Response to Combined Peptide Receptor Radionuclide Therapy and Checkpoint Immunotherapy with Ipilimumab Plus Nivolumab in Metastatic Merkel Cell Carcinoma

J Nucl Med. 2022 Mar;63(3):396-398. doi: 10.2967/jnumed.121.262344. Epub 2021 Sep 2.


For patients with Merkel cell carcinoma (MCC) who are refractory to immune checkpoint inhibition (ICI), treatment options are limited. Few cases of MCCs have been reported to show responses to peptide receptor radionuclide therapy (PRRT). A combination of PRRT and ICI has not been reported in MCC to date. A patient with metastatic MCC, who was resistant to first-line avelumab and acquired resistance to ipilimumab/nivolumab (IPI/NIVO) with additional radiotherapy, presented with multiple distant metastases. After confirmation of SSTR expression, treatment was continued with an additional 4 doses of IPI/NIVO combined with 2 cycles of PRRT. Treatment was well tolerated, with transient hemotoxicity and mild nausea. Restaging after 3 mo demonstrated an exceptional response. This case demonstrates the feasibility of combined treatment with IPI/NIVO and PRRT as an option for MCC patients progressing under ICI. Prospective evidence confirming the additive value of combining ICI and radionuclide therapy in a larger cohort is needed.

Keywords: Merkel cell carcinoma; PD-L1; PRRT; SSTR; immunotherapy.

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Carcinoma, Merkel Cell* / drug therapy
  • Carcinoma, Merkel Cell* / etiology
  • Carcinoma, Renal Cell / drug therapy
  • Female
  • Humans
  • Immunotherapy
  • Ipilimumab / therapeutic use
  • Kidney Neoplasms / pathology
  • Male
  • Nivolumab / therapeutic use
  • Prospective Studies
  • Radioisotopes* / therapeutic use
  • Receptors, Peptide / therapeutic use
  • Skin Neoplasms* / drug therapy
  • Skin Neoplasms* / therapy


  • Ipilimumab
  • Radioisotopes
  • Receptors, Peptide
  • Nivolumab