Concentration of Ofatumumab in the Breast Milk of Lactating Women With Relapsing Forms of Multiple Sclerosis

Inclusion Criteria: 1. Written informed consent must be obtained before any study assessment is performed. 2. Participant is female with a relapsing form of MS and at least 18 years of age at the time of providing consent. 3. Participant must be postpartum at the time of enrollment, plan to be exclusively breastfeeding and willing to provide breast milk samples. 4. Participant has delivered term infant (at least 37 weeks gestation). 5. Participant must plan to initiate or re-initiate or have initiated or re-initiated treatment with ofatumumab between 2 to 24 weeks postpartum. The decision to be treated with ofatumumab and to breastfeed is made in accordance with the treating physician and must be completely independent of the decision to participate in this study. Exclusion Criteria: 1. Use of any investigational drugs within 5 half-lives of enrollment, or within 30 days or until the expected pharmacodynamic effect has returned to baseline, whichever is longer. 2. Participant taking medications prohibited by the study protocol at screening. 3. Pregnant woman, confirmed by positive serum pregnancy test during screening. 4. Female of childbearing potential should use effective contraception as per local label. 5. Participant has history of chronic alcohol abuse or drug abuse…