Background: PBI-1402 is a novel orally active low molecular weight synthetic compound with erythropoiesis stimulating activity. Furthermore, a clinical phase I study showed that PBI-1402 induced a ...significant increase (100%, p < 0.0001, compared to placebo) of relative and absolute reticulocyte count in healthy volunteers after 21 days of oral treatment and was devoid of significant side effects.
Outcomes: The objectives of this clinical phase Ib/II trial were to study the safety and tolerability of PBI-1402 and to assess its biological efficacy on hemoglobin (Hb) level and red blood cell (RBC) count in patients with Chemotherapy-Induced Anemia (CIA).
Methods: An open label phase Ib/II trial, monitored by a US CRO (Pharm-Olam International), was conducted in patients developing anemia after chemotherapy treatment. Three cohorts of 6 CIA patients received 8 weeks of treatment with PBI-1402 once a day, at different doses, and were monitored every two weeks for safety, tolerability, Hb level, RBC count and blood chemistry. Patients remained on their chemotherapy during PBI-1402 treatment.
Results: To date, 12 CIA patients have completed their PBI-1402 treatment. 83% of patients demonstrated a significant increase in RBC (p = 0.015) and 66% in Hb (p = 0.038). Among the responders, the mean Hb increase was 1.1 g/dL (p = 0.0007) from a baseline Hb value of 9.8 g/dL. No patient required a blood transfusion and only one patient had an Hb content below 9 g/dL (8.9 g/dL). PBI-1402 was well tolerated and no significant side effects were observed.
Conclusion: PBI-1402, via a mechanism of action distinct from erythropoietin, induced sufficient erythropoiesis to raise the RBC level and Hb in CIA patients. In addition, PBI-1402 is safe and well tolerated. PBI-1402 offers the potential for a novel therapy of the anemia of CIA.
Graft-versus-host disease (GVHD) is the principal cause of morbidity and mortality after hematopoietic stem cell transplantation. Even the most potent immunosuppressive agents often fail to control ...GVHD. Because of its unique cell-mediated approach, photopheresis represents an appealing alternative for the treatment of GVHD, particularly in its chronic form. Photodynamic therapy (PDT) using TH9402 (4,5-dibromorhodamine methyl ester), a photosensitizer, which upon activation with visible light, exhibits specific toxicity against activated T lymphocytes, while preserving resting T cells, has emerged as a potentially interesting alternative treatment modality for GVHD patients. However, the immunologic mechanisms involved in GVHD modulation by PDT still remain obscure. Since CD4+CD25+FoxP3+ regulatory T cells (Tregs) have an inhibitory effect on GVHD, we sought to determine the role of Tregs in the context of photopheresis using TH9402 for GVHD modulation. We first evaluated, using flow cytometry, the impact of PDT on activated T cells and Tregs obtained from steroid-refractory chronic GVHD patients. High (10 uM) and low (1,32 uM) TH9402 concentrations were compared to measure their ability preserve Tregs. Interestingly, low intensity TH9402 treatment demontrated particularly interesting features, resulting in the elimination of more than 90% of activated CD4+CD25+FoxP3- and CD4+CD44high T cells, while preserving 95% of CD4+CD25+ FoxP3+ cells (p<0.001; n=5 pts). The proportion of live CD4+CD25+ FoxP3+ cells increased from 51.8±5.2% to 89.0±5.9% (mean±SD; pre and post PDT, respectively; p<0.01) thus enriching the graft in Tregs. Next, we evaluated the ability of PDT treated mononuclear cells to inhibit the proliferation of untreated MNCs from cGVHD pts. The addition of PDT cells reduced the proliferation of cGVHD T lymphocytes by 41–76% (p<0.001, n=6 pts). This inhibitory effect disappeared following inhibition of Pgp-171 by verapamil, which promoted TH9402 intracellular retention and effector cell elimination upon light exposure, indicating that Tregs must not only be present but viable to exert their suppressive activity. In addition, higher levels of IL-10, but not TGF-β, were secreted when cGVHD cells were exposed to PDT-treated cells (34.7±5.1ng/mL) than when exposed to untreated cells (20.3±3.2ng/mL, p<0.05). Furthermore, the inhibitory effect decreased 5-fold when cGVHD cells were co-cultured for 6 days with CD4+CD25+ depleted PDT cells (p<0.001). Addition of anti-IL-10 monoclonal antibody (mAb) to the co-culture (PDT-treated cells with cGVHD cells) resulted in a 3-fold decrease in the inhibition of cGVHD cell proliferation mediated by PDT-treated cells (p<0.01) and a 1.5-fold decrease when anti-TGF-β mAb was added to the co-culture (p<0.05). In conclusion, our results demonstrate that TH9402 PDT not only eliminates activated T cells, but preserves Tregs, with the functional ability to inhibit residual alloreactive cGVHD cells. This inhibitory effect requires live effector Tregs, secretion of IL-10 and TGF-β expression. With such dual effector mechanisms, photopheresis using TH9402 should translate into improved treatment efficacy and enhanced quality of life for patients with chronic GVHD.
Prostate secretory protein 94 (PSP-94) has been shown to exert anti-tumor activity against prostate cancer cells, particularly in the form of PCK3145, a synthetic peptide corresponding to amino acids ...31–45 of PSP-94. Indeed, when tested in a murine model, this peptide could reduce experimental prostate tumour growth. In addition, when evaluated in a Phase I clinical study, this peptide demonstrated a particularly interesting safety profile, with almost complete lack of toxicity. In order to determine whether PCK3145 could exert cytotoxic activity against other marrow infiltrating cancers, we tested its activity both in vitro and in vivo against non-Hodgkin's lymphoma (NHL) and other hematologic cancers. Interestingly, PCK3145 inhibited the proliferation of human NHL (SR) and myeloma (RPMI-8226) cell lines in vitro. To explore its anti-tumor activity in vivo, the impact of PCK3145 was also measured by inoculating P815 malignant cells into syngeneic DBA mice. First, four groups of 6 DBA mice were injected subcutaneously with 2x104 P815 cells and then treated with subcutaneous injections of PCK3145, and compared to
1.a peptide with the scrambled amino acid sequence,2.PCK5266 (peptide derived from amino acids 52 to 66 of PSP-94), and3.phosphate-buffered saline (PBS).
Treatment with PCK3145 significantly decreased the growth of P815 tumours in comparison to PBS (p<0.001), scrambled peptide (p<0.05) and PCK5266 (p<0.01), confirming in vivo anti-tumor activity and suggesting that tumour growth inhibition is due to the specific amino acid sequence of PCK3145. The same model was used to determine the effect of PCK3145 on metastatic dissemination following intraperitoneal administration of the peptide. PCK3145 treatment led to a decreased number of liver metastasis compared to PBS (p<0.05) and scrambled peptide (p<0.05) controls. In order to determine whether PCK3145 exerted its activity by altering metalloproteinase release, metalloproteinase MMP-9 levels were measured 3 weeks post-tumor cell exposure. MMP-9 levels, measured by ELISA, in the peripheral blood of treated P815 bearing mice were similar to those obtained with healthy animals (12.83±1.890 (mean±SD) ng/ml and 7.183±0.4070 ng/ml, respectively), while MMP-9 levels were elevated in mice treated with PBS and scrambled peptide (35.12±8.559 ng/ml and 22.60±3.944 ng/ml, respectively; p<0.05). We next tested PCK3145 treatment on human SR lymphoma cell line grown subcutaneously in NOD/SCID mice. Similarly to results obtained with murine tumors, treatment with PKC3145 resulted in significant inhibition of SR non-Hodgkin's lymphoma growth compared to treatment with PBS (p<0.001) and scrambled peptide (p<0.01). These results demonstrate that in vivo treatment with PCK3145 can reduce tumor cell proliferation of both murine and human hematologic cancers. In addition, PCK3145 has the potential to inhibit tumor cells dissemination by lowering MMP-9 secretion. Thus, PCK3145 represents a unique peptide demonstrating sequence-specific anti-tumor activity against NHL and other hematologic malignancies. Based on these results, clinical studies are being designed to evaluate its therapeutic activity in humans.
Abstract 1140
Poster Board I-162
Cytomegalovirus (CMV) remains the most significant viral pathogen following allogeneic hematopoietic stem cell transplantation. Pre-emptive therapy has now become the ...most commonly used strategy to prevent CMV disease. However, the use of a very effective anti-viral agent could theoretically minimize the risk of disease caused by CMV and other herpesviridae as well as abrogate prospective surveillance after allogeneic transplant. Valacyclovir, the L-valyl ester oral pro-drug of acyclovir, has excellent bioavailability, resulting in high plasma exposures similar to those following IV acyclovir administration. This property confers to valacyclovir antiviral activity against CMV and other herpesviridae. We hypothesized that universal prophylaxis with valacyclovir until day +100 after allogeneic transplant in recipients at high risk of CMV reactivation would lead to a decreased incidence of CMV viremia.
Between 2003 and 2005, we conducted a prospective, randomized study in two allogeneic transplant centers in the Province of Quebec, Canada. Eligibility criteria included therapy with allogeneic blood or marrow transplantation, recipient CMV seropositivity, ability to follow protocol and give informed consent. One group was randomized to receive high dose acyclovir (500 mg/m2 iv TID from day -1 till oral intake was resumed followed by valacyclovir 2000 mg QID until day +100 after transplant (n=32), while the control group was followed using a PCR-based (Cobas system, Amplicor Monitor CMV test, Roche) preemptive approach (n=23). Valacyclovir doses were adjusted according to renal function. In addition, weekly specimens, from before initiation of conditioning regimen until day +100, were also collected in both groups of patients in order to compare incidences of other herpes viruses viremia (HSV, EBV) by real-time PCR. All patients with a positive CMV viremia were immediately treated with ganciclovir 5 mg/kg BID until disappearance of positive signal (minimum of 2 weeks) followed by 2 additional weeks. Recurrences were treated as inititial episodes. Primary end point was incidence of CMV viremia by day +100.
Both groups of patients were similar regarding age, type of transplant (sibling vs unrelated donor), HLA compatibility, conditioning regimen (myeloablative vs reduced intensity), GVHD prophylaxis, graft nature and content and acute or chronic GVHD incidence. Valacyclovir was highly effective to reduce the incidence of CMV viremia. In the Valacyclovir group, CMV viremia occurred in 6 patients (6/31;19%) compared to 12 (12/23;63%) in the control group. Cox regression demonstrates a protective effect with valacyclovir (HR, 0.28; 95% CI: 0.10-0.74; p=0.01). Time to CMV viremia was identical in both groups (day +39 vs +36); however, the median viral load was lower in the valacyclovir group (748 vs 8043) although this difference did not reach statistical difference. Similar to CMV, both incidences of EBV and HSV viremia were significantly lower in the valacyclovir group (EBV: 4% vs 28%, p=0.005; HSV: 4% vs 30%, p=0.002). Day +100 mortality and at last follow-up are similar in both groups. Valacyclovir use was safe and well tolerated by most allogeneic transplant recipients but required frequent dose modification according to creatinine level.
Valacyclovir prophylaxis until day +100 is effective to prevent CMV, HSV and EBV reactivation after allogeneic hematopoietic transplantation. Further studies in larger numbers of patients are needed to precise the optimal use of valacyclovir in this patient population.
Off Label Use: Valacyclovir was used to prevent CMV reactivation following allogeneic transplantation under an experimental protocol approved by our IRB.
Lactobacillus helveticus strain milano was used for the continuous fermentation of lactic acid in cheese whey-yeast extract permeate medium. Under high dilution rates, the cells were elongated to ...several times their normal size, resulting in wall growth. The cell growth on the fermentor wall caused system instability; however, it prevented cell wash-out under high dilution rates. The packed bed column system using Ca alginate entrapped cells is not suitable for practical applications. Nonuniform pH control, plugging of the column by leaked cells, and decalcification of Ca alginate beads were major drawbacks of the packed bed system.
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.
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.
An automated delivery system for cell culture applications would permit studying more complex culture strategies and simplify measures taken to expose cells to unstable molecules. We are interested ...in understanding how intracellular TAT-HOXB4 protein concentration affects hematopoietic stem cell (HSC) fate; however, current manual dosing strategies of this unstable protein are labor intensive and produce wide concentration ranges which may not promote optimal growth. In this study we describe a programmable automated delivery system that was designed to integrate into a clinically relevant, single-use, closed-system bioprocess and facilitate transcription factor delivery studies. The development of a reporter cell assay allowed for kinetic studies to determine the intracellular (1.4 ± 0.2 h) and extracellular (3.7 ± 1.8 h and 78 ± 27 h at 37°C and 4°C, respectively) half-lives of TAT-HOXB4 activity. These kinetic parameters were incorporated into a mathematical model, which was used to predict the dynamic intracellular concentration of TAT-HOXB4 and optimize the delivery of the protein. The automated system was validated for primary cell culture using human peripheral blood patient samples. Significant expansion of human primitive progenitor cells was obtained upon addition of TAT-HOXB4 without user intervention. The delivery system is thus capable of being used as a clinically relevant tool for the exploration and optimization of temporally sensitive stem cell culture systems. Biotechnol. Bioeng. 2009;103: 402-412.
Benefits of cord blood (CB) transplantation include low rates of relapse and chronic graft-versus-host disease (GVHD). However, CB use has rapidly declined because of the high rates of infections, ...severe acute GVHD, and transplant-related mortality (TRM) as well as prolonged hospitalization. We therefore initiated a clinical trial with UM171, a potent agonist of hematopoietic stem cell (HSC) self-renewal, to attempt to solve these limitations and permit transplantation of smaller, better HLA-matched CBs.
Expansion culture lasted 7 days and patients received a myeloablative conditioning regimen followed by a single CB transplant including both the expanded CD34+ cells and the lymphocyte-containing CD34- fraction.
Between 9/16-11/18, 22 adults with mostly high- to very high-risk hematologic malignancies were transplanted. Median transplant co-morbidity index was 2 (0-5). Five patients had already failed an allogeneic transplant, 3 patients had acute leukemia not in remission, and 2 patients had relapsed/refractory aggressive lymphoma. UM171 treatment profoundly changed the cellular composition of the graft, including a 600 and 8000-fold increase in dendritic and mast cell progenitors, respectively. Neutrophil engraftment was prompt with median time to 100 and 500 neutrophils/μL of 9.5 and 18 days, respectively. Patients seemed to derive clinical benefit from achieving 100 neutrophils rapidly translating into early resolution of febrile neutropenia (median day 7) contributing to shorter hospitalization when compared to conventional CB transplants at same institution with larger cell doses and similar time to 500 neutrophil engraftment. Median CD4 counts at 3 and 12 months were 218 and 413/μL, respectively. Incidence of grade 3-4 acute GVHD was low (9%) and there was no steroid refractory GVHD or moderate-severe chronic GVHD. More than 90% of patients were off immunosuppressive therapy by 12 months. One patient died of TRM (<5%) because of alveolar hemorrhage and 5 patients had relapsed/progressive disease (24%). With a median follow-up of 24 months, 2 year overall, progression-free, and GVHD-and-relapse-free survival were excellent for such a high-risk group at 69%, 72% and 62%, respectively.
A 7-day UM171 expansion CB protocol is feasible and provides clinical benefits beyond engraftment, such as very low TRM. If confirmed, UM171 expansion may overcome the shortcomings of CB transplants while maintaining its benefits of low risk of chronic GVHD and relapse. We have now embarked on a phase 2 trial to confirm if a UM171 modified graft, enriched in dendritic cells, will have a potent antileukemia effect in extremely high-risk patients such as refractory leukemias and high risk mutations (e.g.: p53, EVI-1).
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.
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