FDA Approves Interchangeable Biosimilar to Soliris

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Bkemv (eculizumab-aeeb) is the first interchangeable biosimilar to Soliris (eculizumab) to treat paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome.

FDA announced on May 28, 2024 that it has approved Bkemv (eculizumab-aeeb) as the first interchangeable biosimilar to Soliris (eculizumab) for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis and atypical hemolytic uremic syndrome (aHUS) to inhibit complement-mediated thrombotic microangiopathy.

PNH and aHUS involve the breakdown of red blood cells. PNH causes anemia, thrombosis, pancytopenia, and dark urine. Anemia is also found in aHUS as well as thrombocytopenia and kidney failure.PNH and aHUS are considered rare diseases. A rare disease, according to FDA (1), impacts fewer than 200,000 people in the United States.

Bkemv, a monoclonal antibody, binds to the complement C5 protein, inhibiting activation of the complement system (a part of the human immune system). The breakdown of red blood cells in the bloodstream is prevented by the binding in PNH and aHUS patients. Bkemv, which is the 53rd FDA-approved biosimilar in the US, is only available through a restricted program—Bkemv Risk Evaluation and Mitigation Strategy.

Labeling for Bkemv includes a Boxed Warning that it increases the risk of serious and life-threatening meningococcal infections caused by Neisseria meningitidis. Therefore, FDA states that patients should complete meningococcal vaccination before starting Bkemv or Soliris. Patients should also be monitored for symptoms of meningococcal infections (1).


“As an interchangeable biosimilar, Bkemv is highly similar with no clinically meaningful differences to Soliris. Bkemv has the same safety warnings and is expected to have the same adverse reactions as Soliris,” FDA stated in the press release. “The most frequently reported adverse reactions in the PNH randomized trial for Soliris (≥10% overall and greater than placebo) are headache, nasopharyngitis (common cold), back pain and nausea. The most frequently reported adverse reactions in aHUS single arm prospective trials for Soliris (≥20%) are headache, diarrhea, hypertension, upper respiratory infection, abdominal pain, vomiting, nasopharyngitis, anemia, cough, swelling of lower legs or hands, nausea, urinary tract infections, and fever.”

“Many rare conditions are life-threatening, and many do not have treatments,” said Sarah Yim, director of the Office of Therapeutic Biologics and Biosimilars in FDA’s Center for Drug Evaluation and Research, in a press release (1). “The FDA is committed to help facilitate the development of safe and effective interchangeable biosimilar treatments that can expand access for individuals with rare diseases whose current treatment options are limited.”

In April 2024, FDA approved another biosimilar, Henlius’ HERCESSI (HLX002; trastuzumab-strf), for adjuvant treatment of HER2-overexpressing breast cancer, HER2-overexpressing metastatic breast cancer, and HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma.

“Our patient-centered approach has led us to unwaveringly explore high-quality, effective, affordable, and accessible treatment options, and our determination to promote HLX02 in more than 40 markets around the world is Henlius' response to patients' concerns,” said Jason Zhu, executive director, chief executive officer and chief financial officer of Henlius, in a press release (2). “We look forward to reaching more patients in North America and providing them with more cost-effective access to high-quality biologics.”


  1. FDA. FDA Approves First Interchangeable Biosimilar for Two Rare Diseases. Press Release. FDA.gov. May 28, 2024.
  2. Henlius. Henlius Trastuzumab Receives FDA Approval in the United States. Press Release. April 26, 2024.