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Aims: Information on breastfeeding and safety of biologics in infants is lacking due to difficulties in case collection. We evaluated methods for determining the concentration of biologics in breast milk using a dry filter method that can simplify the collection, storage and transport of breast milk. Methods: To generate dried filter paper (DFP) samples, approximately 30 μL of breast milk was placed onto a Whatman 903 card and punched out. After extraction, the supernatant was measured using an enzyme‐linked immunosorbent assay. Three concentrations of each drug were prepared in liquid breast milk (LBM) and DFP samples to determine their stability up to 28 days after storage at 2–8°C or −20°C for LBM and 25 ± 5°C for DFP. LBM and DFP samples were also provided by nursing mothers using biologics during lactation, and drug concentrations in both samples were compared. The agreement between the two measurement methods was confirmed by Bland–Altman analysis. Results: Breast milk was provided by 12 mothers who used biologics (tocilizumab, abatacept, etanercept, golimumab, sarilumab and belimumab). The coefficients of variation for within‐run and between‐run precision for the six drugs were within 15% for both LBM and DFP, and accuracy was within 90%–110% of the quality controls. After 28 days, concentrations remained at more than 90%. The difference between the values obtained by each method was within the acceptable range of error (−12.1 to +16.6 ng/mL). Conclusions: A method for determining the concentration of biologics using DFP is expected to help improve pharmacotherapy for lactating women. [ABSTRACT FROM AUTHOR]

The demand for tocilizumab is increasing in women who wish to bear children and who have active rheumatoid arthritis. Described here is a woman with rheumatoid arthritis who discontinued her tocilizumab therapy at the end of the first trimester and resumed it after delivery and where tocilizumab levels in maternal serum, infant serum, and the breast milk were measured. Tocilizumab was not detected in maternal serum just before delivery, or in umbilical cord blood or infant serum after birth. Tocilizumab levels in colostrum after intravenous injection were 0.57% of those in serum. Tocilizumab treatment in the first trimester was not associated with a significant drug level in the fetus at delivery and no fetal complications were noted. [ABSTRACT FROM AUTHOR]

Aims: Tocilizumab (TCZ), a humanized anti‐interleukin‐6 receptor monoclonal antibody, is used to treat rheumatic diseases. There is limited information about the administration of TCZ during lactation. The dried spot method, a simple technique for processing biological samples which involves placement of a drop of specimen onto filter paper, has been used in clinical pharmacology to determine various drug concentrations. This study examined the feasibility of sample collection using the dried milk spot (DMS) method for obtaining data about the transfer of TCZ into breast milk. Methods: Concentrations of TCZ determined using DMSs prepared by patients were compared with those using liquid breast milk. Results: In an enzyme‐linked immunosorbent assay of TCZ in DMSs, the accuracy ranged from 93.0% to 113.8% and the precision ranged from 0.3% to 8.4%. All concentrations of TCZ were within 15% of the reference value when analyzed on separate days. TCZ in DMSs at room temperature, 4°C, and −20°C were stable for 28 days. Extracted TCZ concentrations from patient‐prepared DMSs were strongly correlated with those of liquid samples (r = 0.996). In a pharmacokinetic study, the median (range) maximum and minimum concentrations were 113 ng/mL (68‐205) and 8.5 ng/mL (4.8‐13.4), respectively. The milk‐to‐serum ratio at the trough TCZ concentration of 3 lactating mothers were 0.0015, 0.00082 and 0.0014. Conclusions: The DMS method for measuring TCZ transfer into breast milk may be reliable and feasible, and should contribute to evaluating the safety of breast‐fed infants whose mothers receive TCZ during lactation. [ABSTRACT FROM AUTHOR]

The article discusses a study that measured abatacept concentrations in the breast milk of a 41-year-old nursing mother with rheumatoid arthritis and examined the safety of her breastfed infant. Highlights include the approval of the study by the ethics committee of the National Center for Child Health and Development, her treatment with tocilizumab and certolizumab pegol before switching to abatacept treatment, and the infant Apgar scores at one and five minutes.

The article discusses research which investigated safety of tocilizumab use during pregnancy and lactation. Topics explored include the intravenous tocilizumab dosage administered to a pregnant woman with adult-onset Still's disease (AOSD), measurement of tocilizumab concentrations in maternal serum, cord blood, and breast milk, and the health condition of the infant following exposure to tocilizumab.