South Dakota passed a law that allows pharmacists to automatically substitute a biosimilar for a prescribed biological product.  According to the new law, which was signed by South Dakota’s governor on February 12, 2018, the biosimilar must be “interchangeable” with the prescribed biological product under 42 U.S.C. § 262(k)(4) to qualify for automatic substitution.  South Dakota is the 37^th American state to pass a biosimilar automatic substitution law.