Novo Nordisk saw its shares slip 4% after its stock was downgraded and a higher dose of its insulin drug liraglutide failed to greatly impress on weight loss scores in a late-stage clinical trial.

J.P. Morgan analyst Richard Vosser has downgraded shares from neutral to underweight citing concerns over the potential of regulatory delays to hit sales of Tresiba, after regulators last month demanded a new trial looking at the cardiovascular effects of the long-acting insulin, substantially delaying its potential entry onto the market.

In addition, his downgrade was reportedly underpinned by data suggesting a "limited commercial upside" from a higher dose of liraglutide in obesity.

Novo has released headline data showing that overweight patients with type II diabetes given liraglutide 3mg in the 56 week, double-blind, Phase III SCALE trial experienced weight loss of 6%, while those given a lower 1.8mg dose of the drug achieved weight loss of 5%, compared to 2% for those on placebo.

All differences for both doses of liraglutide - a once-daily GLP-1 analogue marketed under the tradename Victoza for diabetes - were statistically significantly different from placebo, and the trial hit all three co-primary endpoints, the Danish drugmaker said, pushing the drug closer to a regulatory approval in weight loss.

However, the difference in the weight loss achieved by the 1.8mg and 3mg forms of liraglutide was not as great as hoped, placing a question mark over the firm's pricing strategy for a higher dose form the drug, according to media reports.

Nevertheless, the firm said it is pleased with the data, and that it is looking forward to getting the results from the two remaining trials in the SCALE programme, which are expected to complete mid year.