FRANCE – The US FDA has approved Enjaymo (sutimlimab-jome) infusion to reduce the need for red blood cell transfusion due to hemolysis (red blood cell destruction) in adults with cold agglutinin disease (CAD).

Sutimlimab-jome, a humanized monoclonal antibody (mAB), is the first and only approved treatment for people with CAD. It works by preventing red blood cell destruction.

CAD is a rare autoimmune hemolytic anemia caused by antibodies called cold agglutinins binding to the surface of red blood cells, triggering a process in which the body’s immune system attacks healthy red blood cells, causing them to rupture (hemolysis).

This causes anemia as well as other circulatory symptoms such as discoloration or pain in the toes and fingers. Patients suffering from CAD frequently require red blood cell transfusions.

Sutimlimab-jome is a humanized monoclonal antibody that inhibits the C1 complex of the classical complement pathway, which causes hemolysis in CAD patients.

The FDA granted approval based on the findings of a study that included 24 adults with CAD who had received a blood transfusion within the previous 6 months.

Sutimlimab-jome was created with the goal of selectively targeting and inhibiting C1s in the classic complement pathway, which is part of the innate immune system.

The mAB inhibits the activation of the complement cascade in the immune system and C1-activated hemolysis in CAD by blocking C1s, preventing the abnormal destruction of healthy red blood cells. Sutimlimab-jome has no effect on the lectin or alternative pathways.

Enjaymo, developed by the French pharmaceutical company Sanofi, is the first and only approved treatment for people with cold agglutinin disease (CAD).

Sanofi acquired the drug rights as part of its US$11.6 billion acquisition of Bioverativ in 2018, but it has faced regulatory setbacks; the FDA issued a complete response letter to Sanofi in November 2020, citing deficiencies in a pre-inspection of a contract manufacturer’s plant.

Route of administration and cost

Enjaymo is administered intravenously, with weekly doses for the first two weeks, followed by biweekly doses. It costs US$1,800 per vial before payer discounts, and dosing is determined by body weight.

According to a company spokesman, the annual cost for a patient weighing between 39 kg (85 pounds) and 75 kg (165 pounds) would be US$280,000 once the treatment was established.

Enjaymo was successful in a second phase 3 study presented in June of last year. After five weeks, 16 of 22 CAD patients who received the drug improved their hemoglobin levels by 1.5 g/dL or more and were free of transfusions and other non-permitted therapies.

Hemoglobin improvements were statistically significant when compared to the placebo.

Enjaymo received FDA breakthrough therapy and orphan drug designations, as well as priority review, on its way to approval. It is also being considered for approval in Europe and Japan.

In other news, the Food and Drug Administration is restricting the use of two of the three monoclonal antibody treatments available in the United States because data shows they are ineffective against the omicron variant, according to the agency.

The two drugs, developed by Regeneron and Eli Lilly, were effective against non-omicron variants earlier in the pandemic.

However, data show that they are ineffective against omicron, which accounts for an estimated 99 percent of COVID-19 cases in the United States.

The drugs are bamlanivimab and etesevimab (given together) and REGEN-COV (casirivimab and imdevimab); the FDA has restricted their use to patients infected with a variant susceptible to these treatments.

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