Antineoplastic/Immunologic (Anti-CD20—Monoclonal Antibody)
PREGNANCY RECOMMENDATION:Limited Human Data—Animal Data Suggest Potential Risk
BREASTFEEDING RECOMMENDATION:Probably Compatible
The use of rituximab in human pregnancy has been described in more than 200 cases. All of the live births were healthy, and none had structural anomalies that were thought to be related to the drug. Use during the second and third trimester may decrease B cell levels, resulting in immunosuppression. As an IgG antibody, it likely crosses the placenta, especially during the second half of gestation, so some fetal exposure will probably occur. However, this limited human pregnancy experience prevents a complete assessment of the embryofetal risk. Animal data did not show any embryofetal toxicity or teratogenicity in one species at doses less than the RHD, but did decrease B cell levels for the first 6 months of life. Using this drug during pregnancy should be based on the pros and cons of the mother’s clinical need for treatment versus any potential fetal risk that might occur from exposure. There is a registry for women who are pregnant and have cancer. For more information, women and health care providers are encouraged to contact the Cancer and Pregnancy Registry at 1-877-635-4499. Hypertension was reported in up to 12% of patients in the clinical trials.
Two reports describing 10 women using rituximab during human lactation were located. Despite the high MW, rituximab was found to be excreted into human breast milk, similar to other IgG antibodies. However, even if it is excreted into breast milk, it will probably be digested in the infant's gastrointestinal tract and not be absorbed. In all cases, milk levels were low at less than 1% maternal levels. Using the maximum milk concentrations, the calculated RIDs were well below 1%. A few minor infant infections were observed, but no other adverse infant effects were noted. Regardless, due to a concern for potential serious adverse effects that might be seen in a breastfed infant, the manufacturer recommends that women not breastfeed while being treated with this drug and for at least 6 months after the last dose. Nevertheless, breastfeeding while using this drug should be based on the mother’s clinical need for treatment versus any potential infant risks that might occur. If used, the infant should be monitored for the most common reported adult side effects of nausea and headache (both leading to irritability), fever, diarrhea, lymphopenia, anemia, and various infections.