Clinical Report: Successful Treatment of Metastatic Extramammary Paget’s Disease
Background
Metastatic extramammary Paget’s disease is a rare and aggressive cancer with a poor prognosis, particularly in cases with lymph node or visceral metastases. Approximately 40% of mEMPD cases overexpress the Her2/neu protein, making it a significant target for precision-based systemic therapies.
Data Highlights
Case presentation of a 73-year-old man with mEMPD treated with trastuzumab deruxtecan.
Key Findings
The patient had low Her2/neu expression (++/+++).
Next-generation sequencing revealed a high tumor mutation burden (30Muts/Mb) and mutations in ERBBR2, PIK3CA, and PTEN.
Initial treatment with trastuzumab and pembrolizumab resulted in no clinical response.
Trastuzumab deruxtecan led to a partial clinical and radiological response, including regression of lymphadenopathy and bladder lesions.
HER2-targeted strategies have shown high efficacy in mEMPD.
Conventional therapies have limited efficacy, with progression-free survival of approximately 5 to 7 months.
Clinical Implications
The case suggests that trastuzumab deruxtecan may be a treatment option for patients with mEMPD exhibiting low Her2/neu expression.
Conclusion
This case highlights the use of trastuzumab deruxtecan in managing metastatic extramammary Paget’s disease in patients with specific molecular characteristics.
