Sanofi Enjaymo gets USFDA okay for cold agglutinin disease

CAD, a rare autoimmune hemolytic anemia, is caused by antibodies called cold agglutinins binding to the surface of red blood cells, which starts a process that causes the body's immune system to mistakenly attack healthy red blood cells and cause their rupture (hemolysis). As red blood cells have the vital job of carrying oxygen throughout the body, patients with CAD may experience severe anemia, which can result in fatigue, weakness, shortness of breath, light-headedness, chest pain, irregular heartbeat, and other potential complications. CAD is a chronic and rare blood disorder that impacts the lives of an estimated 5,000 people in the U.S.

Enjaymo is a humanized monoclonal antibody that is designed to selectively target and inhibit C1s in the classical complement pathway, which is part of the innate immune system. By blocking C1s, Enjaymo inhibits the activation of the complement cascade in the immune system and inhibits C1-activated hemolysis in CAD to prevent the abnormal destruction of healthy red blood cells. Enjaymo does not inhibit the lectin and alternative pathways.

The approval of Enjaymo in the U.S. is based on positive results from the 26-week open label, single arm pivotal Phase 3 study in patients with CAD (n=24) who have a recent history of blood transfusion, also known as the CARDINAL study.

In the study, Enjaymo met its primary efficacy endpoint, which was a composite endpoint defined as the proportion of patients who achieved normalization of hemoglobin (Hgb) level ≥12 g/dL or demonstrated an increase from baseline in Hgb level ≥2 g/dL at the treatment assessment time point (mean value from weeks 23, 25, and 26) and no blood transfusion from weeks 5 through 26 or medications prohibited per the protocol from weeks 5 through 26. Secondary endpoints were also met, including improvements in hemoglobin and normalization of bilirubin.

• The majority of patients (54%; n=13) met the composite primary endpoint criteria with 63% (n=15) of patients achieving a hemoglobin ≥ 12 g/dL or an increase of at least 2 g/dL; 71% (n=17) of patients remaining transfusion-free after week five; and 92% (n=22) of patients did not use other CAD-related treatments.
• For the secondary measures on disease process, patients enrolled experienced a mean increase in hemoglobin level of 2.29 g/dL (SE: 0.308) at week 3 and 3.18 g/dL (SE: 0.476) at the 26-week treatment assessment timepoint from the mean baseline level of 8.6 g/dL. The mean reduction in bilirubin levels (n=14) was by -2.23 mg/dL (95% CI: -2.49 to -1.98) from a mean baseline level of 3.23 mg/dL (2.7-fold ULN).

Following the completion of the 26-week treatment period of CARDINAL (Part A), eligible patients continued to receive Enjaymo in an extension study.

The recommended dose of Enjaymo is based on body weight (6,500 mg for people 39-75 kg and 7,500 mg for people >75 kg). Enjaymo is administered intravenously weekly for the first two weeks with administration every two weeks thereafter.

Enjaymo is expected to be available in the U.S. in the coming weeks. The U.S. list price, or wholesale acquisition cost, of Enjaymo is $1,800 per vial. Actual costs to patients are generally anticipated to be lower as the list price does not reflect insurance coverage, co-pay support, or financial assistance from patient support programs. 

Enjaymo received FDA Breakthrough Therapy and Orphan Drug designation, and priority review, which is reserved for medicines that, if approved, would represent significant improvements in safety or efficacy in treating serious conditions. Outside of the U.S., sutimlimab has been submitted to regulatory authorities in Europe and Japan and reviews are ongoing.