Inside Sanofi’s Hemophilia Research

Sanofi scientists are expanding the therapeutic possibilities for hemophilia patients through continuous discovery and innovation. Their goal is to give families with hemophilia more choices for treatment.

People with hemophilia live all over the world and face different challenges throughout their lives. This rare genetic condition affects a person’s ability to generate blood-clotting factors. It can cause spontaneous or prolonged bleeding, often into the joints and soft tissues, leading to other health problems. The most common way to treat hemophilia is by replacing the reduced or missing factor in a patient’s blood.

While steady advances in hemophilia treatment over the past decades have been significant, frequent intravenous infusions remain a burden for many people living with hemophilia, and the duration of protection remains a driving concern for those who seek a more active life or physically demanding profession. But there is no one-size-fits all solution.

The development of extended half-life factor replacement therapies was revolutionary, setting off a whirlwind of innovation in the field. These treatments provide protection from bleeding with an infusion of clotting factor that increases factor levels for longer than standard treatments at the time.¹

Since then, Sanofi has launched its rare blood disorders franchise through strategic acquisitions. It is leveraging a broad range of technologies and small-biotech experience to develop potential therapies that could go beyond incremental improvement.

Sanofi scientists and bioengineers are now investigating three new approaches to hemophilia treatment: an extended half-life factor replacement therapy, a rebalancing RNA Interference (RNAi) therapy, and a potentially curative gene therapy. 

• Factor replacement therapy, the cornerstone of hemophilia care, replaces missing blood-clotting factors in the body and requires intravenous injections. Together with Sobi, Sanofi is taking a unique bioengineering approach to extended half-life factor replacement therapy, aiming to provide high, sustained protection against bleeds. With this uniquely designed molecule, the companies’ goal is to provide near normal factor levels for more than half the week.
• Rebalancing RNAi therapy, a new approach under investigation in the clinic, aims to rebalance pro-coagulant and anti-coagulant proteins in the blood that regulate clotting. RNA is responsible for translating DNA instructions into proteins in the body. Sanofi researchers are using small, “interfering” RNA molecules (RNAi) to prevent the body from manufacturing a protein that inhibits coagulation. Their ambition is to develop a once-monthly, subcutaneous, single-dose treatment that could be used for hemophilia A and B, with or without inhibitors (antibodies that attack replacement factors).²
• Gene therapies ultimately aim to cure patients by reprogramming their DNA to produce the missing factor. This requires delivering corrected DNA to a patient’s cells using a retrovirus. 

Sanofi researchers are exploring how to deliver corrected DNA to liver cells using a type of retrovirus called a lentivirus. Their goal is to create a gene therapy that would be durable and effective in all patients, including children. This approach is still in the experimental phase, and it will be many years before patients can benefit from it, and until scientists know how long the effect will last.

¹ https://ashpublications.org/blood/article-pdf/133/5/389/1552163/blood872291.pdf
² https://ashpublications.org/blood/article/134/Supplement_1/1138/426679/Fitusiran-an-RNAi-Therapeutic-Targeting