Isatuximab (isatuximab-irfc; Sarclisa®) is an IgG1 monoclonal antibody that binds to the glycoprotein CD38 expressed on the surface of haematopoietic and tumour cells. It is being developed by Sanofi, under a license from Immunogen, for the treatment of haematological malignancies. In March 2020, intravenous isatuximab (in combination with pomalidomide and dexamethasone) was approved in the USA for the treatment of adult patients with multiple myeloma who have received ≥ 2 prior therapies, including lenalidomide and a proteasome inhibitor. Isatuximab has also received a positive opinion in the EU for the treatment of relapsed and refractory multiple myeloma. This article summarizes the milestones in the development of isatuximab leading to the first approval in the USA.