ALBERT

Description: Bone marrow stromal cells (BMSC, also known as bone marrow-derived “mesenchymal stem cells”) have been used to treat acute graft-versus-host disease (GVHD) and other complications following allogeneic hematopoietic stem cell transplantation (SCT). We conducted a phase I trial using third party, early passage, BMSC for patients with steroid-refractory liver or gastrointestinal GVHD, tissue injury or marrow failure following SCT to investigate safety and clinical responses following BMSC infusion. To identify mechanisms of BMSC immunomodulation and tissue repair, patients were monitored for plasma GVHD biomarkers, cytokines, growth factors, and lymphocyte phenotype before and after BMSC infusion. BMSCs were prepared from marrow aspirates from healthy volunteers with the expansion of 3 passages. Ten subjects were infused a fixed dose of 2 x 106 BMSCs /kg weekly for 3 doses. There was no treatment related toxicity (primary endpoint). Eight subjects were evaluable for response assessment at 4 weeks after the last infusion. Five of the seven patients with steroid-refractory acute GVHD achieved complete remission (CR), two of two patients with tissue injury (pneumomediastinum/ pneumothorax) achieved resolution but there was no response in two subjects with delayed marrow failure. Rapid reductions in inflammatory cytokines occurred after the first BMSC infusion (fig1). Clinical responses correlated with a fall in biomarkers (Reg 3α, CK18, and Elafin) relevant for the site of GVHD, or CK18 for tissue injury. The GVHD complete responders survived significantly longer (〉300 days vs a median of 33 days), had higher baseline absolute lymphocyte and central memory CD4 and CD8 counts but there was no clear difference in natural or induced Tregs. Cytokine changes also segregated with survival. These results confirm that BMSC are associated with rapid clinical responses and biomarker normalization in steroid-refractory GVHD and PM. However BMSC were ineffective in patients with more aggressive GVHD with lower lymphocyte counts, which suggest that effective GVHD control by BMSC, requires a relatively intact immune system. Early detection and BMSC treatment appear important in patients with refractory GVHD. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: High risk myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) commonly affect individuals of advanced age with multiple co-morbidities unsuited for curative standard treatments with allogeneic stem cell transplantation (allo-SCT) or intensive chemotherapy (ICT). New reduced intensity therapeutic approaches bringing improved life expectancy are needed for such patients. We conducted a phase I clinical trial to evaluate the safety and activity of sequential therapy with low-dose clofarabine followed by lenalidomide in older high risk MDS or AML. We hypothesized that lympho-depletion by clofarabine could "reboot" lymphocyte reactivity against the malignancy and promote favorable immune modulation by lenalidomide. Here we report preliminary clinical outcomes and associated cellular and molecular immune profiles. Methods: Four subjects (median age 68 years, range-60-79) with relapsed or refractory high-risk MDS (IPSS risk score〉intermediate 2) or AML were enrolled to the protocol (12-H-0146, clinicaltrials.gov ID: NCT01629082). All subjects had been previously treated with at least one hypomethylating agent. Subjects received a single course of intravenous low-dose clofarabine 5mg/m2/d for five days, followed by consolidation therapy with oral lenalidomide with dose escalation from 25 mg daily up to 50 mg daily for 2 cycles. In the absence of dose limiting toxicity (DLT) or disease progression, subjects received lenalidomide maintenance 10 mg daily in 28 day cycles, with dose adjustments, for up to 12 cycles. Blood and marrow samples were collected before starting clofarabine, before consolidation with lenalidomide, and during maintenance. Multiparameter flow cytometric analysis was performed to characterize T cell subsets (memory T cells, T regs), natural killer (NK) cells, with functional markers representing T cell exhaustion (PD-1, LAG-3, TIM-3, PDL-1), activating and inhibitory NK cell receptor (KIR, LIR1, NKG2A, CD57). Relative changes in RNA expressions of target genes related to cancer immunology were evaluated by PCR array. Results: Of four subjects enrolled, two subjects showed responses at 28 days post clofarabine and at 28 days post first cycle of lenalidomide. These two responders tolerated subsequent maintenance lenalidomide for 4-6 months. The other two subjects were non-responders. Three subjects were taken off study due to disease progression on day 70, 162, and 206, and 1 subject for DLT on day 69. The clinical trial is now closed without dose escalation beyond the first cohort for reasons of poor accrual and lack of long term responses. In responders immunophenotype analysis showed a decrease in CD4+ %PD-1 expression in blood or bone marrow (0.87±0.29 fold change) after clofarabine and lenalidomide treatment, rising again after lenalidomide discontinuation in one responder (Figure). In contrast, CD4+ %PD-1 expression was increased in non-responders (1.23±0.19 fold change). In pre-treatment samples terminally differentiated CD57+ NK cell with high LIR1 expression (34.6±23.5%) were increased. In responders, both the levels of CD57 and LIR1 expression fell with reciprocal increase in CD56brightNK cells, suggesting restoration of NK cell repertoires after clofarabine. RNA expression profiles in one responder on maintenance lenalidomide showed significant up-regulation of gene expressions in IL-1A, FASLG, ICAM1, IL-27, WT1 (p

Description: Abstract 1967 Following allogeneic stem cell transplant (SCT), late-onset severe pulmonary complications occur in more than 10% of patients and confer an increased risk of mortality in the first few years post transplant. Whether pulmonary repair can occur subsequently is not well characterized. We prospectively collected pulmonary data on 138 (60 female, 78 male) recipients of allogeneic SCT from HLA identical siblings surviving 〉 5 years. The median age at transplant was 36 years. Indications for transplant were CML (63), AML (31), MDS (19), ALL (12) and others (14). 126 patients received ≥1200 cGy TBI-based conditioning with or without lung shielding, 3 received 400 cGy TBI-based conditioning and 9 patients received no irradiation. The graft was ex vivo T cell depleted in 131 recipients except six who received non-myeloablative SCT. Of the survivors, 26 had no cGvHD, 70 had cGvHD lasting less than 3 years and 42 had prolonged cGvHD requiring systemic immunosuppression for more than 3 years. Of the 17 patients who died beyond 5 years, 4 died of pulmonary causes, including two with lung cancer. Pre-transplant abnormalities (〈 80% predicted) in PFTs were found in 15.9% of subjects in the following declining frequency: FVC%, VC, TLC, FEV1, DLCO_Adj (adjusted for hemoglobin and alveolar ventilation) Hb/VA and FEV1/FVC. Baseline (BL) PFTs served as the reference for all subsequent measurements at 5, 10 and 15 years for each survivor. The only parameter showing a clinically significant decline post transplant was DLCO_Adj at the 5-year mark, with subsequent normalization [paired t-test]. The median DLCO_Adj at 5, 10 and 15 years were 88%(p

Description: Abstract 4099 Long term survivors of allogeneic SCT have increased risk factors for cardiovascular disease. The reason for this is unclear but chronic GVHD (cGVHD) has been implicated as a potential cause. We prospectively evaluated the impact of cGVHD on cardiovascular risk profiles in 109 allogeneic stem cell transplantation survivors. Transplants were performed at a single center between 1993 and 2006. Sixty-four survivors were informative at 5 years, 45 at 〉 10 years and 35 at both 5 and 10 years post-transplant. Median ages at transplant, 5 and 10 year follow-up were 34, 40 and 46 years, respectively. There were 62 male and 47 female survivors. Diagnoses at transplant included CML (56), acute leukemia (29), MDS (13), and others (9). Ninety-nine patients received 12–13Gy TBI-based conditioning followed by a 4-log T cell depleted SCT (15 marrow and 84 peripheral blood). Ten patients received non-myeloablative conditioning followed by unmanipulated peripheral blood stem cells. There were clinically relevant increases in prevalence of hypertension (p=