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Published on: February 7, 2021
Exceptionally rapid response to pembrolizumab in a SMARCA4-deficient thoracic sarcoma overexpressing PD-L1: A case
Kohichi Takada1, Shintaro Sugita2, Kazuyuki Murase1
1Department of Medical Oncology, Sapporo Medical University School of Medicine, Sapporo, Japan.
Abstract:
SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) is a new clinical entity characterized by SMARCA4 inactivation and has a dismal prognosis because of rapid growth. Effective treatments for SMARCA4-DTS have not yet been developed. Most recently, anti-programmed cell death 1 receptor (PD-1) blockade has been effective for SMARCA4-deficient lung cancer and malignant rhabdoid tumor-like tumors. Here, we describe a patient with SMARCA4-DTC who experienced a marked response to the administration of pembrolizumab. A 70-year-old female was referred to our department for treatment of SMARCA4-DTC. Positron emission tomography-computed tomography had revealed a left mediastinal tumor, peritoneal dissemination and multiple cutaneous metastases at diagnosis. Immunohistochemical analyses revealed 60% of tumor cells expressed programmed cell death ligand 1 (PD-L1). The patient was given pembrolizumab as first-line treatment. Pembrolizumab suppressed tumor growth dramatically, with only one dose leading to a partial response. Our case suggests the immunohistochemical analysis of PD-L1 expression be undertaken for patients with SMARCA4-DTS and that pembrolizumab treatment may be a promising strategy for PD-L1-positive SMARCA4-DTS.
Insights
SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) shows poor prognosis. This case highlights pembrolizumab as a promising treatment for PD-L1-positive SMARCA4-DTS, demonstrating a dramatic response after one dose.
Area of Science:
- Oncology
- Immunotherapy
Background:
- SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) is a rare and aggressive cancer with limited treatment options.
- Recent successes with anti-programmed cell death 1 receptor (PD-1) therapy in related SMARCA4-deficient tumors suggest potential efficacy.
Observation:
- A 70-year-old female patient with advanced SMARCA4-DTS presented with mediastinal, peritoneal, and cutaneous metastases.
- Immunohistochemical analysis revealed programmed cell death ligand 1 (PD-L1) expression in 60% of tumor cells.
Findings:
- The patient received pembrolizumab as first-line treatment for SMARCA4-DTS.
- A dramatic tumor response, achieving partial response after a single dose, was observed with pembrolizumab therapy.
Implications:
- This case suggests PD-L1 expression analysis should be considered for SMARCA4-DTS patients.
- Pembrolizumab may represent a promising therapeutic strategy for PD-L1-positive SMARCA4-DTS, warranting further investigation.
