To present real-world outcomes of pregnancies occurring during treatment with cladribine tablets.

During clinical trials, only few (16) cladribine exposed pregnancies occurred, with 3 healthy newborns so far. Most women decided to terminate their pregnancy (n=10). Due to its potential genotoxic potential, therapy with cladribine is contraindicated during pregnancy and women are advised not to become pregnant 6 months after the last dose. After the approval of cladribine few additional pregnancies occurred.

The aim of this abstract is to provide an update on outcome of pregnancies in patients exposed to cladribine tablets in real world setting in order to allow the best possible counselling to therapists and patients.

Pregnancies less than 6 month after the last cladribine cycle documented in the Merck Serono Safety Database and in the German Multiple Sclerosis and Pregnancy Registry (DMSKW) are presented. Information on pregnancy outcomes and disease course was collected with a standardized questionnaire in regular telephone interviews during pregnancy and postpartum from women registered in the DMSKW.

10 pregnancies in women with MS occurred less than 6 months after the last cladribine cycle (7 Merck PV database/3DMSKW). Two further pregnancies were fathered by male MS patients. So far, 2 healthy babies, 1 spontaneous abortion and 3 elective abortions were reported. 4 pregnancy outcomes are unknown and 2 pregnancies are ongoing (>20 gestational week and normal ultrasound up to now). Updated information will be presented at the time of the meeting. None of the pregnancies was terminated due to congenital abnormalities.

Our data add useful information on very few pregnancies with healthy newborns shortly after Cladribine exposure. Our study is limited by the very small sample size. It is important to counsel women and men to avoid pregnancies within 6 months after the last intake of oral cladribine and to use effective contraception.