Access to Innovative Treatments Act of 2023 This bill requires the Centers for Medicare & Medicaid Services (CMS) to review adverse national coverage determinations of drugs under Medicare within 30 days of receiving a request to do so. (Under the bill, adverse national coverage determinations are denials or limitations of coverage that are inconsistent with the drug's approval by the Food and Drug Administration.) The bill's requirements do not apply if the CMS already conducted such a review within a two-year period. The bill also prohibits the CMS from applying prior coverage determinations that were made for drugs before they were approved by the FDA if such determinations are inconsistent with the drug's approval.