Hongtao Liu, MD, PhD

2012

Department of Medicine, University of Chicago

Prophylactic Donor Lymphocyte Infusion after T Cell Depleted Allogeneic Stem Cell Transplant In High Risk Patients With Hematologic Malignancies

Prophylactic Donor Lymphocyte Infusion after t-Cell Depleted Allogeneic Stem Cell Transplant  In High Risk Patients With Hematologic Malignancies

Although allogeneic stem cell transplant (allo-SCT) is the only curative treatment for many high risk patients with hematologic malignancies, including acute myeloid leukemia, the outcome after stem cell transplant for patients with active disease is still very poor. Dr. Liu’s study will focus on patients with high risk hematologic malignancies undergoing allo-SCT. The primary objective of this clinical trial is to assess progression-free survival at 2 years after stem cell transplantation for high-risk hematologic malignancies receiving T-cell depleted grafts, followed by an escalating dose regimen (EDR) of prophylactic donor lymphocyte infusion (DLI) compared to historical controls not receiving DLI. DLI is a clinically available and established treatment for relapse after stem cell transplant that is most effective for minimal residual disease. Dr. Liu hypothesizes that prophylactic DLI after T-cell depleted stem cell transplant will accelerate the donor-derived immune reconstitution (thus preventing relapse of disease as well as decreasing the rate of opportunistic infections, especially viral infections) and that it will also eliminate minimal residual disease to keep the hematologic malignancies in remission. Prevention of relapsed disease with few and tolerable side effects will result in longer survival in those patients who have poor outcomes with currently available treatment strategies. The studies on immune re-constitution and minimal residual disease control will provide scientific insight on immune regulation following prophylactic donor lymphocyte infusion, which could provide a platform to design future immune-based therapies, including application of antibodies to known negative immune regulators, and further enhancement of immune re-constitution by lymphocyte growth factors or regulators.

Final Report

2012 CRF Young Investigator Award - Final Report

1. Background:

Allogeneic stem cell transplant (allo-SCT) is the only curative treatment for many high risk patients with hematologic malignancies. Although there has been tremendous progress in the past couple of decades in allo-SCT, the outcome after SCT for patients with active disease are still very poor. We have successfully employed in vivo T-cell depletion with Alemtuzumab for over 10 years at the University of Chicago and confirmed lower rates of acute and chronic GVHD and good overall survival for many patients. Not surprisingly, the relapse of disease remained a major issue after transplant, and there has been very little progress in reducing the incidence of relapse following allo-SCT. Donor lymphocyte infusion (DLI) is a clinically available and established treatment for relapse after SCT that is most effective for minimal residual disease (MRD). With the support from CRF, we were able to conduct a prospective pilot clinical trial to assess the role of prophylactic DLI for patients early after allo-SCT to prevent relapse. The study focused on patients with high risk hematologic malignancies, i.e. those with leukemia not in remission, lymphoma not achieving at least a partial response undergoing allo-SCT. The primary objective of the clinical trial is to assess the feasibility of early immunosuppression withdrawal followed prophylactic dose escalation DLI to prevent disease relapse in the high risk patients with hematologic malignancies. In additional to the clinical treatment fo the patient to prevent disease relapse, correlative studies have been conducted to understand the effect of pDLI on the elimination of MRD, and activation of leukemia or tumor specific immune response.

2. Hypothesis:

We hypothesize that: (1) Prophylactic DLI after T-cell depleted SCT is feasible and will prevent disease relapse with tolerable toxicities such as GVHD. (2) Prophylactic DLI will eliminate MRD to keep the hematologic malignancies in remission through induction of leukemia or lymphoma specific immune response.

3. Results:

During the support period of the grant, we are able to reach the targeted enrollment of 56 patients,

59 pts were enrolled prior to HCT conditioning between June 2013 and October 2015. 33 pts (56%) had AML, including 19 pts not in remission. Pts received fludarabine, melphalan (n=38), busulfan (n=20) or TBI/etoposide (n=1), alemtuzumab 100mg over 5 days and tacrolimus. Withdrawal of immunosuppression (WOI) was planned for day 60 post-transplant if no GVHD or relapse, followed by escalated doses of pDLI every 4-8 weeks at pre-defined doses (2 to 50×105 CD3+ cell/kg for MRD; 1 to 20x105for MUD). Results: 29 pts (49%) did not undergo WOI due to GVHD (n=14), early relapse (n=9), death (n=5) or graft failure (n=1), and 7 (12%) underwent WOI but did not receive pDLI due to GVHD (n=5), death (n=1), or too early (n=1). The primary endpoint of successful WOI and receipt of at least one pDLI was achieved in 23 (39%) pts, with 5, 6, 4, 4, and 4 pts received 1, 2, 3, 4 and 5 pDLI respectively. Median time from transplant to 1stpDLI was 96 days (range 87 to 164). After pDLI, 5 pts developed grade I-IV aGVHD but all responded to steroids; 3 pts developed cGVHD. 33 pts (55%) were MRD, and were more likely than MUD pts to receive at least one pDLI (58% vs 15%; p<0.01) or to get WOI (70% vs 27%, p<0.01). 19/33 (58%) MRD pts received at least one pDLI, while only 8/26 (31%) MUD pts were able to have early WOI and only 4 (15%) received at least one pDLI. Median PFS and OS for all pts were 9.6 and 13.1 months, with deaths were mostly due to relapse (68%), GVHD (16%) or infection (10%). Pts receiving at least one pDLI had two-year PFS and OS of 59% and 51% from HCT, respectively. 7 out of the 23 pts (30%) relapsed, however, there were only two (17%) relapses among 12 pts who received >=3 pDLI. Our prospective trial demonstrated that early WOI followed by dose-escalation pDLI is feasible and may provide favorable results after TCD MRD HCT for pts with high risk hematologic malignancies.

The abstract was already accepted for presentation at 2016 ASCO (American Society of Clinical Oncology) annual meeting in June, 2016 held in Chicago. The correlative studies also demonstrated step-wise decreasing of MRD marker of WT1 qPCR level in the patients who received pDLI and remained in remission. The manuscript is in preparation.

On the other hand, in order to have better historical data for this prophylactic DLI study, We performed a retrospective analysis to examine pre-HCT variables for pts with high risk AML or MDS who underwent reduced intensity conditioning (RIC) for T-cell depleted HCT from 2002-2012. 127 pts were evaluable based on inclusion criteria; 96 AML (disease status: 60 PIF/Refractory, 36 relapse), 31 MDS (disease status: 12 RAEB-1, 10 RAEB-2, 5 CMML, 4 active disease/progressing); median age was 56 years (range 18-71); sex: 78 M, 49 F. 18 pts had low risk, 52 had intermediate risk, and 49 had high risk cytogenetic profiles at diagnosis. 8 pts had an inadequate sample or did not have cytogenetic analysis. Of the 36 pts who relapsed prior to HCT, only 3 pts relapsed after > 12mo of induction and 14 pts relapsed between 6 and 12 mo, but 19 pts relapsed after < 6mo of induction; median age at first relapse was 53 years (range 25-68); 31 pts had only 1 relapse while 5 pts had multiple relapses. 9 of 60 pts evaluated showed a FLT3 ITD mutation. 32 of 45 evaluable pts had high C-reactive protein levels at study entry (>5mg/L). Nearly all pts had ECOG performance status of 0 to 1. Right now, the dataset is undergoing statistical analysis and would be presented at the national meeting late this year.

Interim Report

2012 Young Investigator Award - 2013 Interim Report

This study focuses on patients with high risk hematologic malignancies, i.e. those with leukemia not in remission, lymphoma not achieving at least a partial response undergoing allo-SCT. The primary objective of the clinical trial is to assess progression-free survival (PFS) at 2 years after SCT for high-risk hematologic malignancies receiving T-cell depleted (TCD) grafts followed by an escalating dose regimen (EDR) of prophylactic DLI compared to historical controls not receiving DLI.

Aim 1: To determine if prophylactic DLI will prevent disease relapse in high risk patients with hematologic malignancies after RIC TCD SCT with acceptable GVHD in a single arm Phase II clinical trial. A single arm Phase II trial will be conducted to determine whether the prophylactic DLI after TCD SCT will improve the 2 year DFS with tolerable incidence of GVHD.

Aim 2: To determine whether prophylactic DLI will accelerate the donor-derived immune reconstitution and eliminate MRD in high risk patients with hematologic malignancies after RIC TCD SCT. We hypothesize that prophylactic DLI will enhance the donor-derived immune reconstitution to prevent opportunistic infections; will help to eliminate MRD to prevent relapse.

During the support period of the grant, 17 patients were enrolled on the study since it received IRB approval on 3/26/13 (three patients with matched unrelated donors were enrolled before the NMDP IRB approval of the study, and thus were later removed from the study). One patient died early from complication of SCT, 2 patients had early GVHD before early immunosuppression; and one patient developed GVHD with early immunosuppression withdrawal. 6 patients tolerated early immunosuppression withdrawal and 4 patients received first dose of DLI, 2 patients were scheduled to receive first pDLI in 2 weeks; So far, only one patients developed GVHD after second dose prophylactic dose DLI (the donor is 9/10 matched related donor). Another three patients are still in their early phase of transplantation. Four more patients have been scheduled to have transplant on this study.

The enrollment on the study is very fast, since it is the only study we have for high risk patients with hematologic malignancies undergoing stem cell transplant in our center at this time. We will have interim analysis after 10^th patient on the study finished all the planned DLI. We are optimistic that at least 50% of participant will get at least one dose prophylactic DLI. Correlative study samples were collected during the treatment course, which will be analyzed during the second year period of the grant.

In order to have better historical data for this prophylactic DLI study, we performed a retrospective analysis to examine pre-HCT variables for patients with high risk AML or MDS who underwent reduced intensity conditioning (RIC) for T-cell depleted HCT from 2002-2012. Our primary objective was to critically assess which variables may serve as prognostic factors that predispose patients to better or worse clinical outcomes. Inclusion criteria for our study included adult patients: (a) who received RIC; (b) undergoing first allogeneic HCT without previous HCT; (c) with high risk disease status; and, (d) who are not in remission at time of HCT. Based on previous studies, pre-HCT variables considered for analysis include: C-reactive protein, number of courses of induction chemotherapy, number of previous relapses, time of relapse after induction therapy, age at relapse post induction therapy, presence of molecular FLT-ITD mutations, bone marrow blast percentage at HCT, neutrophil nadir, cytogenetic profiles, and ECOG performance status. Using univariate and multivariate analysis, we aim to show how different pre-HCT variables correlate with post-HCT outcomes: namely, incidence of graft versus host disease, progression free survival, and overall survival.

127 patients were evaluable based on inclusion criteria; 96 AML (disease status: 60 PIF/Refractory, 36 relapse); 31 MDS (disease status: 12 RAEB-1, 10 RAEB-2, 5 CMML, 4 active disease/progressing); median age was 56 years (range 18-71); sex: 78 M, 49 F. 18 patients had low risk, 52 had intermediate risk, and 49 had high risk cytogenetic profiles at diagnosis. 8 patients had an inadequate sample or did not have cytogenetic analysis. Of the 36 patients who relapsed prior to HCT, only 3 patients relapsed after > 12mo of induction and 14 patients relapsed between 6 and 12 months, but 19 patients relapsed after < 6mo of induction; median age at first relapse was 53 years (range 25-68); 31 patients had only 1 relapse while 5 patients had multiple relapses. 9 of 60 patients evaluated showed a FLT3 ITD mutation. 32 of 45 evaluable patients had high C-reactive protein levels at study entry (>5mg/L). Nearly all patients had ECOG performance status of 0 to 1.

2 patients did not have pre-HCT induction chemotherapy, 46 patients had one, 47 patients had two, and 32 patients had three or more courses; 79 patients had pre-HCT BM blast percentage < 10%, 16 had between 10-20%, 31 had > 20%; 70 patients had pre-HCT BM cellularity < 20%, 56 had > 20%; One patient’s pre-HCT BM was inadequate for analysis. Graft sources included: 108 PBSC (64 matched related, 44 matched unrelated), and 19 haploidentical PBSC plus a cord blood unit.

Right now, all the data fields have been filled, and we expect that with further statistical analysis of our results, we can identify which variables predict favorable or unfavorable clinical outcomes prior to HCT. This provides us with the potential to optimize therapeutic strategies and identify subgroups of high-risk patients with AML or MDS who are more likely to benefit from HCT. By detecting the prognostic factors that correlate with post-HCT outcomes, we advance our understanding of how patients with hematologic malignancies vary in their response to HCT.

The statistics analysis is in progress, and we hope we could present the results soon at a national meeting, such as ASCO next year. Many of these patients had research study samples available; we are also in the process of obtaining samples to check WT1 PCR level before and after allo-SCT to see if WT1 MRD before and after SCT will predict relapse and survival.