Sales of drugs to treat ulcerative colitis in seven major markets will grow by “a modest” $800 million to 2019, forecasts a new report.

Sales in these markets – the US, France, Germany, Italy, Japan, Spain and the UK – will be driven by uptake of three treatments: Abbott/Eisai’s Humira (adalimumab), Centocor Ortho Biotech/Merck/Mitsubishi Tanabe Pharma/Janssen’s Simponi (golimumab) and Millennium Pharmaceuticals’ vedolizumab, according to the study, from Decision Resources.

Also fueling sales growth will be the expanding number of diagnosed prevalence of ulcerative colitis in the US, it adds.

Humira and Simponi, both subcutaneous tumor necrosis factor-alpha (TNF-alpha) inhibitors, are currently in late-stage clinical development for the treatment of moderate to severe ulcerative colitis and will receive approval for this indication in 2011 and 2013, respectively, according to the study. Uptake of these two emerging therapies will be fueled by increased physician acceptance of TNF-alpha inhibitors for the treatment of moderate to severe ulcerative colitis and also by patient preference for more conveniently-delivered subcutaneous anti-TNF-alpha therapies, it adds.

The study goes on to predict that Humira will challenge Centocor Ortho Biotech/Merck/Mitsubishi Tanabe Pharma’s Remicade (infliximab) as the most frequently-prescribed agent within the TNF-alpha inhibitor drug class in 2019, as a result of its earlier entry into the ulcerative colitis market and also because of physician familiarity with the product as a result of its use in Crohn’s disease.

Drug failures in late-stage clinical trials have plagued the clinical development of additional therapies for moderate to severe ulcerative colitis, for which the greatest levels of unmet need remains, it says. Thought leaders interviewed for the study consider Millennium’s cell adhesion molecule inhibitor vedolizumab to be one of the most promising emerging therapies, with a novel mechanism of action, out of several which are currently in mid- to late-stage clinical development, says Decision Resources analyst Bingnan King, who points out that Phase III clinical trials for vedolizumab in ulcerative colitis and Crohn’s disease are currently underway in both the US and Europe.

The study also reports that the chronic, long-term use of TNF-alpha inhibitors for ulcerative colitis treatment - and, to a smaller extent, of novel biologics - will contribute to an increase in sales of maintenance therapies from $1.1 billion in 2009 to approximately $1.8 billion in 2019. Additionally, the more slowly-growing acute market will increase from approximately $384 million in 2009 to approximately $531 million in 2019, it forecasts.