Patterns of Disease Modifying Therapy Utilization in Women with Multiple Sclerosis Before, During, and After Pregnancy
Anna Shah1, Riley Bove2, Angela Applebee3, Katrina Bawden4, Celeste Fine5, Robin Avila6, Nicholas Belviso6, Filipe Branco6, Kinyee Fong6, James Lewin6, Jieruo Liu6, Sarah England6, Megan Vignos6
1University of Colorado, Rocky Mountain MS Center, 2Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, 3St. Peter's Health Partners, 4Rocky Mountain MS Clinic, 5Gilbert Neurology, 6Biogen Inc.
Objective:
To evaluate disease-modifying therapy (DMT) utilization for the treatment of multiple sclerosis (MS) before, during and after pregnancy. 
Background:
Pregnancy is a common consideration for women with MS; MS onset is typically between the ages of 20-45 years, i.e., during the child-bearing years. Pregnancy and postpartum care are a significant factor influencing DMT selection for many patients with MS. To date, few DMTs are considered safe to continue during pregnancy and real-world treatment patterns before, during and after pregnancy remain uncharacterized. 
Design/Methods:
In this retrospective, observational study, the US MarketScan Commercial and Medicaid claims database was assessed for female patients aged 18-55 years, with an MS diagnosis and ≥1 delivery-related inpatient or outpatient claims from 01January2016─30April2021. 
Results:

A cohort of 944 patients was identified; 688 (73%) were commercially-insured and 256 (27%) received Medicaid. Prevalence of DMT use declined sharply during pregnancy, from 36.3% of patients in the 6 months prior to pregnancy (pre-pregnancy) to 17.9%, 5.3% and 5.8% in trimesters (T) 1, 2 and 3, respectively. Postpartum DMT utilization increased to 20.9% at 0–3 months and 24.4% at 4–6 months. Of all patients (n=944) in the pre-pregnancy period, the most frequently used DMTs were glatiramer acetate (15.0%), dimethyl fumarate (6.4%), interferon (5.4%) and natalizumab (5.2%). Of patients treated with any DMT in T1, patients were more likely to continue treatment into T3 if treated with natalizumab and glatiramer acetate (60.9% [T1] to 10.9% [T3] and 54.8% [T1] to 20.7% [T3], respectively) compared with interferon (36.7% [T1] to 8.2% [T3]), fingolimod (35.1% [T1] to 8.1% [T3]), dimethyl fumarate (28.1% [T1] to 7.0% [T3]), or ocrelizumab (6.7% [T1] to 0% [T3]).

Conclusions:
DMT utilization declined sharply during pregnancy; it gradually increased postpartum but remained below pre-pregnancy use. Infusibles administered every 6-12 months (e.g., anti-CD20 medications) may have been underestimated.
10.1212/WNL.0000000000203853