Nonmyeloablative Stem Cell Transplantation Research Articles

CD25 Expression Is Associated with Inferior Clinical Outcomes in Elderly Patients with Acute Myeloid Leukemia

Background: Elderly patients with acute myeloid leukemia (AML) show unfavorable biologic characteristics and inferior clinical outcomes compared to younger patients. Because some elderly patients can benefit from intensive chemotherapy, the identification of prognostic markers is important for therapeutic decision-making. CD25 (interleukin 2 receptor alpha) has been reported to be highly expressed in leukemia stem cells and correlate with adverse outcomes in younger (less than 60 years) patients with AML. However, the significance of CD25 expression in elderly patients with AML has not yet been investigated.Methods: We retrospectively reviewed 154 newly diagnosed AML (de novo, secondary) patients aged 60 years or over (median: 69, range: 60-85 years), admitted between 2005 and 2013 to Jichi Medical University Hospital. Blast cells from bone marrow at diagnosis were identified by flow cytometry (FCM) using CD45/side scatter properties. CD25 expression in the blast region was analyzed by FCM combined with single- and two-color staining.Results: The two-color FCM analysis showed that CD25 was expressed in CD34, CD117, and CD13-positive blast cells. The median CD25 expression of the blast cells was 0.7% (range: 0-75.3%). On the basis of CD25 expression in bone marrow blasts from healthy volunteers (n=5; median, 3.2%; range, 1.5-5.6%), we defined CD25 expression >10% as positivity. In this setting, we identified CD25-positive blasts in 21 patients (14%). CD25+AML was characterized by the MDS/MPN history (30%) and, a low or zero frequency of favorable cytogenetics (0%), FAB M2 subtype (5%), and FAB M3 subtype (0%) compared with CD25-AML (n=133). Among the 118 patients who underwent induction chemotherapy, including 75 patients who received a combination of anthracyclin and cytarabine (Ara-C), 69 (58%) achieved complete remission (CR). CD25+AML was associated with an inferior CR rate (20 vs. 64%, respectively, P=0.003), inferior event-free survival (EFS) (1-year EFS, 0 vs. 33%, respectively, P< 0.001), and inferior overall survival (OS) (2-year OS, 13 vs. 38%, respectively, P=0.003) compared with CD25-AML. On multivariate analysis using the following factors: cytogenetics, age (over 75 years), MDS/MPN history, and intensity of induction chemotherapy, CD25-positivity was a significant risk factor for the CR rate (HR: 8.0, 95% CI: 1.7-36.6; P=0.008) and EFS (HR: 2.3, 95% CI: 1.1-4.7; P=0.021). For CD25+AML, the CR rate was higher with induction chemotherapy using a regimen of low-dose Ara-C combined with granulocyte colony-stimulating factor (50%) than that using a regimen of daunorubicine and Ara-C (0%). However, there was no significant difference in OS between patients with CD25+AML treated with induction chemotherapy and those who treated with best supportive care (2-year OS, 13 vs. 11%, respectively, P=0.29). There were no patients with CD25+AML received stem cell transplantation due to disease progression.Conclusion: This study demonstrated that CD25 is an independent prognostic factor for elderly AML patients. The prognosis of CD25+AML patients is extremely poor; therefore, it is necessary to develop alternative approaches, such as a regime including anti-CD25 antibody, therapy targeting leukemia stem cells, and nonmyeloablative stem cell transplantation. DisclosuresNo relevant conflicts of interest to declare.

The Aryl Hydrocarbon Receptor Antagonist Stemregenin 1 Stimulates Expression of NK Cell Related Transcription Factors, Thereby It Facilitates Generation of Highly Functional NK Cells in Vitro

IntroductionAllogeneic stem cell transplantation (SCT) can be a curative treatment for hematological malignancies. The therapeutic effectiveness is attributed to the graft-versus-tumor (GVT) effect, mediated by alloreactive T cells and natural killer (NK) cells. Although T cells can induce a potent GVT effect, they can also induce graft-versus-host disease (GVHD), causing high morbidity and mortality. Interestingly, after non-myeloablative allogeneic SCT, early NK cell repopulation has been associated with decreased relapse rates, without increasing GVHD incidence, illustrating a possible role for donor NK cell adoptive transfer after allogeneic SCT. However, isolation of sufficient numbers of activated NK cells from donor origin is challenging. Recently, it has been described that antagonizing the aryl hydrocarbon receptor (AhR) using the antagonist StemReginin1 (SR1) promotes expansion of human hematopoietic stem cells. Furthermore, AhR turned out to regulate differentiation of multiple immune cells like dendritic cells, regulatory T cells, γδ T cells, and also NK cells. Therefore, we investigated if SR1 could enhance NK cell generation in a cytokine-based culture system.MethodsCD34+ hematopoietic progenitor cells (HPCs) were isolated using immunomagnetic beads from G-CSF mobilized aphaeresis material. These HPCs were expanded during 14 days in medium containing SCF, Flt3L, TPO, IL-7 and IL-15 and subsequently differentiated into NK cells using IL-15 and IL-2. HPC-NK cell expansions were performed with or without SR1. RNA was collected from the cultures weekly and expression of NK cell related genes was analyzed using qPCR. After 35 days, HPC-NK cells were assessed for their cytolytic functions against acute myeloid leukemia (AML) and multiple myeloma (MM) cell lines and primary AML blasts. In addition, expression levels of typical NK-activating receptors and differentiation markers were analyzed by flow cytometry.ResultsInterestingly, SR1 induced expression of TOX, ID2, EOMES, GATA3 and SH2D1B, which are important factors involved in early and late NK cell differentiation. In addition, SR1 improved the expansion, differentiation, and functionality of the NK cells generated. In the presence of SR1, we were able to expand PB-derived HPCs up to 1000-fold in 5 weeks. The SR1-generated HPC-NK cell products contained 80 – 92% NK cells, which expressed high levels of activating NKG2D and natural cytotoxicity receptors. Furthermore, functional analysis showed marked degranulation and cytokine release upon co-culture with AML and MM cell lines and efficient lysis of primary AML blasts at low NK-target ratios.ConclusionAddition of the AHR antagonist SR1 in our culture system induces expression of transcription factors involved in NK cell differentiation and thereby facilitates the generation of high numbers of functional NK cells from G-CSF mobilized CD34+ progenitor cells. These NK cells hold great promise for future donor NK cell-mediated therapy after allogeneic SCT. DisclosuresNo relevant conflicts of interest to declare.

Achieving Tolerance in a Mismatched VCA Transplant While Reducing The Risk of GVHD: Goal of Transient Chimerism.

Background: Vascularized composite tissue allograft (VCA) transplantation offers the opportunity to restore form and function. Life-long immunosuppression limits clinical applicability. A promising method is the development of mixed chimerism. We've shown that a non-myeloablative stem cell transplant can lead to tolerance in a mismatched dog model (450cGy TBI). This protocol has been limited by skin graft-versus-host disease (GVHD). We observed animals that after an initial period lost their stem cell allograft but remained tolerant to the VCA while those that retained full donor cell chimerism inevitably developed GVHD. The hypothesis for this study was that our transplant protocol could be used to induce tolerance to a recipient VCA without the need for persistent donor cell chimerism. Methods: 5 haploidentical canine recipients received a non-myeloablative conditioning regimen of 350cGy TBI, mobilized donor stem cell and VCA transplantation, followed by a short course of immunosuppression (MMF: 56 days/Cyclosporine: 70 days). Peripheral blood chimerism was evaluated by PCR techniques weekly. VCA rejection was followed clinically and confirmed histologically after biopsy. Results: All 5 tolerated the conditioning regimen. Two rejected their stem cells early (<5 weeks). One rejected the stem cells at post-operative day (POD) 35 and rejected the VCA transplant following the cessation of immunosuppression. The other was euthanized for persistent fevers at POD 84 with no sign of VCA rejection. One fully engrafted, converted to 100% donor chimerism, and had long-term tolerance to the VCA but developed skin GVHD. 2 dogs demonstrated a prolonged period of transient chimerism (7 to 10 weeks post-transplant) before rejecting their donor stem cells without acute rejection of their donor VCAs. Later in the study both of these animals demonstrated evidence of chronic rejection. Neither developed skin GVHD. Conclusions: We demonstrate that our non-myeloablative protocol allows for selective rejection of donor stem cells and elimination of GVHD risks without acute rejection of the VCA transplant while persistent donor chimerism can lead to GVHD.

The clinical and financial burden of pre-emptive management of cytomegalovirus disease after allogeneic stem cell transplantation—implications for preventative treatment approaches

Background aimsAlthough cytomegalovirus (CMV) infection after allogeneic stem cell transplantation (SCT) is rarely fatal, the management of CMV by pre-emptive medication for viral reactivation has toxicity and carries a financial burden. New strategies to prevent CMV reactivation with vaccines and antiviral T cells may represent an advance over pre-emptive strategies but have yet to be justified in terms of transplantation outcome and cost. MethodsWe compared outcomes and post-transplantation treatment cost in 44 patients who never required pre-emptive CMV treatment with 90 treated patients undergoing SCT at our institute between 2006 and 2012. Eighty-one subjects received CD34+ selected myeloablative SCT, 12 umbilical cord blood transplants, and 41 T-replete non-myeloablative SCT. One hundred nineteen patients (89%) were at risk for CMV because either the donor or recipient was seropositive. Of these, 90 patients (75.6%) reactivated CMV at a median of 30 (range 8–105) days after transplantation and received antivirals. ResultsThere was no difference in standard transplantation risk factors between the two groups. In multivariate modeling, CMV reactivation >250 copies/mL (odds ratio = 3, P < 0.048), total duration of inpatient IV antiviral therapy (odds ratio = 1.04, P < 0.001), type of transplantation (T-deplete vs. T-replete; odds ratio = 4.65, P < 0.017) were found to be significantly associated with increased non-relapse mortality. The treated group incurred an additional cost of antiviral medication and longer hospitalization within the first 6 months after SCT of $58,000 to $74,000 per patient. ConclusionsOur findings suggest that to prevent CMV reactivation, treatment should be given within 1 week of SCT. Preventative treatment may improve outcome and have significant cost savings.

Transient liver function abnormality following treatment with rabbit antithymocyte globulin for nonmyeloablative hematopoetic stem cell transplant: Two case reports

Rabbit antithymocyte globulin (rATG) is increasingly used in nonmyeloablative hematopoetic stem cell transplant (HSCT). Elevated liver function tests (LFTs) have been reported for antithymocyte globulin in the treatment of aplastic anemia, but not when used in a conditioning regimen for HSCT. We describe two cases of patients receiving a conditioning regimen for HSCT containing rATG who developed a transient, severe transaminase elevation. In the first case, a 66-year-old woman with a history of acute myeloid leukemia received the first dose of rATG and the patient's transaminases were found to be extremely elevated within a few hours. The aspartate transaminase (AST) peaked at 1286 U/L and alanine transaminase (ALT) peaked at 991 U/L and both resolved within a week. In the second case, a 72-year-old woman with a history of non-Hodgkin lymphoma received the first dose of rATG and the AST and ALT were found to be 1212 U/L and 689 U/L, respectively, 1 h after finishing the infusion. Like the previous case, the transaminase elevation resolved within a week. LFT abnormalities induced by rATG during conditioning therapy for HSCT may be transient and have a rapid onset after the first dose, but quickly subside without any complications or sequelae. It is important to follow the LFTs closely, as well as monitor for any signs and symptoms of acute liver failure.

Prophylactic G-CSF mobilized donor lymphocytes infusion after non-myeloablative stem cell transplantation prevents relapse in patients with high-risk leukemia

To evaluate the anti-leukemia effects of prophylactic G-CSF mobilized donor lymphocytes infusion (pG-DLI) and its relationship with the incidence of graft-versus-host disease (GVHD) in high-risk leukemia patients with non-myeloablative stem cell transplantation (NST). 12 patients with high-risk leukemia were analyzed, including Ph⁺ acute lymphocytic leukemia (n=1), acute leukemia (AL) with persistent non-complete remission (n=2), acute myeloid leukemia (AML) with central nervous system (CNS) relapse (n=3), hybrid AL (n=1), secondary AML evolving from myelodysplastic syndrome (MDS/AML) (n=2), chronic myeloid leukemia in accelerated phase (CML-AP) (n=1), CML in blastic phase (CML-BP) (n=2). All patients received non-myeloablative conditioning and pG-DLIs were administered 30-40 days post transplantation if no signs of GVHD were present. The percentage of donor cell chimera was analyzed by short tandem repeat-polymerase chain reaction (STR-PCR) just before and after pG-DLI. The incidence of leukemia relapse and GVHD were observed. 12 high-risk leukemia patients with a median age of 38 (range: 29-52) years received G-DLI at a median interval of 35 (32-40) days. The median numbers of infused mononuclear cells (MNCs), CD34⁺, and CD3⁺ cells/kg recipient body weight was 2.3×10⁸/kg, 1.7×10⁶/kg, and 0.6×10⁸/kg, respectively. 10 of 12 patients had full donor chimera before pG-DLIs and conversion from mixed to full donor chimera occurred in the other 2 patients shortly after pG-DLI. Grade II acute GVHD (aGVHD) was observed in only 2 patients and chronic GVHD (cGVHD) developed in 6 patients, including involvement of skin (n=3), skin and intestine (n=2), liver (n=1). 1 patient died of cGVHD. With a median follow-up of 40 (24-64) months, 7 patients are alive in remission, with 3-year actuarial overall survival (OS) and disease-free survival (DFS) rates of the same 58.3%. Our findings indicate that pG-DLI after NST does not increase the risk of aGVHD, but could enhance the capacity graft-vs-leukemia and prevent relapse in high-risk leukemia patients.

Signal One and Two Blockade Are Both Critical for Non-Myeloablative Murine HSCT across a Major Histocompatibility Complex Barrier

Non-myeloablative allogeneic haematopoietic stem cell transplantation (HSCT) is rarely achievable clinically, except where donor cells have selective advantages. Murine non-myeloablative conditioning regimens have limited clinical success, partly through use of clinically unachievable cell doses or strain combinations permitting allograft acceptance using immunosuppression alone. We found that reducing busulfan conditioning in murine syngeneic HSCT, increases bone marrow (BM):blood SDF-1 ratio and total donor cells homing to BM, but reduces the proportion of donor cells engrafting. Despite this, syngeneic engraftment is achievable with non-myeloablative busulfan (25 mg/kg) and higher cell doses induce increased chimerism. Therefore we investigated regimens promoting initial donor cell engraftment in the major histocompatibility complex barrier mismatched CBA to C57BL/6 allo-transplant model. This requires full myeloablation and immunosuppression with non-depleting anti-CD4/CD8 blocking antibodies to achieve engraftment of low cell doses, and rejects with reduced intensity conditioning (≤75 mg/kg busulfan). We compared increased antibody treatment, G-CSF, niche disruption and high cell dose, using reduced intensity busulfan and CD4/8 blockade in this model. Most treatments increased initial donor engraftment, but only addition of co-stimulatory blockade permitted long-term engraftment with reduced intensity or non-myeloablative conditioning, suggesting that signal 1 and 2 T-cell blockade is more important than early BM niche engraftment for transplant success.

Low tumor burden is associated with early B-cell reconstitution and is a predictor of favorable outcome after non-myeloablative stem cell transplant for chronic lymphocytic leukemia

Reconstitution, engraftment kinetics and tumor cell clearance were analyzed after reduced intensity conditioning hematopoietic cell transplant (RIC-HCT) in patients with chronic lymphocytic leukemia (CLL). Patients were transplanted from unrelated (n = 40) or related (n = 10) donors after fludarabine and 2 Gy total body irradiation followed by cyclosporine and mycophenolate mofetil. The vast majority of patients (96%) engrafted with absolute neutrophil count (ANC) > 0.5 × 109/L at day + 22. CLL cells decreased (median 2%, range 0–69%) within 28 days, but disappeared by day + 180 after HCT. Donor T-cell chimerism increased to > 95% at day 56 and donor B-cell chimerism to 94% at day + 360. Overall survival was 51 ± 8%, incidence of progression 37 ± 7% and non-relapse related mortality (NRM) 30 ± 7% at 4 years. The most common causes of NRM were graft-versus-host disease (GvHD) (14%) and sepsis (6%). Disease status at HCT was significantly associated with early B-cell reconstitution (p = 0.04) and with increased risk of relapse/progression in univariate and multivariate analysis (p = 0.022). Tumor cells were undetectable by day + 180, although B-cell reconstitution did not occur until 1.5 years after RIC-HCT. The best predictors for progression-free survival (PFS) and overall survival (OS) were complete response (CR) or first partial response (PR1) and the absence of bulky disease at transplant, respectively.

Autologous nonmyeloablative hematopoietic stem cell transplantion in newly diagnosed childhood type 1 diabetes mellitus: the first year report

Autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) in newly diagnosed and young adult type 1 diabetes mellitus (T1DM) was reported. We report our first year AHST experience in newly diagnosed childhood T1DM. 7 patients with T1DM (HbA1c 11.7%-14%, 4 with diabetic ketoacidosis, aged 5.0-13.7 years) diagnosed within the previous 3 months by clinical findings and hyperglycemia and confirmed with positive antibodies against GAD65, IA2, ICA or insulin. Hematopoietic stem cells were mobilized with cyclophosphamide and granulocyte colonystimulating factor and then collected from peripheral blood by leukapheresis and cryopreserved. The cells were injected intravenously after conditioning with cyclophosphamide and rabbit antithymocyte globulin. Major side effects, changes in exogenous insulin requirements, HbA1c, C-peptide levels are analyzed. During a 12- to 18-month follow-up, 6 (6/7, 85.7%) patients became insulin free 1-3 months after AHST, 1 patients failed (5 year old) to acquire insulin free, all the patients resumed normal school study. The preprandial, predormital blood glucose were ranged from 3.9-6.0 mmol/L with the HbA1c level between 4.6%-6.1% in insulin-independent patients. Vomiting, anorexia, short-term fever, hair loss occurred in all the patients during AHST, convulsion occurred in 1 patients due to severe sodium water retention, leukocytopenia was evident in the first 1-3 months after AHST, one patients suffered from acute bronchitis 2 months after AHST. No other systemic organ lesions were found in all the patients. High-dose immunosuppression and AHST were performed with acceptable toxicity in 7 patients with newly diagnosed childhood T1DM. With AHST, beta cell function was improved and induced insulin independence in the majority of the patients.

Current state of art for transplantation paradigms in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare and aggressive lymphoproliferative disorder characterized, with few exception, by poor prognosis. A correct diagnosis is still hampered by the heterogeneity and rarity of disease. Historically, PTCLs were treated like aggressive B-cell lymphoma with anthracycline-based combination chemotherapy with disappointing results. Neither dose intensification nor dose escalation of chemotherapy has been successful in prolonging the survival of PTCL patients. Due to this discouraging scenario, new therapeutic strategies have been tested. A therapeutic program including hematopoietic stem-cell transplantation (SCT) may represent an interesting strategy for high-risk patients. Although no randomized trials are available, autologous SCT may offer a chance of cure in chemosensitive disease. Nonmyeloablative allogeneic SCT has shown a curative potential with limited toxicity, and it is actively being investigated. We will review the role of the current therapeutic approach to PTCL focusing on the most recent advances in SCT.

P-286 Azacitidine pretreatment followed by non-myeloablative SCT in patients with high-risk myelodysplastic syndrome: Prospective, open label, multicenter, phase II trial

P-286 Azacitidine pretreatment followed by non-myeloablative SCT in patients with high-risk myelodysplastic syndrome: Prospective, open label, multicenter, phase II trial

O-014 Azacitidine versus best supportive care before non-myeloablative allogeneic stem cell transplantation for MDS: A study by the SFGM-TC

O-014 Azacitidine versus best supportive care before non-myeloablative allogeneic stem cell transplantation for MDS: A study by the SFGM-TC

Romiplostim resistance in secondary failure of platelet recovery

Romiplostim, a thrombopoietin mimetic, is FDA approved for the treatment of thrombocytopenia in patients with refractory immune thrombocytopenia. Given the success of thrombopoietin agonists in the treatment of immune thrombocytopenia, data in other clinical settings are emerging. In the bone marrow transplant setting, secondary failure of platelet recovery and persistent thrombocytopenia are associated with increased mortality. In this case, romiplostim was attempted in a chronic lymphocytic leukemia patient who underwent a matched, unrelated donor, non-myeloablative stem cell transplant. This patient experienced profound thrombocytopenia despite dose escalation. Anti-thrombopoietin or anti-romiplostim antibodies were not detected by specific assays. Furthermore, the patient remains in disease remission with full chimerism. This case demonstrates that heavily pre-treated patients with limited bone marrow reserve may not respond to thrombopoietin agonists.

Acute colonic pseudo-obstruction following allogeneic stem cell transplantation successfully treated by neostigmine

Acute colonic pseudo-obstruction (ACPO), also known as Ogilvie's syndrome, is a rare clinical syndrome of massive large bowel dilatation without mechanical obstruction, which may cause significant morbidity and mortality. Treatment focuses on decompressing a severely dilated colon. The proposed theory that this severe ileus results from an imbalance in the autonomous regulation of colonic movement supports the rationale for using neostigmine, a reversible acetylcholinesterase inhibitor, in patients who failed conservative care. Although gastrointestinal complications are frequent following allogeneic stem cell transplantation (SCT), the incidence of ACPO in a transplant setting is unknown and, if not vigilant, this adynamic ileus can be underestimated. We describe the case of a patient with myelodysplastic syndrome undergoing non-myeloablative allogeneic SCT from a partially human leukocyte antigen-mismatched sibling donor, and whose clinical course was complicated by ACPO in the early post-engraftment period. The ileus was not associated with gut graft-versus-host disease or infectious colitis. After 3 days of conservative care, intravenous neostigmine (2 mg/day) was administered for 3 consecutive days. Symptoms and radiologic findings began to improve 72 hours after the initial injection of neostigmine, and complete response without any associated complications was achieved within a week. Thus, neostigmine can be a safe medical therapy with successful outcome for patients who develop ACPO following allogeneic SCT.

Lenalidomide and Low Dose Dexamethasone As First Line Therapy for Newly Diagnosed Patients with Primary Plasma Cell Leukemia

AbstractAbstract 729 Introduction:The prognosis of primary plasma cell leukemia (PPCL) remains poor. The “novel agents” have recently shown promising results in PPCL patients in case reports or small retrospective series. Here we describe the first prospective, multicenter, phase II clinical trial of PPCL, where lenalidomide in combination with low dose dexamethasone (Ld) was tested as initial therapy in newly diagnosed patients fulfilling the IMWG diagnostic criteria of PPCL. Patients and methods:Ld regimen consisted of lenalidomide 25 mg/d for 21 days and oral dexamethasone 40 mg on days 1, 8, 15, and 22 for each 28-day cycle. After 4 cycles, responding patients not eligible for stem cell transplantation (SCT) continued until 8 cycles of full-dose Ld, followed by a maintenance dose of single agent lenalidomide equal to 10 mg/d on days 1–21 of each 28-day cycle. Patients responding after 4 cycles and eligible for SCT proceeded according to the treatment centre’s transplant policy. Patients not responding after 4 cycles or progressing during this treatment were considered off-study. Appropriate dose reductions (in particular for patients with reduced renal function at baseline), double contraception methods and anti-thrombotic/anti-infective prophylaxis were recommended. The primary end-point was early response rate according to IMWG uniform response criteria. Secondary end-points were PFS, OS, feasibility and efficacy of SCT, safety. Results:According to the Simon optimal two-stage adaptive design, twenty-three patients were enrolled in between March 2009 and May 2011. The male/female ratio was 1.1, and median age was 60 years (range 44–80). The median absolute number and percentage of circulating plasma cells were 4.280/μl (range 1.500–114.660) and 34% (range 21–90) respectively. Fifteen patients (65.2%) had abnormal renal function at presentation. Twenty-one patients (91.3%) were tested by FISH analysis and cytogenetic abnormalities were detected in all of them, del13q being the most frequently found (16 patients). Seventeen patients showed multiple chromosomal lesions. Involvement of chromosome 14 was observed in 18 patients, three of whom showed t(4;14). Chromosome 1q gain and del17p were detected in 10 and 7 patients, respectively. In the intention-to-treat (ITT) population, overall response rate (ORR) after at least one Ld cycle was 73.9% (17/23), with 8 patients (34.7%) achieving partial remission (PR), 5 (21.7%) very good PR (VGPR), 3 (13%) complete response (CR), and 1(4.3%) near CR (nCR) (VGPR or better: 39%). In the efficacy-evaluable (EE) population, 14 out of 15 patients who received the initially planned 4 Ld cycles (65.2% of the ITT population) responded (ORR 93.3%), achieving 5 PR (33.3%), 5 VGPR (33.3%), 1 near-CR (6.6%) and 3 CR (20%) (VGPR or better: 59.9%). The maintenance phase was reached and safely performed in 4 responding patients not eligible for SCT, 3 of whom relapsed after 2, 8 and 22 months, respectively. After Ld induction therapy, 8 patients received single (n. 4) or double (n. 4) autologous SCT (ASCT); another patient underwent a sequence of ASCT followed by non-myeloablative allogeneic SCT (AlloSCT). Six eligible patients did not receive ASCT frontline, due to initial Ld failure or adverse events; three of them underwent single ASCT (n. 2) or tandem ASCT/non-myeloablative AlloSCT (n. 1) after a bortezomib-based salvage therapy, achieving 2 CR and 1 PR. After a median follow-up of 23 months, median OS and PFS in ITT population were not reached and 22 months, respectively. All transplanted patients remained alive, although three of them relapsed and started salvage treatments; OS was 12 months in the 11 patients who did not receive ASCT (p < 0.001). The correspondent figures for PFS were 29 and 16 months, respectively (p < 0.01). Considering ITT population, multivariate analyses showed that SCT was positively correlated to both OS and PFS. There were 17 episodes of grade 3/4 non hematological toxicity, which occurred in 13 patients (5 infections, 3 renal, 3 metabolic, 2 gastro-intestinal, 2 skin, 1 fatigue, 1 thromboembolic), causing early interruption of Ld treatment in 4 patients. Grade 3/4 hematological toxicity (mainly neutropenia) occurred in 11 patients (47.8%). Conclusions:Ld may be a feasible and effective initial therapeutic option for PPCL, particularly in patients who receive ASCT after a short course of induction treatment. Disclosures:Musto:Celgene: Honoraria, Research Funding. Off Label Use: Lenalidomide as first line therapy of plasma cell leukemia. Petrucci:Celgene: Honoraria. Cascavilla:Celgene: Honoraria. Di Raimondo:Celgene: Honoraria. Caravita:Celgene: Honoraria. Morabito:Celgene: Honoraria. Offidani:Celgene: Honoraria. Bringhen:Celgene: Honoraria. Boccadoro:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Palumbo:Celgene: Consultancy, Honoraria.

Post-Transplant Pulmonary Function Abnormalities Normalize in Survivors by the Second Decade After Allogeneic Stem Cell Transplantation

AbstractAbstract 1967Following allogeneic stem cell transplant (SCT), late-onset severe pulmonary complications occur in more than 10% of patients and confer an increased risk of mortality in the first few years post transplant. Whether pulmonary repair can occur subsequently is not well characterized. We prospectively collected pulmonary data on 138 (60 female, 78 male) recipients of allogeneic SCT from HLA identical siblings surviving > 5 years. The median age at transplant was 36 years. Indications for transplant were CML (63), AML (31), MDS (19), ALL (12) and others (14). 126 patients received ≥1200 cGy TBI-based conditioning with or without lung shielding, 3 received 400 cGy TBI-based conditioning and 9 patients received no irradiation. The graft was ex vivo T cell depleted in 131 recipients except six who received non-myeloablative SCT. Of the survivors, 26 had no cGvHD, 70 had cGvHD lasting less than 3 years and 42 had prolonged cGvHD requiring systemic immunosuppression for more than 3 years. Of the 17 patients who died beyond 5 years, 4 died of pulmonary causes, including two with lung cancer. Pre-transplant abnormalities (< 80% predicted) in PFTs were found in 15.9% of subjects in the following declining frequency: FVC%, VC, TLC, FEV1, DLCO_Adj (adjusted for hemoglobin and alveolar ventilation) Hb/VA and FEV1/FVC. Baseline (BL) PFTs served as the reference for all subsequent measurements at 5, 10 and 15 years for each survivor. The only parameter showing a clinically significant decline post transplant was DLCO_Adj at the 5-year mark, with subsequent normalization [paired t-test]. The median DLCO_Adj at 5, 10 and 15 years were 88%(p<0.001), 98%(p=NS) and 100%(p=NS) of BL, respectively. Multivariable modeling (forward-stepwise multiple regression) identified the presence of chronic GVHD (p=0.017) and abnormal BL DLCO_Adj (P=0.023) as the only factors associated with the decline in DLCO_Adj at 5 years but excluded smoking, conditioning intensity, TBI dose to the lungs and demographic variables. In conclusion, poor pulmonary function as measured by DLCO_Adj within 5 years of SCT can normalize by 10 years. Chronic GVHD and pretransplant DLCO_Adj are important contributory factors. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Mini Test Dose of Intravenous Busulfan (Busulfex®) in Allogeneic Non-Myeloablative Stem Cell Transplantation, Followed by Liquid Chromatography Tandem-Mass Spectrometry

Busulfan (Bu) has been used for almost 3 decades in the conditioning of hematopoietic stem cell transplant. Bu has a very diverse gastrointestinal absorption which in association with its emetic effect in high doses makes inter- and intra-individual oral bioavailability and thus systemic exposure very variable and difficult to predict (1, 2, 3). If the systemic exposure is below the therapeutic window there is an increased risk of lack of engraftment (4) and, in chronic myelogenous leukemia (CML) patients, disease relapse (5), while overexposure results in an increased incidence of high-dose related toxicities like hepatic veno-occlusive disease (6, 7). It is important to note that “busulfan concentration-response relationships are regimen-, age- and disease-dependent”, as emphasized by McCune et al (8). Therapeutic dose monitoring (TDM) gained an important role in the setting of oral Bu dose as it became clear that the level of systemic exposure influenced the toxicity, engraftment and relapse rates. To give an idea of the importance of TDM, a test dose prior to starting the conditioning regimen with home-administered oral Bu in 153 patients evidenced that as many as 68% of them would have drug exposures out of the therapeutic window (900–1,500 μM·min) with the standard dose of 1mg/kg of ideal body weight every 6 hours (9). An intravenous (i.v.) formulation was developed to overcome these issues and avoid the utilization of TDM, However, in a series of 6 studies using intravenous Bu in adults, 72 to 91% of the patients achieved the target AUC without dose changes, while 10 to 82% of children achieved it in a series of 5 studies with the intravenous drug (10). Clearly, a need for TDM even when i.v. is used still persists. Many different strategies using single or repeated sampling in different points of the therapy were proposed to improve TDM results (10). However, since TDM can only be useful if Bu determinations are timely delivered and many transplant centers do not have a facility to perform Bu determination, new approaches using pharmacokinetic analysis of a sub-therapeutic test dose administered a few days earlier to predict the ideal dose were proposed. In one such study, 7 patients received a test dose of 0.8 mg/kg, followed by 0.8 mg/kg/dose every 6 hours for 15 doses (11). Bu concentrations were obtained and mean drug clearance was determined after the test, first and 13th doses. The utilization of a test dose demonstrated bioequivalence ( 20% variability). However, when the same 0.8 mg/kg test dose assay was compared to the intravenous Bu in continuous infusion for 90 hours in other 7 patients, they showed similar clearances (12). The next step was to examine the ability of the test dose clearance to base the calculation of the 90 hour continuous infusion dose (13). All 4 patients tested had AUCs within the desired range and no adjustments were required after 18 hours. More recently, Beri et al. (14) used a 0.8 mg/kg i.v. test dose (1/4 of the standard daily dose). Without the test dose, 23% of the 17 patients would have fallen below and 12% above the therapeutic range. With the test dose, no patients had a sub-therapeutic AUC and only 12% had an AUC above the therapeutic window. In this work, in order to further reduce the unnecessary exposure and adverse effects of the test dose process, we investigated bioequivalence of a very low sub-therapeutic test dose (1/10 of the standard daily dose) of i.v. Bu (Busulfex®). For this purpose we developed a sensitive and fast liquid chromatography tandem-mass spectrometry (LC-MS/MS) method which allowed us to measure Bu in a wide concentration range required in the study.

Natural killer cells can exert a graft-vs-tumor effect in haploidentical stem cell transplantation for pediatric solid tumors

Little progress has been made with regard to the survival of children with metastatic and refractory solid tumors. Preliminary data from haploidentical stem cell transplantation (haplo-SCT) suggested a clinically beneficial allograft-vs-tumor effect associated with natural killer cell (NK) donor-recipient mismatch. We hypothesized that interaction between activatory receptors on NK cells and their ligands on tumor cells could be also important. To evaluate the NK-cell-mediated allograft-vs-tumor effect, we conducted a pilot study of haplo-SCT on six children with refractory solid tumors. Our specific goal for this study was NKG2D-major histocompatibility complex class I-related chain A interaction. Tasks include specific immunoassays that support haplo-SCT in refractory solid tumors. Patients suffered from neuroblastoma (n = 1), Ewing sarcoma (n = 2), a desmoplastic tumor (n = 1), nasopharyngeal carcinoma (n = 1), and embryonal rhabdomyosarcoma (n = 1). Pretransplantation disease status showed progressive disease in 2 patients, partial remission in 2 patients, and complete remission in 2 patients. NK-cell mismatch was present in three donor-recipients. Ligands for NKG2D receptors, major histocompatibility complex class I-related chain A and UL16 binding protein 2 were overexpressed in six of six and four of six tumors, respectively. NK cells led early immune reconstitution. After haplo-SCT, three patients were in complete remission, one patient showed partial remission, and two patients were in stable disease. With a median follow-up of 14 months, three patients were alive and in complete remission, and three patients had died; two due to progressive disease and one of transplant-related toxicity. Blocking NKG2D-major histocompatibility complex class I-related chain A interaction in vitro reduced NK-cell cytotoxicity. Our preliminary results suggest a beneficial effect from haplo-SCT in refractory solid tumors.

Response of HER2+ breast cancer patients to allogeneic cell immunotherapy.

e13013 Background: The immune mechanism of non-myeloablative allogeneic stem cell transplantation has been shown to be effective in debulking chemotherapy-resistant metastatic cancer despite the presence of immunoavoidance mechanisms, but this immune effect is intimately related to GVHD toxicity limiting the clinical application. An allogeneic cell therapy (aCT) with intentionally mismatched, CD3/CD28 microbead-conjugated CD4+ memory cells exhibiting both Th1- and NK-like properties designed to elicit autologous anti-tumor effects in the context of graft rejection was evaluated in a FDA-approved phase I/II clinical trial of 42 refractory metastatic solid tumor patients with a variety of indications. No objective tumor response was observed, however there was evidence of enhanced survival and immune-mediated tumor debulking without GVHD toxicity. RECIST overestimated tumor burden, as responding tumors swelled and appeared larger on CT. Multi-parameter analysis identified serum IL-12 as a predictor of enhanced survival. 50% were IL-12+ and survived a median of 211 days vs. 131 days for IL-12- patients (p&lt;.009). Methods: An analysis of IL-12+ responders was conducted to determine the indication with the highest IL-12 response. Results: 9 of 16 refractory metastatic breast cancer (mBC) patients were IL-12+. The Her2+ subset of mBC were 100% IL-12+ (5 of 5) with a median survival of 416 days, while the 11 Her2- patients had a median survival of only 134 days (p&lt;0.05). Conclusions: Normally, Her2+ tumors are more aggressive and have a poorer prognosis than Her2- tumors. The enhanced response to aCT in Her2+ mBC may be due to high titers of anti-Her2 IgG1 antibodies known to be present in these patients. aCT upregulates host FcgR expression on host monocytes through a CD40L-CD40 mechanism. The FcgR bind IgG1 antibodies and mediate ADCC tumor lysis. We hypothesize that patients expressing tumor-specific IgG1 autoantibodies are more likely to respond to aCT. Serum autoantibodies to tumor-associated antigens thus may be a predictive biomarker for aCT responders. The combination of natural or exogenous tumor-specific IgG1 Abs with aCT may be a platform for refractory metastatic tumor debulking leading to increased overall survival.

Durable responses after donor lymphocyte infusion for patients with residual multiple myeloma following non-myeloablative allogeneic stem cell transplant

The role of donor lymphocyte infusion (DLI) in mediating the graft-versus-myeloma (GvM) effect after allogeneic hematopoietic stem cell transplant (allo-HCT) is not clearly defined. We evaluated the safety and utility of DLI in patients with either persistent or recurrent multiple myeloma (MM) after allo-HCT. Twenty-three patients with MM received DLI after allo-HCT at the University of Texas M. D. Anderson Cancer Center between July 1996 and June 2008. Eight patients received preemptive DLI for residual disease (RD) while 15 patients received DLI for the treatment of recurrent or progressive disease (PD). We evaluated the response to DLI and the factors that may predict a response. Median DLI dose was 3.3 × 107 CD3 + cells (range 0.5–14.8 × 107). Grade II–IV acute graft-versus-host disease (GvHD) was seen in five patients (22%). Median follow-up in surviving patients was 24 months. Five of 23 patients (22%) achieved a complete or a very good partial response (two CR, three VGPR), while eight patients (34%) had stable disease (SD) after the DLI. Patients who received DLI for RD had a higher response rate (≥ VGPR 50% vs. 7%, p = 0.03), a longer overall survival (28.3 vs. 7.6 months, p = 0.03) and a trend toward longer progression-free survival (11.9 vs. 5.2 months, p = 0.1). In this largest single institution study, we conclude that the use of preemptive, non-manipulated DLI for RD after reduced-intensity conditioning allo-HCT is encouraging, and it was associated with a higher response rate and a longer overall survival when given preemptively. The role of DLI needs to be further explored in prospective clinical trials.