A new report from the Commonwealth Fund explains that the federal 340B Drug Pricing Program was created to allow safety-net hospitals and clinics to purchase outpatient prescription drugs at significant discounts so they could stretch their resources to serve more financially vulnerable patients. But as 340B continues its rapid expansion over the last two decades, the efficacy of the program in reducing patient costs has come into question, and pharmaceutical companies have stepped up their efforts to rein in the program. The document examines the reasons behind the program’s growth, the claims and counterclaims made by drugmakers and healthcare providers, and how federal regulators and Congress are responding.