The market for disease-modifying multiple sclerosis therapies will expand at an annual rate of 10% to 2018, peaking at nearly $21 billion that year, say new forecasts.

Market growth will be driven by the launch of at least six premium-priced disease-modifying therapies and expected price increases in the US market, says the study, from Decision Resources. 

Among the new entrants, Biogen Idec's Tecfidera (dimethyl fumarate) is expected to have the greatest clinical and commercial success, due to its compelling clinical profile, and capture over $4 billion in 2018 sales in the US, France, Germany, Italy, Spain, UK and Japan.

Decision Resources expects the coming years to "usher in a transformative era, as the burgeoning number of treatment options fragment and further complicate an already-complex treatment algorithm." Recent launches of additional oral agents, including Tecfidera and Genzyme's Aubagio (teriflunomide), will be followed by more convenient reformulations of platform injectables and three highly-efficacious monoclonal antibodies (MAbs) - Genzyme/Bayer HealthCare's Lemtrada (alemtuzumab), Roche/Genentech's ocrelizumab and Biogen Idec/AbbVie's daclizumab.

Initial uptake of novel therapies will be constrained, as a conservative prescribing base, grappling with these agents' unique risks and benefits, continues to rely on time-tested products, but reliance on current mainstays will decrease over time as neurologists gain confidence in and clinical experience with newer therapies, it says. 

Conversely, Biogen Idec's Tysabri (natalizumab) will remain a valued treatment option thanks to progressive multifocal leukoencephalopathy risk stratification protocols, which permit the selection of best-fit candidates and mark an important step in tailoring treatment choice in MS.

And a significant commercial milestone and key inflection point in the MS market will be the launch of the first generic disease-modifying drugs, in particular generic oral therapies, expected by the second half of the 2012-2022 forecast period. A lesser impact is expected from biosimilar interferon betas, assuming such products reach the market within the next decade.

Overall, the report expects the availability of lower-cost alternatives to cause the market to contract 3% annually from 2018 to 2022.

"Given the need for enhanced therapeutic choice to enable individualised treatment decisions, we expect each new therapy can establish its own clinical niche. Also of particular interest is the resurgence of industry focus on developing much-needed treatments for progressive forms of MS, which could produce landmark approvals for this underserved patient population," says Georgiana Kuhlmann, senior business insights analyst at Decision Resources.