ZURICH: RoActemra drug helped to reduce symptoms in rheumatoid arthritis patients better than Abbott Laboratories' top-selling Humira when given as a single treatment, the Swiss drugmaker said on Wednesday.

The phase IV trial showed that after 24 weeks of treatment 65 per cent of patients who received RoActemra experienced a 20 per cent reduction in swollen and tender joints compared with 49 per cent of those on Humira, Roche said.

Humira is one of the world's top-selling medicines, garnering more than $8 billion a year, but is facing growing competition from other therapies including a pill being developed by Pfizer.

“Despite these strong efficacy results, it is difficult to asses whether these trial results can be successfully exploited to bring about a change in physicians' prescription habits,” said Vontobel analyst Andrew Weiss, who forecasts peak sales for RoActemra of 2 billion Swiss francs ($2.1 billion).

Karsten Jung, head of GPS Immunology at Roche, said the aim of the trial was to give comparative data to doctors to help them to decide in favour of RoActemra, also known as Actemra outside of Europe, when prescribing treatment.

“Among a treatment environment of nine different medicines, it is very difficult to make an individual treatment decision for the physician. They are looking for reasons why they should choose one over the other,” Jung told Reuters.

Roche's drug is approved in the United States and Europe for use in patients who are either intolerant to or have failed to respond to other medicines to treat inflammation. RoActemra had sales of 184 million Swiss francs in the first-quarter, up 46 per cent year-on-year.

Roche shares were trading up 0.9 per cent by 0751 GMT, in line with the European healthcare index.

About 1 per cent of the world's adult population has rheumatoid arthritis, a potentially crippling condition in which the body's own immune system attacks the joints.

Rheumatoid arthritis and related diseases have been one of the most lucrative areas for drugmakers, with more than $20 billion in annual sales.

Patients are usually treated with a combination of protein-based biologic therapies and methotrexate (MTX). About one third of all patients, however, are largely intolerant to MTX and take a single drug rather than a combination of drugs, Roche said.

“The study used the maximum Actemra dose and the minimum Humira dose allowed for monotherapy treatment, so results may be biased in favour of Actemra,” Abbott spokeswoman Raquel Powers said.

The results of the study of 326 patients will be presented on June 8 at the European League Against Rheumatism (EULAR) meeting in Berlin.

($1 = 0.9637 Swiss francs)