PD-L1 Expressing Recurrent Clear Cell Carcinoma of the Vulva with Durable Partial Response to Pembrolizumab: A Case
Manavi Sachdeva1, Natalie Y L Ngoi2, Diana Lim3
1Department of Medicine, National University Health System Singapore, Singapore, 119074, Singapore.
Background:
The optimal treatment and molecular landscape of recurrent clear cell carcinoma of the vulva (VCCC) are unknown. No reported data exist regarding the efficacy of anti-programmed death 1 (PD-1) immune checkpoint inhibition in VCCC. We report on a patient with chemotherapy-refractory recurrent VCCC, who was found to have high tumor programmed death-ligand 1 (PD-L1) combined positive score (CPS), and subsequently experienced a durable partial response (PR), after treatment with off-label fifth-line pembrolizumab.
Case Presentation:
A forty-year-old Filipino woman presented to our center with recurrent VCCC that had progressed on multiple prior lines of cytotoxic chemotherapy. She had a large 25 cm fungating left groin tumor causing marked lower limb lymphedema, pain and limited mobility. PD-L1 CPS by immunohistochemistry was 45. She was treated with off-label pembrolizumab monotherapy and had a dramatic clinical, biochemical and radiological partial response. The progression-free survival of this patient's VCCC after treatment with pembrolizumab, defined as the time from initiation of pembrolizumab until disease progression (by Response Evaluation Criteria in Solid Tumors (version 1.1)), was 8 months. While receiving pembrolizumab, she was diagnosed with concurrent secondary myelodysplastic syndrome with excess blasts (MDS-EB), thought to be related to her prior exposure to multiple lines of cytotoxic chemotherapy. This eventually progressed to acute myeloid leukemia (AML), leading to her demise. Overall survival from time of initiation of pembrolizumab till death was 16 months.
Conclusion:
Pembrolizumab was active in this patient with chemotherapy-refractory VCCC which harbored high PD-L1 CPS. Further studies to determine the role of immune check-point blockade in the treatment of VCCC are warranted.
Insights
This case study shows that pembrolizumab, an anti-PD-1 therapy, can be effective for advanced vulvar clear cell carcinoma (VCCC) resistant to chemotherapy. High PD-L1 expression predicted a positive response, warranting further research into immune checkpoint inhibitors for VCCC.
Area of Science:
- Oncology
- Immunotherapy
- Gynecologic Oncology
Background:
- Recurrent clear cell carcinoma of the vulva (VCCC) lacks established optimal treatment strategies.
- The role of immune checkpoint inhibition, specifically anti-programmed death 1 (PD-1) therapy, in VCCC is not yet defined.
- This report addresses the efficacy of PD-1 blockade in a chemotherapy-refractory VCCC case.
