Soliris Treatment for aHUS May Not Increase Risk for Miscarriages, Small Study Suggests

Treatment with Soliris (eculizumab) in pregnant women with atypical hemolytic uremic syndrome (aHUS) may not increase the risk of miscarriage, according to the analysis of a small group of patients enrolled in the Global aHUS Registry.

Marie Scully, MD, of University College London, presented the results of the analysis at the 2019 Congress of the International Society on Thrombosis and Haemostasis, held recently in Melbourne, Australia. The presentation was titled “Pregnancy outcomes in patients with atypical haemolytic uraemic syndrome.”

aHUS is characterized by the progressive destruction of red blood cells, resulting in blockages in small blood vessels — called thrombotic microangiopathy — that result in organ injury. However, how the disease affects pregnancy is poorly known.

“Pregnancy outcomes in [this patient population] are not well reported,” Scully said in a press release.

The researchers aimed to highlight the impact of aHUS and one of its main approved therapies, Soliris (eculizumab), in pregnancy outcomes. To do so, they analyzed data from pregnant women diagnosed with aHUS enrolled in the Global aHUS Registry database (NCT01522183). That worldwide retrospective-prospective registry assesses the natural history of aHUS, and the post-approval (post-marketing) long-term safety and efficacy of Soliris.

Soliris, an engineered monoclonal antibody developed and marketed by Alexion, works by specifically targeting a component, called protein C5, of the complement system — a part of the immune system chronically and uncontrollably activated in aHUS patients.

The team analyzed 34 pregnancies — 24 pregnancies among women who received treatment with Soliris, and 10 who did not have the medication. Among the women given Solaris, 17 received the therapy according to the prescription doses.

The proportion of live births was 58% in women treated with Soliris and 80% in those without the treatment. The number of elective terminations were 33% in Soliris-treated women and 10% in those untreated.

Relapse of aHUS occurred in three patients, one treated with Soliris and two who were not.

Five women, all of them treated with Soliris, received dialysis during pregnancy, including one patient who had an aHUS relapse.

In all the patients analyzed, there were no cases of babies with malformations or anomalies within three months of birth.

Genetic analyses revealed that mutations in complement genes were higher among women treated with Soliris (63%) compared with those who did not receive the therapy (33%).

Overall, the “real world data from the Global aHUS Registry showed no increase in poor outcomes in pregnant patients exposed to eculizumab with the proportion of miscarriages consistent with the general population (up to 20% of pregnancies),” the researchers said.

They noted, however, that the analysis may be limited by the low number of pregnancies analyzed. Further evaluation of this aHUS subpopulation is ongoing, the researchers said.

The investigators disclosed a working link with Alexion, the manufacturers of eculizumab.