Methotrexate-Asparaginase-Dexamethasone Regimen for Blastic Plasmocytoid Dendritic Cell Neoplasm treatment

Abstract 2194 Blastic plasmacytoid dendritic cell neoplasm (BPDCN), previously named CD4 CD56 haematodermic neoplasia is a rare malignancy, associated with poor prognosis; it affects older patients and has a typical clinical pattern, with initially skin involvement and evolution toward leukaemia. To date, best responses for patients younger than 60 yrs are obtained after induction chemotherapy acute lymphoblastic leukaemia-like and allogeneic bone marrow transplantation (Dalle, BJD 2010); for older patients there is no standardized treatment in first line; the CHOP or CHOP-like regimens don't improve the outcome of these patients. We report our experience in 6 patients with BPDCN treated with Methotrexate-Asparaginase (MTX ASP) steroid regimen, active in lymphoid malignancies. From august 2006 to December 2009, 6 patients (pts) were newly diagnosed BPDCN according to main immunophenotyping features of this entity: CD4+, CD56+, HLA-DR+, CD123+, absence of B-, T- and myeloid associated markers (Tsagarakis, Leukemia Research, 2010); the mean age was 62 yrs (range, 55–74); 83% were males; 100% of patients presented at diagnosis with cutaneous disease and bone marrow involvement; all patients received the MTX-ASP steroid regimen; 4 pts were treated in 1st line and 2 pts in relapse, after CHOP-like regimen. The treatment schema was: Methotrexate 3g/m2 day 1, L-asparaginase 6000UI/m2, on day 2, 4, 6, 8 and Dexamethasone 40 mg day 1 to 4; the treatment was administered monthly till progression. Results: Overall complete remission (CR) rate was 83, 3% after 3 cycles: 5 pts were in CR and one patient had a progressive disease (PD). The 5 responders followed the same regimen until progression (total number of cycles for 6 to 11). The mean CR duration was 7, 8 months. One patient underwent allo HSCT after 7 courses and is still alive. The MTX-ASP regimen was well tolerated without severe haematological and non-haematological toxicity; there was no episode of infection and despite high doses of L-Asparaginase, no deep venous thrombosis was seen. Conclusions: The BPCDN treatment is not standardised, mainly due to the rarity of this entity; for younger patients best responses are obtained after allogeneic bone marrow transplantation and induction chemotherapy LAL-like; for older patients the CHOP or CHOP-like regimens don't improve the outcome of these patients. In our experience, methotrexate-asparaginase steroid regimen induces a high rate of CR and seems an interesting treatment option especially for older patients. The treatment toxicity is acceptable. We need to standardize our therapeutic approach in this rare malignancy. Disclosures: No relevant conflicts of interest to declare.