Zosano Pharma has started enrolment in a Phase II/III clinical trial being conducted to assess C213 for the acute treatment of adults with cluster headache.

C213 is an investigational formulation of zolmitriptan and is delivered using the company’s ADAM patch technology. ADAM is made of titanium micro-projections that are coated with the drug.

The randomised, double-blinded, multi-centre, placebo-controlled Phase II/III trial will assess the safety and efficacy of C213 compared to placebo in a total of 120 patients.

Participants will be treated with 1.9mg or 3.8mg of C213 or placebo.

Cluster headache is a neurological condition causing severe unilateral temporal and orbital pain that lasts from 15 minutes to three hours. Patients may suffer cluster headache episodes up to eight times per day.

Currently, more than 300,000 people in the US suffer from the debilitating neurological condition.

Zosano Pharma Clinical Development and Medical Affairs vice-president Dr Don Kellerman said: “We are pleased to expand the application of our ADAM microneedle technology beyond our lead development indication for the acute treatment of migraine with this advanced stage clinical study in cluster headache.

“This population suffers from excruciating and debilitating pain and has limited effective treatment options with no new FDA-approved drugs for the acute treatment of cluster headache since the 1990s.”

The trial’s co-primary endpoints are the proportion of participants experiencing pain relief at 15 minutes and the proportion of patients who have pain relief maintained from 15 to 60 minutes.

The trial will also measure multiple secondary outcomes, including incidence of adverse events and serious adverse events, pain freedom and use of rescue therapy.

Kellerman added: “We are excited that the clinically significant pain freedom and relief observed in our migraine trial will potentially also be demonstrated in the cluster headache clinical trial.”