SAR3419 is a potential new therapy for the treatment of CD19+ non-Hodgkin's lymphoma (NHL) and other B-cell malignancies. It was created by ImmunoGen and licensed to Sanofi preclinically as part of a broader collaboration between the companies.

In Phase I testing, SAR3419 demonstrated activity across the array of NHL histological subtypes. It also was active against both rituximab-refractory and rituximab-responsive disease and was generally well tolerated. Initial data from the weekly dosing study were reported at ASCO and the 11th International Conference on Malignant Lymphoma in June 2011.

The Phase II assessment of SAR3419 focuses on evaluating the compound for diffuse large B-cell lymphoma (DLBCL), the most common type of NHL, and for B-cell acute lymphoblastic leukemia (B-ALL). SAR3419 advanced into Phase II testing in October 2011.