MEK Inhibitor and a PDL1 Inhibitor Patients With Locally Advanced and/or Metastatic Soft Tissue Sarcoma

The proposed study conducted in adult and pediatric patients aims to evaluate the safety and clinical activity of atezolizumab + cobimetinib in advanced/metastatic soft tissue sarcomas (up to 80 patients).

The hypothesis of the proposed combination is as follows: cobimetinib via MEK1/2 inhibition could modify the tumor microenvironment and improve the response of T cells against tumor cells. Therefore, the addition of cobimetinib to atezolizumab may improve immune recognition and result in improved anti-tumour activity. The combination of cobimetinib and atezolizumab showed clinical activity in a Phase I trial in patients with metastatic colorectal cancer (Atezolizumab 840 mg every 2 weeks and Cobimetinib 60 mg/d) with a disease control rate of 31%. Atezolizumab and cobimetinib are currently being tested in pediatrics in the iMatrix clinical trial with no major safety concerns to date. A molecular screening step is mandatory for all patients enrolled in this trial in order to document MAPK pathway status and Tumor Mutational Burden (TMB) using FoundationOne test (FOne Heme).