Cimzia in New Moms Found Safe for Nursing Babies

LAS VEGAS -- New mothers taking certolizumab pegol (Cimzia) for inflammatory arthritic disorders or Crohn's disease may safely breastfeed their infants without worry about exposing them to significant amounts of the drug, a researcher reported here.

Analysis of breast milk taken from 17 nursing mothers receiving the tumor necrosis factor inhibitor showed levels far below those that would raise concern, said Caroline Hwang, MD, of the University of Southern California in Los Angeles.

During a platform session at the American College of Gastroenterology annual meeting, Hwang reported that the mean "relative infant dose" -- the ratio of estimated infant exposure to the mother's drug dose -- was 0.125%. She said that, in general, relative infant doses below 10% are "considered unlikely to be of concern to infant well-being."

Certolizumab pegol could not be detected in about half of the 137 breast milk samples taken during the study with the highly sensitive ELISA assay used, which had a lower limit of 0.032 mcg/mL for quantitation.

The highest level in any sample was 0.076 mcg/mL, which, if that had been the average across all samples, would still have led to a relative infant dose of less than 1%.

Confirming the apparent safety of maternal certolizumab pegol for infants, adverse effects reported for infants in the study were essentially those "that could be anticipated in an untreated population of a similar age," Hwang said. Most infant events were upper respiratory infections. One baby developed a Candida infection that had also infected the mother.

Called CRADLE, this was a post-marketing study sponsored by UCB Pharma, the drug's manufacturer. Hwang said it was the first analysis to look specifically at the drug's penetration into breast milk. The drug's current label states that safety for breastfed infants is unknown.

However, said Hwang, the researchers expected that infant exposure would be "minimal."

CRADLE recruited 18 women using certolizumab pegol for its approved indications (inflammatory arthritis or Crohn's disease) who were on maintenance dosing -- i.e., having had at least three doses since starting or restarting therapy. One participant was determined to be a "screening failure" and her breast milk was not analyzed, but she and her infant were still included in the adverse event analysis.

Estimates of infant exposure were based on an assumed breast milk consumption of 150 mL/day, which Hwang said is an accepted average for fully breastfed 2-month-old babies. Breast milk samples were taken every other day over a 2-week period, beginning immediately before a scheduled drug dose. In the case of one participant who was on a 4-week dosing schedule, an additional breast milk sample was taken immediately prior to her next dose. Adverse event data were collected for 5 weeks after the final breast milk sample.

Maximal drug concentrations in breast milk were seen about a week after the mothers received their drug injection.

Safety data reported for the "screening failure" participant whose breast milk was not analyzed indicated that the mother had a herpes zoster infection and galactostatis; data on her infant were not available. Among the other 17 mother-infant pairs, seven of the mothers and nine of the infants had no adverse events recorded in the study.

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