Background/Purpose: Certolizumab pegol (CTZ) is a TNFα inhibitor indicated for the treatment of women affected by rheumatoid arthritis (RA) throughout the whole pregnancy. Some concern, regarding a possible immunosuppression of the newborns, still exists. We aimed to assess the immune response and the presence of infective adverse events among the long-term followed-up offspring of RA mothers, treated by CTZ during pregnancy.

Methods: In a 4-years observational gap, we prospectively enrolled 12 newborns born to RA women, that signed an informed consent about children recruitment. The outcomes were a 24-months follow-up of the offspring health status, including infections, and, in case of routine/emergency lab test, assessment of the vaccine response according to the administered ones: esavalent diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b and Hepatitis B virus combined vaccine (DTaP-IPV/Hib/HBV). Immune response was assessed by the following: anti-PRP antibodies (Abs) to Hib, diphtheria antitoxin and polio virus Abs, by neutralisation assays. Tetanus, pertussis and Anti-HBs Abs by ELISA (Thermo Fisher Scientific, Cleveland, OH, USA). The serology response was compared to the general population byKruskall-Wallis and reverse regression curves statistical analyses (SAS V.6.12, Chiltern International Limited, Berkshire, UK). The immunogenicity cutoffs were set according to literature references.

Results:

Among the 12 children constituting the study population, 2 had to be investigated for suspected infections and one for an episode of foreign body ingestion. According to the protocol, a blood sample taken from the planned lab tests, was sent for the assessment. Hib: the proportion of observed infants with an anti-PRP level >0.15 mg/ml was 93.2% (95% CI 86.6 to 96.7) compared with 100% (95% CI 96.4 to 100) to the reference population. The difference was 6.8% (90% CI 2.8 to 12.1). Regarding diphtheria-tetanus, pertussis, polio and HBV, the protective responses (respectively: >0.01 IU/ml, >0.01 IU/ml, >1:8 and ≥10 mIU/mL) were 99% in the study population. As the upper bound of the 90% CI was >10%, this difference confirms the non-inferiority of immune response for these children.

Conclusion: Our data are limited, since an ethical issue rises from proposing a series of blood drawns to pediatric population. Regarding the reasons of consultations, to notice that none of them suffered from serious infections requiring hospitalization or parenteral antibiotic administration. The vaccine schedule was reported as well tolerated. Their immune response, finally, was shown to be adequate and superposable to the healthy population, including the administration of an alive vaccine (polio). These results further confirm the long-term overall safety of CTZ administration during pregnancy of RA patients, regarding both the mothers and their offspring.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/adequate-vaccine-response-according-to-the-italian-schedule-among-the-offspring-of-women-affected-by-rheumatoid-arthritis-and-treated-throughout-pregnancy-by-certolizumab-pegol-case-series/