Multiple sclerosis (MS) is a chronic neurological disease of adults that affects over 1 million people worldwide. Relapsing-remitting MS, characterized by acute attacks (relapses) followed by complete or partial remissions, is the most common type of MS at disease onset. Over time, most patients develop secondary-progressive disease. Costs for patients, caregivers, healthcare providers and insurers, and society in general are high because of the progressive disability and long-term care associated with MS. Historically, drug therapy has represented a relatively small component of the overall cost of the disease and indirect costs have accounted for most of the costs. Although not curative, disease-modifying agents are available for first-line use in patients with relapsing-remitting MS; the goals of therapy are to reduce the frequency and severity of relapses and postpone disease progression. All of the disease-modifying agents are associated with high cost-utility ratios. Subcutaneous (SC) interferon-beta-1a (Rebif(R) section 1) is a disease-modifying therapy that demonstrates significant benefits on all outcome measures of clinical trials [relapse rate, relapse severity, progression of disability, magnetic resonance imaging (MRI) burden of disease and MRI activity] in patients with relapsing-remitting MS. In a large, 2-year, double-blind trial, SC interferon-beta-1a 44mug three time weekly decreased the number of relapses by 32% and delayed disease progression by 9.4 months with compared with placebo. In addition, patients treated with SC interferon-beta-1a had 78% fewer active lesions than placebo recipients when evaluated by MRI scans. A 2-year extension of this trial demonstrated the persistence of positive effects with treatment. Results from a large, assessor-blinded, randomized trial in patients with relapsing-remitting MS show a significant short-term therapeutic advantage for SC interferon-beta-1a over IM interferon-beta-1a. At week 24 of treatment, 74.9% of patients who received SC interferon-beta-1a 44mug three times weekly were relapse-free compared with 63.3% of those who received intramuscular (IM) interferon-beta-1a 30mug (Avonex(R)) once weekly. Moreover, there were fewer mean active lesions per MRI scan in SC interferon-beta-1a recipients than in IM interferon-beta-1a recipients (0.7 vs 1.3 lesions). The most frequently reported adverse event with SC interferon-beta-1a is injection site inflammation (>60% of patients). SC interferon-beta-1a treatment is associated with the well recognized adverse events which accompany interferon therapy including flu-like syndrome and dose-related effects on elevation of liver enzymes and reduction in white blood cell indices. The reduction in relapses, hospital admissions and courses of corticosteroid therapy seen with SC interferon-beta-1a compared with placebo results in decreased costs within the healthcare system. The delay in disease progression may reduce both direct (e.g. paid caregivers and adaptive equipment) and indirect (e.g. disability payments and lost income) costs and will likely be distributed across multiple healthcare and non-healthcare systems. In conclusion, SC interferon-beta-1a is a valuable first-line disease-modifying therapy in the treatment of patients with relapsing forms of MS. The high acquisition costs of interferon-beta-1a must be weighed against the long-term benefits of therapy.
