Is Rituximab safe while breastfeeding?

Effects on the breastfed infant

A woman received rituximab 375 mg/square meter once weekly for 4 weeks beginning at week 30 of gestation. Her infant was born at 40 weeks of gestation and was exclusively breastfed with no major health issues. At 4 months of age, the infant's B-cell population and immunoglobulin levels did not appear to be affected.[ 11 ] A woman received an IV infusion of 1000 mg of rituximab at about 3 months postpartum. Her infant who was fully breastfed had no serious infections during the lactation period and developed normally during a 1.5 year follow-up period.[ 2 ] A retrospective cohort study from the German Multiple Sclerosis and Pregnancy Registry database identified 5 mothers who received rituximab during breastfeeding. Three mothers receive one dose of rituximab while nursing, one received 500 mg and two received 1000 mg. The infants breastfed for 1.6, 1.8 and 0.3 months, respectively. Infant blood counts were normal at 1 to 1.5 months after the mothers doses. A blood count was not performed in the third infant. One infant developed omphalitis, but all had normal development. The fourth woman received rituximab 250 mg on day 55 postpartum and ocrelizumab 300 mg on day 333 postpartum. She breastfed for 22.9 months after the rituximab dose. Her infant had normal blood counts at 45 and 213 days after the rituximab dose, but had conjunctivitis and otitis media during this time.[ 12 ] A woman was diagnosed with B-cell lymphoma at 27 weeks of pregnancy. Labor was induced at 34 4/7 weeks and treatment was begun with a standard regimen of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone in unspecified doses on a 21-day cycle, starting on day 2 postpartum. She pumped and discarded her milk and fed her infant donor milk for the first 10 days of each cycle and then breastfed her infant for the remaining 10 days before the next treatment cycle. The 10-day period of breastfeeding abstinence was determined by using about 3 half-lives of vincristine. After complet

Effects on milk supply

Relevant published information was not found as of the revision date.

Levels in milk

Maternal Levels. A patient who had granulomatosis with polyangiitis received rituximab 1000 mg intravenously while exclusively breastfeeding her infant. Milk samples were collected daily for 4 days starting 7 days after the infusion. Milk rituximab concentrations averaged 0.5 mcg/L (range 0.4 to 0.6 mcg/L).[ 2 ] A woman with ANCA-associated vasculitis was treated with rituximab 500 mg intravenously at week 19 postpartum. The median concentration of rituximab in milk samples collected on 4 consecutive days was 3 mcg/L (range 0 to 4 mcg/L). The relative infant dose to the infant was estimated to be 0.007%.[ 8 ] An international, multicenter study of patients with multiple sclerosis or neuromyelitis optica spectrum disorder collected breastmilk samples from 26 women who were receiving rituximab. Milk samples were collected at a mean of 2.6 months (range 0.1 36.0) postpartum. The women received 500 mg once (n = 2) or twice (n = 9) or 1000 mg once (n = 11) or twice (n = 4) and milk samples were collected before and up to 90 days after the dose. Where measurable, the peak concentration in milk usually occurred between 1 and 7 days after the dose. Milk concentrations were virtually undetectable at 90 days after a dose. For women who received a single 500 mg dose, the average milk concentration was 0.03 mg/L, and the peak was 0.04 mg/L. For 10 women who receive a single 1000 mg dose, the average milk concentration was 0.04 mg/L, and the peak was 0.07 mg/L. For women who received two 500 mg doses, the average milk concentration was 0.02 mg/L, and the peak was 0.1 mg/L. For women who received two 1000 mg doses, the average milk concentration was 0.2 mg/L and the peak was 0.6 mg/L. Based on the average milk levels, infants would receive a dose between 0.003 and 0.03 mg/kg daily.[ 9 ] Six mothers with relapsing-remitting multiple sclerosis received 500 or 1,000 mg of rituximab postpartum. Breastmilk was collected at six time points: pre infusion, two days after infusion, after

Alternatives LactMed lists

• Immune Globulin
• Certolizumab Pegol
• Etanercept
• Infliximab
• Tocilizumab