How to measure patient enrollment (on budget and on time)

There are many questions when planning a clinical trial. But one of those questions is the main one:

How many patients can we enroll?


And the answer is everything but straightforward or easy to provide. Yet, answering this one question could mean the world to a biotech startup that just raised its funding and gives 90% of it to a CRO to manage the clinical trial needed for bringing them to the next stage. This puts the CROs in a very complicated position – they are the experts on clinical research, yet, they don’t always have the data and the tools to predict patient recruitment.

As I mentioned in my previous articles, I spent most of my time, speaking to and working with CROs and sponsors to help them plan their clinical trials more efficiently (which includes meeting the enrollment target). Thanks to the hundreds or maybe even thousands of conversations I had in the last years, I came across a few repeated methods you can use to answer this question:

Site Surveys

This is what all the traditional CROs are doing and probably the only known way to get direct feedback on the protocol and the ability of the site to recruit patients. 

  • The Good – it gives you a precise number of patients and you start building a better understanding of the capabilities the site has, as well as their willingness to engage with the study.
  • The Bad – It takes a lot of time to get a response back. Most of the good sites get bombarded by site survey requests. On top of that, some of them don’t always pay extra attention to how accurate the data they provide is. 

Historical Recruitment Rate (RR)

RR is a huge topic in and of itself. If you want to learn more about it, you can read my previous article. If the CRO has been working recently on a similar protocol and knows the situation in the different countries (i.e. patient populations and interest in trial participation), while is also aware of the prevalence/incidence data there, there is a good chance they can predict how many patients they can enroll for a certain period of time.

  • The Good – it is a pretty quick and efficient way to provide the sponsor with a general idea of what to expect. 
  • The Bad – Of course this number won’t be as accurate as the one coming from the sites.

Asking KOLs

KOLs are the kings both for clinical research and market access after that. It’s believed that they are the people who know the most about the patients and doctors in the given country.

  • The Good – If you engage with KOLs early on, they might become your best advocate on a country or sometimes even international level.
  • The Bad – It’s really hard and expensive to attract their attention and get all the data you need. Plus, you have to do it country by country.

Mining EHRs

We all dream of the day when EHRs will be everywhere and they will automatically match patients to clinical trial protocols. Nowadays, they have been used to support the feasibility process for identifying sites and can also very accurately answer how many patients are at the sites.

  • The Good – thanks to technology they can also go into details like not only patients but potentially eligible patients at the site. You can use that to enhance the patient recruitment process as well.
  • The Bad – very few sites are equipped with a quality EHR system and also big portion of the medical history of each patient is not on a file but still on doctors’ notes. 

No matter what method you choose or how you combine them, I believe it’s important to also remember that the number of patients available is just one metric that doesn’t mean patients enrolled

It happens often, that people choose sites because of their access to patients and don’t ever check how many competitive clinical trials they currently work on. Besides, it’s the patient’s choice to participate or not in your clinical study. If you want to learn how to measure patients’interest in clinical trials, you can also check one of my articles on the topic.

About the Author: Maya Zlatanova is a healthtech entrepreneur, CEO and Co-founder of FindMeCure Ltd. – a company dedicated to bringing clinical trials closer to patients through technology and innovation. FindMeCure’s focus is on utilising data to prevent clinical trials and patient recruitment delays. She is also a member of the Alliance for Clinical Research Excellence and Safety and an industry speaker (Logipharm, Eyeforpharma, Scope Summit, Clinical Innovation Partnerships etc.)

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