Exhibit 99.5
Dear Colleagues,
Today we announced Sanofi’s plans to acquire Principia, a late-stage biopharmaceutical company focused on developing treatments for immune-mediated diseases, and the company that discovered our investigational Bruton’s tyrosine kinase (BTK) inhibitor SAR442168. Both the company’s pipeline and their platform technology are attractive to us, and we’ve established a solid working relationship with their team through our work on ‘168.
This acquisition will bring multiple BTK inhibitors into our pipeline, as well as Principia’s Tailored Covalency® chemistry platform, which should augment our internal capabilities as we look to maintain leadership in the discovery and development of oral medicines. The ability to block or disrupt BTK in the signaling pathways of key cell types of the immune system shows promise for stopping inflammation and tissue destruction related to autoimmune diseases. The Principia platform allows the design of both reversible covalent and irreversible covalent small molecule inhibitors that are more selective with less off-target effects. The optimized target residence time has potential to deliver a desired efficacy with a stronger safety profile.
We believe that ’168 and rilzabrutinib, a program in Phase 3 development at Principia, have the potential to be the type of “pipeline in a product” medicines that we are seeking to develop. As you may recall, we recently initiated our Phase 3 program in multiple sclerosis for ‘168. With this planned acquisition, we anticipate that commercialization of ‘168 will be more efficient and, by owning the full rights to the molecule, we will be able to invest in the expansion of the ‘168 development program into other central nervous system diseases and therapeutic areas.
Rilzabrutinib is an oral BTK inhibitor currently being evaluated in a Phase 3 program for patients with moderate to severe pemphigus, a rare, debilitating autoimmune disease that causes blistering of the skin and mucous membranes. A Phase 3 program for immune thrombocytopenia, a disease that causes high risk for bleeding events, is expected to be initiated by the end of 2020, following impressive Phase 2 results. Principia also has an ongoing Phase 2 program for IgG4-related diseases, which is driven by chronic inflammation, immune cell infiltration, and fibrosis within organs that can lead to severe morbidity. A third program, PRN473, is a topical agent BTK inhibitor currently in Phase 1 development for immune mediated diseases that could benefit from localized application to the skin.
Today marks the first step in this process. Until the deal is completed, which we expect to occur during the fourth quarter of this year, subject to conditions, such as antitrust clearance and other customary requirements, Principia will continue to operate as a separate company.
Please join me in welcoming the Principia colleagues to the Sanofi family. We are excited by these programs and their potential impact across our therapeutic areas, and by the addition to our research organization. We believe this acquisition will significantly advance our work to reduce suffering of patients living with debilitating immunological diseases.
Regards,
John Reed