Final results from the Betaseron (interferon ß-1b) Pregnancy Registry: a prospective observational study of birth defects and pregnancy-related adverse events.

OBJECTIVE: Women with multiple sclerosis are often diagnosed and treated during their reproductive years. Limited data are available on the safety of treatment during pregnancy. The Betaseron Pregnancy Registry prospectively monitored women exposed to interferon ß-1b (IFNß-1b) during pregnancy to estimate the rates of birth defects, spontaneous abortions (SABs) and other negative outcomes in this population. DESIGN: From 2006 to 2011, this observational registry enrolled women exposed prior to conception or during pregnancy (but prior to or without abnormalities on prenatal screening). Follow-up continued from enrolment through the 4-month paediatric visit. SETTING: Patients in the USA who met these criteria were enrolled in the registry. RESULTS: The registry enrolled 99 pregnant women; 3 were lost to follow-up. The earliest exposure to IFNß-1b occurred during the first trimester for 95 pregnancies and in the third trimester for 1 pregnancy. There were 99 birth outcomes (3 twins), including 86 (86.9%) live births, 11 (11.1%) SABs and 2 (2%) stillbirths. Birth defects were reported in five (5.1%) cases. Rates of birth defects and SAB were not significantly different from population comparators. No developmental concerns were identified at the 4-month paediatric visit. CONCLUSIONS: The small sample size limits the ability to draw definitive conclusions; however, there was no pattern to suggest increased negative outcomes with IFNß-1b. CLINICAL TRIALS REGISTRATION NUMBER: NCT00317564.

Survival in MS: a randomized cohort study 21 years after the start of the pivotal IFNß-1b trial.

OBJECTIVE: To examine the effects of interferon beta (IFNß)-1b on all-cause mortality over 21 years in the cohort of 372 patients who participated in the pivotal randomized clinical trial (RCT), retaining (in the analysis) the original randomized treatment-assignments. METHODS: For this randomized long-term cohort study, the primary outcome, defined before data collection, was the comparison of all-cause mortality between the IFNß-1b 250 µg and placebo groups from the time of randomization through the entire 21-year follow-up interval (intention-to-treat, log-rank test for Kaplan-Meier survival curves). All other survival outcomes were secondary. RESULTS: After a median of 21.1 years from RCT enrollment, 98.4%(366 of 372) of patients were identified, and, of these, 81 deaths were recorded (22.1% [81 of 366]). Patients originally randomly assigned to IFNß-1b 250 µg showed a significant reduction in all-cause mortality over the 21-year period compared with placebo (p = 0.0173), with a hazard ratio of 0.532 (95% confidence interval 0.314-0.902). The hazard rate of death at long-term follow-up by Kaplan-Meier estimates was reduced by 46.8% among IFNß-1b 250 µg-treated patients (46.0% among IFNß-1b 50 µg-treated patients) compared with placebo. Baseline variables did not influence the observed treatment effect. CONCLUSIONS: There was a significant survival advantage in this cohort of patients receiving early IFNß-1b treatment at either dose compared with placebo. Near-complete ascertainment, together with confirmatory findings from both active treatment groups, strengthens the evidence for an IFNß-1b benefit on all-cause mortality. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that early treatment with IFNß-1b is associated with prolonged survival in initially treatment-naive patients with relapsing-remitting multiple sclerosis.