Accelerated enrollment of Phase III (PEGASUS) pivotal trial of PRN 1008 to treat pemphigus vulgaris. --Principia Biopharma Inc.

Principia Biopharma Inc. announced updated anticipated timing for final results in its ongoing pivotal Phase III clinical trial of PRN 1008 data in patients with pemphigus, as well as complete response rates from its Phase II Part B open-label trial . "We are delighted to see the interest in our Phase III PEGASUS trial and through the hard work of our investigators, study coordinators and our own clinical team, we believe the accelerated enrollment timelines now project us to have final data in the second half of 2021 as opposed to the first half of 2022,” said Dolca Thomas, MD, Principia’s chief medical officer. “And we are pleased to see that the complete response (CR) rate in the Phase II Part B trial was 40 percent (six patients) despite most patients being initially treated at a sub-therapeutic dose 400 mg once daily.” Among the 15 patients dosed in Part B of the Phase II trial,nine (60 percent) achieved the primary endpoint of control of disease activity (CDA) by week four on low dose corticosteroids (less than or equal to 0.5 mg/kg per day) . 12 of 15 (80 percent) patients achieved CDA by week 12 . Nine (60 percent) of the 15 patients have achieved a PDAI score (a scoring system to indicate disease severity) of 1 or 0. Safety of PRN 1008 is consistent with Phase II Part A trial and has been well-tolerated in Part B with no treatment related serious adverse event reported. Final data from the Phase II Part B trial will be submitted for presentation at an upcoming medical conference . About PEGASUS -- the Phase III Trial of PRN 1008 : Principia is currently enrolling patients in a global, randomized, double-blind, placebo-controlled, pivotal, Phase III clinical trial, the PEGASUS study, in approximately 120 patients to evaluate PRN 1008 versus placebo using a background treatment of tapering doses of CS (corticosteroids). The trial entry criteria include patients with moderate to severe pemphigus who are either newly diagnosed or relapsing with chronic disease. This demographic will potentially represent three quarters of the pemphigus patient population. The primary efficacy endpoint is the ability of PRN 1008 to achieve durable CR on very low-dose CS (low dose corticosteroids) (5 mg/day) at 37 weeks of treatment. Durable CR is defined as a state in which all lesions have healed, and no new lesions have appeared for a period of at least eight weeks. Key secondary endpoints include cumulative CS use and time to CR. After 37 weeks, all patients will have the option to be treated with active PRN 1008 therapy in an open-label extension period of 24 weeks. Comment: Pemphigus vulgaris is a rare, potentially life-threatening orphan autoimmune disease associated with painful chronic blistering of the skin..