Principia Biopharma has reported positive top-line results from a Phase II trial of PRN1008 to treat patients with pemphigus vulgaris (PV) and pemphigus foliaceus (PF).

The trial met its primary efficacy endpoint after more than 50% of the patients achieved control of disease activity (CDA) within four weeks of treatment with PRN1008.

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PRN1008 was also reported to be generally well tolerated during the course of the open-label trial.

Results also showed sustained clinical efficacy at 12 weeks, which was a secondary endpoint of the trial.

Principia has now commenced the pivotal, global, randomised, double-blind, placebo-controlled Phase III PEGASUS trial that intends to examine PRN1008 in patients with moderate to severe pemphigus.

“PRN1008 has the potential to effectively treat patients’ disease and significantly reduce dependence on harmful corticosteroid doses.”

The trial’s lead principal investigator Dr Dedee Murrell said: “PRN1008 has the potential to effectively treat patients’ disease and significantly reduce dependence on harmful corticosteroid (CS) doses, which have been the mainstay of treatment in this disease, and may usher in a new era of steroid-sparing, oral therapy for patients suffering from the disease.”

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Principia has enrolled 27 patients to investigate the potential of the drug to induce rapid onset of clinical response as part of the Phase II PRN1008 trial.

The aim is to enable tapering and / or avoidance of CS use, reducing autoantibody levels while having minimal and reversible effects on the patient’s immune system.

Patients with newly diagnosed or relapsing, mild or moderate pemphigus were included in the trial.

They received a twice-daily dose of oral PRN1008 for 12 weeks followed by a post-treatment follow-up period lasting the same duration.

Principia has already begun an extension to the trial to increase the active treatment period from 12 to 24 weeks, with a post-treatment follow-up period of four weeks.

The company expects to unveil top-line results from its extension phase in the second half of next year.

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