Rhesus pregnancy: immunotherapy to protect the foetus

In rhesus pregnancy, antibodies from the pregnant mother can lead to anaemia for the foetus in the uterus. To treat anaemia, doctors today give blood transfusion to the foetus through the umbilical cord. This is a delicate procedure that requires quite some specialist experience. A new study show that the drug nipocalimab is a good alternative. The results of the phase 2 trial were recently published in the New England Journal of Medicine. 

UZ Leuven was one of the 20 hospitals that tested the new drug in pregnant mothers that had already suffered a problematic rhesus pregnancy before. In 7 of the 14 women that were monitored the baby did not life in the the previous pregnancies. After treatment with the drug nipocalimab 13 out of the 14 babies survived: a very good result, especially if you know that rhesus disease and the immunity problem usually get worse in ever pregnancy. 

Nipocalimab is a biochemical antibody that resembles human antibodies. It has the ability to readily bind to cells in the layers of the placenta, thus retaining the mother's antibodies and preventing them from entering the uterus. The results of the phase 2 study are encouraging for the phase 3 study that will now be started. In the new study, in which UZ Leuven is also participating, people with milder form of rhesus pregnancies will also receive the product and be compared with pregnant women who receive a placebo drug during a rhesus pregnancy. Any woman who already had a rhesus pregnancy in the past with at least one blood transfusion to the uterus is eligible to participate in the study. If the product can be approved after that phase 3 study, it could be the first non-surgical treatment for rhesus pregnancies.

Prof. Dr. Roland Devlieger

Image source: UZ Leuven

Prof. Dr. Roland Devlieger, gynaecologist at UZ Leuven, says: “It is the first time that we have found a drug that can prevent the mother's antibodies to transfer to the foetus. A rhesus pregnancy continues to be a dangerous disorder. In Belgium, we screen every pregnant woman for antibodies and and we can intervene in time to prevent severe anaemia and death of the baby. But in some countries, it remains an important health problem. What's more, a blood transfusion remains a delicate procedure that can only be performed in specialised hospitals with experienced doctors. The excellent results of immunotherapy with nipocalimab can therefore be a game changer for the follow-up of women with a rhesus pregnancy.” 

Also in other foetal diseases caused by the wrong combination of antibodies in the foetus and the mother, this kind of immunotherapy may be important, for example in incompatible maternal and foetal platelets or in congenital foetal heart disease. UZ Leuven will participate in follow-up studies for both rhesus pregnancies and incompatible platelets. 

Source: UZ Leuven

14.08.2024

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