The molecular properties of nipocalimab determine its ability to lower anti-platelet antibodies and prevent fetal and neonatal alloimmune thrombocytopenia (FNAIT) without compromising other immune functions, according to a recently published review in mAbs.
Nipocalimab is a neonatal Fc receptor (FcRn) blocker. FcRn is responsible for maintaining and recycling immunoglobulin G (IgG) and transporting it through the placenta. When nipocalimab binds to the receptor, it prevents it from performing its normal functions, which causes potentially harmful antibodies to be broken down and cleared from the bloodstream.
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Molecular analysis of the drug revealed that it has a molecular crystal structure that selectively binds to the IgG binding site of FcRn with higher affinity than human IgG. The binding of nipocalimab to FcRn is highly specific, which means that there is no danger of it binding to other similar structures and affecting immune functions.
For example, the human leukocyte antigen (HLA)-A2 protein, which performs vital immune system functions, has a very similar structure as FcRn. However, nipocalimab does not target it.
Furthermore, chemical tests showed that nipocalimab binds to FcRn optimally under physiological pH and temperature conditions.
“Nipocalimab selectively reduces circulating IgG levels without detectable effects on other adaptive and innate immune functions,” the authors wrote.
Nipocalimab in clinical trials
Several clinical studies have shown that Nipocalimab can effectively treat FNAIT and other diseases in which IgG plays a fundamental role, such as myasthenia gravis (MG), rheumatoid arthritis (RA), hemolytic disease of the fetus and newborn (HDFN), and Sjögren disease.
According to clinical trials, nipocalimab is well tolerated and does not cause any severe adverse effects. Furthermore, unlike other FcRn blockers, it does not alter albumin metabolism. Further, larger studies are currently underway to confirm its effectiveness and safety.
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