Whitepaper Finds Genetic Testing in Rare Disease Studies Increasingly Used to Determine Eligibility

Rare Daily Staff

A new analysis of actively recruiting clinical trials suggests that genetic testing and other genomics-based eligibility requirements are becoming a central practical challenge in rare disease drug development, especially for gene, RNA, and protein replacement therapies.

The analysis, from precision medicine and clinical trial services company Sano Genetics, found that much of the rare disease trial activity is concentrated among specialist biotechs, not only the largest pharmaceutical companies.

The white paper found that for a growing number of rare disease trials, the challenge is no longer simply developing a treatment. It is finding, diagnosing, and connecting the right patients, often before a clinical development program has advanced very far.

The study examined 4,565 clinical trials that were actively recruiting as of June 2, 2026, across the United States, United Kingdom, European Union, Japan and South Korea. The researchers found that 15 percent of the trials, or 691 studies, targeted rare diseases. Of the full trial pool, 1,143 studies, or 25 percent, involved genetics in some way, including genetic testing for eligibility, mutation-specific study designs and gene-directed treatments. A total of 372 trials were both genetics-related and focused on rare disease.

The report underscores a reality for many families affected by rare conditions: a clinical trial may not be accessible unless a patient has received the right molecular diagnosis and meets a narrowly defined genetic criterion.

Nearly all recruiting gene therapy trials in the analysis, 94 percent, involved genetics, and 67 percent targeted a rare disease. RNA therapies showed a similar pattern, with 59 percent involving genetics and 50 percent focused on rare conditions. Among protein replacement trials, 63 percent targeted rare diseases and 45 percent involved genetics.

Those figures matter because such studies often recruit from small, geographically scattered patient populations. A person may have symptoms consistent with a rare disorder but remain unable to participate in a trial until diagnostic testing confirms the specific gene or variant required by the protocol.

The authors found that genetics is increasingly common throughout medicine, but genetic testing may play a particularly consequential role in rare diseases because a precise diagnosis can determine whether a patient is identified, referred and found eligible for an experimental treatment.

The analysis also suggests that trial sponsors may need to build genetic testing and patient identification plans earlier in development than they traditionally have.

For patients and families, this can mean that the path to a trial begins well before a nearby research site opens. It may require a clinician to recognize a possible rare disorder, refer the patient for specialized evaluation, order or arrange genetic testing, interpret the result and connect the family with an appropriate study.

That process can be difficult for people who lack access to specialists, face insurance barriers to testing or live far from academic medical centers. The report did not measure those barriers directly, but its findings underscore why diagnostic access and patient finding infrastructure have become increasingly important in rare disease research.