Successful Pregnancies During Ongoing Eculizumab Therapy in Two Patients With Complement-Mediated Thrombotic Microangiopathy

In patients with pregnancy-associated complement gene variant–mediated thrombotic microangiopathy (cTMA), terminal complement blockade is used for treatment of cTMA flares during pregnancy or following delivery. We report pregnancy and delivery outcomes of 2 genetically high-risk patients with cTMA, including 1 kidney transplant recipient, during ongoing eculizumab therapy. In both patients, the first manifestation of cTMA occurred independent from pregnancy. One patient has a history of 2 uneventful pregnancies with prophylactic plasma infusions, and the other has a history of early abortion during long-term eculizumab therapy following kidney transplantation. Overall, pregnancy and delivery outcomes under ongoing eculizumab therapy in our 2 patients with preserved kidney function were excellent as compared with other patients reported in the literature. Eculizumab plasma concentrations were maintained in the therapeutic range during pregnancy and were also detectable in cord blood. Results of cord blood analysis showed deficient complement activity, with low factor and regulator levels, most likely reflecting the age of the neonates and presence of eculizumab in cord blood. In conclusion, pregnancy during ongoing eculizumab treatment appeared to be safe in 2 women with a history of high-risk genetic cTMA and excellent kidney function, even following kidney transplantation.