Orion and Abbott Laboratories' Simdax (levosimendan), developed as a new option in heart failure treatment, has achieved mixed results in a clinical trial involving patients whose condition was deteriorating despite standard treatment.

According to the results of REVIVE II, announced at the American Heart Association annual meeting earlier this week, patients receiving Simdax were more likely to improve clinically and less likely to deteriorate than patients receiving standard treatment.

But this promising finding was accompanied by a trend towards increased mortality when patients who received Simdax were compared to those on placebo in the study. Although this difference was not statistically significant – and the trial was not big enough to measure survival reliably – the finding, combined with the results of an earlier trial of Abbott’s Tricor (fenofibrate) in diabetics with high cholesterol, dampened Abbott’s share price.

Simdax is not yet approved in the USA, and investors seemed to be concerned that the mortality data could affect its chances of securing clearance by the Food and Drug Administration (FDA), according to analysts at JP Morgan. Simdax is already approved in 40 other countries around the world.

All eyes are now on the results of the SURVIVE study of Simdax in heart failure patients, which will provide a closer look at mortality data and are due to be presented at the AHA later today.

Acutely decompensated - or worsening - heart failure is a major public health problem, since it is associated with costly hospitalisation and a high risk of death. REVIVE II suggests that Simdax may improve longer-term outcomes in a large group of high-risk patients, said the researchers who carried out the study, .

In REVIVE II, Simdax was administered as an injected dose based on body weight and then as a continuous intravenous infusion for 24 hours. A calcium sensitiser, Simdax uses a novel mechanism to help the heart beat more strongly and the blood vessels to relax, so that more blood can circulate around the body to the vital organs.