Glatiramer acetate versus interferon beta-1a for subcutaneous administration: comparison of outcomes among multiple sclerosis patients.
BACKGROUND
We compared the outcomes of multiple sclerosis (MS) patients treated with either glatiramer acetate (GA) (Copaxone, Teva Pharmaceutical Industries, Israel) or interferon beta-1a for subcutaneous administration (IFN beta-1a-SC) (Rebif, Merck Serono, Switzerland).


METHODS
Data were obtained from i3's Lab Rx Database from July 2001 to June 2006. We established an 'intent-to-treat' (ITT) cohort (n=845) of patients diagnosed with MS who began therapy on either GA (n=542) or IFN beta-1a-SC (n=303) and had continuous insurance coverage from 6 months before to 24 months after the date they began taking the medication. We also created a 'continuous use' (CU) cohort (n=410) of individuals who, in addition to the criteria listed above, used either GA or IFN beta-1a-SC within 28 days of the end of the 2-year-post period. Using multivariate regressions, we examined both the 2-year total direct medical costs and the likelihood of relapse associated with the use of these two MS medications. We defined relapse as either being hospitalised with a diagnosis of MS, or being diagnosed with MS during an outpatient visit and then prescribed steroids within a 7-day period. All regressions controlled a wide range of factors that have potentially affected outcomes.


RESULTS
In the ITT cohort, patients who started therapy on GA had a significantly lower 2-year risk of relapse (5.92% versus 10.89%; P=0.0305), as well as significantly lower 2-year total medical costs (US$41,786 versus US$49,030; P=0.0002). In the CU cohort, patients who used GA also had a significantly lower 2-year risk of relapse (1.94% versus 9.09%; P=0.0049) and significantly lower total medical costs (US$45,213 versus US$57,311; P<0.0001).


CONCLUSIONS
Results indicate that, compared with the use of IFN beta-1a-SC, use of GA is associated with significantly lower probability of relapse as well as significantly lower 2-year total direct medical costs. In addition, these results are more pronounced among patients defined as continuous users.
Castelli-Haley
Jane
J
Teva Neuroscience, Kansas City, Missouri, USA.
Oleen-Burkey
MerriKay
M
Oleen-Burkey
Merry-Kay A
MK
Lage
Maureen J
MJ
Johnson
Kenneth P
KP
D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D000328:Adult; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D004334:Drug Administration Schedule; D005260:Female; D000068717:Glatiramer Acetate; D006801:Humans; D007279:Injections, Subcutaneous; D000068556:Interferon beta-1a; D016899:Interferon-beta / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D009103:Multiple Sclerosis / Q000188:drug therapy*; D010455:Peptides / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D012008:Recurrence; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
D000276:Adjuvants, Immunologic; D010455:Peptides; D000068717:Glatiramer Acetate; D016899:Interferon-beta; D000068556:Interferon beta-1a