Press Release

Riliprubart earns orphan drug designation in the US for
antibody-mediated rejection in solid organ transplantation
• Ongoing phase 2 study evaluating riliprubart for the potential prevention and treatment
of active antibody-mediated rejection in kidney transplant recipients
• Riliprubart was also designated orphan drug for the investigational use in chronic
inflammatory demyelinating polyneuropathy in the US and EU

Paris, June 25, 2025. The US Food and Drug Administration (FDA) has granted orphan drug
designation to riliprubart for the investigational treatment of antibody-mediated rejection
(AMR) in solid organ transplantation. This designation reflects Sanofi’s commitment to
addressing a critical unmet need in transplant medicine, where AMR remains a significant
challenge with no FDA-approved treatments available. The FDA grants orphan drug designation
to investigational therapies addressing rare medical diseases or conditions that affect fewer
than 200,000 people in the US.

Alyssa Johnsen
Global Therapeutic Area Development Head, Immunology and Inflammation, Sanofi
"Orphan drug designation for riliprubart marks an important milestone in our mission to address
critical challenges in transplant medicine leveraging our expertise in immunology. Antibody
mediated rejection represents a serious threat to transplanted organs and patient survival.
Through riliprubart's innovative mechanism of action, we hope to bring forward a treatment
option that could significantly improve outcomes for kidney transplant recipients."

Riliprubart is currently being explored in multiple clinical studies across different indications in
transplant and neurology. A phase 2 clinical study is currently ongoing, exploring its potential
in kidney transplant recipients (NCT05156710). The study includes two patient cohorts: those
at risk of developing rejection and those with active forms of antibody-mediated rejection. In
addition, Sanofi is conducting two phase 3 studies exploring riliprubart in chronic inflammatory
demyelinating polyneuropathy (CIPD), a rare neurological disorder, specifically in patients
refractory to standard of care (MOBILIZE, clinical study identifier: NCT06290128), and in IVIg-
treated patients (VITALIZE, clinical study identifier: NCT06290141). The broad clinical
development program for riliprubart emphasizes Sanofi's commitment to exploring riliprubart’s
potential across multiple immune-mediated conditions with high unmet medical needs.

About Riliprubart
SAR445088 (riliprubart) is a potential first-in-class, IgG4 humanized monoclonal antibody that
selectively inhibits activated C1s in the classical complement pathway of the innate immune
system. Riliprubart is currently under clinical investigation, and its safety and efficacy have not
been evaluated by any regulatory authority. For more information on riliprubart clinical
studies, please visit www.clinicaltrials.gov.

About AMR
Antibody-mediated rejection is a serious complication that may arise after solid organ
transplantation, occurring when the recipient’s immune system produces antibodies that attack
the transplanted organ. Sensitized recipients, who have pre-existing antibodies that target
foreign antigens including those found on transplanted organs, face a high risk of developing
antibody-mediated rejection. Subsequent immune response can lead to inflammation, organ
damage, and organ failure if left untreated.

About Sanofi
Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s
lives and delivering compelling growth. We apply our deep understanding of the immune

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system to invent medicines and vaccines that treat and protect millions of people around the
world, with an innovative pipeline that could benefit millions more. Our team is guided by one
purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive
progress and deliver positive impact for our people and the communities we serve, by
addressing the most urgent healthcare, environmental, and societal challenges of our time.
Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY

Media Relations
Sandrine Guendoul | +33 6 25 09 14 25 | sandrine.guendoul@sanofi.com
Evan Berland | +1 215 432 0234 | evan.berland@sanofi.com
Léo Le Bourhis | +33 6 75 06 43 81 | leo.lebourhis@sanofi.com
Victor Rouault | +33 6 70 93 71 40 | victor.rouault@sanofi.com
Timothy Gilbert | +1 516 521 2929 | timothy.gilbert@sanofi.com
Léa Ubaldi | +33 6 30 19 66 46 | lea.ubaldi@sanofi.com

Investor Relations
Thomas Kudsk Larsen | +44 7545 513 693 | thomas.larsen@sanofi.com
Alizé Kaisserian | +33 6 47 04 12 11 | alize.kaisserian@sanofi.com
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Keita Browne | +1 781 249 1766 | keita.browne@sanofi.com
Nathalie Pham | +33 7 85 93 30 17 | nathalie.pham@sanofi.com
Tarik Elgoutni | +1 617 710 3587 | tarik.elgoutni@sanofi.com
Thibaud Châtelet | +33 6 80 80 89 90 | thibaud.chatelet@sanofi.com
Yun Li | +33 6 84 00 90 72 | yun.li3@sanofi.com

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