Sanofi Scores FDA Nod for Rare Anemia Drug

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The U.S. Food and Drug Administration approved Sanofi's proposed drug to address red blood cell destruction in patients living with a rare form of anemia called cold agglutinin disease (CAD). 

Enjaymo (sutimlimab-jome) is a humanized monoclonal antibody that works by selectively targeting and inhibiting C1s in the classical complement pathway of the immune system. Blocking C1s thwarts the activation of the complement cascade in the immune system and C1-activate hemolysis in CAD. This prevents the abnormal destruction of healthy red blood cells without inhibiting lectin and alternative pathways. 

The FDA's decision is based on favorable results from Sanofi's Phase III CARDINAL trial, a 26-week open label, single arm study on 24 CAD patients. Enjaymo met the primary endpoint of efficacy in the trial, where patients achieved hemoglobin (Hgb) normalization or showed an increase from baseline in Hgb levels and no blood transfusions were needed from week 5 to 26. Secondary endpoints were also achieved, such as bilirubin normalization and Hgb level improvements. 

Of the 24 participants, 54% (13) met the primary endpoint of having ≥ 12 g/dL in hemoglobin or an increase of at least 2 g/dL, 71% (17) did not require transfusion after the 5th week, while 92% (22) did not need to undergo other CAD-related treatments. Common adverse reactions included viral infection, respiratory tract infection, dyspepsia, diarrhea, arthritis, cough, arthralgia, and peripheral edema. There were serious adverse reactions observed, but none led to the drug's discontinuation. 

CAD is a rare autoimmune hemolytic anemia caused by cold agglutinins binding to red blood cells, which then causes the immune system to mistakenly attack them and cause hemolysis. This chronic blood disorder affects around 5,000 people in the U.S. alone. 

"For people living with cold agglutinin disease, it is as if their body's immune system is waging a war on itself. The relentless destruction of healthy red blood cells is a daily, silent reality for people with CAD. For the first time, we have a treatment that targets complement-mediated hemolysis, which is the underlying cause of the red blood cell destruction in many CAD patients," said Catherine Broome, M.D., an associate professor of medicine at Georgetown University Lombardi Comprehensive Cancer Center and principal investor of the study, in a statement. 

Enjaymo is administered intravenously every week for the first two weeks and then every two weeks after that. It had already received FDA Orphan Drug and Breakthrough Therapy designations. 

The drug, which will be rolled out to the U.S. market in the following weeks, has an estimated cost of $1,800 per vial. Actual costs to patients are expected to be lower, with co-pay support, insurance coverage and financial help from patient programs. Sanofi also established the Enjaymo Patient Solutions program, which provides co-pay assistance and disease education, plus other services, to eligible patients. 

Sanofi has already submitted to regulatory authorities in Japan and Europe.