TAVNEOS for Otolaryngologic Manifestations of Granulomatosis With Polyangiitis

Inclusion Criteria: * GPA diagnosis defined by score of ≥5 on 2022 ACR/EULAR Classification Criteria for GPA * Active GPA (both newly diagnosed and relapsing disease) in the ENT domain within 1 month prior to screening, where the active disease is defined as a score of ≥2 on a GPA ENT disease activity score (7 items scored as 1= present 0= absent) performed by direct endoscopic visualization of the upper airway and audiometric evaluation, if applicable, by a single expert otolaryngologist. Items included in the GPA ENT disease activity score are: * Bloody rhinorrhea (Daily blood stained nasal discharge) * Objective stridor (Stridor assessed by doctor) * Inflammation on nasal examination (Ulcers, granulation, friable mucosa on rigid nasal endoscopy. Excluding crusting) * Inflammation on flexible laryngoscopy (Ulcers, granulation, friable mucosa in the larynx) * Inflamed TM\*/middle ear (Persistent inflammation or granulation tissue in tympanic membrane/middle ear) * Sudden sensorineural hearing loss (30db drop in 3 frequencies within 72 hours) * Other ENT/upper airway manifestations of active GPA observed during structured ENT exam including but not limited to lacrimal gland dacryocystitis and endobronchial disease * Age 18 and older * Willing and able to comply with treatment and follow-up procedures * Men and women of reproductive potential must agree to use an acceptable method of birth control during treatment and for twelve months after completion of treatment. * Willing and able to provide written informed consent * Adequate liver function as defined by AST or ALT \<2x Upper Limit of Normal Exclusion Criteria: * Creatinine \>4.0mg/dl or GFR \<15 at baseline or dependence on dialysis * Respiratory failure requiring mechanical ventilatory support or had experienced alveolar hemorrhage requiring invasive pulmonary ventilation support anticipated to last beyond the screening period of the study * Previous treatment with TAVNEOS within 6 months of screening * Inability to comply with study and/or follow-up procedures at investigator discretion. * Intravenous glucocorticoids in the 4 weeks prior to screening except as premedication prior to infusion of rituximab * Pregnant or breast-feeding * Any other known multi-system autoimmune disease including eosinophilic granulomatosis with polyangiitis (Churg-Strauss), systemic lupus erythematosus, IgA vasculitis (Henoch-Schonlein), rheumatoid vasculitis, Sjogren's syndrome, anti-glomerular basement membrane disease, or cryoglobulinemic vasculitis * Required dialysis or plasma exchange within 12 weeks prior to screening * Have had a kidney transplant * Any of the following within 12 weeks prior to screening: symptomatic congestive heart failure requiring prescription medication, unstable angina (unless successfully treated with stent or bypass surgery), clinically significant cardiac arrhythmia, myocardial infarction or stroke * History or presence of any form of cancer within the 5 years prior to screening, with the exception of excised basal cell or squamous cell carcinoma of the skin, or carcinoma in situ such as cervical or breast carcinoma in situ that has been excised or resected completely and is without evidence of local recurrence or metastasis * Evidence of tuberculosis based on interferon gamma release assay (IGRA), tuberculin purified protein derivative (PPD) skin test, or chest radiography (X rays or CT scan) done at screening or within 6 weeks prior to screening * HBV, HCV, or HIV viral screening test showing evidence of active or chronic viral infection done at screening or within 6 weeks prior to screening * Received a live vaccine within 4 weeks prior to screening * WBC count less than 3500/uL, or neutrophil count less than 1500/uL, or lymphocyte count less than 500/uL before start of dosing * Evidence of hepatic disease: AST, ALT, alkaline phosphatase, or bilirubin \>3 times the upper limit of normal before start of dosing * Known hypersensitivity to avacopan or inactive ingredients of the TAVNEOS capsules * Participated in any clinical study of an investigational product within 30 days prior to screening or within 5 half-lives after taking the last dose * Participated previously in an TAVNEOS study * Concurrent use of strong inducers of the CYP450 ie. carbamazepine, phenobarbital, phenytoin, rifampin, or St. John's wort * Known hypersensitivity to avacopan or inactive ingredients of the avacopan capsules (including gelatin, polyethylene glycol, or Cremophor) * History or presence of any medical condition or disease which, in the opinion of the Investigator, may place the patient at unacceptable risk for study participation