Clinical research professionals and staff members say that one of their biggest challenges in conducting a clinical trial is patient recruitment which is obtaining a sufficient number of participants for a clinical trial.

If the clinical research team fails to enroll enough study subjects into a clinical trial, this may, by default, extend the study timeline, increasing resource usage and costs. A prolonged study startup may delay a drug or treatment reaching the market, extending the time, and its availability for the general public.

Clinical trial market

The clinical trial market is huge and growing rapidly. A total of 2,119 active studies were registered in the year 2000 on and is now with 280,000 active clinical research studies. This indicates that the market’s value is multiplying, and experts expect it to reach $65.2 billion by 2025.

A report from the U.S. Department of Health and Human Services estimates that the total cost associated across all Phases of a clinical trial may range from $44 million to $115.3 million, depending on the drug’s therapeutic area. and fewer than one in 10 drugs that enter clinical trials make it to market.

Statistics of patient recruitment failures

Along with the increasing clinical trial market, there are also huge hurdles in patient recruitment, here are some interesting statistics

  • According to the National Institutes of Health (NIH), more than 80% of clinical trials in the United States fail to meet their patient recruitment timelines. These delays increase costs, may deplete resources, and prolong the time to enter the market.
  • As much as 86% of clinical trials do not reach recruitment targets within their specified time periods
  • According to an analysis of registered trials, 19% were trials were closed or terminated early because they could not accrue enough participants
  • According to the FDA, only six percent of clinical trials are completed on time, and 80% of all trials are delayed at least one month because of unfulfilled enrollment.

Patient recruitment for clinical trials

When a clinical trial fails to recruit a sufficient number of participants, it becomes impossible to draw accurate conclusions, and even promising therapies can seem to underperform.

Patient recruitment in clinical research depends on the following factors

  • The clinical trial design that can engulf more patients (for example unnecessary restrictive inclusion and exclusion criteria may reduce patient recruitment scope)
  • Clinical investigators’ capabilities such as investigator understanding of trial requirements, number of patient visits, inexperience in the recruitment of patients for trials, etc.
  • Clinical research site reach to the number of patients, travel distances from home, patient pool available for recruitment
  • Whether the trial supports Direct To Patient options, virtual sites, or allows minimal site visits for patients
  • Type of trials – for example, rare disease trials or cancer trials where patient recruitment is more challenging due to fewer sites or patient population
  • Timelines and budget allotted for patient recruitment and cost incurred due to trial delays, or special incentives for patients.

Strategies to improve patient recruitment for clinical trials

There are many theories and ideas to improve patient recruitment, but they may not provide a 100% solution and vary with trials. However, these may help to improve the scenario to an extent.

  • Complete understanding of the regulatory requirements 
  • Conducting clinical trial feasibility
  • Building a perfect patient and stakeholders connecting strategies
  • Patient-centric clinical trial protocol designs
  • Applying novel and digital trends

Let’s discuss some of the strategies that many times neglect and require more precise consideration to ensure sufficient patient recruitment and prevent clinical trial delays.

Understand the regulatory

Before designing a clinical trial, it is crucial to understand the complete regulatory requirements to conduct, complete, and produce quality clinical trial data. 

Various regulators have different requirements and these vary with the type of trial. For example, patient recruitment in rare diseases is a nightmare for many researchers, so many regulators such as the FDA consider adaptive methodologies in recruiting a few patients and extrapolating the safety data. 

The US FDA and European Medicines Agency (EMA) have developed guidelines to support the design of clinical trials for small populations.

  • Regulators are open to discussing the adoption of alternative methodologies and evidence sources to enhance the overall evidence base.
  • The FDA furthermore encourages early communication to assist in drug evaluation, and scientific, and medical questions that may arise throughout the clinical investigation.
  • The Pharmaceuticals and Medical Devices Agency (PMDA) in Japan offers advice on alternatives to traditional methodologies at face-to-face meetings during early development stages.

Budget planning

Develop an adequate budget for advertising, partnering (patient recruitment service providers), special patient incentives if required, cost incurred if delayed, etc,

Develop an initial recruitment budget that accounts for appropriate factors for patient outreach.

  • Accentuate site activation timelines and realistic enrollment periods in resource determination.
  • Plan the budget early to ensure that recruitment costs are anticipated and covered.
  • Ensure a well-researched communication strategy is deployed in order to achieve efficient and effective communication and outreach.

Conduct feasibility

Patient recruitment is sourced from different channels, with 75% originating from good sites and the rest from various sources. This emphasizes the significance of comprehending site capabilities prior to initiating a clinical trial. Conducting clinical trial feasibility studies is a way to accomplish this understanding.

Most companies initiate their trials without a proper understanding of the region. They often lack knowledge about the patients available for recruitment and the capabilities of investigators in patient recruitment.

Here is where conducting clinical trial feasibility helps in minimizing these wrong assumptions and increases the probability of trial success

Learn more about clinical trial feasibility

Conducting feasibility before initiating help in

  • Clinical investigator experience in recruiting patients and site capabilities
  • Understand the timeline for study initiation, conduction, and completion of the trial
  • Region pool for patient recruitment
  • Site facilities
  • Local ethical and regulatory requirements
  • Suggestions and feedback on the trial protocol to achieve goals and desired outcomes

Start your clinical trial feasibility here >

Feasibility questionnaire

For successful feasibility, it’s important to design a well-structured feasibility questionnaire to get all the answers or queries and extrapolate the likeness of the success of your clinical trial. Develop an ideal questionnaire that includes site profile, investigator experience, site capabilities, site infrastructure, institutional resources, and target population access.

Learn about the feasibility questionnaire and its significance

Click here to download the feasibility questionnaire

Protocol designs

Consider broadening the eligibility criteria such that it doesn’t affect the outcome of the trial but includes more patients in the trial. Understand the complete goal of the trial and design the exclusion criteria. Develop realistic eligibility criteria

  • Identify and eliminate items that are not necessary for ensuring the safety of participants.
  • Eliminate items that are not directly relevant to answering the primary research question.
  • Include patients in protocol planning and design

Consulting local representatives while designing a protocol is another approach to better understanding patients’ needs and what are patients expecting from a clinical trial as it may vary from region to region.

Limitation of protocol complexity to reduce the burden of participation is another strategy

  • Reduce procedures to those directly related to the scientific question.
  • Consider the invasiveness and risks involved in the study.
  • Limit activities that create additional work for sites and patients which leads to unnecessary complications.

Looking to prepare/improve protocol design?

For existing protocol designs, it is highly recommended to get help from experts to bring improvisation that can help in enhancing patient recruitment.

Note: “Ask Credevo Expert” will be charged @ $50 / inquiry. Any inquiry requiring more than 30 min of the expert’s time will incur additional charges.

However, if protocol design is still being prepared, it’s a great opportunity to optimize it from patient recruitment considerations.

Connect with patients

The next step in clinical trials is how to find or connect with patients. Nowadays several approaches have been developed by various companies along with traditional methods like web advertising, apps, posters in patient communities or hospitals, and direct communications with patients who visit clinics. 

Rare disease clinical trials involve other approaches such as rare disease communities and organizations that maintain complete patient databases along with their contact details. Such information helps researchers to directly find patients and connect with them.

Various apps have been developed and many organizations are providing special services in patient recruitment. In special cases where patient recruitment is challenging, partnering with those organizations that have better connectivity and approach to patients is wise in order to minimize trial delays.

If involving a CRO, know how they would recruit patients, what the previous measures are taken to recruit patients, and what was the success rate


Can the subject access the clinical trial site? how frequently? Can the trial allow DTP, and virtual sites, or minimize the number of visitors to the site?

Choose sites that are easily accessible to patients. Some of the trials require very few site visits and can be monitored through tracking devices or through communications, and while some trials do not allow this, for example, oncology trials often require continuous infusions, and nursing may be required. 

  • Some organizations are coming up with new adaptive methods such as direct-to-home trials where nursing staff or physicians visit patients’ homes and monitor.
  • considering patient shipment service providers or consulting groups who take the patient responsibility of bringing them to the clinical trial sites
  • utilizing communications such as Skype calling or video calling and monitoring digitally.
  • Partnering with direct-to-patient and direct-from-patient service providers who collect the biological samples and ship them to the sites or labs for testing

Information to patients

Lack of appropriate information is the biggest obstacle preventing people from enrolling in clinical trials

Conveying information through a short investigation evaluating video and audio-visual materials might help and give a clear understanding of the process and treatment methodology to the participants. this may not only help in recruitment but also in retirement. This puts a clear idea of the invasive processes involved or any untraditional method or process involved during the study.

Using an electronic approach during study startup, enrollment may reduce both patients. Understanding the language barriers is also important and simplification of language used in the informed consent forms is very important.

Others have looked at enhancing recruitment and retention by giving greater consideration to participant contact and convenience, financial support for patient recruiters, incentives, and compensation for participation

Advertising for patient recruitment in clinical trials

How do you recruit patients? The answer to this question has two implications one using frees sources and the second is using paid advertisements. this has to be established before starting a process.

  1. Develop a messaging system that resonates with the audience
  2. Establish your online advertising database
  3. Create compelling and valuable content
  4. Know where to put your advertising materials

Plan A should always consider free techniques such as from own website postings, posting on social media like Facebook, utilizing notice boards in medical or hospital communities, utilizing patient communities databases, etc.

Next comes plan B using paid advertisements. and here are the following considerable points before initiating

  • Use of online social platforms like Facebook, Twitter, Youtube, patient communities, and forums
  • Creating an online forum for participants to share experiences
  • Creating shared research databases that contain the target population
  • Advertisements in magazines, newspapers, posters, and radio
  • Using websites
  • Using patient databases maintained by organizations to assess eligibility 


Even after a successful recruiting method, there’s still room for participants to drop out, for which reasons may include

  • Difficulty to understand the trial procedure
  • miss communication or poor understanding of the trial
  • The trial’s treatment method is not the participant’s preferred method

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