prednisone + vinblastine + 6-mercaptopurine

This is a combination chemotherapy regimen consisting of three small molecule drugs—prednisone, vinblastine, and 6-mercaptopurine. Prednisone is a synthetic glucocorticoid corticosteroid with anti-inflammatory and immunosuppressive properties. Vinblastine is a vinca alkaloid that inhibits microtubule formation, thereby arresting cell division in metaphase. 6-mercaptopurine (also known as mercaptopurine) is an antimetabolite that interferes with purine nucleotide synthesis, inhibiting DNA and RNA synthesis in rapidly dividing cells. This combination has been used primarily for the treatment of hematologic malignancies such as Langerhans cell histiocytosis (LCH) and other rare histiocytic disorders. In LCH, prednisone plus vinblastine forms the backbone of first-line therapy; 6-mercaptopurine may be added for patients with risk organ involvement or more aggressive disease[2][3][7]. The regimen aims to suppress abnormal immune cell proliferation while targeting malignant or dysregulated hematopoietic cells.