FDA Approves Mepolizumab (Nucala) for EPGA

The US Food and Drug Administration (FDA) has approved mepolizumab (Nucala) as the first drug specifically for adults with rare autoimmune disease eosinophilic granulomatosis with polyangiitis (EGPA).

EPGA, formerly known as Churg-Strauss syndrome, causes vasculitis, an inflammation in the wall of blood vessels of the body. It’s characterized by asthma, high eosinophil levels, and small- to medium-sized blood vessel inflammation in patients. It is prevalent in about 10.7 to 14 of every 1 million adults.

Nucala, a subcutaneous injection previously approved to treat adolescents and adults with severe asthma with an eosinophilic phenotype in 2015, was given Priority Review and Orphan Drug designations by the FDA.

The treatment is an interleukin-5 antagonist monoclonal antibody produced by GlaxoSmithKline (GSK), backed by 52-week, phase 3 clinical trial (MIRRA) comparing Nucala to placebo.

In the MIRRA trial, patients received 300 mg of Nucala or placebo, each administered once every 4 weeks, while continuing a daily oral corticosteroid (OCS) therapy. OCS was tapered during the treatment period, starting a week 4.

Researchers assessed Nucala’s efficacy, with a primary endpoint of reaching disease remission while on an OCS dose of 4 mg prednisone or less.

The patients with EGPA receiving 300 mg Nucala reported significantly greater accrued remission time versus the placebo population, and a higher proportion of Nucala patients achieved remission at both week 36 and 48.

A significantly greater rate of patients administered 300 mg Nucala also reached remission by week 24, and retained remission for the remainder of the study, versus the placebo population.

Adverse events commonly reported in the Nucala patient population included headache, injection site reaction, back pain, and fatigue. However, percentage of patients to experience adverse events were comparable between the patient groups — 97% of Nucala patients and 94% of placebo patients, according to GSK.

The significance of patients’ retention of remission is due to patients with EGPA often suffering recurring relapses that could cause permanent tissue and organ damage, Michael Wechsler, MD, MIRRA principal investigator and Professor of Medicine at National Jewish Health in Denver, CO, said.

“These are key treatment goals and this approval is an important milestone both for treating physicians and for patients,” Wechsler said.

The trial was the largest prospective treatment study conduction in the rare disease, GSK Global Respiratory Franchise senior vice president Eric Dube said.

“Following physician and patient experience with Nucala in severe eosinophilic asthma, we are thrilled that the FDA has expanded the use of this medicine to patients with EGPA, another eosinophil-driven disease, enabling GSK to make it available to patients,” Dube said.

Nucala for the treatment of adults with EGPA is now available in the US market, and GSK has stated various patient assistant programs for treatment affordability are available for those who qualify.

A press release regarding the approval was made available.