Case of metastatic kaposi sarcoma successfully treated with anti-PD-1 immunotherapy

Abstract

Introduction Kaposi sarcoma (KS) is an angioproliferative malignancy associated with HHV-8. It is mostly observed in patients affected by HIV and/or chronic immunosuppression, while classic KS without underlying immunosuppression are relatively rare. Systemic chemotherapy is used for advanced diseases, although there is no consensus in treatment algorithms. With the demonstration of PD-1 expression in KS, immune-checkpoint-inhibitors (ICI) emerged as possible treatment options. Notwithstanding, the data of ICIs is limited to case reports/series. Herein, we present a case of advanced classic KS, which has been treated successfully with nivolumab. Case report 82-year-old male patient was investigated for erythematous lesions on thigh. Punch biopsy lead to KS diagnosis. Abdominal CT showed lymphadenopathies in the inguinal region. After radiotherapy follow-up, patient had shown vertebral & gastric metastases. Because of the PSA elevation patient was diagnosed with prostatic adenocarcinoma. Metastases were investigated for origin. The lesions showed no uptake in Ga-68 PET-CT, therefore accepted as KS metastases. Patient rejected chemotherapy options and consented to immunotherapy trial. Management and outcome: Nivolumab was initiated 3\u2009mg/kg bi-weekly with 12-dose protocol. After nivolumab patient wellbeing is improved and control endoscopy shown no metastases. With these findings patient has been assessed as complete response. Discussion ICI on KS is still a blurred option to be included in standard regimens; but progressive understanding of PD-1 expression and its role in disease progression may be a milestone for further treatment algorithms on KS. Besides good efficacy, tolerability of ICIs could be helpful patients with comorbidities precluding the use of chemotherapy.