Disease-modifying Drugs
DMDs have been shown to reduce the frequency and severity of clinical attacks in patients with MS.[24,25,26,27,28,29,30,31,32,33] These drugs are taken on a long-term basis and have been shown to be the best defense in slowing down the natural course of MS. DMDs will not prevent recurring symptoms, and they are not approved to treat PPMS. The National Multiple Sclerosis Society's medical advisory board agrees that DMDs are most effective when started early in the course of the disease. The FDA has approved six DMDs for the treatment of MS: Avonex (interferon beta-1a), Betaseron (interferon beta-1b), Copaxone (glatiramer acetate), Rebif (interferon beta-1a), Novantrone (mitoxantrone), and Tysabri (natalizumab). Avonex is reserved for the relapsing forms of MS and a single episode of MS if MRI features are consistent. Betaseron is approved to treat relapsing forms of MS and SPMS with relapses. Copaxone and Rebif are reserved for the treatment of RRMS only. Finally, Novantrone is used to treat worsening RRMS and is indicated for PRMS or SPMS, while Tysabri treats relapsing forms of MS as monotherapy. The mechanisms of action, dosages, and adverse effects of DMDs are illustrated in Table 3.
DMDs are designed to reduce the occurrence of new demyelinating lesions, resulting in reduced frequency and severity of attacks, and to prevent permanent damage to nerve axons.[24,25,26,27,28,29,30,31,32,33] The advantages and disadvantages of each DMD are related to adverse effects, dosing schedules, routes of administration, and expense. Generally, these drugs are very costly and are not covered under most formulary plans; however, since they are injectable, some insurance plans will provide reimbursement under the medical benefit instead of under the drug benefit. In addition, each DMD has an industry-sponsored association that provides support, financial assistance, and patient information. For example, if patients are on Copaxone, they would be supported by the program Shared Solutions (Table 3).
US Pharmacist. 2009;34(1):HS3-HS9. © 2009 Jobson Publishing
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