A novel therapy that reduces blood levels of a potentially toxic protein in women with preeclampsia, a dangerous complication of pregnancy, may someday address the therapeutic dilemma posed by the condition – balancing life-threatening risks to the mother with the dangers early delivery poses to a fetus. “Introducing new therapies in pregnancy is uncommon because of the need to avoid extra risks to both the mother and baby,” says Ravi Thadhani, MD, MPH, of the MGH Division of Nephrology, co-corresponding author of the report published online in the journal Circulation. “In this paper we suggest that a disease affecting thousands of women around the world may one day be managed by the therapy we developed.
The ultimate cause of preeclampsia remains a mystery, but substances released by the placenta into the bloodstream may be involved. The current study focused on a protein called Flt-1 that blocks a major vascular growth factor and is elevated in the bloodstream of women with very preterm (before 32 weeks of gestation) preeclampsia. Thadhani and his colleagues adapted the blood-filtering technology apheresis to develop a method of rapidly removing soluble Flt-1 from the bloodstream and collaborated with researchers at two German hospitals on a pilot clinical study.
After the team showed the technology could safely reduce elevated Flt-1 levels in patients, five women who had developed preeclampsia at stages of pregnancy when delivery would be risky for the babies, received multiple treatments. While a group of women receiving standard preeclampsia treatment required delivery an average of 3.6 days after hospital admission, the pregnancies of the five treated women were maintained for two to three weeks. Their babies still were born early but had no major complications. “An attractive feature of our approach is that it is based on removing something instead of on giving a drug, which means it can be carefully controlled and, if necessary, quickly turned off,” Thadhani says. “While this study is too small to allow us to say that our treatment was responsible for extending these patients’ pregnancies – that will require a larger, randomized clinical trial – this first step holds promise.”