FOI release

Request for information - Ref: FOI2026/00317

Some or all of the information requested was not provided because we didn't hold it.

Case reference FOI2026/00412

Received 16 April 2026

Published 2 June 2026

Request

1. Failure to Address Current Statutory Duties. While the MHRA may not hold the historical 1963 files, the Agency assumed statutory responsibility for the safety, efficacy, and quality of medicines in 2003. Regulation is a continuous act, not a historical event. I therefore request a review of why the following current information was not disclosed: • The Scientific Evidence Review or Rationale held by the MHRA post-2003 that justifies the continued regulatory "gold standard" status of T4-monotherapy, despite published evidence regarding deiodinase (DIO2) polymorphism and T3-conversion failure. • The Marketing Authorisations (Product Licences) currently held by the MHRA for Levothyroxine products, specifically the sections outlining the clinical trials or grandfathered data used to validate T4-monotherapy as an exclusive first-line treatment.

Response

See attached

Documents

• FOI2026_00412 (redacted).pdf (757.9 KB)

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