Testing the Combination of Two Anti-cancer Drugs, DS-8201a and AZD6738, for The Treatment of Advanced Solid Tumors Expressing the HER2 Protein or Gene, The DASH Trial

The dose escalation phase of this trial identifies the safety, side effects and best dose of ceralasertib (AZD6738) when given in combination with trastuzumab deruxtecan (DS-8201a) in treating patients with solid tumors that have a change (mutation) in the HER2 gene or protein and have spread to other places in the body (advanced). The dose expansion phase (phase Ib) of this trial compares how colorectal and gastroesophageal cancers with HER2 mutation respond to treatment with a combination of ceralasertib and trastuzumab deruxtecan versus trastuzumab deruxtecan alone. Ceralasertib may stop the growth of tumor cells and may kill them by blocking some of the enzymes needed for cell growth. Trastuzumab deruxtecan is a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug, called deruxtecan. Trastuzumab attaches to HER2 positive cancer cells in a targeted way and delivers deruxtecan to kill them. Ceralasertib and trastuzumab deruxtecan may be safe, tolerable and effective in treating patients with advanced solid tumors expressing the HER2 protein or gene.