Sanofi receives US approval for oral ITP blockbuster

Sanofi’s new ITP drug rilzabrutinib, approved by the FDA based on the results of the LUNA 3 Phase III study, is expected by analysts to achieve peak sales of up to US$5bn, although previously approved drugs have only generated US$2.8bn in 2023. There are several reasons for this: as the only approved oral drug, it is cheaper, better tolerated, easier to take and, thanks to its target, Bruton’s tyrosine kinase, it is also more effective than the approved Syk inhibitor fostamatinib and the TPO receptor antagonist romiplostim, both of which only modulate platelet count, and the FcRn inhibitor efgartigimod, which reduces the number of autoantibodies.

This is because the active ingredient rilzabrutinib, which Sanofi has been developing since 2020 following its acquisition of Principia Biopharma for US$3.7 billion, inhibits two processes underlying the autoimmune response in ITP: the production of autoantibodies in B cells and the Fcγ receptor-mediated immune response in phagocytes. Furthermore, rilzabrutinib is also being developed in other indications, such as the skin disease pemphigus vulgaris, warm AIHA haemolytic anaemia and Sjögren’s syndrome. Clinical studies with rilzabrutinib as an MS treatment have failed .

Following approval in the United Arab Emirates and the United States, regulatory authorities in China and the European Union, which together account for US$1.4bn of the current market, are reviewing the approval of rilzabrutinib.