SAR405838 is undergoing evaluation in a phase 1 trial in which the maximum tolerated dose (MTD) was established as 300 mg once daily (NCT01636479); 21 patients with de-differentiated liposarcoma (DDLPS) were enrolled in an MTD expansion cohort to assess efficacy in patients whose tumours exhibited genomic amplification of MDM2. Pharmacokinetics (PK), pharmacodynamics and efficacy data have been reported elsewhere8. This evidence concerns the gene MDM2 and liposarcoma.