Treatment patterns in multiple sclerosis: administrative claims analysis over 10 years

Treatment patterns for the MS disease-modifying therapies (DMT) have changed over time. The objective of this study was to examine and describe treatment patterns in MS over a 10-year period.

MS patients who filled a DMT prescription between January 1, 2001 and December 31, 2010 were identified from Clinformatics for DataMart affiliated with OptumInsight. Two cohorts were identified: those with a DMT prescription in 2003 and those with a DMT prescription in 2008. Treatment patterns were examined 2 years before and after the anchor prescriptions for each cohort.

Comparing treatment patterns prior to the two anchor prescriptions, interferon-beta (IFNβ)-1a IM (Avonex) and IFNβ-1b (Betaseron) gained the most users in 2001-2003, while IFNβ-1a IM and IFNβ-1a SC (Rebif) gained the most users from 2006-2008. In the 2 years following the two anchor prescriptions, treatment patterns changed. From 2003-2005, 21.2% of IFNβ-1a SC users and more than 15.0% of IFNβ-1a IM and IFNβ-1b users changed to another interferon or glatiramer acetate (GA; Copaxone), while 12.5% of GA users changed to an interferon, most often IFNβ-1a SC. From 2008-2010 the largest proportion of changes from each of the interferons and natalizumab (NZ; Tysabri) were to GA, while those switching from GA were most often changed to IFNβ-1a SC. Those with a 2008 anchor prescription for NZ were most often changed (57%) to GA.

In retrospective database analyses the presence of a claim for a filled prescription does not indicate that the drug was consumed, and reasons for changes in therapy are not available. The study design looking forward and backward from the anchor prescriptions may have contributed to differences in the proportion of patients seen with no observable change in DMT. Claims-based data are also constrained by coverage limitations that determine the data available and limit the generalizability of results to managed care patients.

Changes in treatment patterns in the first half of the observation period were reflective of the addition of IFNβ-1a SC to the market in 2002. Following the 2003 and 2008 anchor prescriptions there were differences in treatment patterns, with more IFNβ-1a IM users being changed to IFNβ-1a SC after the 2003 anchor DMT, and more of each of the interferons and NZ being changed to GA following the 2008 anchor DMT. With the introduction of oral therapies for MS, treatment patterns will again be impacted.