{
  "url": "https://openlegislation.uk/human-medicines-regulations-2012/schedule-9A/paragraph-6",
  "json_url": "https://openlegislation.uk/human-medicines-regulations-2012/schedule-9A/paragraph-6.json",
  "legislation": "uksi/2012/1916",
  "legislation_title": "The Human Medicines Regulations 2012",
  "legislation_url": "https://openlegislation.uk/human-medicines-regulations-2012",
  "path": "schedule/9A/paragraph/6",
  "kind": "paragraph",
  "number": "6",
  "heading": null,
  "text": "(1) This paragraph applies for the purposes of the definition of “similar active substance” in relation to biological medicinal products other than advanced therapy medicinal products.\n(2) The principal molecular structural features are the structural components of an active substance that are relevant for the functional characteristics of that substance.\n(3) The principal molecular structural features may be composed of a therapeutic moiety or a therapeutic moiety in combination with an additional structural element significantly contributing to the functional characteristics of the active substance.\n(4) An additional structural element as described in paragraph (3) may be conjugated, fused or linked by other means to the therapeutic moiety or may be an extension of the therapeutic moiety protein backbone by additional amino acids.\n(5) Substances with structural elements for which similar methods of modification or conjugation technology are used usually result in similar substances.\n(6) Biological active substances which differ from the original biological substance only with respect to minor changes in the molecular structure are to be considered similar.\n(7) In relation to proteinaceous substances—\n(a) if the difference in structure between them is due to post-translational events, such as different glycosylation patterns, substances are usually to be considered similar; however, exceptionally some post-translational modifications may result in a non-similar substance if there is significant effect on the functional characteristics of the substance;\n(b) if the difference in the amino acid sequence is not major, substances are usually to be considered similar; therefore two pharmacologically related protein substances of the same group, for example, having differences related to N-terminal methionine, naturally extracted as opposed to recombinant nucleic acid-derived proteins or other minor variants, are usually to be considered similar; however, the addition of a structural element may result in substances not being considered similar if this significantly affects the functional characteristics of the substance;\n(c) monoclonal antibodies binding to the same target epitope are usually to be considered similar; however, two monocloncal antibody conjugates or fusion proteins may be considered not to be similar if either the Complementary Determining Region sequences of the antibody or the additional structural element of the conjugated monoclonal antibody is different.\n(8) In relation to polysaccharide substances—\n(a) if the substances have identical saccharide repeating units, even if the number of units varies, the substances are usually to be considered similar; and\n(b) a conjugated polysaccharide vaccine compared to a non-conjugated polysaccharide vaccine containing the same antigen is considered not to be similar.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Sch. 9A inserted (31.12.2020) by The Human Medicines (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/775), reg. 1, Sch. 4 (as amended by S.I. 2020/1488, reg. 1, Sch. 2 para. 191); 2020 c. 1, Sch. 5 para. 1(1)"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/2012/1916/schedule/9A/paragraph/6",
    "retrieved_at": "2026-10-29T01:24:34.993203+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}