How Does Cladribine Exposure Affect Pregnancy Outcomes in Women With MS?

Women with multiple sclerosis (MS) who became pregnant after cladribine exposure, in general, had excellent disease control during pregnancy and early postpartum and delivered healthy newborns, according to study results presented at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2023, held in San Diego, California, from February 23 to 25.

To date, published data about pregnancy outcomes following cladribine treatment for MS are scarce.

Researchers from St Josef Hospital in Germany sourced data for the study from the German Multiple Sclerosis and Pregnancy Registry (DMSKW). Women (N=55) who became pregnant after receiving cladribine treatment were contacted by telephone during which they responded to a standard questionnaire about disease course and pregnancy outcomes. Patient responses were confirmed with the treating neurologists, gynecologists, and/or pediatricians.

The women were exposed to cladribine after their last menstrual period (n=3), during the 6 months prior to their last menstrual period (n=18), and prior to 6 months before their last menstrual period (n=34). The women who were exposed longer than 6 months before their last menstrual period were considered to have no pregnancy exposure to cladribine.

As of the analysis of these data, 31 healthy babies were born, and 3 spontaneous abortions and 1 socially motivated elective abortion had occurred. There were also 2 reported cases of congenital malformations, 1 of which was a major atrial septum defect and the other was a minor hemangioma. A total of 19 normal pregnancies were ongoing. One patient was lost to follow-up.

Most women reported a stable disease course during pregnancy. Among those who completed their pregnancy (n=35), 1 reported a relapse event during pregnancy and among those with 30 or more days of postpartum (n=30), 1 reported a postpartum relapse.

The major limitation of this study was the small sample size.

These data indicated that pregnancy after cladribine treatment for MS was associated with generally healthy newborns and that few women experienced a disease relapse during pregnancy or the initial postpartum period.

The researchers concluded, “It is important to counsel women to avoid pregnancies within 6 months after the last intake of CLAD [cladribine] and to use effective contraception.”