Pfizer's Lyrica has met its targets in two clinical trials, taking place in Europe and the US, separately assessing the drug's effect on male reproduction and the nature of symptoms following treatment discontinuation. 

The drug giant said that top-line results from a post-approval trial required by US regulators investigating the impact of Lyrica (pregabalin) on sperm quality found that the drug does not affect the reproductive function in healthy males when compared to placebo.

A total of 222 males took part in the multicentre, double-blind, randomised, Phase IV trial, and the primary endpoint - the proportion of subjects with a 50% or more reduction in sperm concentration from baseline to end of study - was met, the firm said.

Meanwhile, Pfizer also announced top-line data from a study looking at Lyrica's long-term safety in patients with Generalized Anxiety Disorder (GAD), showing that discontinuation symptoms were low after tapering treatment after three months and six months.

The European Medicines Agency requested the study to determine the relationship between dose and duration of treatment on discontinuation symptoms, including rebound anxiety, after long-term treatment with the drug in GAD patients.

A total of 621 patients too part in the study, which confirmed that, in a large, prospective placebo controlled study at least, discontinuation of Lyrica was well tolerated compared with placebo.

Results showed that efficacy was kept up after three months, "with a slight continued improvement in patients up to six months of treatment", findings which are "generally consistent with those demonstrated in the Phase III registration trials," the firm said.

Moreover, any adverse events recorded from both trials were consistent with findings from previous studies, throwing up no additional concerns on safety.

Lyrica is approved for various indications in 120 countries and regions around the world, and has a green light the treatment of GAD in adults in the European Union and other territories but not in the US.