Biosimilar Insulin Access Act of 2020 This bill establishes that, if the Food and Drug Administration (FDA) finds that an insulin is biosimilar to a reference product, the insulin shall be deemed interchangeable with the reference product. (A biological product is biosimilar to a reference product if the two products are highly similar and have no clinically meaningful differences; the reference product generally receives FDA approval first, but the biosimilar product is typically less expensive.) Under current law, a biological product that is biosimilar to a reference product may be deemed interchangeable with the reference product only if it meets additional requirements. Current law provides that interchangeable products may be substituted for each other without the prescriber's involvement.