Disease control rate (complete + partial response (PR) + stable disease) was 93%/88% in pts with DDLPS/well-differentiated LPS (WDLPS), respectively. A confirmed PR was achieved in 5 pts (2 DDLPS, 3 WDLPS); 3 pts (2 DDLPS, 1 WDLPS) had an unconfirmed PR. Of the pts enrolled into phase Ia, 5/11 with DDLPS and 4/8 with WDLPS achieved a PFS >10.5 months. For pts with other solid tumours, 2/4 with MDM2-amplified biliary tract cancer and 1 with MDM2-amplified pancreatic adenocarcinoma had a confirmed PR.