ALBERT

Description: The optimal source of donor hematopoietic stem cells (HSC) is controversial. Granulocyte colony stimulating factor (G-CSF) mobilized peripheral blood (G-PB) has replaced bone marrow (BM) as the most common allograft source in adults but is associated with donor morbidity and higher rates of chronic graft versus host disease (GVHD) compared to BM. The CXCR4 antagonist plerixafor (Px) mobilizes HSC into the PB (Px-PB) faster than G-CSF and preliminary data suggest both quantitative and qualitative differences in allograft content that may impact clinical outcomes. We sought to assess the efficacy and safety of transplanted allografts collected following mobilization with Px alone in HLA-identical sibling transplantation. This was a Phase II, two-strata, multi-center prospective trial (NCT01696461) to evaluate Px-PB allografts prior to reduced intensity conditioning (RIC) and myeloablative conditioning (MAC) based hematopoietic cell transplantation (HCT). Patients aged 18-65 years with an HLA-ID sibling donor and a hematological malignancy suitable for HCT were eligible. The primary objective was to determine the proportion of donors whose cells could be successfully mobilized and collected with a sufficient CD34+ cell dose using Px as the sole mobilizing agent. Px mobilization was considered successful if ≥ 2.0x10^6 CD34+ cells/kg recipient weight were collected in no more than two leukapheresis (LP) collections. All donors receiving Px were included in the analysis of the primary objective based on the intention-to-treat principle. Secondary objectives included the incidence of acute and chronic adverse events in donors, rates of hematopoietic engraftment, donor chimerism, rates of acute and chronic GVHD, non-relapse mortality (NRM), progression free survival (PFS) and overall survival (OS) for the recipients. From July 2013 to December 2014, 64 donor/recipient pairs were enrolled at 12 centers. Donors received Px at 240μg/kg subcutaneously 4 hours prior to LP. LP was performed processing at least 4X blood volume for up to two consecutive days (a third day was allowed for low CD34+ cell yields after 2 LP procedures) to achieve a target CD34+ cell dose of ≥ 4.0 x 10^6/kg recipient weight with a minimum goal of ≥ 2.0 x 10^6/kg. All allografts were cryopreserved. GVHD prophylaxis included cyclosporine or tacrolimus in combination with methotrexate, mycophenolate mofetil, or sirolimus. G-CSF was given routinely post HCT only to MAC recipients. Patient demographics are provided in Table 1. The median donor age was 56 years (18-65). 64% of the donors were male. Donors underwent one (23%), two (72%), or three (5%) LP procedures. 63 of 64 (98%) donors achieved the primary objective. The median total CD34+ cell dose/kg recipient weight collected within 2 days was 4.6 (0.9-9.6). Maximal donor toxicity following Px injection and LP was grades 0 (30%), 1 (52%), 2 (17%), and 3 (2%). Bloating, flatulence, abdominal pain, headache, paresthesisas, injection site reaction, and dizziness were the most commonly observed toxicities. Bone pain was not observed. The one grade 3 toxicity was a vasovagal episode felt related to LP and unlikely to Px. Toxicities typically resolved within a week of LP. The median follow up is 6.3 months. Median days to ANC (〉0.5 x10^9/L) and Platelet count (〉20 x 10^9/L) recovery were 13.5 (10-148) and 19 (1-76) after MAC and 14.5 (0-25) and 18 (0-141) after RIC, respectively. The cumulative incidence of acute GVHD grades 2-4 and 3-4 at day 100 were 47% (95% CI: 30-64) and 9% (95% CI: 2-22) after MAC and 19% (95% CI: 6-38) and 5% (95% CI: 0-18) after RIC. Probability of NRM at day 100 was 4% (95% CI: 0-13) and 0% after MAC and RIC, respectively. The probability of OS at day 100 was 97% (95% CI: 88-100) and 90% (95% CI: 78-98) after MAC and RIC, respectively. In conclusion, this is the first multi-center trial to demonstrate that as an alternative to G-CSF, Plerixafor rapidly, safely, and effectively mobilizes sufficient numbers of CD34+ cells from HLA-ID sibling donors for HCT following both RIC and MAC regimens. Engraftment was generally prompt and early results of secondary endpoints in recipients are encouraging. Longer follow-up and more extensive analysis of donor allografts and recipient outcomes will be presented at the time of the meeting. Research support was provided in part by Genzyme, a Sanofi Company. Table 1. Characteristics of recipients Table 1. Characteristics of recipients Disclosures Chen: Bayer: Consultancy, Research Funding. Devine:Genzyme: Research Funding.

Description: Abstract 4127 In the age of novel targeted agents, autologous stem cell transplant (ASCT) remains the standard of care for younger patients with newly diagnosed multiple myeloma (MM), offering similar treatment responses and overall survivals as standard chemotherapeutic agents but with the added benefit of a prolonged treatment-free period. Nevertheless, a standard of care for stem cell mobilization for ASCT has yet to be determined. Even in the era of new mobilization agents such as Plerixafor, Cyclophosphamide (Cy) and G-CSF combination remains the preferred mobilizing approach for patients with MM. Several studies have shown that Cy improves the stem cell yield at the expense of increased toxicity, but whether the administration of this chemotherapeutic agent pre-transplant has any impact on the long-term event-free and/or overall survival of myeloma patients remains controversial. In this study, we present a retrospective analysis of 186 patients with newly diagnosed MM who underwent ASCT with high-dose melphalan 200 mg/m2 (HDM) between December of 2000 and 2008 at our Institution. Eighty-three patients were mobilized with single agent G-CSF and 103 patients received high dose Cy (4 gm/m2) and G-CSF combination. Patient characteristics were similar between the treatment groups, including: age, gender, disease stage, and disease status prior to transplant. However, toxicity post-mobilization with Cy/G-CSF was significantly higher compared with G-SCF alone, including: febrile neutropenia (23%), hemorrhagic cystitis (8%), GI toxicity (57%), re-hospitalization due to complications and transplant delay (14%). The overall post-transplant toxicity was similar in the 2 groups, though the treatment related mortality was slightly higher in the Cy/G-CSF arm (4% versus 2%). Post transplant responses were not significantly different in the 2 groups, with 60% of patients achieving a VGPR or better after ASCT in the G-CSF group and 49% in the Cy/G-CSF group (p = 0.33). The median event-free survivals (EFS) for the Cy/G-CSF and G-CSF cohorts were 21.6 and 22.6 months, respectively, (p = 0.62) yielding no significant difference (Figure 1). Similarly, with a median follow up for surviving patients of 34.3 and 32.7 months, the median overall survivals were 68.2 and 62.3 months (p = 0.23) for the Cy/G-CSF and G-CSF cohorts, respectively (Figure 2). This retrospective analysis confirms that the addition of high dose Cy as part of the mobilizing regimen offers no improvement on the transplant outcome for patients with newly diagnosed myeloma and should therefore only be used in cases of difficult stem cell mobilization. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: Despite a well-established risk of chronic kidney disease (CKD) in 20-30% of patients undergoing AlloHCT, the benefits of treating serious infections, such as cytomegalovirus (CMV), with nephrotoxic drugs often outweigh this risk. Given a lack of consensus on the optimal management of post-transplant Human-Herpes Virus 6 (HHV6) reactivation, our center has taken an aggressive stance toward screening for and treating HHV-6 viremia with foscarnet, a nephrotoxic drug with an unknown impact on long-term renal function. Methods: To clarify the impact of foscarnet exposure on long-term renal function after transplant, we conducted a retrospective cohort study of all adult patients who underwent AlloHCT at Duke from June 2002 - Feb 2016 (n=997). HHV6 viral loads were checked weekly for the first 90 days after umbilical cord blood and haploidentical transplants, and as clinically indicated (e.g. cytopenias, encephalopathy) in others. Foscarnet treatment for HHV6 viremia was given at the physician's discretion. Data were abstracted with a web-based clinical research query tool and manual chart review. Estimated glomerular filtration rate (eGFR) was calculated with the CKD-EPI equation based on repeated measures of serum creatinine (Cr) values at baseline, 90 days (n=839), 6 months (n=720), and 12 months (n=491) after transplant. Acute Kidney Injury (AKI) and Acute Kidney Failure (AKF) were defined as 2 and 3x baseline Cr, or 〉50% and 〉75% decrease in eGFR, respectively. Multivariate logistic regression was used to estimate the association of foscarnet exposure on the probability of 〉30% decline in eGFR at 90 days, 6 months, and 12 months after adjustment for confounders. Results: Of the 997 patients included in the study, 45% (n=448) were treated with foscarnet. Patients treated with foscarnet were slightly older (median age 52yrs vs. 49yrs), less likely to receive myeloablative conditioning, and more likely to be CMV positive, receive an alternative donor graft (umbilical cord blood or haploidentical), and experience acute GvHD. The most frequent indications for treatment were CMV (n=257, 57.4%) and HHV6 (n=140, 31.3%). In the first 90 days post-transplant, when most patients were treated with foscarnet, patients exposed vs. unexposed had similar rates of AKI/AKF: AKI 59.2% vs. 59.2%; p=0.99; AKF 26.1% vs. 27.3%; p=0.67. There was no difference in eGFR at 90 days, but patients treated with foscarnet had significantly lower eGFRs at 6 months and 12 months (Figure 1). There was a significant difference in the decline in eGFR from baseline to 12 months: median -29.1 (mL/min/1.73m2) (interquartile range (IQR) -50.8 to -10.7) vs. -22.2 (-37.4 to -7.4); p=0.002. After adjustment for age, race, acute and chronic GVHD, conditioning regimen, donor type, treatment with alemtuzumab, and HHV6 status, patients treated with foscarnet were more likely to experience a 〉30% decrease in eGFR from baseline to 12 months compared to those who were not (Odds Ratio 1.8 (95% CI 1.11-2.93); p=0.02). In this multivariate model, acute and chronic GVHD were not significant predictors of eGFR decline at 12 months. Unadjusted median survival was 11.9 months (95% CI; 10.1-14.0 months) and 20.8 months (95% CI; 15.8-25.4 months) for patients treated vs. not treated with foscarnet, respectively (p30% in eGFR are strongly associated with a 10-year risk of end-stage renal disease and mortality in 〉60% and 50% of patients in the general population, respectively, (Coresh, et al. JAMA 2014), this information should be considered as one weighs the risks vs. benefits of treating HHV6 viremia following AlloHCT. Disclosures Horwitz: Gamida Cell: Research Funding.

Description: Previously we have demonstrated that multiple myeloma cell lines and primary cells express CD52, the antigenic target of Campath-1H, and that they undergo apoptosis following treatment with alemtuzumab in-vitro (Gasparetto et al. ASH #3210,2002). Based on these observations, we initiated a clinical trial where patients with advanced, multiply relapsed MM were treated with subcutaneous (sc) alemtuzumab as a single agent. Nine patients (6 men/4 women, age range 45–69 yrs) were initially treated with the standard dose of 30mg sc three times per week for up to 12 weeks. All patients had at least 4 lines of prior therapy and 8/9 patients had undergone high dose chemotherapy followed by autologous peripheral blood stem cell transplant. Treatment related toxicities included pancytopenia in all patients with grade IV neutropenia in the first four patients, necessitating withdrawal from study. Subsequently, all patients were treated with G-CSF and aggressive transfusion support and no further patients were removed from study due to cytopenias. All patients were prophylaxed with Famvir, Fluconazole and Septra and no opportunistic infections were noted during treatment. Two patients developed acute renal insufficiency that reversed when alemtuzumab was discontinued. One patient completed the entire 12 weeks of treatment. One patient had a PR with a 40% reduction in M-protein after two months of treatment, which reversed once Campath-1H was discontinued. Pharmacokinetic studies of one patient demonstrated that it required 8–10 weeks of treatment using the sc protocol to achieve serum levels of alemtuzumab of 1ug/ml, the level considered to be tumoricidal in-vivo. Based on this observation, the treatment protocol was modified so that the initial week of escalating doses was given IV to achieve more rapid therapeutic levels. Following this, sc alemtuzumab was given as above. One patient with non-secretory multiple myeloma with relapsed disease following 5 prior lines of therapy has been treated with this modified protocol. Treatment with alemtuzumab and growth factor support in this patient has been well tolerated except for the development of RSV pneumonia. At 4 weeks, a PET scan demonstrated a significant overall decrease in metabolic activity in multiple bony areas consistent with a response to treatment. These initial results suggests that alemtuzumab is associated with significant toxicities in patients with advanced multiple myeloma including pancytopenia, infections and possibly renal insufficiency but all of these were reversible and have been minimized with aggressive prophylactic therapy. Alemtuzumab does appear to have modest activity against MM in this heavily pre-treated group suggesting that it should be explored in combination with other agents and at earlier stages of disease.

Description: High-dose therapy plus autologous stem cell transplant (ASCT) is the standard of care for patients with multiple myeloma (MM) aged ≤65 years. Melphalan–prednisone (MP)-based therapy is the standard for non-ASCT candidates but is not typically used for transplant-eligible patients as prolonged therapy with melphalan can adversely affect stem cell collection. The phase 3 VISTA study demonstrated the superior efficacy of bortezomib plus MP (VMP) versus MP in previously untreated MM patients ineligible for ASCT. In this phase 2 study, we evaluated the efficacy of a shorter course of VMP on a different treatment schedule as induction therapy prior to ASCT or as frontline therapy in non- ASCT candidates. Patients aged ≥18 years with previously untreated MM received up to six 28-day cycles of bortezomib 1.3 mg/m2 IV, days 1, 4, 8, and 11, plus oral melphalan 6 mg/m2 and oral prednisone 60 mg/m2, days 1–7. After 2–6 cycles, ASCT-eligible patients could proceed to stem cell mobilization (G-CSF 10 mg/kg/day ± GM-CSF 250 mg/m2/ day or cyclophosphamide 4 g/m2 + GM-CSF) and conditioning with melphalan 200 mg/ m2 (140 mg/m2 if aged 〉65 years). Response was assessed every two cycles and post- ASCT by International Uniform Response Criteria. The primary end point was complete response (CR) rate to VMP. A total of 45 patients were enrolled; 27 were male. Median age was 63 years (range 33–75). MM subtype was 67% IgG, 16% IgA, and 9% each κ- and λ- light-chain; 37% of patients had ISS Stage III MM, 22% had ECOG performance status 〉1, and 70% had ≥40% plasma cells in bone marrow. In total, 20 patients proceeded to ASCT. Median duration of VMP was 4 cycles in both non-ASCT (range 1–6) and ASCT (range 2–6) patients. Response rate (best response) to VMP was 95% (42 of 44 evaluable patients), including 9% stringent CR (sCR), 9% CR (18% ≥CR [95% CI: 7%, 30%]), 27% very good partial response (VGPR), and 50% partial response (PR). Best response was achieved after cycle 2 in 10 patients, cycle 4 in 25 patients, and cycle 6 in 7 patients. All 20 ASCT patients had successful stem cell mobilization; median yield of CD34+ cells/ kg was 5.6 x 106 (range 2.3–12.2 x 106), in a median of 2 collection days. Post-transplant responses were 10% sCR, 20% CR, 55% VGPR, and 5% PR; the remaining 2 patients need further follow-up for response assessment. Response improved post-VMP to post-ASCT in 10 patients (6 PR to VGPR, 2 PR to CR, 2 VGPR to CR). After median follow-up of 14.0 months (range 7.4–47.7) and 14.6 months (range 8.2–42.9) in non-ASCT and ASCT patients, respectively, both median time to progression and progression-free survival were 19.8 months (95% CI: 14.3 months, not estimable [NE]) in non-ASCT patients and 27.9 months (95% CI: 14.6 months, NE) in ASCT patients. A total of 7 patients (5 non- ASCT, 2 ASCT) have died; 1-year survival rate was 82% (95% CI: 59%, 93%) in non- ASCT patients and 95% (95% CI: 69%, 99%) in ASCT patients. Most common grade 3/4 adverse events in all 45 patients during VMP therapy included peripheral neuropathy (24%), thrombocytopenia (20%), neutropenia (18%), and infection (9%). Only 1 patient had deep-vein thrombosis. In conclusion, VMP represents a highly effective therapy for previously untreated MM, with 45% of patients achieving VGPR or better, including 18% sCR/CR. Toxicities were predictable and generally manageable. Short-course VMP therapy did not negatively impact stem cell mobilization, supporting its use as induction therapy prior to ASCT. Very high post-transplant response rates were seen, with 85% of patients achieving ≥VGPR, including 30% sCR/CR. Since achievement of CR/VGPR is associated with improved long-term outcomes in MM, the preliminary outcome data presented here appear promising; however, longer follow-up is required.

Description: Abstract 4048 Introduction: Chemotherapy + GCSF mobilization and GCSF alone are the most common mobilization regimens for autologous stem cell transplant (ASCT). We examined the benefits and limitations of both regimens in terms of mobilization success, predictability and costs. Methods: A retrospective, multi-center chart review was conducted of multiple myeloma (MM) and lymphoma patients mobilized between January 1, 2006 and December 31, 2007 for ASCT. Patients were excluded if they were mobilized with plerixafor (Mozobil®) or enrolled in a clinical trial of mobilization regimens. Data collected included demographics, disease and treatment history, mobilization regimen, blood counts, aphaeresis, remobilization, cells transplanted, time to engraftment and resource use. Stem cell collection practices and related clinical outcomes were analyzed separately for patients that were mobilized with chemotherapy + GCSF vs. GCSF alone. Resource use was evaluated using US unit cost data. Results: Data were collected for 227 consecutive patients from 11 centers (143 patients that received a chemotherapy + GCSF mobilization regimen and 84 patients who received GCSF alone). Total cells collected were significantly higher in the chemotherapy + GCSF mobilization group compared to GSF alone (18.6 × 106/kg vs.7.0 × 106/kg, p

Description: Key Points NOTCH2 activation confers a marked increase in BCR responsiveness by cGVHD patient B cells that associates with increased BLNK. ATRA increases the IRF4-to-IRF8 ratio and blocks aberrant NOTCH2-BCR activation without affecting cGVHD patient B-cell viability/function.

Description: Background: Although complete remission rates for AML are near 70% with combination induction and consolidation chemotherapy, most patients will relapse and die from the disease or treatment complications. New agents with unique mechanisms are needed. One such class of therapeutics are fusion proteins consisting of protein synthesis inactivating peptide toxins fused to tumor cell selective ligands. DT388-IL3 is one such fusion protein. Rationale: In preclinical studies, DT388-IL3 was cytotoxic to the IL3 receptor expressing leukemia cell lines but not toxic to IL3 receptor negative cell lines. This agent was less toxic to normal progenitors and not toxic to early hematopoietic stem cells. The majority of AML progenitors overexpress IL3 receptors. Animal model work in mice bearing human leukemia cells has demonstrated anti-leukemia efficacy which is dose dependent with this agent. Toxicities in monkeys include vascular leak syndrome and pancytopenia observed only at the highest doses. The MTD in monkeys was estimated at 60mcg/kg/day. We report preliminary data on the use of DT388-IL3 fusion protein in humans from an ongoing phase I trial. Pharmacokinetics; clinical and immune response to this novel fusion protein are also being followed. Patients and Methods: Patients with refractory AML were eligible. The first dose level was qd M-W-F X six doses of DT388-IL3 at 4mcg/kg/day with dose escalation planned for subsequent patients. Patients with progression of disease or unacceptable study drug toxicity were to be removed from the study. Toxicity was graded according to NCI CTCAE version 3.0. Three patients have been treated with DT388-IL3. Serum samples were collected and will be assayed for anti-DT388-IL3 antibodies prior to and after treatment. Blood samples were obtained to measure circulating levels of active DT388-IL3 and its half life. Patient blasts were also collected prior to treatment for later analysis of expression of IL3 receptors. Result: Two patients tolerated the treatment schedule(of six doses) without any significant toxicities. Mild fever, headaches, nausea were noted. Both of these patients had progression of disease-one during treatment and one on day 15 bone marrow biospy. The above mentioned patients died secondary to disease complications at 2 weeks and 18 weeks after their last dose of the study agent respectively. DT388-IL3 levels on these two patients post infusion were below the the reliable detectable limits of the assay. The third patient became febrile and hypotensive after the first dose. The hypotension persisted and she did not receive any further doses. This patient is alive 5 weeks later with supportive care alone. DT388-IL3 levels following this patient’s dose are as follows: 2min post infusion 34.3ng/ml, 30min post infusion 1.9ng/ml, 60min post infusion 0.075ng/ml, 120min post infusion 0.003ng/ml, 240min post infusion undetectable. Conclusion: Preclinical/animal studies suggest that DT388-IL3 has anti-leukemia efficacy. Preliminary data from our ongoing phase I trial reveals minimal study agent related toxicity and no life threatening complications at this first dose level. Dose escalation is planned as per protocol.

Description: Introduction: Early response rates to non-myeloablative therapy are encouraging, however long term remissions remain elusive. Manipulating donor lymphocyte infusions (DLI) to preferentially infuse Natural Killer (NK) cells, typically comprising 3–5% of a DLI graft, may promote better antitumor and anti-infective surveillance while reducing risk of graft versus host disease (GVHD). We investigated the feasibility of providing NK cell-enhanced DLI following T cell-depleted non-myeloablative allogeneic transplants. Methods: Patients underwent an alemtuzumab and fludarabine-based non-myeloablative preparative regimens from a 3-6/6 HLA matched related donors. At 6 weeks posttransplant, those who engrafted and did not have sevee GVHD received NK cell-enhanced DLIs, repeated x2 at 8-week intervals. For DLI, NK cells were enriched in a single step using the CliniMACS CD56 Reagent and CliniMACSplus instrument, per manufacturer’s protocols (Miltenyi Biotec Inc, Auburn, CA). The total cell dose infused in patients receiving HLA-mismatched DLI was no more than 0.5 X 106 CD3+CD56neg cells/kg patient weight. Patients receiving HLA-matched DLI (6/6) received no more than 106 CD3+CD56neg cells/kg patient weight. Analysis: The primary endpoints for feasibility were mortality, occurrence of severe acute GVHD or other unacceptable toxicity, response and duration of response. Efficacy was measured by Progression Free Survival (PFS) and Overall Survival (OS). NK cell function was used as a primary endpoint for immune recovery. NK cell function was measured by flow cytometry using methods that we had previously validated using unfractionated PBMC and CD56+-enriched NK cell preparations. Results: The NK cell selections worked well with only one device failure resulting in low purity. NK cell purity was 92%+/− 3.5 and yield 74% +/− 16. The resulting cell preparations had low frequencies of CD4+, CD8+ and gamma-delta T cells. Table 1- Clinical feasibility of enhancing DLIs for NK cells using the Miltenyi system. % PURITY % YIELD CD3+CD56-/KG × 10e5 TOTAL CD56+10e7 CD3+CD56 KG × 10e6+/ CD3-CD56+ ×10e6 Median 95.32 83.44 5.34 1.12 1.94 9.21 St Dev 7.96 21.35 10.46 0.65 2.22 7.91 Mis Median 97.46 77.80 2.74 1.44 3.67 9.21 St Dev 3.24 24.05 7.79 0.61 2.41 5.56 Ten patients enrolled had HLA-matched (6/6) sibling donors. Of these, 3 had AML, 2 ALL, 3 follicular lymphoma/CLL, 1 myeloma, and 1 myeloproliferative disorder. At entry, six had active disease, 3 were in 2nd CR and 1 was in 1st CR with high risk ALL. These patients received a total of 15 NK cell-enhanced DLI. Infusions were well tolerated with 2 cases of overall grade 2 (grade 3 skin; grade 1 gut), and one case of grade 3 GVHD (grade 3 skin; grade 1 gut and liver). Four of 10 remain alive and in continuous complete remission. Fourteen patients enrolled had HLA-mismatched (3-4/6) related donors. Six had AML, 3 transformed AML, 2 ALL, 1 T cell NHL, 1 myeloproliferative disease and 1 severe aplastic anemia. At time of transplantation, only 1 subject was in CR1, 7 were in CR2, 6 were relapsed/refractory. These patients received a total of 27 NK cell enhanced- DLI. Despite the HLA mismatch, the infusions were well tolerated with 4 cases of overall grade 1 GVHD (primarily skin), 2 grade 2, and 1 grade 4 (gut and liver). Infections were a concern with 1 patient dying of infection while 2 others experienced sepsis. Further, 3 had parainfluenza, 1 VZV, and 2 polyoma virus in the bladder. Eight patients remain alive and 7 are in continuous remission. NK cell function was measured in 22 patients (Figure 1). Figure 1: (A) At 6 to 8 weeks post-transplant, some NK cell function had returned in 7 of 22 patients. Among other patients, 7 patients demonstrated low NK cell function (bracket) while 8 others did not recover lymphocytes (not shown). (B) The impact of NK DLI was monitored in 7 patients that had not previously responded. Of those patients, 4 responded within 6 to 8 weeks post-DLI. (C) In one patient, NK cell function returned gradually following a 2nd and 3rd DLI. Figure 1:. (A) At 6 to 8 weeks post-transplant, some NK cell function had returned in 7 of 22 patients. Among other patients, 7 patients demonstrated low NK cell function (bracket) while 8 others did not recover lymphocytes (not shown). (B) The impact of NK DLI was monitored in 7 patients that had not previously responded. Of those patients, 4 responded within 6 to 8 weeks post-DLI. (C) In one patient, NK cell function returned gradually following a 2nd and 3rd DLI. Conclusion: NK cell enhanced DLI can be safely delivered following T cell depleted nonmyeloablative allogeneic transplantation. Subsequent infusions may allow for improved function. Longer follow up is needed to evaluate affects on long term toxicity and durability of response.

Description: Abstract 3466 Donor cell leukemia (DCL) in the setting of bone marrow/hematopoietic stem cell transplant (HCT) has not been well characterized. We analyzed 9 cases of DCL and performed a literature review (table). The indications for transplant and subtypes of DCL are shown (table). The 6 myelodysplastic syndrome (MDS) cases included 1 case of refractory cytopenia with multilineage dysplasia (RCMD), 2 cases of refractory anemia and 3 cases which were unclassifiable. Conventional cytogenetic analysis was performed on all 9 cases of DCL (table). All 9 cases had engraftment studies performed either by short tandem repeat analysis (3) or FISH analysis for donor gonosomal complement (6) when DCL was diagnosed. Seven cases had either engraftment studies or cytogenetic analysis performed periodically after HCT to test the donor cell engraftment and engraftment was confirmed in all. FISH analysis for monosomy 7, del(7q) and del(5q) was retrospectively performed on preserved donor cells in 4 cases after DCL was diagnosed. A low level of abnormalities was observed in preserved donor cells for the cases with del(7q) (2.9%) and del(5q) (8.2%). The 2 cases of AML received chemotherapy. Of the MDS cases, 2 received donor cell infusion, 1 received 6 cycles of revlimid, and 3, along with the case of CLL, received either supportive therapy or were simply observed. Six cases have clinical follow up ≥ 5 months and of these, 1 died of disease (AML) while the other 5 are alive, including 4 MDS and the 1 CLL. The disproportionate detection of DCL in sex mismatched HCT suggests a probable under-detection in the sex-matched population. In our analysis, the interval between HCT and diagnosis of DCL (table) falls within the range of currently reported cases. When stratified by type of DCL, the T-LGL group demonstrates presentation significantly earlier than other groups (Fig. A), indicating pathogenesis of T-LGL may involve a distinct pathway. When stratified by types of primary disease, the interval of the neoplastic group is shorter than that of benign group (Fig. B), implying that pre-HCT treatment may play a role in the pathogenesis of DCL. When stratified by stem cell sources, UCB group shows shorter latency than the other sources (Fig. C), suggesting a higher risk of DCL in this cell source. The low level cytogenetic abnormalities of preserved donor cells in our series and the longer latency of the benign group suggest that donor cells with an intrinsic defect may be predisposed to evolve into DCL. Total cases (%) Reported cases (%) Current cases (%) Number of cases 83 74 9 Age (years)     Median/range 37.0/3~70 36.0/4~62 53.0/3~70 Gender     Male 43 (52.4) 38 (52.0) 5 (55.6)     Female 39 (47.6) 35 (48.0) 4 (44.4) Primary disease     Neoplasms 76 (91.6) 67 (90.5) 9 (100)     Non-neoplasms 7 (8.4) 7 (9.5) 0 (0.0) Donor     Related 59 (72.0) 54 (74.0) 5 (55.6)     Unrelated 23 (28.0) 19 (26.0) 4 (44.4)     Sex-matched 28 (34.6) 27 (37.5) 1 (11.1)     Sex-mismatched 53 (65.4) 45 (62.5) 8 (88.9) Donor cell source     BM 48 (63.2) 44 (65.7) 4 (44.4)     BHSC 16 (21.0) 13 (19.4) 3 (33.3)     UCB 12 (15.8) 10 (14.9) 2 (22.2) 2nd neoplasm (DCL)     AML 31 (37.4) 29 (39.2) 2 (22.2)     MDS/MPN* 27 (32.5) 21 (28.4) 6 (66.7)     ALL 20 (24.1) 20 (27.0) 0 (0.0)     T-LGL 4 (4.8) 4 (5.4) 0 (0.0)     CLL 1 (1.2) 0 (0.0) 1 (11.1) Interval (months)     Median/range 24.0/1~312 24.0/2~312 26.0/1~193 Cytogenetics     Normal 21 (28.0) 20 (30.3) 1 (11.1)     Abnormal 54 (72.0) 46 (69.7) 8 (88.9)     -7 or del(7q)** 15 (27.8) 10 (21.7) 5 (62.5)     +8** 2 (3.7) 2 (4.4) 0 (0.0)     Del(20)** 4 (7.4) 2 (4.4) 2 (25.0)     Del(5q)** 2 (3.7) 1 (2.2) 1 (12.5)     11q23** 3 (5.6) 3 (6.5) 0 (0.0) Other abnormalities** 28 (51.9) 28 (60.9) 0 (0.0) Follow up (months)     Median/range 8.5/1~108 9.0/1~108 6.0/1~68     Died of disease 28 (46.7) 27 (52.9) 1 (11.1) DCL, donor cell leukemia; BM, bone marrow; BHSC, blood hematopoietic stem cells; UCB, umbilical cord blood; AML, acute myeloid leukemia; MDS, myelodysplastic syndrome; ALL, acute lymphoblastic leukemia (including B-cell and T-cell ALL); T-LGL, T-cell large granular lymphocyte leukemia; CLL, chronic lymphocytic leukemia. All the numbers represent the cases with data available. * One case of myeloproliferative neoplasm is included in this category. ** The percentage is calculated using number of total cytogenetic abnormalities in each column as denominator. Disclosures: No relevant conflicts of interest to declare.