Teva Pharmaceutical Industries has presented promising data from a late-stage trial of a longer-acting version of its blockbuster multiple sclerosis drug Copaxone.

The Israeli drugmaker announced positive top-line results from a Phase III trial assessing 40 mg of Copaxone (glatiramer acetate) injection administered subcutaneously three times a week compared to placebo in relapsing-remitting MS patients. The one-year study, which recruited more than 1,400 patients, showed that the high dose met the study’s primary endpoint by significantly reducing the annualised relapse rate by 34.4% compared to placebo.

Teva added that initial analysis of the data indicates that secondary endpoints were achieved, with the exception of reduction in brain atrophy. Following the initial 12-month, placebo-controlled phase, there will be an ongoing open-label extension of the trial.

Copaxone is currently sold as a 20mg daily injection and is a huge earner.  First-quarter sales reached $909 million, up 8%, and last month Teva said the drug should come in at around $3.80 billion. However oral MS drugs, notably Novartis' Gilenya, (fingolimod), are expected to eat into market share and  Copaxone patents start to expire in the USA in 2014;  if approved, the longer-acting version could help ward off these threats.