This research project is in progress. PCORI will post the research findings on this page within 90 days after the results are final.
What is the research about?
A rare disease is one that affects fewer than 200,000 people in the United States. There are more than 6,800 rare diseases, which together affect 25–30 million Americans. Patients with rare diseases need effective treatment. The best way to know which treatments are effective is through clinical studies. However, studying rare diseases can be hard because so few people have each rare disease. New study designs and methods to analyze data can help researchers study rare diseases and find effective treatments for them.
One way to study rare disease treatments is with a kind of study called small n sequential multiple assignment randomized trials (snSMARTs). In snSMART studies, researchers assign people to their first treatment by chance. After some time, the researchers check how well the treatment is working. Then, patients for whom the treatment works stay on the treatment, and researchers assign patients for whom the treatment isn’t working to a new treatment by chance.
The snSMART design has some advantages over standard study designs where patients can get only one treatment, or where all patients must get a sequence of two treatments. First, snSMARTs allow patients to continue a treatment if they respond positively to it, or switch treatments if they don’t. Second, in snSMARTs, researchers can get more information from a smaller group of patients because some patients receive more than one treatment. These benefits of snSMARTs can encourage patients to join a study and stay in it.
In this project, the research team is developing new methods to help researchers analyze data from snSMARTs.
Who can this research help?
Results from this study may help researchers who study rare diseases to get better information from snSMART studies looking at the effectiveness of treatment for patients with rare diseases.
What is the research team doing?
The research team is developing statistical methods to improve snSMARTs in several ways. First, the team is creating a new method to combine information from patients in a study to compare treatments or sequences of treatments. This step includes creating an online calculator to figure out the ideal number of patients, or sample size, for an snSMART. Second, the team is developing methods to make snSMARTs more flexible. As a result, patients might be more likely to get the treatment that is performing best in the study. Researchers can also drop treatments that aren’t working from a study. Third, the team is developing methods for describing the balance of benefits and harms from the treatments. These methods consider common measures of treatment success, such as whether the treatment cures the disease or improves symptoms, and less common measures of treatment success, such as quality of life.
Researchers who study rare diseases, patients with rare diseases, and family members are giving feedback on the study design and methods.
Research methods at a glance
|Goal||To develop statistical methods that increase efficiency of and decrease bias in small n sequential multiple assignment randomized trials (snSMARTs) for studying rare diseases|
- Ida Hakkarinen
- Kori Jones
Other Stakeholder Partners
- Peter Merkel
- Jennifer Miller
- Rajen Mody
- Susan Murphy
- Christian Pagnoux