Sutimlimab Has Potential to Treat Warm Autoimmune Hemolytic Anemia

A newly published case report suggests sutimlimab (Enjaymo) may be an effective treatment for some patients with warm autoimmune hemolytic anemia (wAIHA).

Sutimlimab-jome was approved by the FDA in February to treat cold agglutinin disease (CAD), which along with wAIHA are the 2 major forms of autoimmune hemolytic anemia. The new report, published in Cureus, suggests the therapy might also work for some patients with wAIHA. The authors said the key difference between CAD and wAIHA is that CAD is completely mediated by the complement system, while wAIHA is only partially complement mediated.

Sutimlimab is a humanized monoclonal antibody targeting the complement-specific serine protease C1s, which activates the classical component pathway. The authors said there are no therapies approved specifically to treat wAIHA but that novel therapies are under investigation that could someday change the treatment landscape for these patients. Steroids, immunosuppressants, and splenectomy have historically been the standard treatments.

In their case report, the study investigators describe a 30-year-old Hispanic female who appeared in the emergency department with symptoms that included fatigue, dyspnea, dizziness on exertion, headache, vomiting, diarrhea hematuria, and sinus tachycardia. The patient had a history of hypothyroidism and received a wAIHA diagnosis 3 years earlier. Blood tests revealed hemoglobin of 5.1 g/dL and elevated total bilirubin of 2.5 mg/dL.

A direct antiglobulin test confirmed autoimmune hemolysis and the patient was started on rituximab (Rituxan) and steroids. She later received a diagnosis of systemic lupus erythematosus (SLE). At first, the patient was receiving transfusions every 48 to 72 hours, the authors said, but despite treatment with steroids and rituximab, she soon needed daily transfusions and then multiple transfusions per day. Meanwhile, the patient’s bilirubin levels were also rising, peaking at 65.3 mg/dL. The patient was eventually transferred to the intensive care unit.

By that point, she had not responded despite therapy with rituximab plus steroids and intravenous immunoglobulin. The patient’s hemodynamics contraindicated plasmapheresis, and she was put on cyclophosphamide due to her SLE flare.

“Unfortunately, her symptoms and labs did not show significant improvement after cyclophosphamide administration,” the authors said.

After consulting with hematologists, the investigators turned to sutimlimab, hoping it would control hemolysis and delay the need for red blood cell (RBC) transfusions. The patient was started on 6500 mg of sutimlimab administered intravenously once weekly for 2 weeks. The first and second doses were administered on days 28 and 35. Improvement came quickly.

Prior to the first dose of sutimlimab, the patient’s RBC count was 1320/dL, with a hemoglobin of 3.2 g/dL and a hematocrit value of 8.5 g/dL. The patient was given 2 units of packed RBCs (PRBC) following sutimlimab. Soon, the patient’s RBC count jumped to 1890/dL, with hemoglobin of 6 g/dL and hematocrit at 16.9 g/dL. Meanwhile, total bilirubin soon fell to 7.7 mg/dL after the first transfusion.

“This is the first time during the patient’s hospitalization that she had a response of more than 1 g/dL increase in hemoglobin with only 2 units of PRBC transfusion,” the authors said. “The patient reported global improvement in symptoms during morning rounds.”

The patient’s need for transfusions decreased within the first week, and following the second dose, her bilirubin level fell to 4.4 mg/dL.

The investigators said this is believed to be the first case report of a patient with wAIHA being treated with sutimlimab since the drug’s approval for CAD. They said their experience suggests certain patients with wAIHA could benefit from the drug.

“It is postulated that our patient had [the] complement-mediated subtype of wAIHA, and activation of the classical complement pathway and its eventual inhibition at the level of C1s by sutimlimab-jome were responsible for this patient’s positive clinical response,” they wrote.

Additional study is warranted to see whether and when sutimlimab should be used for patients with wAIHA, they concluded.

Reference

Tahhan F, Huynh B, Xu P. Novel monoclonal antibody therapy in a patient with treatment-refractory warm autoimmune hemolytic anemia. Cureus. Published online June 17, 2022. doi:10.7759/cureus.26051