Dose Escalation and Expansion Study of SAR443216 in Participants With Relapsed/Refractory HER2 Expressing Solid Tumors

Part 1: Objective response rate (ORR) of SAR443216 in all participants

Objective response rate is defined as the proportion of participants who achieve a complete response (CR) or partial response (PR) per RECIST v1.1.

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months

Part 1: Duration of response (DoR) of SAR443216 in all participants

Duration of response per RECIST v1.1 is defined as the interval from the first documentation of CR or PR to the earlier of the first documentation of definitive disease progression or death due to any cause, whichever occurs first

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months

Part 1 and Part 2: Progression Free Survival (PFS)

Progression free survival (PFS) will be assessed by the Investigator per RECIST v1.1 and will be summarized using the Kaplan-Meier method

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part1 and 5.5 months for Part 2

Part 2: Safety of SAR443216

Number of participants with treatment emergent adverse events (TEAEs), serious adverse events (SAEs), and lab abnormalities according to NCI CTCAE Version 5.0

Time frame: Baseline until the end of the study, up to approximately 9.5 months

Part 1 and Part 2: Pharmacokinetic Parameter: Cmax of SAR443216

Maximum observed plasma concentration

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part 1 and 5.5 months for Part 2

Part 1 and Part 2: Pharmacokinetic Parameter: Ctrough of SAR443216

Plasma concentration observed just before treatment administration during repeated dosing

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part 1 and 5.5 months for Part 2

Part 1 and Part 2: Pharmacokinetic Parameter: t 1/2 of SAR443216

Terminal half-life associated with the terminal slope (λz)

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part 1 and 5.5 months for Part 2

Part 1 and Part 2: Pharmacokinetic Parameter: AUC0-τ of SAR443216

Area under the plasma concentration versus time curve

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part 1 and 5.5 months for Part 2

Part 1 and Part 2: Evaluation of SAR443216 immunogenicity

Incidence of ADA induction and ADA persistence

Time frame: From date of enrollment until the end of treatment, up to approximately 3.5 months for Part 1 and 5.5 months for Part 2