By Jolan Eszter Walter, MD, Ph.D., division chief, pediatric allergy and immunology programs, University of South Florida Health and Johns Hopkins All Children’s Hospital
Clinical trials for rare conditions often face significant challenges, primarily due to low patient enrollment. One of the main barriers is the difficulty in obtaining a definitive diagnosis. However, advances in genetic testing offer promising solutions to overcome this issue.
Genetic Testing and Rare Disease Trials
In the era of genomic medicine, conducting genetic testing at the earliest stages of diagnosis can greatly enhance trial enrollment. By identifying genetic markers associated with rare diseases, clinicians can more accurately determine patient eligibility for clinical trials. This approach not only streamlines the diagnostic process but also ensures that patients with rare conditions receive the most appropriate and innovative treatments.
Several pharmaceutical companies are leading the charge in this regard. They are partnering with genetics laboratories to offer sponsored programs aimed at increasing participation in genetic testing. These initiatives also help patients qualify for investigational treatments.
For example, Pharming Healthcare, Inc. provides free genetic testing to patients in the U.S. and Canada who show clinical signs of APDS (activated PI3K delta syndrome). The program also extends free testing to any blood relatives of patients with mutations in the PIK3CD or PIK3R1 genes. This strategy aims to reduce barriers to diagnosis and treatment for rare genetic immunodeficiencies.
The Importance of Early Genetic Testing
Early genetic testing is particularly critical for patients with primary immunodeficiencies (PIs). These conditions are often elusive and can be mistakenly diagnosed as other, more common diseases. APDS, for instance, caused by variants in the PIK3CD or PIK3R1 genes, can manifest as respiratory infections, viruses, cytopenias, gastrointestinal issues, and lymph node enlargement. Without genetic testing, however, it can be confused with conditions like Evans syndrome, monogenic combined immunodeficiencies, common variable immune deficiency, autoimmune lymphoproliferative syndrome, autoimmune cytopenias, or even certain cancers.
A 2020 study by the Jeffrey Modell Foundation underscores the value of genetic testing in patients with PIs. After sequencing 158 patients, researchers found that clinical diagnoses were revised for 45% of participants, treatment approaches were adjusted for 36%, and disease management was modified for 40%. This highlights the transformative impact of genetic testing on patient care.
Closing the Knowledge Gap
To fully harness the benefits of genetic testing, it is crucial to address the lack of knowledge among healthcare providers. While many doctors at leading academic institutions are familiar with genetic testing, many others are not using it or are undertrained in its application.
To bridge this gap, education initiatives are essential. A grassroots series of workshops can provide a platform for honest discussions about knowledge gaps and practical training. In a recent effort, Dr. Walter organized a small workshop at her facility, where medical geneticists and primary care physicians learned more about immunology. She plans to offer similar events in the future.
Dr. Walter encourages colleagues with expertise in genetic testing to lead their own workshops. By fostering a community of knowledgeable healthcare providers, we can ensure that patients with rare conditions receive the best possible care.
Establishing Trial Eligibility
While genetic testing is a crucial step in establishing trial eligibility, it may not be the final step. Genetic variants of uncertain significance (VUS) pose a challenge. These variants do not have a clear link to the patient’s symptoms, making diagnosis more complex. Other factors that affect trial enrollment include age, severity of illness, and treatment history.
In cases where genetic testing indicates a variant of uncertain significance, doctors may need to conduct additional tests, such as family variant testing, functional testing, and immunophenotyping. Efforts are underway to make these tests more accessible outside of major academic centers, making it easier for community-based specialists to participate in rare disease research.
Challenges in Patient Participation
Beyond eligibility criteria, there are several challenges that can hinder patient participation in clinical trials. These include:
- Patient health status: Patients who are asymptomatic or well-managed with standard therapies may not feel motivated to participate in clinical trials. Conversely, innovation is often driven by patients whose conditions are refractory to existing treatments.
- Comprehensive care: Participating in a trial can add complexity to a patient’s healthcare regimen. Patients may need to see both study investigators and their regular doctors, requiring careful coordination of care.
- Awareness: Most healthcare providers are not prepared to provide a detailed list of clinical trials when patients inquire. However, patients can explore available studies on clinicaltrials.gov.
Expanding Newborn Screening
To further improve outcomes for patients with rare conditions, genetic testing should be integrated into routine newborn screenings. Many newborns are already screened for conditions like sickle cell anemia and severe combined immunodeficiency (SCID). If newborn screening included assays for all inborn errors of immunity, we could detect and treat rare diseases earlier, preventing long-term disability or even death.
While newborn screening can raise concerns among parents, Dr. Walter believes that knowledge empowers parents to provide better care for their children. By identifying genetic predispositions early, we can intervene before symptoms arise, ensuring better health outcomes.
Conclusion
Advancements in genomic technology offer a pathway to improving clinical trials for rare diseases. By integrating genetic testing into the diagnostic process, we can identify more trial participants and provide patients with access to innovative treatments. Through education initiatives, continuous research, and expanded newborn screening, we can make significant strides in the fight against rare diseases.
Jolan Eszter Walter, MD, Ph.D., is an international expert in primary immunodeficiencies and immune dysregulation, serving as division chief of pediatric allergy and immunology programs at the University of South Florida Health and Johns Hopkins All Children’s Hospital. Her research focuses on understanding diseases linked to immune system disorders and developing strategies for early detection and precision treatment.
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