Author Affiliation: National Organization for Rare Disorders, Danbury, Connecticut (firstname.lastname@example.org).
To the Editor: Dr Kesselheim and colleagues found that pivotal trials for orphan cancer drugs often have fewer patients and use different trial designs than trials for drugs for more prevalent cancers.1 Rare diseases by definition have small patient populations; trials in such populations will commonly have fewer patients than those for more prevalent diseases. Recruitment of participants for such studies is challenging, and trials of new agents for orphan diseases may, of necessity, be nonrandomized and open label because of the size of the patient populations available for the studies and the nature of the diseases.
Saltonstall PL. Clinical Trials of Orphan Drugs for Cancer. JAMA. 2011;306(14):1545-1546. doi:10.1001/jama.2011.1463