Improving Patient Retention in Ophthalmology Clinical Trials has a major impact on the success of ophthalmology studies, and it’s only getting more challenging to recruit and retain trial participants. For clinical trials overall, studies have shown that 100 potential candidates must be identified for every 9 subjects who will ultimately be enrolled, and only 7 of 9 enrolled subjects will end up completing the study.[1]    

Why Subjects Drop Out

Although there are multiple potential reasons for subject early withdrawal from clinical trials, we’ve identified four underlying factors that are important to consider for ophthalmology studies.

Protocol complexity and design  

In general, the amount of time and effort a subject is willing to expend on trial participation is proportional to the impact the disease under study has on their daily life.

For indications that are vision-limiting or may cause blindness, especially for heritable diseases, subjects have a powerful emotional connection to the study. Subjects with these diseases are often motivated by a desire to contribute to the advancement of available care, knowing that it may lead to prevention of vision loss for their children or grandchildren, or others, in the future. They are typically willing to put in significant effort during their study involvement, including completing longer, more frequent visits, and extra travel, often over extended periods of time.

However, if the impact of the indication is minimal while the protocol is strenuous, we begin to see a higher rate of subject dropouts. This is especially true if the study activities are significantly more complex than the requirements for Standard of Care (SOC) visits, and when an alternative therapy is available.

“Protocol complexity has to make sense for the indication.”

— Ashley Perez, Clinical Lead, Lexitas

Placebo and sham

For studies with a placebo or sham arm, subjects that fail to notice improvement in their condition, or that experience worsening of their condition, will often assume they are receiving placebo or sham. This can create a sense of futility in continuing with study participation and a desire to return to SOC treatment, if available.

Expectation of care is not met

As part of a clinical study, trial participants may expect to receive attention and care above what they normally receive from their standard ophthalmology visits. This expectation is valid, as clinical trial participants often undergo much more frequent, detailed, and lengthy visits, in addition to receiving additional testing at no charge.

However, these advantages to trial participation often result in undesirable consequences, such as longer wait times, additional burden of travel to the site, and increased physical and mental strain on the trial subject. If these undesirable consequences begin to outweigh the advantages of trial participation, subjects are more likely to end their study involvement early.

Enrollment of non-optimal subjects

A common contributing factor for subject withdrawal can be choosing the wrong candidate for enrollment. Subjects enrolled in the study despite conflicting circumstances (such as large travel distances, inability to secure transportation, lifestyle conflicts such as an inflexible work schedule, or physical limitations that make adherence to the protocol difficult) are often more likely to withdraw from the study early once these factors become too burdensome. Study eligibility criteria that are too inclusive and fail to exclude those with diseases or conditions that reduce the likelihood of subject study completion also contribute to the enrollment of poor candidates. This often leads to withdrawal later in the trial.

10 tips to increase enrollment and improve trial retention

1. Protocol development

When evaluating the trial protocol and comparing it to the likelihood of subject retention, it’s important to ask, “How difficult will the study be for subjects to comply?” and “How feasible will the study be for sites to carry out?”

When developing the trial protocol, we recommend that sponsors and CROs work closely with team members who are experienced with both the indication and with how study activities will differ from SOC. This should involve careful consideration of the frequency of assessments and complexity of the visits, as well as the study eligibility criteria. If the site is struggling to complete the assessments due to their complexity, or because of conflicts between the order of assessments and their normal clinic routine, it makes the subject’s visit more difficult and can lead to longer appointments. If the eligibility criteria allow non-optimal candidates to be enrolled, we often see a higher rate of subject non-completion. On the other hand, if the eligibility criteria are too restrictive, recruitment will suffer, and the enrollment phase of the trial can last much longer.

Thoughtful input from experienced vendors, the CRO, and the sponsor is necessary during protocol development to make the visits as seamless as possible for sites and subjects, and to ensure the right candidates are eligible. Feedback from sites after protocol implementation is also a useful resource that should be utilized. Sites are often the first to identify areas of the protocol that impede enrollment or lower subject satisfaction. Although a protocol amendment is never ideal, the potential cost and time savings, and secured subject retention that may result from early implementation of an amendment, can justify the effort.

Knowing that inclusion of a placebo or sham can lead to issues with subject recruitment and retention, we suggest that sponsors carefully consider if and how these should be incorporated. Is it possible to use an active comparator instead of a placebo or sham? If not, is it possible to allow use of rescue medication under certain circumstances, and are the conditions to meet rescue appropriate? Is there a way to provide all subjects in the study with active investigational product at some point in the study, or for the study to become open label?

“There is an entire team that oversees the subject’s care and safety, from the PI, to the medical monitor, and all the way to the physicians evaluating the subject’s required protocol images in the reading center. There are many medical professionals to ensure the subject receives the best care possible.”

— Rebecca Herndon, Clinical Lead, Lexitas

When placebo or sham are necessary for the protocol, subject education is crucial. The sponsor should ensure sites provide well-rounded subject training on the importance of placebo or sham in the success of the trial and the increased measures that are in place to ensure subject safety. When subjects in these trials express their concern or opinion that they are in the placebo or sham arm, it is critical that sites are trained to provide assurance that the subject’s safety is being monitored at the highest level, and to remind subjects of the importance of their contribution to the success of the study regardless of which arm they are in. For instance, even if they are in the sham or placebo arm now, the success of the study could lead to FDA approval of the investigational product making it an available option for them or others in the future. Each subject’s completion of the study with quality data contributes to the outcome.

2. Site selection and training 

Selecting the correct sites is key for subject retention throughout the course of the trial. If the sites selected for the study are not well-suited to begin with, the odds of high subject recruitment and retention are lowered.

Based on our experience with managing various ophthalmology studies, we recommend that sponsors consider the following factors to help drive recruitment and retention:

3. Recruitment strategies

Recruitment techniques vary vastly between companies and sites. Some sites have a large referral network and like to use referral letters and/or dinners, while others have a large database of potential subjects from their current patient list. Some sites use third-party systems or recruiters that analyze electronic medical records to identify potential subjects. Others use a study coordinator or site recruitment specialist who is often more familiar with the patient population and can identify barriers to subjects completing a trial. In addition, if sites are geographically isolated, it might lead to increased travel time and expenses. If the site is forced to recruit candidates that live far away, the sponsor may incur significant costs for travel stipends or reimbursement, while subjects will be more likely to withdrawal early due to the travel burden.

In addition to ensuring selection of sites that meet all requirements for conducting protocol assessments, sponsors should carefully review the recruitment strategies utilized by potential sites and limit selection to those with adequate access to the subject population, and that have the resources to effectively identify good study candidates. CROs can also aid in this process by providing feedback from previous trials. They can identify experienced sites that have had access to the needed subject populations, while also being able to recruit and retain their subjects with high success for the trial duration.

4. Site-subject relationship

The importance of a positive site-subject relationship in supporting subject retention cannot be overstated. As previously mentioned, subjects often have high expectations for the level of care and accommodations they will receive in return for their participation. Sites that can boast of strong, established relationships with their patients, active PI subject involvement, amenities for trial participants (such as a designated waiting area or exam rooms and having meals or beverages provided), or that can provide other examples of their exemplary care should be a priority for site selection.

5. Site training

The sponsor should ensure proper education of the site staff occurs so that knowledge and proper care is transferred to each trial participant. The site must ensure that subjects are thoroughly educated in exactly what the protocols are, what is expected of their participation, and what they can possibly gain throughout the course of the trial. It is also critical that sites are properly trained on what to do when issues arise, as subject safety is always a top priority in any clinical trial.

“Research shows that patients participating in clinical trials actually tend to have better clinical outcomes than patients in regular care due to more frequent and closer follow up.”

— Rebecca Herndon, Clinical Lead, Lexitas

Subject support

In addition to the site’s important role in ensuring subject retention, it is crucial that sponsors support subject retention by providing transportation assistance and subject stipends that are appropriate for the study.  

6. Transportation

Often, transportation can be a valuable recruitment aid for sites that have subjects struggling to receive their SOC visits due to travel difficulties. When the protocol further increases the number of required visits, transportation becomes a key factor in subject recruitment and in the willingness of enrolled subjects to complete the study. Sponsors should consider how to alleviate this concern for subjects. For example, they might provide a mileage reimbursement or travel stipend, or contract with a vendor to provide transportation for each visit. In our experience, subjects and sites reported the highest satisfaction when private transportation was provided through contracted services that were paid directly by the study and allowed for ease of advance scheduling for visit transportation.

7. Appropriate stipends

Subject stipends can go a long way to incentivize subjects to participate and feel their participation is valued in a trial. We have both repeatedly seen subject stipends be the ‘make or break it’ decision for some subjects to join or remain in a trial. This is especially true for studies that have long participation periods, sometimes lasting years. While subjects may not expect much reimbursement for a quick telephone visit, they are likely to expect a more substantial stipend for multi-hour office visits. If the visit frequency, duration, or complexity is significantly higher than would be required for SOC, the need for adequate reimbursement is more critical. We have seen low stipend amounts for strenuous visits leading to higher rates of subject withdrawal. Stipend amounts should reflect the relative time and energy spent by the subject.

8. The right technology

The number of technology resources available for clinical trials is continuously expanding. Sponsors should thoughtfully evaluate all available options and identify those that would benefit their study, and potentially improve subject retention.

 “At Lexitas, we have a wealth of experience working with vendors for these systems, as well as team members that have first-hand experience implementing them at the site level to ensure successful selection and utilization of the technology.”

— Ashley Perez, Clinical Lead, Lexitas

ePRO systems

The best example of this would be the use of electronic patient-reported outcomes (ePRO) devices and systems, which allow subjects to easily answer questionnaires, report changes in health or medications, and document treatment compliance using their phone or a provided device rather than a paper form.

This method can contribute greatly to reducing subject burden and aiding adherence. Devices can alert subjects to take their dose or perform an activity, while paper forms often get lost or left at home. This ease of use and flexibility helps improve retention by removing some of the burden from the subject.

The use of ePRO, however, should only be used when appropriate for the study subject population. For example, studies with an elderly population may have a reduced benefit from the use of ePRO if these participants have more difficulty utilizing electronic devices.

Electronic consent

Another important example is the use of electronic consent, which can be developed to include more visual aids, increased font sizes, utilization of videos, and even reading of the Informed Consent Form (ICF) to the subject. This improves the quality of the informed consent process because it meets the needs of subjects with different learning styles, while increasing the subject’s willingness to thoroughly review the ICF and fully consider the details of study involvement.

Better-informed subjects result in better subject retention because they have a more thorough understanding of what the trial involves before they agree to participate. On the other side, less informed patients are more likely to drop out.

9. Specialized experts

By creating teams with diverse ophthalmology backgrounds, CRO experts can provide insight into potential issues that could arise so they can be addressed early in the project or prior to site activations. A best practice is to work with a network of people with experience in the study indication and targeted subject population. They can help identify issues and provide recommendations to improve recruitment and retention. And they can help write a well-thought study protocol for a successful trial.  

10. Work with an ophthalmology-focused CRO

Many sponsors don’t have the resources necessary to develop and implement clinical trial recruitment and retention strategies to get the most from their ophthalmology studies. Contracting a CRO that has a team knowledgeable about both clinical ophthalmology and research is key to a successfully executed ophthalmic study with high patient retention.

As clinical trial participants develop higher expectations, successful recruitment and retention is becoming more challenging. But with the right ophthalmology focused CRO in your corner, you can develop more strategic recruitment strategies which result in higher retention rates. To learn more about how you can better recruit, serve, and retain clinical trial subjects for your ophthalmological studies, contact our team at Lexitas today.

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Rebecca Herndon – Rebecca is a Clinical Lead with Lexitas. She has her BS degree from the College of Natural Science at Colorado State University. She has over a decade in clinical ophthalmology in various areas including general ophthalmology, glaucoma, retina, cornea, refractive surgery, and pediatric ophthalmology. She also has four years of experience in clinical research in several areas including but not limited to: gene therapy, device trials, intracameral implants, IVT drug therapies, and oral capsules.

Ashley Perez – Ashley is a Clinical Lead with Lexitas and obtained her BS degree in Ecology & Evolution from UC Santa Cruz. Ashley has a combined 8 years of experience in ophthalmology including roles at the clinical practice (ophthalmic assistant), research site (study coordinator), and CRO level (CRA and Clinical Lead). She has worked with a wide range of ophthalmic indications of both the anterior and posterior segment.

1. “Retention in Clinical Trials: Keeping Patients on Protocols,” Advarra. March 23, 2021. https://www.advarra.com/resource-library/retention-in-clinical-trials-keeping-patients-on-protocols/#