A Los Angeles-led pilot trial suggests a dialysis-style blood filter might give some of the region’s highest-risk pregnancies a little more breathing room. In a small international study of 16 women with very preterm preeclampsia, researchers used a device to strip a specific placental protein from the blood and saw pregnancies continue a median of about 10 days after admission. The work is still early, but investigators say going after sFlt-1, the protein in question, could eventually reshape how clinicians handle severe early preeclampsia.
What the trial did and found
The team ran a single-arm, open-label pilot trial, splitting participants into a phase A dose-finding group of 7 women and a phase B multiple-dose group of 9. The treatment used extracorporeal apheresis to selectively remove circulating sFlt-1.
In phase B, each apheresis session cut sFlt-1 levels by about 16.7% and lowered mean arterial pressure. Drops in sFlt-1 tracked with blood-pressure improvements, with a Spearman correlation of 0.63, and pregnancies in treated patients continued a median of 10 days from admission. Reported side effects were generally mild, including transient hypocalcemia, minor puncture-site bleeding, and a single episode of false labor.
The authors stressed that this was an early signal-finding study and called for controlled trials to confirm safety and benefit, according to Nature Medicine.
How the filter works and local reaction
Investigators engineered a high-affinity immune protein that latches onto sFlt-1 and built it into an adsorber column used during extracorporeal apheresis. Maternal blood is circulated through the column, where sFlt-1 is captured, then the blood is returned to the patient without stripping out essential components, according to a Cedars-Sinai news release.
The hospital reports that the 16 women who received the treatment experienced blood-pressure improvements and normal fetal growth while on therapy. Co-corresponding author Ananth Karumanchi said the team “found a way to potentially buy that time safely,” framing the approach as a possible bridge to a safer delivery window.
For families living through severe preeclampsia, even a few days can feel massive. A mother who has faced the condition told SFGATE that a brief delay can be decisive for a baby’s brain and lung development.
Why it matters
Preeclampsia and related hypertensive disorders remain a major global threat. Reviews estimate they account for roughly 70,000 to 76,000 maternal deaths and about 500,000 infant deaths worldwide each year.
Because the only definitive cure for severe preeclampsia is delivering the baby, often before the fetus is fully ready, any approach that safely postpones birth by even days could reduce neonatal complications and deaths, as described in a recent review on ScienceDirect.
Next steps and cautions
Both the study authors and outside experts caution that the findings are preliminary and that larger, randomized trials modeled on regulatory standards will be needed before this apheresis strategy can move anywhere near routine care. As SFGATE reported, study leaders say a formal treatment-versus-no-treatment trial is the logical next step.
The Cedars-Sinai release notes that the project received support from Miltenyi Biomedicine and Aggamin Pharmaceuticals and lists several authors’ competing interests, highlighting the need for independent replication and long-term safety data.
For Los Angeles clinicians and expectant families, the pilot results are a cautiously hopeful signal, not a green light. Whether this blood filter stays an experimental lifeline or eventually becomes standard care will depend on larger controlled trials and years of follow up for both mothers and their children.
