AstraZeneca's Fasenra (benralizumab) has secured FDA approval for the treatment of adult patients with eosinophilic granulomatosis with polyangiitis (EGPA), a rare immune-mediated vasculitis. This approval marks a significant advancement in the treatment landscape for EGPA, offering a new option for patients who often face debilitating symptoms and limited treatment choices.
The FDA's decision was based on the positive results from the Phase III MANDARA trial, a randomized, double-blind, active-controlled study that compared the efficacy and safety of Fasenra to mepolizumab, the only other approved EGPA treatment. The trial, published in The New England Journal of Medicine, enrolled 140 adult patients with relapsing or refractory EGPA, randomizing them to receive either a single 30 mg subcutaneous injection of Fasenra or three separate 100 mg subcutaneous injections of mepolizumab every four weeks.
Key Findings from the MANDARA Trial
The MANDARA trial demonstrated that nearly 60% of Fasenra-treated patients achieved remission, a rate comparable to that of mepolizumab-treated patients. Remission was defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 and an oral corticosteroid (OCS) dose of ≤4 mg/day. Importantly, 41% of Fasenra-treated patients were able to fully taper off oral corticosteroids (OCS), compared to only 26% in the mepolizumab arm (difference: 16%; 95% CI: 1, 31).
Clinical Significance
"This approval is great news for patients with EGPA in the US who continue to suffer from debilitating symptoms," said Dr. Michael Wechsler, Professor of Medicine and Director of The Asthma Institute at National Jewish Health, and International Coordinating Investigator of the MANDARA trial. "Patients often rely on long-term oral corticosteroids, which can cause serious and lasting side effects. Benralizumab is a much-needed treatment option, with data showing that not only is remission an achievable goal for EGPA patients, but benralizumab can also help patients taper off steroid therapy."
Understanding EGPA
EGPA, formerly known as Churg-Strauss Syndrome, is a rare, immune-mediated inflammatory disease characterized by inflammation of small to medium-sized blood vessels. It is estimated that approximately 15,000 patients in the US live with EGPA. The disease can result in damage to multiple organs, including the lungs, upper airway, skin, heart, gastrointestinal tract, and nerves. Common symptoms include extreme fatigue, weight loss, muscle and joint pain, rashes, nerve pain, sinus and nasal symptoms, and shortness of breath. Without treatment, EGPA can be fatal.
Fasenra's Mechanism of Action
Fasenra (benralizumab) is a monoclonal antibody that binds directly to the interleukin-5 receptor α subunit (IL-5Rα) on eosinophils and induces antibody-dependent cell-mediated cytotoxicity (ADCC), leading to eosinophil depletion. By reducing eosinophil levels, Fasenra helps to reduce inflammation and prevent organ damage in EGPA patients.
Safety and Tolerability
The safety and tolerability profile of Fasenra in the MANDARA trial was consistent with its known profile. The most common adverse reactions reported in clinical trials include headache and pharyngitis.
Implications for Treatment
The approval of Fasenra provides a valuable new treatment option for EGPA patients, particularly those who struggle with the side effects of long-term corticosteroid use. Its convenient once-monthly subcutaneous administration also offers an advantage for patient adherence. With approximately half of EGPA patients also having adult-onset severe eosinophilic asthma, Fasenra addresses a critical unmet need in this patient population.
