Histiocytic Neoplasms, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Histiocytic neoplasms are rare hematologic disorders accounting for less than 1% of cancers of the soft tissue and lymph nodes. Clinical presentation and prognosis of these disorders can be highly variable, leading to challenges for diagnosis and optimal management of these patients. Treatment often consists of systemic therapy, and recent studies support use of targeted therapies for patients with these disorders. Observation ("watch and wait") may be sufficient for select patients with mild disease. These NCCN Guidelines for Histiocytic Neoplasms include recommendations for diagnosis and treatment of adults with the most common histiocytic disorders: Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease.

Reduced-Intensity Conditioning with Fludarabine, Melphalan, and Total Body Irradiation for Allogeneic Hematopoietic Cell Transplantation: The Effect of Increasing Melphalan Dose on Underlying Disease and Toxicity

Disease relapse and toxicity are the shortcomings of reduced-intensity conditioning (RIC) for allogeneic hematopoietic cell transplantation (alloHCT). We hypothesized that adding total body irradiation (TBI) to and decreasing melphalan (Mel) from a base RIC regimen of fludarabine (Flu) and Mel would increase cytoreduction and improve disease control while decreasing toxicity. We performed a phase II trial of Flu 160 mg/m², Mel 50 mg/m², and TBI 400 cGy (FluMelTBI-50, n = 61), followed by a second phase II trial of Flu 160 mg/m², Mel 75 mg/m², and TBI 400cGy (FluMelTBI-75, n = 94) as RIC for alloHCT. Outcomes were compared with a contemporaneous cohort of 162 patients who received Flu 125 mg/m² and Mel 140 mg/m². Eligibility criteria were equivalent for all 3 regimens. All patients were ineligible for myeloablative/intensive conditioning. The median (range) follow-up for all patients was 51 (15 to 103) months. Day 100 donor lymphoid chimerism and transplant-related mortality, neutrophil and platelet engraftment, acute and chronic graft versus host disease incidence, overall survival (OS), and progression-free survival (PFS) were equivalent between FluMel, FluMelTBI-50, and FluMelTBI-75. Stomatitis wasdecreased for FluMelTBI versus FluMel (P < .01). PFS for patients not in complete remission on alloHCT was improved for FluMelTBI-75 versus FluMel (P = .03). On multivariate analysis, OS (P = .05) and PFS (P = .05) were significantly improved for FluMelTBI-75 versus FluMel. FluMelTBI-75 is better tolerated than FluMel, with improved survival and disease control.

Phase II study of pentostatin in patients with corticosteroid-refractory chronic graft-versus-host disease

PURPOSE

Therapy for patients with chronic graft-versus-host disease (cGVHD) is based on prolonged immunosuppression with corticosteroids. There is no standard therapy for patients whose cGVHD does not resolve with corticosteroid treatment. Pentostatin, a potent inhibitor of adenosine deaminase, has activity in acute GVHD. We examined the toxicity and efficacy of pentostatin in a prospective phase II trial in corticosteroid-refractory cGVHD.

PATIENTS AND METHODS

Patients of any age were eligible. Patients received pentostatin 4 mg/m2 intravenously every 2 weeks for 12 doses, and continued therapy as long as benefit was documented. Corticosteroid taper was begun after three doses of pentostatin. Responses were graded in real time in the skin, mouth, and liver using objective response criteria.

RESULTS

Fifty-eight heavily pretreated (median, four prior regimens) patients (median age, 33 years) were enrolled. Results are shown as an intent-to-treat analysis. Of the 58 patients, a total of 32 (55%; 95% CI, 42% to 68%) had an objective response, as evaluated by use of a new grading scale. Infection was the most significant toxicity, with 11 grade 3 to 4 infectious events. The survival at 1 and 2 years was 78% (95% CI, 64% to 86%) and 70% (95% CI, 57% to 80%), with cGVHD with/without infection accounting for the majority of deaths.

CONCLUSION

Pentostatin has immunosuppressive effects that are currently being explored further for treatment of cGVHD.

Pentostatin - pharmacology, immunology, and clinical effects in graft-versus-host disease

Pentostatin (deoxycoformycin), is one of a number of purine analogues. The drug was originally designed to mimic a form of severe combined immune deficiency, characterised by marked T lymphopenia but variable B cell function. Clinically, the drug has been used primarily to treat a rare type of leukaemia - hairy cell leukaemia. Recently, the drug has seen increasing attention as an immunosuppressant. This review will cover the basic pharmacology and immunological effects of pentostatin. The clinical use of this agent in prevention and treatment of graft-versus-host disease will be examined. Although many of these studies are ongoing, this agent has promise as a novel immunosuppressive agent with a new mechanism of action.