Pregnancy Generally Safe for Women With aHUS, Study Suggests

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by Vanda Pinto PhD |

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If closely monitored, women with atypical hemolytic uremic syndrome (aHUS) can have successful and uncomplicated pregnancies, including those on dialysis or patients who had undergone a kidney transplant, according to a new study.

Additionally, researchers confirmed that patients can safely and effectively be treated with Soliris (eculizumab), an approved therapy for aHUS marketed by Alexion Pharmaceuticals, during pregnancy.

The study, “Pregnancy in Women with Atypical Hemolytic Uremic Syndrome,” was published in the journal Nephron.

aHUS is a rare condition characterized by the formation of blood clots in small blood vessels that can cause kidney damage. In some women, the disease can be triggered or aggravated by pregnancy. Patients with aHUS are known to have a higher risk of experiencing life-threatening complications during pregnancy and childbirth.

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Despite emerging data on maternal and fetal outcomes in women with aHUS, pregnancy outcomes are still not well-documented.

To address this, an international group of researchers analyzed data from women who became pregnant after receiving an aHUS diagnosis and who were part of the Global aHUS Registry (NCT01522183).

This registry has been collecting data since 2012 on patients with aHUS from all over the world, including those not receiving any treatment and those being treated with Soliris or Ultomiris (ravulizumab).

A total of 44 pregnancies in 41 patients were analyzed. Soliris had been used in 24 of these pregnancies, with most women (79.2%) receiving the medication’s standard dose (1,200 mg every two weeks). Three women required dialysis during pregnancy, and six had previously undergone a kidney transplant.

Many people with aHUS carry genetic mutations in genes involved in the regulation of the complement cascade — a part of the immune system that, when triggered, causes inflammation and blood clotting. Harmful mutations were identified in nearly 50% of the women, the most frequent being in genes encoding the complement factors CFH, CFB, and C3.

Excluding abortions, 85.3% of the pregnancies resulted in live births. Abortions occurred in 22.7% of the pregnancies and 9% of the pregnancies resulted in miscarriage. Fetal death was reported in one pregnancy.

Among the 23 pregnancies where women were not on dialysis or had previously received a kidney transplant, eight resulted in premature births. In half of these pregnancies, Soliris had been used. Nine newborns were born with low birth weight (less than 2.5 kg or 5.5 lbs). No fetal malformations or anomalies were documented.

“This real-world study suggests that pregnancy is possible in women with aHUS,” the researchers wrote. “Live birth proportions were high, albeit with high rates of premature birth, miscarriage proportions were low, and elective terminations observed were likely driven by perceived fear of potential complications.”

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“Our results also show that [Soliris] has a good safety profile and is effective during pregnancy, either as a prophylactic or curative treatment, even in dialyzed or transplanted patients,” they wrote.

The researchers noted that patients should still receive continuous observation at high-risk pregnancy clinics and that analysis of a larger group of patients would produce more robust data.

This study was funded by Alexion.