Vera Therapeutics has initiated a Phase III clinical trial of atacicept to treat IgA nephropathy (IgAN), an autoimmune disease of the kidney also known as Berger’s disease.

The placebo-controlled, multinational, double-blind, multicentre, randomised pivotal ORIGIN 3 study will assess the efficacy and safety of atacicept 150mg in IgAN patients who continue to have persistent proteinuria.

Patients who remain at high disease progression risk despite taking a stable prescribed regimen of angiotensin II receptor blocker (ARB) or angiotensin-converting enzyme inhibitor (ACEi) are also enrolled.

Preserving the renal function compared to placebo and determining the effect of atacicept on proteinuria are the study objectives.

The study includes a 104-week double-blind treatment period in which 188 participants will be administered subcutaneously with atacicept 150mg once weekly and 188 subjects with a placebo.

It also includes a four-week screening period, a 52-week open-label extension along with 26-week follow-up period.

Change in proteinuria as evaluated by urine protein to creatinine ratio (UPCR) at week 36 is the primary endpoint while the annualised rate of change in estimated glomerular filtration rate (eGFR) up to week 104 is the key secondary endpoint.

Change in eGFR up to week 52, change in Gd-IgA1, and time from randomisation to the first occurrence of composite kidney failure endpoint event are considered as additional secondary endpoints.

Vera Therapeutics CEO Marshall Fordyce said: “Building upon positive data from our Phase IIb trial that show atacicept’s best-in-class potential, initiation of the pivotal ORIGIN 3 trial is a crucial milestone in the advancement of its clinical development.

“Our Phase II results have shown that atacicept targets the source of IgA nephropathy and improves kidney function as measured by statistically and clinically significant reductions in proteinuria.

“As we enrol this pivotal Phase III trial, we plan to share longer-term Phase II results later in 2023 and 2024.”

Atacicept is a dual inhibitor of the cytokines B lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL).