Generic Drug Pricing Fairness Act - Amends part D (Voluntary Prescription Drug Benefit Program) of title XVIII (Medicare) of the Social Security Act to require each contract entered into with a prescription drug plan (PDP) sponsor with respect to a PDP the sponsor offers to prohibit the PDP from entering into a contract with any pharmacy benefits manager (PBM) to manage the prescription drug coverage provided under such plan, or to control the costs of the prescription drug coverage under it, unless the PBM adheres to specified criteria when handling personally identifiable utilization and claims data or other sensitive patient data.

Revises requirements for contracts with PDP sponsors to require that the PDP sponsor disclose to applicable pharmacies the sources used for making any update of the prescription drug pricing standard, and if the source for such a standard is not publicly available, disclose to such pharmacies all individual drug prices to be so updated in advance of their use for the reimbursement of claims.

Requires the PDP sponsor, as well, to establish a process to appeal, investigate, and resolve disputes regarding individual drug prices that are less than the pharmacy acquisition price for a drug.