Successful pregnancy and lactation outcome in a patient with Gaucher disease receiving enzyme replacement therapy, and the subsequent distribution and excretion of imiglucerase in human breast milk

Background: Enzyme replacement therapy (ERT) with imiglucerase is a well-established, effective treatment for Gaucher disease. However, there have been no published reports regarding the excretion of imiglucerase into human breast milk and its effects on the nursing infant.Objective: This letter reports on the successful pregnancy and lactation of a patient with Gaucher disease receiving treatment with imiglucerase, and the subsequent distribution and excretion of imiglucerase in human breast milk.Methods: A 39-year-old Japanese female (height, 164 cm; weight, 55 kg) with Gaucher disease had 2 successful pregnancies and continued ERT through both. The study was conducted 6 months after the first delivery. She was administered a 1-hour infusion of imiglucerase 60 U/kg that coincided with her regular every-2-week regimen. Serum and breast-milk samples were obtained before and up to 24 hours after administration. Breast-milk samples were also obtained from 10 nursing mothers with galactorrhea as controls.Results: The preinfusion level of breast-milk β-glucocerebrosidase was 0.008 nmol/h/mL. The peak of serum β-glucocerebrosidase activity (0.119 nmol/h/mL) was obtained at the end of the 1-hour infusion period. Slightly increased enzymatic activity (0.016 nmol/h/mL) was observed in the first breast milk sampled after imiglucerase infusion.Conclusions: We report a case of successful pregnancy and breastfeeding in a Japanese patient with Gaucher disease. A small amount of imiglucerase was found to be excreted into human breast milk, but only in the first milk produced after infusion.