Granulomatosis with polyangiitis (GPA) is a rare autoimmune disease that causes inflammation in small and medium-sized blood vessels, affecting organs such as the lungs, kidneys, and sinuses. We report the case of a 66-year-old man with relapsing GPA. He first presented with sinus and ear symptoms, which were managed with steroids and other immunosuppressive drugs. After many years of remission, he relapsed with nasal congestion, nosebleeds, and lung nodules. During his latest flare, he was treated with high-dose prednisone, rituximab, and avacopan, a new oral drug that blocks the C5a receptor. Avacopan helped reduce inflammation and allowed for a significant decrease in steroid use. The patient's rapid improvement supports the role of avacopan as a steroid-sparing agent in GPA management, offering a promising way to reduce the harmful side effects of long-term steroid therapy.