Update the regulation of pharmacy benefit managers

HB 5109 updates West Virginia's regulations for pharmacy benefit managers (PBMs) by clarifying key definitions and duties in the Pharmacy Audit Integrity Act. The bill directly affects pharmacies, PBMs, health benefit plans, and patients by standardizing terms like "pharmacy benefits management" (which includes claims processing, network management, and rebate administration) and defining "affiliate" relationships to prevent conflicts of interest. Key mechanisms include requiring clear disclosure of how PBMs determine reimbursement rates (like "maximum allowable cost") and restricting certain ownership ties between PBMs and pharmacies. The changes aim to increase transparency in prescription drug pricing and billing practices without altering coverage rules. This is a definitional update, not a new benefit or funding measure.