Pancreatic Adenocarcinoma: Principles of systemic therapy…Useful in Certain Circumstances...Pembrolizumab (if MSI-H, dMMR, or TMB-H [≥10 mut/Mb])

KEYTRUDA is a programmed death receptor-1 (PD-1)-blocking antibody indicated:...for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [≥10 mutations/megabase (mut/Mb)] solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options.

A CT-guided biopsy of the lung lesion revealed undifferentiated carcinoma with spindle cell malignant neoplasm with osteoclast-like giant cells consistent with UCOGC...While the patient was undergoing IMRT, tissue from her lung metastasis was sent for NGS (FoundationOne, Foundation Medicine), which revealed alterations to the BRAF oncogene and the tumor suppressor genes NF1, PIK3A, CDKN2A, TERT promoter, and TP53. The tumor was microsatellite-stable with a high TMB (32 mutations per megabase [mut/Mb])...The patient continued pembrolizumab cycles 8 through 19 with continued reduction of the pancreatic primary and brain metastasis and complete resolution of the pulmonary metastasis biopsied at diagnosis. Cycles 20 through 46 showed continued response in all lesions...