SALT LAKE CITY—Patients with multiple sclerosis (MS) who use glatiramer acetate have significantly fewer relapses and lower medical costs, compared with those who use interferon beta-1b, reported researchers at the 133rd Annual Meeting of the American Neurological Association.
A Retrospective Analysis
Kenneth P. Johnson, MD, Professor Emeritus of Neurology at the University of Maryland and Director of the Maryland Center for Multiple Sclerosis in Baltimore, and Maureen J. Lage, PhD, Managing Member of HealthMetrics Outcomes Research in Groton, Connecticut, retrospectively studied data from the i3 LabRx Database. This health claims database includes laboratory test results, hospitalization data, pharmacy data, and demographic information for more than 20 million individuals from a major US managed care organization. Data were collected from July 2001 through June 2006.
Patients were included in the continuous use cohort (n = 418) if they used either interferon beta-1b or glatiramer acetate continuously for at least 24 months.
Costs were calculated as direct medical costs, which included inpatient, outpatient, and prescription drug services. These were based on paid amounts (eg, insurer and health plan payments, copayments, and deductibles). All costs were converted to 2006 values using the medical component of the Consumer Price Index.
Relapse was defined as either a hospitalization with a primary diagnosis of MS or an outpatient visit with a diagnosis of MS accompanied by a prescription for steroids within seven days after the outpatient visit.
One hundred ten patients received interferon beta-1b (mean age, 43.96; 76% female) and 308 patients received glatiramer acetate (mean age, 44.23; 82% female). The mean number of outpatient prescription medications totaled 4.18 and 4.42, respectively. Approximately 98% of patients in both groups had commercial insurance.
Hypertension was the most frequent comorbidity, occurring in 19 patients in the interferon beta-1b group and 39 patients in the glatiramer acetate group. Other comorbidities included anxiety, depression, diabetes, and high cholesterol. Concomitant medication uses included adrenal, anticholinergic, anticonvulsant, antiviral, cerebral stimulant, genitourinary, and skeletal muscle agents.
Eleven patients from the interferon beta-1b group and 23 from the glatiramer acetate group had a preperiod hospitalization with MS diagnosis (ie, six months before the date of first use of interferon beta-1b or glatiramer acetate).
Interferon Beta-1b: Costlier, With More MS Relapses
According to Drs. Johnson and Lage, in the two years following initiation of therapy, subjects who received interferon beta-1b had a 10.92% chance of relapse, while those taking glatiramer acetate had a 2.09% risk. The two-year total direct medical costs associated with the use of interferon beta-1b was $53,185; this amount was greatly reduced for subjects taking glatiramer acetate, with a direct two-year cost of $48,130.
This study was limited by the use of an administrative claims database that included only patients with medical and prescription benefit coverage. The medical claims data precluded the use of physician- or patient-reported functioning. In addition, the study used a different method for defining relapses than those used in traditional clinical studies; however, the algorithm was applied equally to both groups. The authors also stated that the study focused only on direct medical costs, despite other research that has indicated that the indirect costs of MS are also large.
Results Depict “Real Life” Data
Despite these limitations, the results are consistent with prior research. “Based on all of the currently available published data, glatiramer acetate is not only better tolerated but also shows significantly better clinical efficacy than interferon beta-1b for relapsing MS and is less costly,” Dr. Johnson commented in an interview with Neurology Reviews.
“While this is a direct comparison of the two drugs, it differs from the recent head-to-head trial data. This analysis was of the outcomes over two years of MS patients [in the US] who were not rigidly defined, as is required in a clinical trial, but depended on personal treatment decisions of US physicians, mainly neurologists practicing in all regions of the US,” concluded Dr. Johnson. “In my view, this analysis comes closer to the ‘real life’ situation in the US.
—Marguerite Spellman