Atezolizumab with bevacizumab, paclitaxeland carboplatin was effective for patients with SMARCA4-deficient thoracic sarcoma.

Abstract

SMARCA4-deficient thoracic sarcoma(DTS) is a recently noted progressive thoracic malignancy. We recently experienced three cases of SMARCA4-DTS who were treated with atezolizumab in combination with bevacizumab, paclitaxeland carboplatin (ABCP) as the first-line therapy. Immunohistopathological analysis revealed absent expression of SMARCA4 in all cases. The tumor mutational burden was over 11/Mb and mutations in SMARCA4 and TP53 were detected in all three cases. Partial response to ABCP treatment was observed in all three cases, with a progression-free survivalof approximately 6months or longerand a continuous response of 1year or longer in one case. The first-line ABCP treatment demonstrated durable efficacy in SMARCA4-DTS regardless of the degree of PD-L1 expression.