MT-5111: This phase I/II is investigating the appropriate dose level and effectiveness of a new cancer drug (MT-5111) in people with HER2-positive solid cancersA Phase 1 Open-label, Multicenter Dose Escalation and Expansion Study of MT-5111 in Subjects With Previously Treated Advanced HER2-positive Solid Tumors

Summary

This study will be conducted in two parts. Part 1 (dose escalation) aims to determine the recommended phase 2 dose (RP2D) to be used in Part 2. Part 1 will consist of participants with any type of HER2-positive solid cancer. Part 2 (dose expansion) aims to confirm how safe and tolerable the RP2D of MT-5111 is. Part 2 will consist of people with any type of HER2-positive solid cancers, including breast cancer, gastric or gastroesophageal adenocarcinomas. MT-5111 will be administered via intravenous infusion over about 30 minutes on the same day every week (i.e., on day 1, day 8 and day 15 of each cycle).