MACOP-B regimen in the treatment of adult Langerhans cell histiocytosis: experience on seven patients

Adult Langerhans cell histiocytosis (LCH) is a rare disease. The combination of vinblastine and prednisone, given in a 6-month course, is the standard of care but prospective randomized trials are lacking. We report our monocentric experience in the treatment of seven adult patients with multisystem (MS) LCH (n = 3) or single-system multifocal (SS-m) LCH (n = 4) with the short-course intensive chemotherapy regimen methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone and bleomicin (MACOP-B). The overall response rate was 100% [five complete response (CR), two partial response (PR)]. After a median follow-up of 6.5 years, four patients are in first continuous CR and three patients relapsed after 5, 8 and 62 months, respectively. Four patients were evaluated with positron emission tomography (PET) scan: all three PET-negative patients at the end of treatment had a long-lasting response with only one patient relapsing after 5 years. PET scan detected additional bone lesions at diagnosis in two of four patients, changing the treatment program in one of them. MACOP-B regimen seems to be very active in the treatment of adult MS or SS-m LCH, with long-lasting responses in five of seven patients. PET scan merits further evaluation in the initial staging and in the evaluation of the response to chemotherapy.