The "Defending Affordable Prescription Drug Costs Act" aims to protect 340B covered entities and their contract pharmacies from discriminatory practices by health insurers, pharmacy benefit managers, and pharmaceutical manufacturers. The bill prohibits these entities from engaging in various discriminatory actions, including:

1. Establishing lower reimbursement rates for 340B drugs compared to non-340B drugs based solely on the drug's 340B status.
2. Imposing different fees, chargebacks, adjustments, or conditions on reimbursement based on 340B status.
3. Denying or limiting participation in standard or preferred pharmacy networks based on 340B status.
4. Imposing inconsistent audit requirements related to inventory management systems.
5. Requiring claims-level data or documentation identifying 340B drugs as a condition of reimbursement, unless mandated by the Centers for Medicare and Medicaid Services.
6. Requiring a 340B covered entity to reverse, resubmit, or clarify a claim after initial adjudication unless these actions are part of normal pharmacy business.
7. Interfering with a 340B covered entity's choice to use a contract pharmacy for drug distribution or dispensing.
8. Including provisions in contracts that discriminate against 340B covered entities or restrict patient choice in receiving prescription drugs.
9. Placing restrictions or additional charges on patients choosing to receive 340B drugs that differ from those applied to non-340B drugs.
10. Excluding 340B covered entities from networks or refusing to contract with them for reasons not applicable to non-340B entities.
11. Imposing any other restrictions or practices not imposed on non-340B entities.

The act also specifies that nothing in this chapter applies to the Medicaid program when it provides reimbursement for covered outpatient drugs. Additionally, it prohibits pharmaceutical manufacturers and their agents from interfering with the acquisition or delivery of 340B drugs to contract pharmacies and from imposing additional terms not required by federal law.

340B covered entities are required to submit annual reports detailing their participation in the 340B program, including financial data and the impact of savings on patient care. The state auditor general is granted the authority to investigate compliance and enforce the provisions of the act. Violations of the act will be treated as violations of existing laws regarding deceptive and unfair sales practices. The act is set to take effect on October 1, 2025.