Patients Before Middlemen Act or the PBM Act This bill prohibits pharmacy benefit managers (PBMs) under the Medicare prescription drug benefit or Medicare Advantage from receiving any income for their services other than bona fide service fees. Specifically, PBMs may not receive any income other than flat, bona fide service fees that are specified in their contracts with prescription drug plan (PDP) sponsors. Such fees may not be based on drug prices, discounts, rebates, or any other remuneration. PBMs must turn over any excess amounts they receive to the Centers for Medicare & Medicaid Services. PDP sponsors and PBMs must annually certify their compliance with these requirements.