ALBERT

Description: Cord blood (CB) transplants are hampered by low cell dose and high transplant related mortality (TRM). UM171, a novel and potent agonist of hematopoietic stem cell (HSC) self-renewal could solve this major limitation, allowing for CB's important qualities as lower risk of chronic GVHD and relapse to prevail. Hence, we initiated a clinical trial to test the safety and efficacy of UM171 expanded CB (eCB). The procedure was designed to be non-labor intensive and of short duration for it to be clinically viable. Patients (pts) received a myeloablative conditioning regimen. On day(D)-7 of transplant, CB was thawed and CD34+ selected. The CD34- lymphocyte containing fraction was cryopreserved and infused on day of transplant. The CD34+ component was placed in a closed culture system with UM171 and media was injected once a day until D0, when cells were washed and infused. The first 3 pts also received a 2nd nonmanipulated CB (neCB) to permit documentation of eCB engraftment. This fed-batch culture system allowed for small culture volumes, saving cost and labor. Between 6/16-7/17, 16 adults with a median weight and age of 77 kg and 44 years, respectively, were transplanted with a single eCB (13 pts) or with an eCB and a neCB (3 pts). Median final culture volume was 609 mL. The median net viable (v)CD34 fold expansion was 36. Median 1st day of 100 and 500 neutrophils were D+10 and D+19, respectively. Achieving 100 neutrophils was faster than expected and cell dose independent, suggesting that clinically meaningful expansion of an early repopulating myeloid progenitor is at saturation even with smaller CBs. In contrast, attaining 500 neutrophils was accelerated but dependent on infused vCD34+ cell dose. More importantly, patients appeared to derive clinical benefit beyond neutrophil engraftment defined as the 1st of 3 consecutive days of 500 neutrophils. Patients' last day of fever prior to neutrophil engraftment was Day +7, which occurred much earlier than D+19 of engraftment. We offer 2 hypotheses as explanation: i) 100 neutrophils, which are attained much earlier at D+10, provide significant defence against infection, ii) the graft contains a significant proportion of dendritic cell precursors (〉25%) which offer protection during severe neutropenia. When compared to our pts who have received the same conditioning regimen with peripheral blood or marrow, eCB pts were free of fever much earlier (D+7 vs D+15 p

Description: Introduction For patients in need of a hematopoietic stem cell transplant (HSCT) but lacking an HLA matched donor, a haploidentical family donor is a particularly appealing alternative. However, to prevent graft-versus-host disease (GVHD), haploidentical HSCT necessitates intensive in vivo or ex vivo T-cell depletion that results in frequent and often lethal infectious complications and/or high relapse rates, thus decreasing overall survival. To overcome this limitation, we have developed a strategy that photodepletes host-reactive cells from the donor T cell graft, while preserving anti-infection and anti-leukemia reactivity. Patients and Methods In an open-label, multi-center phase 2 clinical trial (CR-AIR-007; NCT01794299), 12 of a planned 23 patients with high-risk hematologic malignancies were treated to date with this immunotherapy approach consisting of donor lymphocytes selectively allodepleted of host-reactive T-cells using photodynamic therapy (ATIR). ATIR was infused 28-32 days after haploidentical CD34-selected HSCT. No post-transplant GVHD prophylaxis was used. These patients were compared to a control group of 28 patients treated in a previous Phase 2 study with an investigational product manufactured using a process different from the Phase 1 trial and resulting mainly in dead and inactive cells instead of ATIR (CR-AIR-004). Results Twelve patients, mean age of 45 (range 21-64), 6 females/6 males with AML (n=9) and ALL (n=3) were treated with ATIR so far. ATIR consisted mainly of T-cells (〉90%), with residual B and NK cells (≤10%). Selective depletion of recipient-reactivity in each ATIR cell graft was assessed using a CFSE-based proliferation assay. Cell division numbers upon stimulation were analyzed using Modfit LT software (Fig 1A), which generated a proliferation index representing viable/reactive T-cells in donor cells (blue) and final ATIR product (green)(Fig 1B). Selective depletion of recipient-reactive T-cells with preservation of reactivity towards 3rd party antigens and anti-CD3/CD28 was observed in all ATIR cell grafts and used as a release criteria in the 007 study. Figure 1: A) CFSE-dilution pattern in Modfit LT software of ATIR stimulated with 3rd party cells. B) CFSE-based proliferation confirmed selective depletion of recipient-reactive T-cells in all grafts (representative depiction). Figure 1:. A) CFSE-dilution pattern in Modfit LT software of ATIR stimulated with 3rd party cells. B) CFSE-based proliferation confirmed selective depletion of recipient-reactive T-cells in all grafts (representative depiction). Preparative regimen consisted of A) FTBI (1200 cGy; n=5) or B) melphalan (120 mg/m2; n=7), along with thiotepa (10 mg/kg), fludarabine (30 mg/m2 x5 d) and ATG (2.5 mg/kg x4 d). Neutrophil and platelet engraftment was achieved in all patients at a median of 12 days (range: 9-35). No patient experienced graft rejection. Patients (n=28) in the 004 control group, mean age of 42 (range 18-61), 13 females/15 males had AML (n=19), ALL (n=6) or MDS (n=3). CFSE proliferation in T-cell grafts could not be assessed a posteriori due to low cell viability. These 004 patients received the same A) FTBI- (n=14), B) melphalan- (n= 10) based preparative regimen as 007 patients, except for 4 patients receiving single fraction (800 cGy) TBI. Neutrophil and platelet engraftment was achieved at a median of 16 days (range: 7-54). Three patients showed secondary graft rejection. Two patients in study CR-AIR-007 developed acute GVHD grade I (skin only) approximately 130 days post HSCT, which was of short duration, (18 and 41 days). Two patients died of infection and no patient relapsed at a mean follow-up of 8 months post HSCT (range 1-14 months). In the CR-AIR-004 control group, 2 patients developed grade I, 1 patient grade II and 3 patients grade III GvHD, none of these cases were lethal. Seventeen patients died of transplant related complications and 2 patients of relapse/disease progression. TRM is 20% in 007 group vs 63% in the 004 control group and OS is 80% in 007 group vs 35% in the 004 control group at 9 months post-transplant (Figures 2A and 2B). Figure 2A Kaplan Meier Transplant Related Mortality: 004 vs 007 (p=0.06) Figure 2B Kaplan Meier Overall Survival (OS): 004 vs 007 (p=0.03) Conclusions These data confirm that a novel immunotherapy strategy consisting of donor lymphocytes selectively photodepleted of alloreactive cells (ATIR) can be manufactured consistently and reproducibly. Results to date show that ATIR is safe and does not cause any grade III/IV GvHD. Moreover, haploidentical HSCT patients treated with ATIR demonstrate very promising TRM and OS rates when compared to the control group. Disclosures Roy: Kiadis Pharma: Consultancy, Research Funding. Foley:Hoffman-LaRoche: Advisory Board/Lectures Other, Honoraria; Lundbeck: Advisory Board/Lectures, Advisory Board/Lectures Other, Honoraria; Sanofi: Advisory Board/Lectures, Advisory Board/Lectures Other, Honoraria; Celgene: Advisory Board/Lectures, Advisory Board/Lectures Other, Honoraria; Pfizer: Advisory Board/Lectures Other, Honoraria; Novartis: Advisory Board/Lectures Other, Honoraria; Jansen: Advisory Board/Lectures Other, Honoraria; Alexion: Advisory Board/Lectures, Advisory Board/Lectures Other, Honoraria; Roche Canada: Honoraria, Research Funding, Unrestricted educational grant, Unrestricted educational grant Other. De Jong:Kiadis Pharma: Employment. Velthuis:Kiadis Pharma: Employment. Gerez:Kiadis Pharma: Employment. Reitsma:Kiadis Pharma: Employment. Wagena:Kiadis Pharma: Employment.

Description: Incidences of grade II–IV aGvhd in the range of 30–50% have been reported in sibling NMA transplant recipients despite prophylaxis with cyclosporine and methotrexate. To date, the ideal Gvhd prophylaxis regimen still remains undefined. Because tacrolimus is more potent than cyclosporine and MMF does not lead to mucositis, we hypothesized that early use of a combination of these two oral agents could offer an effective strategy to prevent Gvhd. We therefore designed an outpatient prospective phase II clinical trial with a NMA conditioning regimen consisting of daily fludarabine 30 mg/m2 and cyclophosphamide 300 mg/m2 for 5 days, followed by infusion of at least 4 × 106 CD34+ cells/kg. All donors were 6/6 matched siblings. Tacrolimus 3 mg bid orally was started on day (D)-8, adjusted to achieve levels of 10–15 nmol/L until D+50, then tapered off by D+100 or +180 according to estimated risk of relapse. MMF 1000 mg bid was given between D+1 to D+50 without taper. Enrollment criteria included age 〉55 years, an estimated increased risk of toxicity with an ablative transplant or participation in a multiple myeloma (MM) sequential therapy. Between 07/2000 and 07/2007, 131 patients (M/F: 75/56) with a median age of 54 years (range: 20–66) have received an allogeneic transplant according to our protocol. Indication for transplant included age (26%), fear of toxicity (28%) or participation in the sequential therapy (48%). Overall, 101 (77%) patients had previously received an autologous transplant. Diagnoses included MM (N=62), non Hodgkin’s lymphoma (NHL; N=46) including low grade (N=33), diffuse large cell (N=5), mantle (N=7) and Sezary (N=1), acute leukemia (N=10), and others (N=13). After infusion of a median of 6.8 × 106 CD34+ cells/kg (range 0.30 to 22.3), engraftment occurred in 95% of patients by D+180. Overall, 15 patients developed grade I–IV conventional aGvhd by D+120, with a Kaplan-Meier (KM) probability of 11.6% (95%CI: 7.1–18.5), a median of 64 (range: 31–120) days after transplant. At presentation, aGvhd grade was I in 5, II in 7, and III in 3 patients, respectively. No grade IV was observed. Organs involved included skin (13/15) or gastro-intestinal (GI; 4/15), but not liver. Additionally, 15 patients (12%; 95%CI: 7.4–19.2) developed an overlap syndrome consisting of clinical and histological features of both acute and cGvhd simultaneously, at a median of 140 (range 92–177) days post transplant. Altogether, the incidence of conventional II–IV aGvhd and overlap syndrome was 19.7% (95%CI: 13.7–27.7). In contrast, extensive cGvhd occurred in 84 patients surviving beyond D+80 (median D+148, range 83–1042), with a cumulative KM incidence at 7 years of 83.3% (95%CI: 74.3–90.6). Involved organs at diagnosis of extensive cGvhd included mouth (100%), skin (89%), liver (65%), eyes (51%), GI (20%), joints (6%) and lungs (6%), similar to other reported series. Nine of 76 (12%) patients at risk are still taking immunosuppressors after 5 years. To date, 37 patients have died; causes of death include relapse of initial malignancy (N=24), cGvhd (N=3), viral or fungal infection (N=3), or other (N=7). With a cohort median follow-up of 33 (range 2.7–86) months, KM probability of non-relapse mortality (NRM) is 15.5% (95% CI: 9.0–26.1) at 7 years. Overall survival (OS) at 1, 3 and 7 years are 88.5% (95%CI: 81.7–92.9), 71.0% (95%CI: 61.1–78.7) and 62.7% (CI: 51.4–72.1), respectively. Following NMA transplant, disease-free survival (DFS) at 3 years is highest in recipients with low-grade NHL (81.4%; 95%CI: 60.5–91.9) and lowest in intermediate grade NHL (40.0%; 95%CI: 6.6–73.4) or leukemia (35.7%; 95%CI: 13.0–59.4). We conclude that early use of tacrolimus and MMF is an effective strategy to prevent aGvhd and leads to very low NRM. Despite a high incidence of extensive cGvhd, OS, DFS and probability of discontinuing immunosuppression are excellent. Future strategies will need to focus on decreasing the incidence of extensive cGvhd without increasing the risk of relapse.

Description: Despite various strategies involving autologous Tx and use of newest drugs with anti-MM activity such as bortezomib and lenalidomide, very few patients with MM currently achieve long-term remission. Allo Tx theoretically remains an attractive option due to evidence of graft-versus-MM activity supported by small series of patients with long-term (〉10 years) complete remissions (CR) following myeloablative Tx, the association between chronic graft-versus-host disease (Gvhd) and CR, and response in 20–30% of relapsed patients following donor leucocyte infusion. However, to date, the ideal strategy using Allo Tx remains uncertain. Early studies using myeloablative regimens have been associated with high (30–50%) mortality rates and late relapses have been observed despite Gvhd. Low (10–22%) reported mortality in NMA regimens is hampered by reduced CR and higher progression rates compared to ablative regimens. Additionally, long-term outcome following NMA transplant remains unclear. In this present study, we sought to compare outcomes of 2 sequential cohorts of patients with MM who underwent Allo Tx in our institution. Between 01/01 and 10/07, patients with newly diagnosed stage II–III MM were invited to participate in a phase II prospective study consisting of vincristine, adriamycine and decadron x 4 cycles followed by autologous blood stem cell Tx with melphalan 200 mg/m2. Within 3 months post autologous Tx, enrolled patients received outpatient NMA Allo Tx from a 6/6 HLA matched sibling donor with a conditioning of fludarabine 30 mg/m2 and cyclophosphamide 300 mg/m2 for 5 days, followed by infusion of 〉4 x 106 CD34+ cells/kg. Gvhd prophylaxis was chosen to take advantage of low incidence of acute Gvhd and putative protective effect of chronic Gvhd: tacrolimus 3 mg bid was started on day (D)-8 then tapered off by D+100, with mycophenolate mofetil 1000 mg bid D+1 to D+50. Our NMA cohort was compared to MM patients who underwent full myeloablative Allo Tx between 06/90 and 01/01, mostly (N=29) with TBI; marrow was used in 54% and all received short course CSA/MTX. A total of 73 patients received NMA Tx (M/F: 43/30, median age 54 years, 73% stage III) and were compared to 39 patients with myeloablative Tx (M/F: 24/15, median age 47 years, 64% stage III). The incidence of grade II–IV acute Gvhd was significantly higher in the myeloablative group (30.7% vs 6.8%; p=0.0004); in contrast, as expected, chronic Gvhd was more frequent at 3 years following NMA Tx (90% vs 59.4%; p=0.0001). At 4 years, transplant related mortality (TRM) following myeloablative Tx was 50% compared to 17% in the NMA group (p=0.0001). Median (range) follow-up in NMA and myeloablative cohorts were 28 (3.5–82.9) and 37 (0.5–139) months, respectively. Kaplan-Meier estimates of overall survival (OS) at 2 (87% vs 59%; p=0.001) and 5 years (67% vs 44%; p=0.001) are significantly better in the NMA cohort. Similarly, disease free survival (DFS) at 2 (87% vs 48.5%; p=0.0001) and 5 years (67% vs 41%; p=0.0001) are also significantly better with the NMA Tx. In conclusion, our sequential auto-NMA Tx protocol is more effective to control MM than myeloablative Tx with significantly less TRM, better OS and DFS. These results might be explained by less advanced disease and higher incidence of chronic Gvhd in the NMA cohort. Future strategies should focus on reducing the relapse rate and incidence of extensive chronic Gvhd while preserving the graft versus MM effect.

Description: Infection and disease relapse are the two major complications occurring after haplo-mismatched stem cell transplantation (SCT). Accelerating immune reconstitution would imply broader applicability of SCT by providing a transplant opportunity to the large number of patients who cannot find an HLA-matched related or unrelated donor. We have previously reported that photodynamic therapy (PDT) using TH9402 could selectively deplete donor alloreactive cell populations while preserving lymphocytes for immune responses. We present results of an ongoing Phase I clinical trial of haplo-mismatched allogeneic stem cell transplant (SCT) supplemented with DLIs PDT depleted of host-reactive T cells. Thirteen patients with high-risk hematologic malignancies (7 AML relapsed or refractory, 1 AML in CR3, 1 refractory ALL, 2 MDS, 1 NHL relapsing after autologous SCT, 1 refractory CLL) entered the trial. Eleven pts are evaluable for acute GVHD and reconstitution. Patients (7 M, 4 F) underwent transplantation with donor cells mismatched at 3 HLA Ags: 5 patients; 2Ags: 5 pts, and DR only: 1 pt). Donor mononuclear cells (MNCs) were incubated with recipient MNCs for 4 days, exposed to ATIR™ treatment (TH9402 PDT), stored frozen, and administered on day 33±6 after transplant at 5 graded DLI dose levels: 1×104 to 8×105 CD3+ cells/kg. Anti-host cytotoxic T lymphocyte precursors (CTLp) were depleted from DLIs by approximately 1.5 logs, and flow cytometry showed greater than 90% elimination of activated T cells (CD4+CD25+ and CD8+CD25+) by ATIR. All stem cell grafts underwent in vitro immunomagnetic T cell depletion using CD34+ positive cell selection. Median age at SCT was 56 years (range: 21–60). Eight patients were in partial remission or had progressive disease, and 3 patients were in complete remission at the time of SCT. Conditioning regimen consisted of TBI (1200 cGy), thiotepa (5 mg/kg) and fludarabine (40 mg/m2/day for 5 days) followed by infusion of CD3 depleted HSC grafts. No GVHD prophylaxis was administered. Evaluable patients showed durable hematologic engraftment: median time to 〉0.5×109 granulocytes/L was 11 days (8–20), and to 〉20×109 platelets/L without transfusion, 12 days (9–137) and all achieved complete donor chimerism. No patient developed acute GVHD (grade II–IV), while 3 patients developed signs of chronic GVHD. Four of the first 6 pts developed infectious complications in the first 6 months, and all resolved rapidly with appropriate therapy, except for EBV-PTLD in the first patient (1×104 CD3). Five patients died: 1 of relapsed CLL and 4 of infections (all after day+310), and all had received DLI containing 1.3 ×105 CD3+ cells (2 pts) or less. No other patient relapsed. The first 6 pts developed 10 infectious episodes (4 lethal), while none of the 5 pts receiving the highest DLI doses of CD3+ cells/kg developed any infection (median follow-up: 318 days). The overall disease-free-survival and survival are 57% at 1 year (median follow-up: 10.5 mo). Our results indicate that the post-transplant infusion of a ATIR-PDT treated DLI is feasible, does not induce acute GVHD, and suggests a clinical benefit for patients receiving the highest DLI doses to accelerate T cell reconstitution. This PDT strategy represents an appealing alternative for older patients and those at high risk for GVHD.

Description: Abstract 1156 Poster Board I-178 Introduction cGVHD is the main cause of impaired quality of life, morbidity and mortality in patients surviving after allogeneic transplantation. To date, no validated biomarkers for diagnosis and follow-up of cGVHD have been established. Among proposed pathophysiological mechanisms, one involves increased turnover of extracellular matrix components as a result of immune-mediated tissue destruction. We hypothesized that analysis of urinary excretion of degradation peptides from collagen (hydroxylysylpyridinoline [HP] and lysylpyridinoline [LP]) and elastin (desmosine [DES]) using high-sensitivity nano-flow liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) might lead to identification of potential biomarkers in patients with cGVHD. Patients and Methods We elected to compare 3 groups: 16 allogeneic transplant recipients with newly diagnosed or relapsing cGVHD before initiation of systemic immunosuppressive therapy (group A), 13 pts with lymphoma who underwent autologous transplantation, in order to measure the impact of high-dose chemotherapy (group B) and 10 healthy volunteers (group C). Clinical characterization of cGVHD was performed according to NIH criteria. Pts already on glucocorticoids and those with bloodstream infection or proteinuria were excluded. Morning urine samples were collected in fasting subjects, then processed and frozen at -80°C until analysis by nanoLC-MS/MS. Samples were purified using mixed-mode strong cation exchange cartridges, derivatized using propionic anhydride and analyzed with nanoLC-MS/MS. Results Pts with cGVHD (group A) were collected at a median of 229 (107-2966) days post transplant; 8 pts had de novo cGVHD, 8 presented with obvious clinical flare-up and 3 had previously suffered from acute GVHD. cGVHD was mild in 1 (6%), moderate in 8 (50%) and severe in 7 (44%) pts. Affected organs included mouth in 12 pts, skin in 11, liver in 11, eyes in 5, GI tract in 5, joints/fascia in 2, genital tract in 1 and lungs in 1. Thrombocytopenia was present in 4 (25%) pts and eosinophilia in 7 (44%). All transplants had been performed for hematological malignancies, using myeloablative (7 pts) or reduced-intensity conditioning (9 pts). Donors were HLA-identical siblings (13 pts), 10/10 (2 pts) or 9/10 (1 pt) unrelated volunteers. Stem cell source was peripheral blood in all but one pts. Pts from group B were collected at a median of 123 (90-377) days post transplant. As shown in enclosed figure, urinary concentrations of DES and HP in group A and B were similar, but both groups showed a marked increase in levels of these compounds compared to group C (p

Description: Introduction Haploidentical family donors are becoming an effective alternative for patients in need of an hematopoietic stem cell transplantation (HSCT) but lacking an HLA-matched donor. However, to prevent graft-versus-host disease (GVHD), intensive in-vivo or ex-vivo T-cell depletion is often utilised, resulting in slow immune reconstitution, frequent and often lethal infectious complications and/or high relapse rates, thus decreasing overall survival. To overcome these limitations, we have developed a strategy that allows additional donor lymphocytes to be infused post-HSCT without the risk of inducing severe GVHD and maintaining the ability to react against infections and leukemic cells. Patients and Methods In this open-label, multi-centre phase 2 clinical trial (CR-AIR-007; NCT01794299), 23 patients with high-risk AML or ALL were enrolled. Patients underwent myeloablative conditioning and were given a CD34+ selected stem cell graft from a haploidentical family donor. In addition, donor lymphocytes from the same donor were processed using a selective photodepletion technology, creating a donor lymphocyte product depleted of alloreactive T-cells (ATIR101). ATIR101 was to be given to patients at 28-32 days post-HSCT at a fixed dose of 2x106 CD3+ cells/kg. No post-transplant GVHD prophylaxis was administered. The primary endpoint of the study is transplant-related mortality at 6 months post-HSCT. Patients are followed to determine disease-free and overall survival. Patients undergoing a similar T-cell depleted haploidentical HSCT without ATIR infusion (CR-AIR-006; NCT02188290) were used as controls. Most centers providing the historic control data also participate in this phase 2 trial with ATIR101. Results Twenty-three patients, median age of 41 years (range 21 - 64), have been enrolled into this study. Seventeen patients, 7 male and 10 female, had AML, 12 in CR1 and 5 in CR2 at the time of HSCT. Six patients, 5 male and 1 female, had ALL, 4 in CR1 and 2 in CR2 at the time of HSCT. Conditioning regimen consisted of a] TBI (1200 cGy; n=10) or b] melphalan (120 mg/m2; n=12), along with thiotepa (10 mg/kg), fludarabine (30 mg/m2 x 5d) and ATG (2.5mg/kg x 4d). No patient experienced graft rejection, with neutrophil and platelet engraftment achieved at a median of 11 and 12 days, respectively (range 8-18, range 9-35). 21 patients to date received ATIR101, at a fixed dose of 2x106 CD3+ cells/kg at a median of 28 days (range: 28-73 days) post-transplant. Median follow-up is 270 Days post-HSCT. No patient developed grade III-IV acute GVHD. Two cases of grade II acute GVHD were reported thus far. The onset of these two acute GVHD cases was delayed, at day 173 and day 247 post-HSCT, 145 and 219 post ATIR respectively. No patient died within the first 100 days post-HSCT. There are 3 deaths as a result of transplant related mortality within 6 months post-HSCT (primary endpoint). When compared to the matched historic control group (N=35), TRM was significantly lower in patients given ATIR101 after a T-cell depleted haplotransplant with a 6-month TRM for HSCT + ATIR101 of 17% versus 34% for HSCT only (Figure 1a). Figure 1a: Kaplan Meier of Transplant related mortality: HSCT + ATIR101 vs HSCT alone (p=0.0075), data as per 3 August 2015. Thus far, in CR-AIR-007 study, only one patient experienced a relapse, which occurred at 90 days post-HSCT and resulted in death of the patient on day 122. The overall survival of patients given ATIR101 is significantly improved, compared to the control group, with a 1-year survival of 67% in the HSCT + ATIR101 group and 20% in the control group (Figure 1b). Figure 1b: Kaplan Meier of Overall Survival: HSCT + ATIR101 vs HSCT alone (p=0.0032), data as per 3 August 2015. Conclusions Addition of ATIR101 to a T-cell depleted haploidentical HSCT protocol significantly improves transplantation outcome, with reduced TRM and improved OS. Specifically, no patient died during the first 100 days post-HSCT. Administration of ATIR101 at the dose of 2x106 cells/kg does not induce severe GVHD, confirming the efficacy of alloreactive T-cell elimination from the donor lymphocyte infusion. We attribute the reduced TRM (mainly infections in the control group) to the additive immunological protection afforded by ATIR101. Moreover, the low number of relapses observed thus far is most encouraging and supports the preservation within ATIR101 of T-cells able to recognize leukemic antigens. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Roy: Kiadis Pharma: Consultancy, Research Funding; Novartis: Honoraria. Rudiger:Kiadis Pharma: Employment. Velthuis:Kiadis Pharma: Employment. Reitsma:Kiadis Pharma: Employment. Gerez:Kiadis Pharma: Employment. Rovers:Kiadis Pharma: Employment.

Description: Many new therapeutic agents have been approved for follicular lymphoma (FL) but none appear to be curative. Despite novel agents, some patients (pts) experience early relapse, become chemorefractory or suffer transformation into more aggressive lymphomas. Options for these pts are limited. High dose chemotherapy with autologous stem transplant (ASCT) prolongs progression free survival (PFS) and overall survival (OS) in FL pts in first relapse and registry data shows favorable outcome with ASCT in cases of histologic transformation. However, ASCT is usually not curative. Myeloablative allogeneic transplant (MT) has produced long term PFS but is hampered by significant non relapse mortality (NRM) while nonmyeloablative transplant (NMT) has a higher relapse rate compared to MT especially in high risk pts. Finally, many transplant studies have excluded these high risk pts such as those with chemorefractory or transformed disease. We hypothesized that a tandem transplant consisting of an ASCT followed by a NMT would confer the same benefit as a MT without the associated high NRM by separating the high dose chemotherapy from graft versus host disease (GVHD) while preserving the graft versus lymphoma effect. The goal of our study was to improve long term PFS in high risk FL pts. We therefore initiated a prospective protocol in April 2003, for pts with high risk relapsed FL as defined by chemorefractory disease, early 1st relapse, 〉1st relapse or transformation into aggressive histology. At least one therapy was attempted to document chemosensitivity prior to ASCT. However, regardless of disease status prior to transplant, pts underwent ASCT followed 3 months later by an outpatient NMT from an HLA-identical sibling. NMT comprised 5 days of fludarabine 30 mg/m2/day and cyclophosphamide 300mg/m2/day followed by an infusion of 〉2x106CD34+ cells/kg. GVHD prophylaxis, chosen to take advantage of the low incidence of acute (a) GVHD and the putative protective effect of chronic (c) GVHD, consisted of tacrolimus starting on day (D) - 8 to achieve levels of 8-12 nmol/L then tapered off by D+100 or D+180 depending on disease risk and of mycophenolate mofetil 1g bid from D+2 to D+50. We previously reported on 27 pts with a follow-up (f/u) of 3 years (yrs). We now report a larger cohort of 40 pts with a median f/u of 8 yrs. Up until July 2015, 40 pts were enrolled with a median age of 50 yrs (34-65). Pts had previously been treated with a median of 3 lines of therapy (2-6). Median time from diagnosis to ASCT was 33 months. Disease status at ASCT was: 14 CR, 16 PR and 10 refractory. Conditioning for ASCT included BEAM/BEAC (n=39), and Cy-TBI (n=1). In addition, 4 pts received radiotherapy after ASCT to sites of previously bulky disease. Median time between ASCT and NMT was 138 days (75-238). Pre NMT disease status was: 25 CR, 12 PR and 3 refractory. Engraftment was prompt in all pts after ASCT and median neutrophil and platelet recovery were respectively 13 days (0-19) and 0 day (0-18) post NMT. Seven pts (18%) developed aGVHD: 2 grade II and 5 grade III. Overall, 29 pts (73%) developed cGVHD: 1 mild, 13 moderate and 15 severe according to NIH revised criteria. Median time to discontinuation of immunosuppression was 22 months. To date, 2 pts have progressed at 11 and 59 months post NMT (one died from relapse and one is now in CR after chemotherapy and DLI) and 5 pts died from either GVHD related complications (n=4) or unknown cause (n=1). All pts alive at last f/u were in CR. With a median f/u of 8 yrs in surviving pts (1-12), OS is 95% at 3 and 5 yrs and 82% at 8 yrs. PFS is 92% at 3yrs, 89% at 5 yrs and 80% at 8 yrs. NRM and relapse rate at 8 yrs are 18% and 6% respectively. Based on our current results in 40 pts, we conclude that ASCT followed by sibling NMT for high risk relapsed FL is associated with excellent disease response and PFS. Furthermore, this tandem strategy appears to be safe and well tolerated. The incidence of cGVHD remains high but could in part explain the impressive PFS in this high risk cohort. This approach should now be further explored in a multi institution setting, include matched unrelated donors and consider the addition of rituximab post-transplant to reduce the incidence and severity of cGVHD with the hope that relapse will not be increased. Figure 1 Figure 1. Disclosures Busque: Pfizer: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau.

Description: PURPOSE: Graft-versus-host disease (GVHD) is the principal complication of allogeneic stem cell transplantation (allo-SCT) and occurs when GVHD T cells recognize differences in major and/or minor histocompatibility antigens expressed by recipient cells. Following cytotoxic regimens, the inflammatory milieu represents a fertile ground for alloreactivity and thymic insults resulting from GVHD are largely responsible for thymic dysfunction and immune-incompetence. Studies have also demonstrated that GVHD insult to the peripheral niche is perhaps the most important factor for limiting thymic independent T cell regeneration. Given that patients with chronic GVHD (cGVHD) are profoundly lymphopenic and that dendritic cells (DCs) play a critical role in T cell homeostasis, we postulated that changes in DC counts could precede the development of clinical signs of acute and/or chronic GVHD. METHODS: 44 patients that received HLA-matched allogeneic SCT were included in this study. Controls consist of 15 patients that received autologous SCT and 30 healthy donors. Flow cytometric analysis was used to measure plasmacytoid DCs (pDCs), myeloid DC type 1 (mDC1), mDC2 and mDC3. Blood samples were obtained at day 0, 1 month post-SCT and then every other month until 1 year. The percentage and absolute counts of naïve CD4+ or CD8+ lymphocytes (TNA); (CD3+ CD45RA+ CCR7+), central memory (TCM); (CD3+ CD45RA+ CCR7neg), effector memory (TEM); (CD3+ CD45RAneg CCR7neg) and terminal differentiation (TTD); (CD45RA+ CCR7neg) was determined by flow cytometry. B lymphocytes and regulatory CD4+ T cells were also evaluated. RESULTS: One month after allo-SCT, we found a significant increase in blood DCs followed by a gradual decrease and stabilization by 3 months post-allo-SCT. During the first year, all DC subsets including pDCs, mDC1, mDC2, mDC3 as well as CD4+ and CD8+ T cells were significantly diminished compared to autologous and healthy controls. Plasmacytoid DCs regeneration was in general the most affected and we found a positive correlation between pDC cells count and the number of naïve and central memory CD4+ lymphocytes. Similarly, pDCs counts also correlated with the number of naïve and memory CD8+ T cells. In contrast, effector CD4+ and CD8+ T cell showed a stronger correlation with mDC1. Patients with grade II-IV acute GVHD had lower DC counts compared with mild grade 0-1 aGVHD and a similar trend was also observed during the development of cGVHD, Importantly, loss of pDCs and mDC1 that preceded the development of cGVHD by 1 month was associated with the development of grade 3 cGVHD whereas loss of DCs during cGVHD was associated with milder 0-2 cGVHD. Thus far, our data support a model wherein loss of pDCs and mDC1 could represent potential biomarkers to predict the severity of cGVHD. Disclosures No relevant conflicts of interest to declare.

Description: Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only curative option for multiple myeloma (MM). Unfortunately, relapses remain frequent and randomized controlled trials have yielded equivocal conclusions. Before these trials were published, selected patients were treated with alloHSCT, but factors affecting long-term success have not been clearly defined. We have analyzed our single-center cohort of MM patients receiving a myeloablative alloHSCT in the 1990's in order to evaluate the impact of several factors on outcomes. Methods We performed a retrospective data collection on all patients treated with myeloablative alloHSCT from a sibling donor at our institution. Probabilities of overall (OS) and progression-free survival (PFS), as well as relapse, nonrelapse mortality (NRM) and graft-versus-host disease (GVHD) incidences were estimated taking competing risks into account when appropriate. Regression analysis using Cox and Fine & Gray models were used to determine factors influencing outcomes. Severity of chronic GVHD was assessed by the proportion of survivors on systemic immunosuppressive therapy. Results Between 1990 and 2001, 39 patients received a myeloablative alloHSCT. Median age was 46 years (range 24-53) and 68% had Durie-Salmon stage III disease. Twenty patients had received more than 4 cycles of prior chemotherapy and 4 patients had been treated with an autologous HSCT. Complete remission (CR) was achieved before allogeneic transplant in 31% patients. All but one donor were 6/6 HLA matches. AlloHSCT was performed within the first year of diagnosis in 69% of patients. Irradiation-based conditioning was used in 77%; stem cell source was bone marrow in 54% and peripheral blood (PB) in 46% of patients. With a median follow-up of 13 years, cumulative incidences of progression and NRM were 43% (95%CI: 26-59; Fig. 1) and 38% (22-54), respectively. Cumulative incidences of grade II-IV acute and extensive chronic GVHD were 29% (16-44) and 40% (24-55). Probabilities of 10-year OS and PFS were 33% (95%CI: 19-48; Fig. 2) and 29% (95%CI: 16-44) In multivariate analysis, the most significant protective factor against relapse was the use of PB as cell source (HR 0.34, CI: 0.14-0.82). The only protective factor for PFS was CR status before transplantation (HR 0.28, CI: 0.09-0.89). Nevertheless, the effect of these variables on overall survival was inconclusive (respectively: HR 0.51, CI 0.22-1.17, and HR 0.39, CI: 0.13-1.19). The time-dependent effect of chronic GVHD on PFS was also statistically non-significant (HR 0.47, CI: 0.14-1.59). The probability of being on systemic immunosuppressive treatment for GVHD in alive patients was 31% (CI: 13-58) at 10 years. Conclusions Myeloablative alloHSCT performed for MM in the 1990's in selected patients allowed a high probability of disease control but with major toxicity as shown by the high NRM risk. A third of patients are alive 10 years after transplantation. Achievement of CR before alloHSCT and the use of PB stem cells were protective against transplant failure. However, small sample size does not allow us to draw conclusions on the effect of other pre-transplant characteristics and GVHD on OS. The risk of relapse in our cohort being comparable to published results in frontline reduced-intensity alloHSCT, superiority of myeloablative HSCT for advanced disease can be hypothesized. Prohibitive NRM risk should encourage efforts to reduce early and late toxicity through better patient and donor selection, conditioning regimen and GVHD prophylaxis. Disclosures: No relevant conflicts of interest to declare.