medwireNews: Results from a small cohort study suggest that pregnant women who are treated with the tumor necrosis factor inhibitor certolizumab pegol have minimal risk for placental transfer of the drug to their babies during late pregnancy.
“Combined with the evidence currently available regarding pregnancy outcomes in women exposed to [certolizumab pegol] during the first trimester, which indicate no increased rate of major congenital malformations,” these findings “support the continuation of [certolizumab pegol] treatment throughout pregnancy when considered necessary to control disease activity,” say the researchers.
Xavier Mariette (Université Paris-Sud, France) and co-authors analyzed maternal, infant, and umbilical cord blood samples from 16 women treated with certolizumab pegol who received the last dose no more than 35 days prior to delivery. The majority (69%) of women were given the drug for rheumatoid arthritis, while the remainder had Crohn’s disease (19%), psoriatic arthritis (6%), or axial spondyloarthritis (6%).
At the time of delivery, mean maternal certolizumab pegol concentrations were “within the expected therapeutic range,” at a median of 24.4 μg/mL, confirming that all participants “were adequately exposed to [certolizumab pegol] at the time of delivery,” report Mariette and colleagues.
Four-fifths of the 15 available umbilical cord samples had no quantifiable levels (<0.032 µg/mL) of certolizumab pegol, while the remaining three samples had levels of 0.035 μg/mL, 0.040 μg/mL, and 0.048 μg/mL, giving a maximum cord:mother ratio of 0.0025.
Of the 14 babies with available data, 13 had no detectable certolizumab pegol at the time of birth, and one had a concentration of 0.042 µg/mL, giving an infant:mother ratio of 0.0009.
And none of the nine infants who were breastfed by mothers who continued to take certolizumab pegol had quantifiable levels of the drug at weeks 4 and 8 after birth.
At the safety follow-up analysis, approximately 5 weeks after the final blood sample was taken, 71.4% of mothers and 31.3% of infants had experienced treatment-emergent adverse events (TEAEs), the majority of which were mild or moderate in severity. A corresponding 14.3% and 6.3% experienced TEAEs considered to be drug related, while 33.3% and 12.5% had serious TEAEs. All serious adverse events were resolved among the infants, as were those in the mothers, with the exception of the delivery of a premature baby.
The researchers caution that the study was limited by collection of maternal blood samples only at the time of delivery, meaning that the pharmacokinetic profile of certolizumab pegol could not be fully characterized during pregnancy.
“It would be valuable to measure maternal [certolizumab pegol] concentrations earlier in pregnancy and to investigate the potential impact of the loading dose in women initiating [certolizumab pegol] treatment while pregnant,” they write in the Annals of the Rheumatic Diseases.
And the team concludes that “our data indicate no to minimal placental transfer of [certolizumab pegol] from mothers to infants, suggesting a lack of in utero foetal exposure during the third trimester.”
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