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APPENDIX 15
Multiple Sclerosis

Multiple sclerosis (MS), the most common of the demyelinating diseases, is characterized by many scattered discrete areas of demyelination. These plaques are the pathologic hallmark of this disease appearing in the white matter areas of the central nervous system (CNS). MS has multiple presentations depending on the location foci of demyelination within the CNS. Some of the common signs of this disease include impaired vision, involuntary eye movements, speech impairments, weakened sense of vibration and position, ataxia and intention tremor, weakness or paralysis of one or more limbs, spasticity, and bladder complications.

At the site of active lesions are accumulations of T-lymphocyte and monocyte macrophages around venules and at plaque margins where myelin is being destroyed. The actual breakdown of myelin can be attributed to the soluble mediators (lymphokines and monokines) released by the inflammatory cells which invade the white matter.

DISEASE BURDEN

Epidemiology

For the purposes of the calculations in this report, the committee estimated that there are 8,000 new cases of multiple sclerosis per year in the United States. It was assumed that all new cases occur between the ages of 15 and 54 years of age.



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Vaccines for the 21st Century: A Tool for Decisionmaking APPENDIX 15 Multiple Sclerosis Multiple sclerosis (MS), the most common of the demyelinating diseases, is characterized by many scattered discrete areas of demyelination. These plaques are the pathologic hallmark of this disease appearing in the white matter areas of the central nervous system (CNS). MS has multiple presentations depending on the location foci of demyelination within the CNS. Some of the common signs of this disease include impaired vision, involuntary eye movements, speech impairments, weakened sense of vibration and position, ataxia and intention tremor, weakness or paralysis of one or more limbs, spasticity, and bladder complications. At the site of active lesions are accumulations of T-lymphocyte and monocyte macrophages around venules and at plaque margins where myelin is being destroyed. The actual breakdown of myelin can be attributed to the soluble mediators (lymphokines and monokines) released by the inflammatory cells which invade the white matter. DISEASE BURDEN Epidemiology For the purposes of the calculations in this report, the committee estimated that there are 8,000 new cases of multiple sclerosis per year in the United States. It was assumed that all new cases occur between the ages of 15 and 54 years of age.

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A15–1 Health Care Costs Associated with Multiple Sclerosis   % of Cases Duration (years) % with Care Cost per Unit Units per Case Form of Treatment Benign 15.00%   Treatment per year   43.3484 100% $100 2.0 Physician B     43.3484 100% $500 1.0 Diagnostic C Relapsing/remitting (secondary progressive) 65%   Treatment per year   43.3484 25% $3,000 1.0 Hospitalization     43.3484 25% $150 4.0 Physician C 43.3484 25% $500 1.0 Diagnostic C 43.3484 100% $100 6.0 Physician B 43.3484 100% $500 1.0 Diagnostic C Primary Progressive 15.00%   Treatment per year   20.0000 25% $225 365.0 Nursing home care     20.0000 100% $100 12.0 Physician B 20.0000 100% $500 1.0 Diagnostic C 20.0000 50% $3,000 1.0 Hospitalization or acute care/rehabilitation 20.0000 50% $150 4.0 Physician C Fulminant 5.00%   Treatment per year   5.0000 75% $225 365.0 Nursing home care     5.0000 100% $100 12.0 Physician B 5.0000 25% $3,000 1.0 Hospitalization or acute care/rehabilitation 5.0000 25% $150 4.0 Physician C 5.0000 100% $500 1.0 Diagnostic C

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Vaccines for the 21st Century: A Tool for Decisionmaking Disease Scenarios For the purposes of the calculation in this report, the committee assumed that there were four scenarios associated with MS. It was estimated that 15% of people with MS experience a lifelong, mild, intermittent disease, associated with an average health utility index (HUI) of .97. It was assumed that most (65%) cases of MS are associated with a relapsing, remitting MS that is associated with an average HUI of .61. 15% of patients were assumed to experience a chronic, progressive disease for 20 years until death from the disease. This is associated with an HUI of .47. The rapid, fulminant expression of MS was assumed to occur in 5% of patients and be associated with a 5-year period of an HUI of .31 until the time of death from the disease. COST INCURRED BY DISEASE Table A15–1 summarizes the health care costs incurred by MS. For the purposes of the calculations in this report, it was assumed that for all scenarios there is a diagnostic phase, followed by a treatment phase which lasts the duration of the patients lifetime. The diagnostic phase was estimated to be approximately the same for all patients with MS: hospitalization and associated inpatient physician costs, visits to a specialist, and extensive diagnostics. For the purposes of the calculations in this report, it was assumed that no costs associated with the diagnostic phase of MS would be averted with a therapeutic vaccine strategy and are not described here. Chronic, treatment costs would be averted by a vaccine strategy. The costs and patterns of care incurred during treatment phase vary greatly depending on the type of MS experienced. For example, it was assumed that all patients with benign and with relapsing-remitting MS visit a specialist and receive a diagnostic work-up each year for the duration of their lifetime. It was assumed that on average, 25% of patients with relapsing-remitting MS but none of the patients with benign MS require hospitalization each year. Patients with primary progressive MS were assumed to incur annual costs over 20 years associated with diagnostics, multiple specialist visits, hospitalization (50% of patients per year), and nursing home care (25% of patients). Patients with fulminant MS were assumed to incur annual costs for 5 years associated with diagnostics, specialist visits, hospitalization (25% of patients per year) and nursing home care (for 75% of patients). VACCINE DEVELOPMENT The committee assumed that it will take 15 years until licensure of a therapeutic MS vaccine and that $360 million needs to be invested. Table 4–1

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Vaccines for the 21st Century: A Tool for Decisionmaking summarizes vaccine development assumptions for all vaccines considered in this report. VACCINE PROGRAM CONSIDERATIONS Target Population For the purposes of the calculations in this report, it is assumed that the target population for this vaccine is all new cases of MS at time of diagnosis. It was assumed that 90% of the target population would utilize the vaccine. Vaccine Schedule, Efficacy, and Costs For the purposes of the calculations in this report, it was estimated that this vaccine would cost $500 per dose and that administration costs would be $10 per dose. Default assumptions of a 3-dose series was accepted. For therapeutic vaccines it was assumed that effectiveness is 40%. Table 4–1 summarizes vaccine program assumptions for all vaccines considered in this report. RESULTS If a vaccine program for MS were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the QALYs gained would be 68,000. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the QALYs gained would be 15,000. If a vaccine program for MS were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the health care costs saved would be $830 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the health care costs saved would be $180 million. If a vaccine program for MS were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the program cost would be $12.2 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the program cost would be $6.7 million.

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Vaccines for the 21st Century: A Tool for Decisionmaking Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $10.8 million for a MS vaccine. If a vaccine program were implemented today and the vaccine were 100% efficacious and utilized by 100% of the target population, the annualized present value of the cost per QALY gained is -$12,000. A negative value represents a saving in costs in addition to a saving in QALYs. Using committee assumptions of less-than-ideal utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the cost per QALY gained is -$11,000. See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported. READING LIST Anderson DW, Ellenberg JH, Leventhal CM, et al. Revised Estimate of the Prevalence of Multiple Sclerosis in the United States. Annals of Neurology 1992; 31:333–336. Koch-Henriksen N. Incidence of Multiple Sclerosis in Denmark 1948–1982: A Descriptive Nationwide Study. Neuroepidemiology 1992; 11:1–10. Miller CM, Hens M. Multiple Sclerosis: A Literature Review. Journal of Neuroscience Nursing 1993; 25:174–179. Multiple Sclerosis Foundation. 1997. Multiple Sclerosis Statistics. URL http://www.msfacts.org/stats.htm (accessed September 26, 1997). Warren S, Warren KG. Prevalence, Incidence, and Characteristics of Multiple Sclerosis in Westlock County, Alberta, Canada. Neurology 1993; 43:1760–1763.

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