More effort must be made to recruit older people to clinical trials to ensure that they reflect the demographic of medicines users, a specialist thinktank has said.

In its Trial and error report, released today, the International Longevity Centre (ILC) urged regulators, pharmaceutical companies and researchers to prioritise age diversity at all stages of the clinical trial process.

While older people are prescribed more medications than any other age group – with 61.6% of all community prescriptions in England between 2007 and 2017 being issued to people aged over 60 – the thinktank said that they were ‘consistently underrepresented’ in trials that test the safety and efficacy of medicines.

While existent non-binding international guidelines recommend the inclusion of at least 100 older participants at the second and third phase of a clinical trial, a 2020 study found that recent trial designs ‘broadly failed’ to meet this target.

The thinktank warned that this lack of age diversity in clinical trials risked patients taking medicines that might not be as effective as they could be or even experiencing adverse reactions – for instance, because metabolic clearance varies significantly between age groups while immune response declines naturally with age.

The ILC called for ‘structural and cultural change’ to ensure that older people were adequately represented, including by representing the diversity of lifestyle and health conditions that people might experience at different ages.

In particular, the report called for the co-production of new international guidelines around age diversity in clinical trials, as well as the creation of a gold standard for inclusive trials to help identify best practice.

It also said regulators should incentivise diverse trial cohorts, while pharmaceutical companies should appoint diversity champions to prioritise age diversity and prioritise technological advances for the benefit of older populations. Researchers should also prioritise gathering age-related data throughout all trials, the ILC said.

The thinktank emphasised that ensuring efficacy of medicines for older people was important in tackling overprescribing, polypharmacy and adherence issues.

It would also result in a ‘better end product which is more suited to changing global demographics’, with an increasing and aging population, the report concluded.

Does involving older people increase the cost of clinical trials?

The report suggested that many clinical trial teams might be put off from involving older participants because using younger, healthier cohorts who are assumed to carry a lower risk of adverse events is often considered to be cheaper and easier.

Would more complex data sets involving older people be useful in clinical trials?

While recruiting younger participants in clinical trials might result in ‘cleaner’, less complex data sets, the thinktank suggested that by recruiting older people, trials teams would be able to gather complex information such as comorbidities and concomitant medications. It added that this ‘nuance and diversity’ was necessary to help researchers understand whether medicines were safe and effective ‘for all patients who may take them’.

Are older people arbitrarily excluded from clinical trials?

The report suggested that some protocols set out by clinical trials might exclude older people disproportionately and without good reason. This might be by excluding people on the basis of other diagnoses – sometimes common conditions among older people like diabetes, hypertension or anaemia – or concerns about compliance.

The ILC suggested that funding for clinical trials could be linked to meeting targets based on age group, but emphasised that a balance must be struck ‘between making age-inclusive targets ambitious and keeping them realistic’ to avoid researchers following the letter rather than the spirit of the target, which could be ‘detrimental to the trial’s primary objectives’.

The ILC’s report draws on a review of existing literature, as well as findings from a roundtable of experts hosted by ILC in January 2023 and one-to-one interviews with eleven expert stakeholders. Experts included pharmaceutical professionals, regulators, academic researchers and clinicians from pharmacology, geriatrics, public health and sociology, contract research organisations, patient advocacy professionals, healthcare technology professionals and other associated professionals.