Patient description: A 57-year-old man was admitted to the clinic because of weight loss and persistent dry cough 4 months ago. Chest computed topography showed bilateral multiple infiltrates in the upper lobes and thickened bronchial walls. There is a documented positive serum MPO-ANCA in his medical record. Transbronchial biopsy revealed necrotic granulomas with multinucleated giant cells and the Wegener's granulomatosis was diagnosed for him. He is treating with corticosteroid and cyclophosphamides since 4 months ago. His Birmingham Vasculitis Activity Score (BVAS) is above 4 since the beginning of his disease. His last physical exam and lab study was performed yesterday and showed the results bellow: A wellbeing, well-nourished man, non-icteric, cooperative and alert Weight: 73 kg Height: 177 BP: 120/80 HR: 90/min RR: 22/min Hgb: 13 g/dl WBC: 8000 /mm3 (Neutrophil: 2700/mm3) Plt: 300000 /ml AST: 40 U/L ALT: 56 U/L Alk P: 147 U/L Bill total: 1.2 mg/dl ESR: 120 mm/hr MPO-ANCA: 153 EU

Clinical trial eligibility criteria: eligible ages (years): 1.0-39.0,  Anaplastic Astrocytoma Anaplastic Ependymoma Anaplastic Ganglioglioma Anaplastic Meningioma Anaplastic Oligodendroglioma Pleomorphic Xanthoastrocytoma, Anaplastic Atypical Teratoid/Rhabdoid Tumor Brain Cancer Brain Tumor Central Nervous System Neoplasms Choroid Plexus Carcinoma CNS Embryonal Tumor With Rhabdoid Features Ganglioneuroblastoma of Central Nervous System CNS Tumor Embryonal Tumor of CNS Ependymoma Glioblastoma Glioma Glioma, Malignant Medulloblastoma Medulloblastoma; Unspecified Site Medulloepithelioma Neuroepithelial Tumor Neoplasms Neoplasms, Neuroepithelial Papillary Tumor of the Pineal Region (High-grade Only) Pediatric Brain Tumor Pineal Parenchymal Tumor of Intermediate Differentiation (High-grade Only) Pineoblastoma Primitive Neuroectodermal Tumor Recurrent Medulloblastoma Refractory Brain Tumor Neuroblastoma. CNS Glioblastoma, IDH-mutant Glioblastoma, IDH-wildtype Medulloblastoma, Group 3 Medulloblastoma, Group 4 Glioma, High Grade Neuroepithelial Tumor, High Grade Medulloblastoma, SHH-activated and TP53 Mutant Medulloblastoma, SHH-activated and TP53 Wildtype Medulloblastoma, Chromosome 9q Loss Medulloblastoma, Non-WNT Non-SHH, NOS Medulloblastoma, Non-WNT/Non-SHH Medulloblastoma, PTCH1 Mutation Medulloblastoma, WNT-activated Ependymoma, Recurrent Glioma, Recurrent High Grade Glioma, Recurrent Malignant Embryonal Tumor, NOS Glioma, Diffuse Midline, H3K27M-mutant Embryonal Tumor With Multilayered Rosettes (ETMR) Ependymoma, NOS, WHO Grade III Ependymoma, NOS, WHO Grade II Medulloblastoma, G3/G4 Ependymoma, RELA Fusion Positive Potential participants will first be screened using the screening inclusion/exclusion shown below. If they meet the requirements of the screening phase, they will then be evaluated for enrollment based on the overall study's as well as the stratum-specific inclusion/  for the applicable stratum, all of which are shown below ALL Participants with recurrent, progressive, or refractory brain tumors Age ≥ 1 year and < 25 years at the time of screening. Exception: Participants with recurrent, progressive, or refractory Medulloblastoma and are ≥ 1 and < 40 years of age at the time of study screening are eligible for screening Participants and/or guardian have the ability to understand and the willingness to sign a written informed consent document according to institutional guidelines ALL Participants with a diagnosis of recurrent, progressive, or refractory low grade glioma (LGG) Previous exposure to a CDK4/6 inhibitor (palbociclib, abemaciclib, or ribociclib) Participants with a history of clinically significant, uncontrolled heart disease and/or repolarization abnormalities Participants with any history of QTc prolongation (i.e. QTc interval of > 450 msec). Participants who meet the requirements of the screening phase will then be evaluated for enrollment based on the overall study's as well as the stratum-specific inclusion/