The Complete Guide To Clinical Trial Marketing: Proven Approaches That Fill Enrollment

The marketing approaches that support clinical trial recruitment and retention, which studies each suits, and how to judge them by randomized patients.

In an analysis of 2,542 randomized surgical trials, 54.1% failed to reach their target enrollment[1]. The usual response is to buy more reach, yet reach is only the first stage of a funnel that also loses people after the enquiry and again after enrollment. This guide sets out the marketing approaches that support clinical trial recruitment and retention, the kind of study each one suits, and how to judge them by randomized patients rather than clicks. Refero does not run recruitment campaigns. We vet and match the clinical research marketing agencies that do, so what follows is written for the buyer, from what those vendors need and see.

Clinical trial marketing at a glance

Enrollment misses are common, and a marketing plan can influence the losses that happen after the click and after consent as much as those before them.

• 54.1% of randomized surgical trials in one analysis missed their enrollment target[1]
• Across six rare disease studies using direct-to-consumer recruitment, 133 of 136 leads who shared their contact details were never enrolled, a 97.8% loss[2]
• A review of digital recruitment found one example in which 8,852 clicks produced nine enrolled participants[3]
• Publicly funded randomized trials typically lose up to 12% of participants, while attrition as high as 70% has been reported[4]
• One delay day costs roughly $500,000 in foregone sales plus about $40,000 in direct trial costs[5]

Marketing for Clinical Trials: The Main Approaches and the Studies They Suit

Clinical trial marketing is recruitment and retention marketing aimed at eligible participants and the people who refer them, and the approaches that fit best depend on how common the condition is, where patients already look for health information, and how many sites can follow up.

Give people a plain-language study page they can qualify against

Every other approach points to a single page that states the study's purpose, eligibility in plain terms, the time commitment, site locations and a contact route. FDA treats recruitment information as the start of the consent process[6], so the page goes through IRB review like any other material, which is easier to plan for when the page is written first rather than last.

Partner with advocacy groups and registries when the eligible population is small

Rare-disease patients are few, well informed and usually connected through support networks and specialist registries, so a study notice shared by a trusted organization finds more of them than broad reach would, and it carries credibility a sponsor cannot buy.

Reach referring physicians when specialists hold the patient lists

Surveys show that patients prefer hearing about studies from their own doctor over any other source, yet few actually hear about one that way[7]. Provider letters and briefings close part of that gap, provided the site can handle a referral the day it arrives.

Treat paid media as one channel among several

Paid media buys reach quickly, and online promotion is the activity the published recruitment literature reports most often, although that count reflects how often it is used rather than how well it performs[8]. It fills only the top of the funnel, so it works best once the study page, pre-screener and call-back process exist.

Channel fit by approach; lead times are relative because they depend on the IRB and each partner.

Take two studies. A rare-disease trial's eligible patients sit in a few advocacy groups, registries and specialist clinics, so its budget goes to relationship time, plain-language materials and a coordinator who can talk to families. A type 2 diabetes trial draws on a very large population, so it is limited by local reach around the sites and by how quickly a site calls someone back, and that moves the same budget toward the study page and pre-screening capacity. The sponsor weighs timeline, the CRO site workload, and the site whether a lead arrives as a booked visit or another name to chase, so the three should agree on the mix before launch.

Pick two or three approaches by working through the population

1. Profile the population: how common the condition is, age, language, and where the sites sit.
2. Map where those people already get health information.
3. Choose the two or three approaches from the table that match, and set funnel metrics for each before launch.

AI pre-screening and record-matching tools work alongside these approaches and add screening throughput rather than reach: in a randomized trial across 4,476 heart failure patients, an LLM-based tool reached an eligibility rate of 20.4% versus 12.7% for manual screening[9].

Compare approaches by cost per randomized patient

The recruitment funnel runs enquiry, pre-screen pass, site contact, screening visit, consent and randomization, and cost per randomized patient counts only the patients who reach the last step.

Cost per randomized patient = total approach cost ÷ patients randomized from that approach

Patients randomized = enquiries × pre-screen pass rate × site contact rate × screening visit rate × consent rate × randomization rate

Worked example, with illustrative numbers only: an approach costing $60,000 brings 2,000 enquiries. Of these, 40% pass the pre-screener (800), 60% of those are reached by the site (480), 30% attend a screening visit (144), two thirds consent (96) and 62.5% of those are randomized (60). Cost per enquiry is $30, which looks efficient, yet cost per randomized patient is $1,000. If the site contact rate rises from 60% to 80% with no extra spend, 80 patients are randomized and the cost falls to $750, whereas buying the same 80 through more reach would cost roughly $80,000.

Use cost per randomized patient to compare approaches that reach different people, because cost per enquiry flatters broad reach. Published benchmarks for recruitment cost per patient vary widely by study type.

Community, Advocacy and Diversity Outreach in Clinical Research Marketing

Default channels miss underrepresented groups because they reach people already close to research sites, so community outreach adds trusted local organizations, clinics and advocacy groups, and materials in the reader's own language. An umbrella review of randomized-trial recruitment linked successful approaches to bilingual or bicultural staff, translated materials and strong community partnerships[10].

FDA's diversity action plan guidance asks sponsors to set enrollment goals by race, ethnicity and sex and to describe their recruitment and retention strategies[11]. It remains a draft marked as non-binding and not for implementation, and FDA's page notes that HHS restored it to its January 29, 2025 version under a court order, so check the current diversity action plan status before treating any element as a requirement. The guidance names no creative style or vendor type, and whether sponsors keep investing in diversity outreach after the guidance's removal was an open question in the trade press[12].

Decentralized and hybrid elements widen who can take part by removing travel and clinic hours as barriers, and the evidence on how decentralized trials change reach, enrollment speed and dropout is worth weighing before choosing that route.

The Follow-Through Gap: Where Recruitment Marketing Loses Patients

From the vendor side, a widely held view is that much of the loss happens after the enquiry and before pre-screening, and that more reach rarely fixes it when sites are slow to call back. That loss is the follow-through gap: the point where marketing has done its job and the study still loses the patient. The evidence supports the view with limits.

In the comparison of six rare disease studies, the authors placed the loss at the stage that needed human contact with the site[2], but six studies cannot show that this is the largest leak everywhere, so the finding argues for adding follow-through to the plan while keeping the channels that bring people in.

Closing the gap depends on marketing and clinical operations agreeing on four things before launch:

• A site call-back window that sites have agreed to and can staff
• A pre-screener approved by the IRB
• Referral source tracked from enquiry through to randomization
• A hand-off that names who owns each lead at each stage

Retention Belongs in the Clinical Trial Marketing Plan

A participant who drops out has to be replaced, so one enrolled seat can mean recruiting twice, which is why retention communication belongs in the marketing plan. Dropout varies widely by condition and design: an umbrella review of 88 systematic reviews of randomized trials opens by noting that publicly funded trials typically lose up to 12% of participants while rates as high as 70% have been reported[4].

Marketing can run the IRB-approved communication around the visits, from reminders that carry location and time to study updates, thank-you messages at points the protocol allows and a plan for sharing results. Travel support and other site operations stay with the site team, and the evidence on retention strategies shows which measures reduce dropout.

IRB Review: The Rules Every Recruitment Approach Has to Pass

Every recruitment approach needs IRB review before first use and after any change[6]. Reviewers commonly look for five things:

• Research is identified as research, and the product as investigational
• No certainty of cure or benefit is stated or implied, and the product is not described as safe or effective[13]
• Compensation is given little prominence and never framed as a benefit of taking part
• Content is limited to what people need to judge interest and eligibility
• The version in use is the version the IRB approved

The checklist applies to every piece, from study pages to provider letters and retention messages. Any pre-screener or form that collects health information also raises privacy questions, which OHRP's guidance asks IRBs to review[14]. This is general information, not legal advice; confirm with regulatory counsel and the IRB of record.

Measuring Clinical Trial Marketing by Randomized Patients

Sponsors judge recruitment marketing by randomized patients, and the conversion rate between funnel stages explains why that number is high or low. Click and lead volume overstates recruitment: one review found 8,852 clicks producing nine enrolled participants, though it noted that the literature is mostly observational, which limits any universal benchmark[3]. Sites control much of the final step, so the rates between stages matter alongside the final count.

Each rate points to a different cause:

• Low pre-screen pass rate: targeting or messaging is bringing in the wrong people
• Low site contact rate: weak follow-through, from slow call-backs or too little site capacity
• Low screening visit rate: scheduling friction or distance to the site
• Low consent or randomization rate: protocol burden or eligibility surprises at the visit

Ask any vendor to define "lead" and "qualified lead" in writing and to report each stage through to randomization, because without those definitions two vendors' reports cannot be compared.

Running Clinical Trial Marketing In-House or With a Partner

Keep clinical trial marketing in-house when the eligible population is small and reachable through investigators and advocacy groups; bring in an outside partner when timeline, call-back capacity or geographic reach holds enrollment back.

Keep it in-house when the population is small and site capacity is spare

Use this route if enough eligible patients are already known to investigators or advocacy partners and the site team can return calls the same day, because an outside partner then mostly adds a hand-off to manage.

Bring in a partner when the timeline is tight or reach spans regions

Use this route if sites lack call-back capacity, enrollment is behind plan, or the population is spread across many regions or needs diverse outreach. Judge fit on site capacity, timeline, therapeutic expertise and reporting depth, and ask for reporting to randomization rather than leads. The vendor types and pricing models are worth comparing before you brief anyone.

If you would rather not run that evaluation alone, Refero screens healthcare marketing and patient recruitment agencies against five published criteria and introduces up to three that fit your brief. It is free for buyers, and there is no obligation to hire anyone we introduce. Tell us what you need.

Frequently asked questions

Why do so many clinical trials miss enrollment targets?

Narrow eligibility, limited access to sites, weak reach and slow follow-through all contribute. Missing is expensive: Tufts CSDD estimates a delay day at roughly $500,000 in foregone sales plus about $40,000 in direct phase II and III trial costs[5].

How is clinical trial marketing different from pharmaceutical product marketing?

Clinical trial marketing informs people about a research study and frames participation as an informed choice, while product marketing promotes a treatment. IRB review applies, no certainty of benefit may be implied[13], and the audience includes referring providers as well as patients.

Which marketing approach works best for rare disease trials?

Advocacy groups, specialist referral networks and registries usually outperform broad reach because the eligible population is small, informed and already connected. In the rare disease studies compared in one published analysis, the loss came after the lead rather than before it[2], so site responsiveness matters as much as the channel.

When should recruitment marketing start in a clinical trial?

Planning starts at protocol and site selection. FDA expects recruitment materials to be submitted to the IRB with the initial review[6], so they are drafted alongside the protocol, and site call-back capacity is agreed before launch.

Can AI help find clinical trial participants?

AI tools can pre-screen records faster. In one randomized trial an LLM-based tool reached an eligibility rate of 20.4% versus 12.7% for manual screening among heart failure patients[9]. Human follow-up, IRB-approved materials and privacy controls are still required, and the gain was in screening throughput, not reach.

Sources

• Shadbolt C, et al. Analysis of Rates of Completion, Delays, and Participant Recruitment in Randomized Clinical Trials in Surgery. JAMA Network Open, 2023. Link
• Applequist J, et al. Direct-to-Consumer Recruitment Methods via Traditional and Social Media to Aid in Research Accrual for Clinical Trials for Rare Diseases: Comparative Analysis Study. Journal of Medical Internet Research, 2023. Link
• Kasahara A, et al. Digital technologies used in clinical trial recruitment and enrollment including application to trial diversity and inclusion: A systematic review. Digital Health, 2024. Link
• McChrystal R, et al. Participant and trial characteristics reported in predictive analyses of trial attrition: an umbrella review of systematic reviews of randomised controlled trials across multiple conditions. Trials, 2025. Link
• Smith ZP, DiMasi JA, Getz KA. New Estimates on the Cost of a Delay Day in Drug Development. Therapeutic Innovation & Regulatory Science (Tufts CSDD), 2024. Link
• US Food and Drug Administration. Recruiting Study Subjects (1998 information sheet). Link
• CISCRP. 2025 Perceptions and Insights Study. Link
• Ndungu A, et al. Using marketing strategies to improve recruitment and retention in clinical trials: a scoping review. Trials, 2026. Link
• Unlu O, et al. Manual vs AI-Assisted Prescreening for Trial Eligibility Using Large Language Models: A Randomized Clinical Trial. JAMA, 2025. Link
• Owusu-Addo E, et al. Recruitment, retention and reporting of variables related to ethnic diversity in randomised controlled trials: an umbrella review. BMJ Open, 2024. Link
• US Food and Drug Administration. Diversity Action Plans to Improve Enrollment of Participants from Underrepresented Populations in Clinical Studies (draft guidance). Link
• Will Pharma Continue Efforts to Diversify Clinical Trials? Medscape, 2025. Link
• NIH Office of Human Subjects Research Protections. Recruitment. Link
• US Department of Health and Human Services, OHRP. Guidance on Institutional Review Board Review of Clinical Trial Websites (2005). Link