Rituximab for the Otolaryngologic Manifestations of Granulomatosis With Polyangiitis

Inclusion Criteria: GPA Specific Inclusion: 1. Patients must have met at least 2 of the 5 modified ACR classification criteria for GPA. These do not need to be present at the time of study entry. The modified ACR criteria are: * Nasal or oral inflammation, defined as the development of painful or painless oral ulcers or purulent or bloody nasal discharge * Abnormal chest radiograph, defined as the presence of nodules, fixed infiltrates, or cavities * Active urinary sediment, defined as microscopic hematuria (\>5 red blood cells per high power field) or red blood cell casts * Granulomatous inflammation on biopsy, defined as histologic changes showing granulomatous inflammation within the wall of an artery or in the perivascular or extravascular area (artery or arteriole) * Positive anti-neutrophil cytoplasmic antibody (ANCA) test specific for proteinase-3, measured by enzyme-linked immunoassay 2. Active GPA 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 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 nasendoscopy. 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 General Medical Concerns: 3. Age 18 and older 4. Willing and able to comply with treatment and follow-up procedures 5. 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. 6. Willing and able to provide written informed consent Rituximab-Specific Concerns: * ANC: \> 1000/mm3 * Platelets: \> 100,000/mm3 * Hemoglobin: \> 7 gm/dL * Adequate renal function as indicated by Cr \>4.0mg/dl * Adequate liver function as defined by AST or ALT \<2x Upper Limit of Normal unless related to primary disease. Exclusion Criteria: Disease-Specific Concerns: 1. Creatinine \>4.0mg/dl 2. Respiratory failure requiring mechanical ventilatory support 3. Previous treatment with rituximab (Rituxan® ) within 6 months of screening 4. History of severe allergic or anaphylactic reaction or serious infusion reaction while receiving rituximab 5. Failure to respond to previous course of rituximab (Rituxan®) administered for treatment of GPA, as determined by the discretion of the PI 5\. History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies 6. Use of the maintenance immunosuppressive agent (methotrexate, azathioprine, mycophenolate mofetil or leflunomide) within 5 drug half-lives prior to baseline 7. Treatment with any other biologic agent, including belimumab, within the past 3 months of screening 8. Treatment with cyclophosphamide (oral or intravenous) within the past 1 month of screening General Medical Concerns: * Pregnancy (a negative serum pregnancy test should be performed for all women of childbearing potential within 7 days of treatment), or lactating. * Inability to comply with study and/or follow-up procedures. Rituximab-Specific Concerns: * History of HIV. * Presence of active infection.. * New York Heart Association Classification III or IV heart disease (See Appendix D). * Concomitant malignancies or previous malignancies within the last five years, with the exception of adequately treated basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix. * History of psychiatric disorder. * At the Investigator's discretion, receipt of a live vaccine within 4 weeks prior to randomization. Positive hepatitis B or C serology is considered a potential exclusion criterion. Hepatitis B screening should include hepatitis B surface antigen (HBsAg) and core antibody (anti-HBc) in all patients. For patients who show evidence of prior hepatitis B infection (HBsAg positive \[regardless of antibody status\] or HBsAg negative but anti-HBc positive), consult with physicians with expertise in managing hepatitis B regarding monitoring and consideration for HBV antiviral therapy before and/or during Rituxan treatment.