(5) Limitation on prices of drugs purchased by covered entities (A) Agreement with Secretary A manufacturer meets the requirements of this paragraph if the manufacturer has entered into an agreement with the Secretary that meets the requirements of section 256b of this title with respect to covered outpatient drugs purchased by a covered entity on or after the first day of the first month that begins after November 4, 1992 . (B) “Covered entity” defined In this subsection, the term “covered entity” means an entity described in section 256b(a)(4) of this title . (C) Establishment of alternative mechanism to ensure against duplicate discounts or rebates If the Secretary does not establish a mechanism under section 256b(a)(5)(A) of this title within 12 months of November 4, 1992 , the following requirements shall apply: (i) Entities Each covered entity shall inform the single State agency under section 1396a(a)(5) of this title when it is seeking reimbursement from the State plan for medical assistance described in section 1396d(a)(12) of this title with respect to a unit of any covered outpatient drug which is subject to an agreement under section 256b(a) of this title . (ii) State agency Each such single State agency shall provide a means by which a covered entity shall indicate on any drug reimbursement claims form (or format, where electronic claims management is used) that a unit of the drug that is the subject of the form is subject to an agreement under section 256b of this title , and not submit to any manufacturer a claim for a rebate payment under subsection (b) with respect to such a drug. (D) Effect of subsequent amendments In determining whether an agreement under subparagraph (A) meets the requirements of section 256b of this title , the Secretary shall not take into account any amendments to such section that are enacted after November 4, 1992 . (E) Determination of compliance A manufacturer is deemed to meet the requirements of this paragraph if the manufacturer establishes to the satisfaction of the Secretary that the manufacturer would comply (and has offered to comply) with the provisions of section 256b of this title (as in effect immediately after November 4, 1992 ) and would have entered into an agreement under such section (as such section was in effect at such time), but for a legislative change in such section after November 4, 1992 .