy S Whelan, Department of Oncology, University College London, UK. T) +44(0)207 380 9346 email: Jeremy.whelan@uclh.nhs.uk
Journal
The Lancet Oncology