LAS VEGAS -- Use of recombinant antithrombin in pregnant women with preeclampsia failed to increase gestational age at delivery, a late-breaking clinical trial presented here found.
Patients randomized to receive recombinant antithrombin delivered a median of 5 days after beginning treatment, compared to 6 days with placebo. The intervention group had a mean gestational age of 28.8 weeks at delivery compared to a mean 29.6 weeks for the placebo group, reported Baha Sibai, MD, of McGovern Medical School at UTHealth.
At a presentation at the Society for Maternal-Fetal Medicine annual meeting, Sibai cited a previous study showing that antithrombin could prolong gestational age, and another indicating that even one additional week of gestational age was associated with substantially less neonatal morbidity.
"Preeclampsia is such an important disease that causes so much neonatal and maternal morbidity, so to try something reasonable to decrease incidence of earlier delivery due to preeclampsia would be incredibly useful," commented Joanne Stone, MD, of Mount Sinai Hospital, who was not involved with the research.
The study, called PRESERVE-1, was conducted at 23 tertiary hospitals. Women were eligible to participate if they had a singleton pregnancy with either early onset preeclampsia or superimposed preeclampsia at 23 to 30 weeks gestation, and were stable enough for expectant management. Preeclampsia was defined by the ACOG Hypertension Task Force.
Overall, 62 patients were randomized to receive a loading dose of 250 mg recombinant antithrombin (ATryn) followed by a continuous infusion of 2,000 mg/24 hours, while 58 patients were randomized to receive an identical saline solution. They received these infusions until delivery or 34 weeks gestation, whichever came first.
Stone added that it was a really difficult trial to do, because of the patient population, but said that the study was "done really well, and the criteria for inclusion were excellent."
"It's a negative study, but this is an important trial in looking at a novel potential therapy that unfortunately didn't work," she commented.
Sibai also noted that the mean antithrombin activity at enrollment within the patient population was 94%, with only 13% having levels <80%.
There were no significant differences in the secondary outcome, which was a neonatal composite outcome score. There were no incidences of neonatal death or retinopathy of prematurity associated with either group. Moreover, there were no cases of maternal death, stroke, or myocardial infarction. There was also no difference in the Kaplan-Meier survival curve between groups.
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