Is Clinical Trial Planning a Game of Numbers?

“Look Before You Leap” is unsurprisingly the principle that all clinical trial sponsors follow. After all, a clinical trial, while being a hundreds of millions or even billions of dollars risk, hopefully, will result in the release of a new compound/treatment to the market. That new product might be the one to turn the company into the next Abbvie or Genentech.

Both biotech firms and even big pharma companies’ future depends on the outcomes of the clinical trials in their pipelines. Any negative result or even news might lead them to “hell” – whether it’s issues with their investors or plummeting stocks. The bottom line, proper planning of clinical trials is crucial.

In some of my previous articles  How Prevalence Data Can Misguide You or Why AstraZeneca and Novartis Are Reshaping Their Clinical Trials Process I went through some of the basics of how clinical trials are planned and some of the essential metrics. Many of you have reached out to learn more about the assessment of new countries and patients’ interest. With the majority we have also discussed:

Is Clinical Trial Planning A Number’s Game?

In order to keep it short, I will provide a summary of the two main conflicting views:


The majority of feasibility experts and CRO business development professionals would confirm that numbers are key when negotiating a strategy for conducting a clinical trial. Numbers are the objective way to predict being:

On-Budget, On-time

Numbers are everywhere. From measuring the CRO’s previous experience based on the number of employees, the number of country offices, and the number of previous clinical trials in the Therapeutic Area to the number of Patients in their network of sites. Here are some other key numbers that are “must” for every clinical trial planning:

Average Recruitment Rate (ARR):

Example: ARR calculated for Germany for the past 5 years, Indication: Psoriasis; Provided by TrialHub.

This is the patient recruitment rate of already completed clinical trials and is measured as the number of patients per month per site. A very helpful metric that can be especially powerful, if you look at the ARR of clinical trials that are very similar to your protocol.

This is believed to give you an objective idea of what you should expect in terms of how many patients should be enrolled for a certain amount of time and then this helps with calculating how many sites will be needed, when and for how long. 

NB! I would strongly suggest that you consider not only the final ARR number but also the number of trials this number is based on. The more trials (I would recommend more than 10) the closer to statistically correct data.

The other way of getting this right is to ask the site, however, most experts know sites often overpromise how many patients they have and how fast they can recruit. For that reason, the same experts usually divide the ‘promised’ numbers from sites by 3! Lastly, if you have historical data about similar clinical trials, this might be your best shot.

Number of Patients in a Site/Hospital:

It became trendy to use the services of EMR/EHR providers such us EPICClinerion  etc. This helps the feasibility teams to check how many patients could be eligible for a particular trial in a given site/hospital. It helps with protocol development, making the final decision on whether the site actually has the patients, and later even for speeding up the pre-screening process.

It’s another story how many hospitals internationally have this data or are allowed to share it with 3rd parties. Providers are usually quite transparent with their network of hospitals which is a good starting point to check their coverage and see how reliable and relevant their numbers are for your protocol.

Number of patients wanted in competing clinical trials

Definitely a must-have! I had a call with a biotech clinical operations manager who shared with me that they are 1 year behind targets just because of another clinical trial directly competing and conducted at the very same sites. 

The competing Phase III trial was completed a few months ago while the biotech one has recruited around 10 patients in 5 sites out of 20 sites in total. This is a common situation that can be avoided if you know upfront which clinical trials are competing for the same pool of patients. 

NB! Make sure to review the ongoing or to-be-started clinical trials at a point in time when you plan to start too. A competing clinical trial today might not be relevant in six months if it plans to finish recruitment by then. You can check for competition on TrialHub.

There are many other essential numbers like:

  • Number of clinical trials conducted in the indication at every site
  • Number of approved and reimbursed drugs in every country
  • Number of completed clinical trials in a given country
  • Number of people searching for clinical trials 


Some experts believe that while numbers are essential, there are important aspects that can’t be measured. Very often these are exactly the aspects that get forgotten while discussing a clinical trial during a bid defense meeting or even internally. They have a fair share of the success of the patient recruitment strategy. This is why I want to list some of them:

The Patient Pathway

Knowing how a patient with a given diagnosis navigates the healthcare system of a country is very important. This can be a deal-breaker when deciding how to build a referral network or which site to choose or even answer questions like:

  • Can a network of GPs help me out to identify new patients?
  • Can I rely on advertising to reach out to potential participants?
  • Which are the most important milestones for a patient prior to considering a clinical trial?

I personally worked on a project a couple of years ago, which was a complete disaster when it comes to patient recruitment (imagine 5 patients enrolled for an entire year). The patients were supposed to be newly diagnosed prior to entering the trial and with no previous treatment experience. The challenge was that the investigators were the specialists treating the potential volunteer, yet the diagnosis was usually provided by a third specialist. Building a network of these specialists that were diagnosing patients was absolutely essential in this case.  

NB! Working together with local communities is very helpful to learn about the patients’ pathway in the country. You can find more on the subject in this article: Two Ways Patient Advocates Complement Key Opinion Leaders And Site Surveys

KOL’s or investigators’ excitement about the clinical trial protocol

Getting KOL’s attention is the goal of every sponsor and CRO. They are the people who will adopt your new treatment option and will distribute this trust among other doctors in the country (who will be your investigators too). Knowing that the investigators really find your treatment a good solution for their patients is key, as this is another reason not only to participate but also to pay extra effort in going back to their patients and providing better help.

I have numerous conversations with investigators that have been working on 3+ clinical trials for the same indication. They would always speak about the drug/device they are excited about. The remaining trials will see enrolled patients only when these patients are not eligible for the first trial.

Measuring this interest is hard to put in numbers, however, speaking with the KOLs in the country and exciting the investigators at investigator meetings and keeping up with distributing this motivation down the road are all things that can bring better results. 


Numbers play a big role in clinical trial planning. However, as the saying goes “the devil is in the details” and we should be paying more attention to the things that can’t be measured too. The marriage of both should bring you to the desired results.

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