Phase I Study of Yttrium-90 Labeled ANTI-CD25 (aTac) Monoclonal Antibody PLUS BEAM for Autologous Hematopoietic CELL Transplantation (AHCT) in Patients with Mature T-CELL NON-Hodgkin Lymphoma, the “a-TAC-BEAM Regimen”

Background: Peripheral T cell lymphomas (PTCL) have a poor prognosis with current treatment regimens. High-dose chemotherapy followed by autologous stem cell transplant (ASCT) has been used as a consolidation strategy in remission states (CR1 or above) endorsed by the NCCN guidelines in appropriate patients. 5 year DFS is reported at 70% for alk -ve anaplastic large cell lymphoma (ALCL) and 30-40% for most other histologies (D'Amore et al, 2012, JCO). It is also performed in the relapsed settings if no previous ASCT performed and allogeneic transplant is not an option. CD25 is a targetable protein expressed differentially in PTCL and antibody based anti-CD25 therapies are efficacious in PTCL i.e denileukin diftitox (Foss et al Blood 2006, Dang et al , BJH 2006) , monoclonal antibody dacluzimab (Waldman et al 1995 Blood). Yttrium-90 (90Y) labeled chimeric antiCD25 antibody basiliximab emits beta particles and has been shown to inhibit the growth of human ALCL tumors and increase survival in SUDHL-1 xenograft mice (Zhang et al 2009 Cancer Biother Radiopharm). Previous investigations at COH by Raubitschek, Colcher et al established a safe does of Yttrium-90 (90Y) labeled basiliximab at 0.4mCi/kg in combination with BEAM. This is a phase 1 clinical trial of a novel conditioning regimen that includes the use of Yttrium-90 (90Y) labeled basiliximab with BEAM chemotherapy for PTCL patients eligible for ASCT. The trial utilizes a modified version of the rolling 6 design (Skolnik et al) to test 3 dose levels of Yttrium-90 (90Y) Basiliximab i.e 0.4mCi/kg, 0.5miC/kg and 0.6mCi/kg with the primary objective of evaluating the safety and tolerability of this combination and to establish the MTD. Secondary objectives include incidence of relapse, OS, PFS, NRM at day 100, 1 year and 2 years post-transplant. Patients and Methods: Dose limiting toxicity (DLT) is defined according to the Bearman and CTCAE 4.03 scales, the latter for hematologic toxicity. The study/treatment schema is shown in Figure 1. Results: From 07/29/2015 to 05/29/2018, 14 patients underwent ASCT on this trial; n=4 at 0.4mCi/kg n=4 at 0.5mCi/kg and n=6 at 0.6mCi/kg. Median age at ASCT was 51 years (range: 18-76), and histologies included; PTCL-nos (n=7); alk-ve ALCL (n=3); angioimmunoblastic T-cell lymphoma (n=2); and intestinal T-cell lymphoma (n=2). Disease status at ASCT were CR1 in12, CR2 in 2 patients. Median number of prior therapies was 1 (range: 1-2). At a median follow-up of 14.4 months (range: