{
  "abstract": "Purpose: Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) breast cancer accounts for approximately 65–70% of all breast cancer cases. First-line treatment for metastatic HR+/HER2– disease typically includes endocrine therapy combined with a CDK4/6 inhibitor, achieving progression-free survival (PFS) of 24–33 months with preserved quality of life. Although CDK4/6 inhibitors are generally well tolerated, they are associated with hematologic and gastrointestinal toxicities. We describe a patient who developed features of chronic immune-mediate polyradiculoneuropathy associated with neurofascin antibodies following initiation of palbociclib.\n\nMethods: We conducted a detailed clinical review of a patient with metastatic HR+/HER2– breast cancer who developed progressive bilateral upper and lower extremity weakness after starting palbociclib. Clinical presentation, laboratory findings, imaging studies, electrodiagnostic testing, and treatment response were reviewed.\n\nResults: A 43-year old female with metastatic HR+/HER2- breast cancer developed asymmetric progressive weakness and sensory symptoms approximately two weeks after initiating palbociclib. Electrodiagnostic testing demonstrated a mixed axonal and demyelinating sensorimotor polyneuropathy meeting EAN/PNS criteria for an acquired inflammatory demyelinating polyradiculoneuropathy. Initial diagnostic considerations included acute inflammatory demyelinating polyradiculoneuropathy (AIDP) and multifocal CIDP (formerly termed multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]). Despite initial improvement following treatment with IVIG, the patient experienced continued neurologic progression requiring plasmapheresis, repeat IVIG, high-dose corticosteroids, and rituximab. Subsequent testing demonstrated anti-neurofascin-155 and anti-neurofascin-186 antibody positivity. Longitudinal follow-up demonstrated significant functional recovery following rituximab therapy.\n\nConclusion: This case suggests a possible association between palbociclib exposure and the development of chronic immune-mediate polyradiculoneuropathy associated with neurofascin antibodies. Clinicians should consider immune mediated neuropathies in patients receiving CDK4/6 inhibitor therapy who develop weakness, sensory deficits, and areflexia. Further investigation is warranted to better characterize potential immunologic effects of CDK4/6 inhibition and their relationship to autoimmune neurologic disease.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Neurology, Henry Ford Health, Detroit, MI USA",
    "Wayne State University School of Medicine, Detroit, MI USA",
    "Department of Hematology/Oncology, Henry Ford Health, Detroit, MI USA",
    "Michigan State University, East Lansing, MI USA"
  ],
  "article_type": "brief report",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Joy Zeynoun"
    },
    {
      "affs": [
        1
      ],
      "name": "Madeline Evans"
    },
    {
      "affs": [
        2
      ],
      "name": "Kimberly Boldig"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Haythem Ali"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7wd4gbr6yr7v8.bib",
  "cited_by": 0,
  "doi": "10.1007/s10549-026-08081-6",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13736406/",
  "id": "7wd4gbr6yr7v8",
  "issns": [
    "0167-6806",
    "1573-7217"
  ],
  "landing_url": "https://doi.org/10.1007/s10549-026-08081-6",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Brief Report"
    ],
    [
      "openalex",
      "2728|Peripheral Neuropathies and Disorders"
    ]
  ],
  "openalex": "W7225232535",
  "pdf_url": "https://link.springer.com/content/pdf/10.1007/s10549-026-08081-6.pdf",
  "pmcid": "PMC13736406",
  "pmid": "42980868",
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7wd4gbr6yr7v8.ris",
  "sources": [
    {
      "first_seen": "2026-11-09T12:21:51Z",
      "native_id": "PMC13736406",
      "source": "pmc",
      "url": "https://doi.org/10.1007/s10549-026-08081-6"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2728|Peripheral Neuropathies and Disorders",
      "subfield": "neurology"
    }
  ],
  "title": "A rare neurological adverse event of palbociclib: a chronic inflammatory demyelinating polyneuropathy (CIDP) mimic",
  "title_text": "A rare neurological adverse event of palbociclib: a chronic inflammatory demyelinating polyneuropathy (CIDP) mimic",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T12:21:51Z",
  "url": "https://research.draconitic.com/paper/7wd4gbr6yr7v8",
  "venue": "Breast Cancer Research and Treatment",
  "versions": []
}