Every step is a struggle for Bruce Zimmerman, whose health has been deteriorating since he was diagnosed with multiple sclerosis eight years ago. In 2019, Zimmerman said, his then-employer offered him an opportunity that sounded irresistible: He and his wife, Becky, could take all-expense-paid trips to the Cayman Islands and the Bahamas to retrieve the medication he needed, Avonex, a drug made by Biogen that currently retails in the U.S. for $2,159 per weekly dose. Through Florida-based