GlaxoSmithKline's fish oil tablet Lovaza is not effective for the prevention of atrial fibrillation  in certain patients, according to new data.

The company has presented data from a 633-patient study  at the American Heart Association meeting in Chicago which examined the efficacy and safety of Lovaza (omega-3-acid ethyl esters) for the prevention of recurrent symptomatic atrial fibrillation. The trial showed no benefit in reducing the recurrence of symptomatic AF in patient groups treated with high-dose, prescription omega-3 fatty acids and placebo, indeed the rate of recurrence to AF or flutter was higher in the Lovaza arm.

GSK noted that previous clinical trials of omega-3 fish oils used in AF "have yielded mixed results" and Murray Stewart, clinical vice president of cardiovascular and metabolic medicines development at the firm, claimed that "based on its size and scientific rigour, this study adds significantly to the body of knowledge of the role and potential effects" of Lovaza. He added that “we will continue to review the data from this study...however, in this patient population there was clearly no benefit".

Lovaza is indicated as an adjunct to diet, to reduce triglyceride levels in adults with severe  hypertriglyceridaemia.  It is a reasonably big earner for GSK and had third-quarter sales of £138 million, up 20%..