Spinifex announces results of Phase 2 clinical trial of EMA401 in postherpetic neuralgia

Spinifex Pharmaceuticals, an Australian pain drug development company, today announces that The Lancet has published the results of its Phase 2 clinical trial of its lead candidate, EMA401, in postherpetic neuralgia (PHN). EMA401 is a novel angiotensin II type 2 (AT₂) receptor antagonist under development as a potential first-in-class oral treatment for chronic pain without CNS side effects. PHN is a painful condition that develops in some patients following herpes zoster (shingles) and where existing therapy does not relieve pain in all individuals.

The Phase 2 trial met its primary endpoint by showing that patients randomised to EMA401 achieved a greater reduction in pain from baseline to the last week of 28 days of treatment than patients randomised to placebo. Analysing all patients randomised (intent to treat population), the mean pain intensity reduction from baseline after 4 weeks treatment was as follows: EMA401: -2.29; Placebo: -1.60; p = 0.007.

A significantly greater proportion of patients on active treatment reported a more than 30% reduction in mean pain intensity score compared to baseline (i.e. responder rate) (EMA401: 57.6%; Placebo: 35.2%; p = 0.0023), meeting a key secondary endpoint.

A subgroup of patients who had moderate or severe pain at study entry continued to take a single existing medicine for their PHN during the study (45% of patients in the EMA401 group and 40% of patients in the placebo group). In this subgroup, patients randomised to EMA401 achieved significantly greater pain reduction when compared to patients randomised to placebo. In addition, pain relief was also observed in those patients that were not taking a single existing medicine for their PHN. These results indicate that EMA401 may have the potential to provide relief for patients with PHN who don't achieve optimal pain relief with current treatments or who don't wish to continue with these medicines due to their side effects.