Ever wondered how patient outcomes are measured in clinical trials?

Innovative approaches to treatment have brought new hope for people with cancer over the past 30 years.

However, we continuously need to evaluate how we define and assess the impact and efficacy of a cancer treatment in patients living with the disease. Today, approaches that are more comprehensive are looking not only to extend patients’ lives, but also to help them maintain their quality of life. The positive impact that new medicines bring to patients reinforces the need to accelerate drug development, but also presents a challenge when using classical endpoints (e.g. survival). This challenge has encouraged scientists to find alternatives ways to measure the benefit of a medicine.

For serious and life threatening diseases such as cancer, combining survival assessments with other efficacy measurements that evaluate earlier and promising data could help to accelerate drug development and approvals. Health authorities occasionally consider these other measurements as ‘surrogates’ for classical survival endpoints. As our understanding of cancer has evolved, so has the importance of combining measurements to help see the broader picture.

These measurements are better known as ‘endpoints’, do you know what they mean?

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The classical survival endpoints

Historically, we have measured the efficacy of cancer treatments in clinical trials in terms of overall survival (OS) and progression-free survival (PFS). While these continue to be meaningful measurements of success in large, late-stage clinical studies, additional exploratory endpoints are added to ensure the full picture of treatment is clear, in the spirit of assessing benefit/risk and getting drugs to patients faster.

Early efficacy endpoints

We have long considered response rate and duration of response to be direct measures of a therapy’s anti-tumour activity, and we tend to use them in early and/or small clinical trials as primary endpoints, or as secondary endpoints in larger trials. Positive data in these studies could help potentially accelerate regulatory approvals.4 Each person may respond differently to a treatment, but these endpoints can indicate, for example, if a therapy could give them months or years longer with their families and loved ones.

Emerging efficacy endpoints

Cancer treatments are evolving, which means that we need new or adapted endpoints to measure efficacy more accurately or efficiently in specific settings such as early disease, blood cancers, or with new treatment modalities like immunotherapy. The ‘emerging endpoints’ work well alongside the ‘classical endpoints’.

Measuring treatment safety

We need to balance the efficacy of treatment with the overall impact of these medicines on people’s daily lives. The safety profile of a drug and its monitoring is a critical component in its development.

Measuring quality of life in patients

In addition to the safety or side effect data that we collect as part of all clinical trials, many additional endpoints aim to capture the overall impact of a treatment on a person. The impact of safety and tolerability in daily life, as well as symptomatic improvement, is what quality of life assessment brings.12

“What will the side effects be? Am I going to be tired all the time? How will this therapy interfere with daily life?” These types of questions have become increasingly important, and symptomatic improvement is considered a direct clinical benefit and an appropriate endpoint for drug approval.12 These endpoints are known as patient-reported outcomes (PROs), and represent the patients’ perception of their own health status or quality of life in the context of a clinical trial. There are several categories within PRO data: