AdvertisementWhy The U.S. Remains The Most Expensive Market For 'Biologic' Drugs In The World03:53Download AudioResumeDecember 19, 2018Sarah Jane TribblefacebookEmailSusie Christoff tried several drugs to cope with her painful psoriatic arthritis before finding Cosentyx worked the best. The problem was the cost. (Chris Bartlett/for Kaiser Health News)