GSK given green light for Churg-Strauss syndrome treatment

GlaxoSmithKline has been given approval by the US drug regulator for a first targeted treatment for eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome.

The US Food & Drug Administration has approved GSK's Nucala, the brand name given to the interleukin-5 (IL-5) antagonist drug mepolizumab, as the first targeted treatment for EGPA.

Glaxo's respiratory chief 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.

"This approval follows the positive results of the largest prospective treatment study conducted in EGPA to date, and now for the first time physicians have a targeted treatment option for this debilitating condition."

EGPA is a chronic rare disease caused by inflammation in the walls of small-to-medium sized blood vessels, with a global incidence generally reported to be in the range of one to four sufferers per million, with an estimated prevalence of approximately 14-45 per million that translates to approximately 5,000 patients with EGPA in the US.

Mepolizumab is not approved for the treatment of other eosinophilic conditions or relief of acute bronchospasm or status asthmaticus.

The approval for EGPA is based on results from the 52-week, Phase III Mirra1 study, conducted as a collaboration between GSK and the National Institute of Allergy and Infectious Diseases, part of the US National Institutes of Health.

The Mirra study evaluated the efficacy and safety of 300mg of mepolizumab administered subcutaneously every four weeks versus placebo as add-on therapy in 136 patients with relapsing and/or refractory EGPA, in comparison to the current standard of care, which is a treatment of corticosteroids plus or minus immunosuppressants.

Both co-primary endpoints of accrued time in remission and proportion of patients achieving remission at both weeks 36 and 48 were found to be statistically significant in favour of mepolizumab, which also met all six secondary endpoints of investigating relapse, remission, and corticosteroid use.

GSK said injection site reactions such as pain, erythema or swelling occurred at a rate of 15% in patients receiving mepolizumab compared with 13% in patients receiving placebo. Eighteen percent of patients receiving mepolizumab reported serious adverse events compared with 26% in the placebo group, with the most frequently reported being asthma worsening/exacerbation, of 3% versus 6%.

The FTSE 100 pharma group said that Nucala for treatment of EGPA is available in the US now and in recognition of the fact that US consumers are increasingly being asked by their insurers to take on more cost sharing, GSK has various patient assistance programmes available for those who qualify.