Trastuzumab plus pertuzumab for non-breast/gastroesophageal HER2-amplified tumors in subprotocol J of NCI-MATCH

NCI-MATCH assigned patients with advanced cancer and progression on prior treatment, based on genomic alterations in tumor tissue. Subprotocol J evaluated the combination of trastuzumab and pertuzumab (HP) for non-breast/gastroesophageal HER2-amplified tumors (copy number ≥ 7). The confirmed ORR was 12% (90% CI 3,4-28,2) with responses in colorectal cancer, cholangiocarcinoma, and urothelial carcinoma, and one additional partial response in a patient with urothelial cancer with an unconfirmed ERBB2 copy number. Median progression-free survival was 3.3 months (90% CI 2.0-4.1) and median overall survival was 9.4 months (5.0-18.9). Treatment-emergent adverse events were consistent with results of prior studies. There was no association between HER2 copy number and response. The authors conclude that HP was active in a selection of HER2-amplified tumors but did not meet the predifined efficacy benchmark.