Data from the first head-to-head trial of Johnson & Johnson’s injectable Risperdal Consta versus Zyprexa has highlighted the benefits of the former’s schizophrenia drug compared with Eli Lilly’s rival oral product.

Newly-published data in the latest edition of the British Journal of Psychiatry show that patients receiving Risperdal Consta (risperidone long-acting injection) experienced a higher incidence of significant clinical improvements, as well as greater improvements in measures of disorganised thinking at 12 months than patients taking Zyprexa (olanzapine). The data showed that both treatments were efficacious and generally well-tolerated but efficacy results suggested that in the long-term patients might benefit more from treatment with the J&J drug.

The study at 48 centres worldwide saw 318 patients were randomised to long-acting risperidone injection and 300 to olanzapine of which 160 and 187 patients, respectively, completed the 12-month trial. The primary measure of efficacy was the change in total score on the positive and negative syndrome scale (PANSS) for both short-term (13 weeks) and long-term (12 months) outcomes and Risperidone Consta achieved a 20% minimum reduction in PANSS total scores in significantly more patients (91% versus 79%) compared with Zyprexa at 12 months.

The data also showed that at the trial’s long term end-point (12 months), a significantly greater improvement on one PANSS factor score (disorganised thoughts) was seen in patients receiving J&J’s drug and the firm noted that improvements in disorganised thinking “are viewed as important because this is one of the barriers to people living with schizophrenia functioning on a day-to-day basis”. However it also acknowledged that significantly greater improvements were seen in anxiety/depression in the olanzapine group.

The trial results also suggest that long-acting risperidone may have a less pronounced effect on weight gain (1.7kg versus 4kg) and body mass index (0.6kg/m2 compared to 1.4kg/m2) than olanzapine. The study was supported by J&J Pharmaceutical Research and Development which also completed the statistical analysis.