The typical clinical trial model may not be best suited for generating evidence that a drug is safe and effective against diseases where patient enrollment can be difficult and diseases progress slowly and unevenly over a long period of time, according to Steven Grossman, who worked on the original Orphan Drug Act in 1983 and is now a policy and regulatory consultant.
Because of his experience with homeless patients, Amarasingham added in his model social variables, in addition to clinical ones, such as the number of home addresses in one year, and whether or not the patient had insurance.