The number of disease-modifying therapies (DMT) approved for the treatment of multiple sclerosis (MS) is expected to double to 2021, and this will intensify market fragmentation, according to new forecasts.

In this new era of enhanced therapeutic potential and complex treatment choices, fragmentation of the world's leading markets - France, Germany, Italy, Japan, Spain, the UK and the US - will intensify, as the MS field strives towards a more individualised approach to treatment, says the study, from Decision Resources.

Investigational MS therapies comprise a diverse mix of oral and parenteral agents, novel compounds, next-generation products and reformulations, the study points out. Among the new oral agents which are expected to launch during this time, Biogen Idec's oral immunomodulator BG-12 will have the greatest commercial success, with major-market sales of around $3 billion in 2017 as a result of clinical data that support a highly-favourable risk/benefit profile, Decision Resources forecasts.

Also in 2017, Novartis/Mitsubishi Tanabe Pharma's first-to-market oral agent Gilenya/Imusera (fingolimod) is expected to produce sales exceeding $2 billion in these major markets. However, other emerging oral competitors - including Sanofi/Genzyme's Aubagio (teriflunomide), which recently launched in the US - are not expecting to achieve blockbuster status, owning to more limited clinical advantages, it says.

Genzyme/Sanofi/Bayer HealthCare's anti-CD52 monoclonal antibody (MAb) Lemtrada (alemtuzumab) and Roche/Genentech's anti-CD20 MAB ocrelizumab will serve as important alternatives for MS patients who respond suboptimally to prior therapy, or for patients who exhibit aggressive or worsening disease activity, the report suggests. However, it also cautions that outstanding safety concerns will likely constrain the adoption of these potentially high-risk/high-reward therapies by a generally conservative neurologist prescriber base, and forecasts that, together with Biogen Idec/Abbott's emerging anti-CD-25 daclizumab, sales of emerging MAbs in these major markets will total around $2 billion in 2021.

In response to this influx of promising new targets, clinicians' reliance on platform injectable therapies such as the interferon-betas and Teva's Copaxone (glatiramer acetate) is projected to wane over time, yielding an aggregate 6% annual decline in major-market sales to 2012, the study forecasts. It expects follow-on products from Biogen Idec - pegylated interferon-beta-1a - and Teva - Copaxone 40mg, three times weekly - to represent useful (albeit somewhat incremental) advances in this evolving market, with both products capturing more than 40% of their respective major-market drug-level patient shares in 2021.

Moreover, by way of risk-factor stratification, the study expects Biogen Idec/Elan's Tysabri (natalizumab) to remain a valuable treatment option in the face of growing competition, capturing around 15% total market share in 2021.

"A clear takeaway from the recently-concluded 28th Congress of the European Committee for Treatment and research in Multiple Sclerosis is that the MS field remains primed for new disease-modifying alternatives to treat patients across the clinical spectrum," comments Decision Resources analyst Jonathan Searles.

"However, while each new product will establish a role in treatment, we forecast a continued reliance on time-tested mainstays, owing to near-term gaps in clinical experience and long-term data with new entrants, coupled with the absence of prognostic or therapeutic response markers to guide more-precise treatment selections," he adds.