INTRUSION: Unraveling the INTRatUmoral PK/PD relatION for SAR408701

The investigators hypothesize that intratumoral exposure of Tusamitamab ravtansine would be an important factor in determining treatment efficacy. The rationale to develop an antibody-drug conjugate, like tusamitamab ravtansine, is that it concentrates the active compound (DM4) in cancer tissues, thus confirming this hypothesis in human subjects would be an important step forward. Combining exposure with measurements of tumor PD reactions in a proper PK/PD study is the goal of the study. Tusamitamab ravtansine is being developed in NSQ NSCLC. The results of the first-in-human study in NSQ NSCLC patients were promising and participants could thus benefit from this treatment. However, other tumor types also express CEACAM5 in tumor cells. The investigators will also recruit metastatic ER+ breast cancer patients and metastatic gastric cancer patients. Hence, there has been more limited data on the safety and efficacy in this patient populations. Addition of these cohorts will help to understand the influence of primary tumor type in determining intratumoral concentrations of Tusamitamab ravtansine. CEACAM5-positive is defined as IHC ≥2+ in intensity in ≥50% of the tumor cells expressing CEACAM5. Yet, the cut-off value for CEACAM5 expression is arbitrarily selected. A PK/PD relation between CEACAM5 expression and exposure would support the current applied cut-off value for CEACAM5 expression.