The U.S. Food and Drug Administration announced that it has approved the first interchangeable biosimilar insulin product. The approval will allow pharmacists to automatically swap out expensive, brand-name insulin with the cheaper generic version.

The FDA said that the biosimilar drug Semglee is interchangeable with Lantus, a widely prescribed insulin analog. Before the FDA approved Semglee, a doctor had to specifically prescribe a generic brand of insulin or approve the substitution. Now, the name-brand drug can be swapped out by a pharmacist without a doctor's approval.

"This is a momentous day for people who rely daily on insulin for treatment of diabetes, as biosimilar and interchangeable biosimilar products have the potential to greatly reduce health care costs," said Acting FDA Commissioner Janet Woodcock, M.D. "Today's approval of the first interchangeable biosimilar product furthers FDA's longstanding commitment to support a competitive marketplace for biological products and ultimately empowers patients by helping to increase access to safe, effective and high-quality medications at potentially lower cost."

A month's supply of Semglee injector pens costs between $150 and $190 without insurance, which is less than half the price of Lantus, which costs between $340 to $520. The approval of Semglee could save patients over $100 billion by 2024.

"Access to affordable insulin is critical and long-acting insulin products, like insulin glargine, play an important role in the treatment of Types 1 and 2 diabetes mellitus," said Peter Stein, M.D., director of the Office of New Drugs in the FDA's Center for Drug Evaluation and Research. "The FDA's high standards for approval mean health care professionals and patients can be confident in the safety and effectiveness of an interchangeable biosimilar product, just as they would for the reference product."