To measure placental and breastmilk transfer of ocrelizumab (OCR) in women with MS and evaluate the impact on B-cell levels in infants potentially exposed during pregnancy (MINORE [NCT04998812]) or breastfeeding (SOPRANINO [NCT04998851]).
Traditional MS pregnancy and breastfeeding management prioritizes infant safety, with the mother at risk of increased disease activity upon disease-modifying therapy discontinuation; however, prospective data to establish safety for mother and baby are lacking.
In MINORE, 35 pregnant women with MS whose last OCR infusion occurred ≤6 months prior to the last menstrual period/during the first trimester were enrolled. Primary endpoint was the proportion of infants with B-cell levels below the lower limit of normal (LLN) at W6 of life. In SOPRANINO, 13 breastfeeding women receiving OCR and their infants were enrolled (W2–24 at infusion). Co-primary endpoints: proportion of infants with B-cell levels <LLN 30 days post-infusion and OCR average daily infant dose (ADID) over 60 days post-infusion. Key secondary endpoints: concentration of OCR in the infant’s umbilical cord blood serum, W6 (MINORE) and 30 days post-infusion (SOPRANINO).
MINORE: OCR was undetectable in most infants, both at birth in the umbilical cord blood (33/35, 94.3%) and at W6 in the serum (32/33, 97.0%); where detectable, OCR levels were close to the limit of quantification and below therapeutic levels. SOPRANINO: OCR levels in breastmilk were negligible (mean ADID: 64.5 µg) and undetectable in infant serum at 30 days post-infusion (9/9, 100%). All infant B-cell levels were above the age-specific LLN in MINORE (W6: 34/34, 100%) and SOPRANINO (30 days post-infusion: 10/10, 100%). Adverse events were typical for delivery, postpartum and infancy and in line with the established OCR safety profile.
The results indicate that breastfeeding and pregnancy planning are compatible with ocrelizumab treatment and can support clinicians caring for women with MS in making evidence-based treatment decisions.