US-based Inotek Pharmaceuticals has started dosing in MATRx-1, the first pivotal Phase III trial of its lead clinical candidate trabodenoson for the treatment of glaucoma.

Trabodenoson is a first-in-class selective adenosine mimetic under investigation for reduction of intraocular pressure.

Approximately 335 patients diagnosed with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) are enrolled in this randomised, double-masked, placebo-controlled Phase III MATRx-1 trial.

The trial is designed to evaluate the efficacy, safety and tolerability of trabodenoson over three months of treatment.

The primary endpoint of the trial will be the reduction of intraocular pressure (IOP) as compared to the placebo treatment arm.

In addition, the trial will contain a timolol 0.5% arm to validate the sensitivity of the patient population.

In the trial, intraocular pressure (IOP) will be measured at four timepoints during days 14, 28, 42, and 84.

Patients will be given three doses of trabodenoson 1,000mcg once daily, 1,500mcg twice daily and 2,000mcg once daily to evaluate the efficacy in intraocular pressure lowering, while maintaining the tolerability and safety profile observed in Phase II trials.

"Patients suffering from glaucoma need new therapies that are both efficacious and well-tolerated."

The trial will include patients with IOP greater than or equal to 24mm Hg and less than or equal to 34mm Hg, which represents the patients most likely to receive treatment for glaucoma or ocular hypertension.

Inotek chief medical officer Dr Rudolf Baumgartner said: "Based on the encouraging Phase II results as well as guidance from the US Food and Drug Administration (FDA), our team has formalised plans for our Phase III programme to support a new drug application (NDA) for trabodenoson in glaucoma.

"If approved, trabodenoson, with its potential for once daily dosing and a mechanism that may compliment currently available glaucoma medications, has potential as a valuable treatment option for physicians managing the IOP of patients with this disease."

The company intends to complete the Phase III MATRx-1 trial in 2016, with top-line results anticipated in the fourth quarter of the same year.

Inotek executive vice president and chief scientific officer William McVicar said: "Patients suffering from glaucoma need new therapies that are both efficacious and well-tolerated.

"Trabodenoson was developed with the objective of restoring the natural pressure-regulating process that occurs in the healthy eye, and thus lowering IOP. The compound specifically targets the adenosine A1 receptor, one of four known receptors for this naturally occurring purinergic regulator.

"Stimulation of the A1 receptor on human trabecular meshwork cells in culture releases proteases, which can digest and remove hydrolysed proteins that can clog the trabecular meshwork, obstructing the eye’s drainage system."

Inotek is focused on the discovery, development and commercialisation of therapies for glaucoma and other eye diseases.

Trabodenoson was developed in the company’s laboratories and designed to restore the eye’s natural pressure control mechanism.