A recent correspondence (M Julsgaard et al.Gastroenterol 2018; 154: 752-65) shows that vedolizumab is detectable in varying concentrations in breastmilk.  The authors collected samples from 5 mothers who were receiving vedolizumab (VDZ) for inflammatory bowel disease.

Key findings:

• Peak VDZ concentration in breastmilk was 0.318 mcg/mL which was 1/179th of the corresponding concentration of the maternal serum levels.
• The authors calculated a maximum oral dose of 0.048 mg/kg/day for breastfed infants based on this peak level. “This minute quantity is furthermore anticipated to undergo proteolysis in the stomach” and be bound/excreted in GI tract.
• VDZ was detectable in all samples for 30 minutes prior to infusion (trough) through 14 days.

This study is in agreement with another study showing that levels in the breastmilk were minute (~1/100) of serum levels (A Lahat et al. J Crohns Colitis. 2018 Jan 5;12(1):120-123).

My take: These are low levels of VDZ –nevertheless further monitoring of infants to determine conclusively whether VDZ enterally causes any adverse effects is warranted.

Views from Mike O’Callahan -Pat Tillman Bridge