It was a bad day for US biotech Repligen after shares sank 28% on news that a mid-stage trial of its experimental bipolar drug failed to hit targets.

A Phase IIb clinical study of RG2417, an oral formulation of uridine, showed that the drug failed to demonstrate a significant improvement in the symptoms of bipolar depression compared to placebo, leaving the programme effectively dead in the water.

Interestingly, response rates to the drug seemed to be better in patients participating at academic compared to commercial sites, with preliminary analyses suggesting a clinically meaningful improvement on the Montgomery-Asberg Depression Rating Scale from weeks 2 through 8 compared to placebo in those enrolled at academic medical centres.

While disappointed with the top-line results, the company said it intends to explore this finding to determine whether there is a path forward for the drug.

In the immediate future, Repligen intends to focus efforts on wrapping up the current Phase III trial for RG1068, a pancreatic imaging agent, and advancing lead compounds for Friedreich’s ataxia and spinal muscular atrophy into the clinic, "while maintaining a low cash burn", it said.

Treatment gaps

Meanwhile, an 11-nation study by US researchers funded by the National Institute of Mental Health has revealed huge gaps in treatment of bipolar disorder around the globe, with the condition being vastly under-treated, particularly in lower-income countries.

According to the research, published online in the Archives of General Psychiatry, around 2.4% of people worldwide have, at one time or another, been diagnosed with the condition, with the US having the highest lifetime rate of 4.4% of the population, and India coming in at the bottom of the table with just 0.1%.

However, the findings also revealed that less than half of patients with bipolar disorder received therapy from an appropriate medical professional, while, in poorer countries, only 25% sought treatment for the illness.