ABSTRACT
The prognosis of patients with mycosis fungoides (MF) and Sezary Syndrome (SS) varies greatly, from near normal life expectancy in patients with early stage, to a median survival of less than 2 years for those diagnosed with advanced stage disease. Initial response to treatment is almost always followed by relapse and, finally, most of patients enter a phase of advanced multi-drug resistant disease with a short life expectancy after multiple lines of treatment. Allogeneic stem cell transplantation (allo-SCT) is usually limited to patients with advanced disease resistant to multiple treatments. Retrospective registry-based studies have shown increased Non-relapse Mortality (NRM) rates in patients with poor performance status, as well as in patients treated with myeloablative conditioning regimens. Another major limitation of allo-SCT is the increased relapse rate which occurs in nearly 50% of the cases, and is probably due to the fact that only heavily pretreated patients with advanced disease are referred for allo-SCT. Due to the paucity of data, the ideal conditioning regimen which will provide the maximum therapeutic benefit without the cost of increased NRM is not currently known. In this article we present our experience with a novel regimen in the treatment of patients with advanced MF/SS.
ABSTRACT
BACKGROUND: Patients with high-risk acute leukemia have a high risk of relapse after allogeneic stem cell transplantation (allo-SCT). In an effort to reduce the relapse rate, various therapeutic methods have been implemented into clinical practice. Among them, prophylactic donor lymphocyte infusion (pro-DLI) has shown significant efficacy. However, the widespread application of pro-DLI has been restricted mostly due to concerns regarding the development of graft versus host disease (GVHD). In the present study, we tested the safety and efficacy of a novel method of prophylactic-DLI based by repetitive administration of low lymphocyte doses. METHODS: DLI was administered to patients with high-risk acute leukemia at a dose of 2 × 106/kg CD3-positive cells. DLI at the same dose was repeated every two months for at least 36 months post-allo-SCT, or until relapse or any clinical or laboratory feature suggested GVHD, whichever occurred first. Forty-four patients with a median age of 53 years (range 20-67) who underwent allo-SCT between 2011 and 2020 were included in our study. Thirty-three patients with high-risk acute myeloid leukemia (AML) and 11 with high-risk acute lymphoblastic leukemia (ALL) after allo-SCT from a matched sibling (MSD, no = 38 pts) or a matched-unrelated donor (MUD, no = 6 pts) received pro-DLI. Twenty-three patients were in CR1, all with unfavorable genetic features; 12 patients were in CR2 or beyond; and 9 patients had refractory disease at the time of transplant. Ten out of 23 patients in CR1 had detectable minimal residual disease (MRD) at the time of allo-SCT. Disease risk index (DRI) was high and intermediate in 21 and 23 patients, respectively. Conditioning was myeloablative (MAC) in 36 and reduced intensity (RIC) in 8 patients, while GVHD prophylaxis consisted of cyclosporine-A in combination with low-dose alemtuzumab in 39 patients or with low-dose MTX in 5 patients, respectively. RESULTS: Thirty-five patients completed the scheduled treatment and received a median of 8 DLI doses (range 1-35). Fifteen out of 35 patients received all planned doses, while DLI was discontinued in 20 patients. Reasons for discontinuation included GVHD development in nine, donor unavailability in seven, disease relapse in three, and secondary malignancy in one patient, respectively. Nine patients were still on treatment with DLI, and they received a median of four (range 2-12) doses. Fourteen percent of patients developed transient grade-II acute GVHD while 12% developed chronic GVHD post-DLI administration. Acute GVHD was managed successfully with short course steroids, and four out of five patients with cGVHD were disease-free and off immunosuppression. With a median follow-up of 44 months (range 8-120), relapse-free (RFS) and overall survival (OS) were 74%, (95% CI, 54-87%) and 78%, (95% CI, 58-89%) respectively, while the cumulative incidence of non-relapse mortality (NRM) was 13% (95% CI, 4-28%). The cumulative incidence of relapse in patients with intermediate and high DRI is 7% and 15%, respectively. CONCLUSION: Prolonged-up to three years-low-dose pro-DLI administered every two months is safe and effective in reducing relapse rate in patients with high-risk acute leukemia. The low-dose repetitive administration DLI strategy reduced the risk of DLI-mediated GVHD, while the prolonged repeated administration helped in preventing relapse, possibly by inducing a sustained and prolonged immunological pressure on residual leukemic cells. This novel strategy deserves testing in larger cohort of patients with high-risk acute leukemia.
