Liver stiffness measurements predict Sinusoidal Obstructive Syndrome after hematopoietic stem cell transplantation

Sinusoidal Obstructive Syndrome (SOS) is a life-threatening complication after hematopoietic stem-cell transplantation (HSCT), characterized by post-sinusoidal portal hypertension. FibroScan is used to assess portal hypertension non-invasively. We assessed transient elastography (TE) applicability in diagnosing SOS. The study included 27 adult patients, 11 underwent TE for high SOS risk pre-HSCT, 17 underwent TE post-HSCT due to bilirubin ≥2 mg/dl with no definite diagnosis of SOS. The first group had median Liver Stiffness Measurement (LSM) of 7.4 kPa (range, 3.3-22.5). Based on LSM results, conditioning regimen was modified for six patients and two of them developed SOS. Only one patient who did not have protocol adjustment experienced SOS. No patient with LSM < 7 kPa developed SOS. The second group had median LSM of 7.7 kPa (4.4-31.5). Median LSM after HSCT was significantly higher in patients who subsequently developed established SOS (n = 10) compared to patients who did not (n = 8), with values of 10.7 kPa (5.6-31.5) and 5.9 kPa (4.4-13.8), respectively (p = 0.02). An LSM cut-off of 7.5 kPa had a sensitivity and specificity of 75 and 80% for diagnosing SOS. In conclusion, pre-HSCT LSM can help adjustment of conditioning regimen in patients with high-risk for SOS. Post-HSCT LSM can help in early diagnosis of SOS.

Fecal microbiota transplantation in capsules for the treatment of steroid refractory and steroid dependent acute graft vs. host disease: a pilot study

Acute graft-versus-host disease (aGvHD) is a serious complication of allogeneic hematopoietic stem-cell transplantation with limited treatment options. The gut microbiome plays a critical role in aGvHD pathogenesis. Fecal microbiota transplantation (FMT) has emerged as a potential therapeutic approach to restore gut microbial diversity. In this prospective pilot study, 21 patients with steroid-resistant or steroid-dependent lower gastrointestinal aGvHD received FMT in capsule form. At 28 days after the first FMT, the overall response rate was 52.4%, with 23.8% complete and 28.6% partial responses. However, sustained responses were infrequent, with only one patient remaining aGvHD-free long-term. FMT was generally well-tolerated. Microbiome analysis revealed dysbiosis in pre-FMT patient stool samples, with distinct microbial characteristics compared to donors. Following FMT, there was an increase in beneficial Clostridiales and a decrease in pathogenic Enterobacteriales. These findings highlight the potential of FMT as a treatment option for steroid-resistant aGvHD. Trial registration number NCT #03214289.

Point-of-care anti-CD19 chimeric antigen receptor T-cell therapy for relapsed/refractory follicular lymphoma

Patients with relapsed/refractory follicular lymphoma (R/R-FL) often require multiple treatment lines. We performed a phase 1b/2 single-center clinical trial of autologous point-of-care anti-CD19 chimeric antigen receptor (CAR) T-cells in R/R-FL patients treated patients with ≥ 2 treatment lines. All 26 patients enrolled received CAR T-cell infusion at a median of 11 days after leukapheresis. Seventy-seven percent of patients had POD24. At enrollment, disease stage was III-IV in 85% of the patients, 77% had high-risk FLIPI score, and 77% had progressive disease. Grade III-IV cytokine release and immune effector cell-associated neurotoxicity syndromes occurred in 12% and 16% of the patients, respectively. Overall response rate at 1-month was 88%. The median follow-up was 15.4 months. One-year overall and progression-free survival were 100% and 63%, respectively. In conclusion, point-of-care CAR T-cell, manufactured within 11 days, induced a high response rate with an acceptable safety profile in patients with high-risk R/R-FL.

Allogeneic Hematopoietic Cell Transplantation after Chimeric Antigen Receptor T Cell Therapy in Large B Cell Lymphoma

Anti-CD19 chimeric antigen receptor T cell (CAR-T) therapy has transformed the care of patients with relapsed/refractory large B cell lymphoma (LBCL). However, approximately 60% of CAR-T recipients ultimately will experience disease recurrence or progression. Salvage therapies after CAR-T treatment failures are of limited efficacy and have a short duration of response. The objective of the present study was to evaluate the role of allogeneic hematopoietic cell transplantation (allo-HCT) after CAR-T therapy in LBCL patients. This was a multicenter observational study reporting the outcome of 39 adult LBCL patients who underwent allo-HCT following anti-CD19 CAR-T therapy. The median patient age was 47 years (range, 20 to 68 years). HLA-matched sibling, HLA-matched unrelated, and alternative donors were used in 36%, 36%, and 28% of transplantations, respectively. Conditioning regimens were primarily of low or intermediate intensity. Disease status at allo-HCT was complete response in 41%, partial response in 38%, and progressive disease in 21%. Allo-HCT was performed at a median of 127 days (range, 82 to 206 days) after CAR-T therapy. A high incidence of hepatic toxicity (28%), including sinusoidal obstruction syndrome (15.4%; 95% confidence interval; [CI], 6.2% to 28.5%), was observed. The 1-year cumulative incidence of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) was 38.5% (95% CI, 23.2% to 53.6%) and 15.4% (95% CI, 6.1% to 28.5%), respectively. The 2-year cumulative incidence of moderate-severe chronic GVHD was 11.1% (95% CI, 3.3% to 24.3%). Overall, 2-year nonrelapse mortality and relapse/progression incidence were 26% (95% CI, 13% to 41%) and 43% (95% CI, 27% to 59%), respectively. With a median follow-up of 32 months, the 2-year overall survival (OS) and progression-free survival (PFS) were 45% (95% CI, 31% to 66%) and 31% (95% CI, 19% to 50%), respectively. In multivariable analyses, pre-HCT elevated lactate dehydrogenase level and transformed lymphoma were predictive of OS and PFS, respectively. Our data suggest that allo-HCT after anti-CD19 CAR-T treatment failure is feasible with a relatively promising efficacy but possibly high toxicity rate.

Second hematopoietic stem cell transplantation as salvage therapy for relapsed acute myeloid leukemia/ myelodysplastic syndromes after a first transplantation

Second allogeneic hematopoietic stem-cell transplantation (HSCT2) is a therapeutic option for patients with AML/ MDS relapsing after a first transplant (HSCT1). However, patients allocated to HSCT2 may be a selected group with better prognosis and the added efficacy of HSCT2 is not well established. We retrospectively analyzed 407 consecutive patients with relapsed AML/MDS after HSCT1. Sixty-two patients had HSCT2 (15%) and 345 did not. The 2-year cumulative incidence rates of non-relapse mortality and relapse after HSCT2 were 26% (95% CI, 17-39%) and 50% (95% CI, 39-65%), respectively. The 5-year overall survival (OS) rates were 25% (95% CI, 14-36%) and 7% (95% CI, 4-10%) in the HSCT2 and no-HSCT2 groups, respectively. Multivariate-analysis identified female gender (HR 0.31, P=0.001), short remission duration after HSCT1 (HR 2.31, P=0.05), acute GVHD after HSCT1 (HR 2.27, P=0.035), HSCT2 from haplo-identical (HR 13.4, P=0.001) or matched-unrelated donor (HR 4.53, P=0.007) and relapse after HSCT1 in earlier years (HR 2.46, P=0.02) as factors predicting OS after HSCT2. Multivariate-analysis of all patients including HSCT2 entered as time-dependent variable identified relapse within 6 months after HSCT1 (HR 2.32, P<0.001), acute GVHD before relapse (HR 1.47, P=0.005), myeloablative conditioning in HSCT1 (HR 0.67, P=0.011), female gender (HR 0.71, P=0.007), relapse in earlier years (HR 1.33, P=0.031) and not having HSCT2 (HR 1.66, P=0.010) as predictive for OS after relapse. In conclusion, HSCT2 is associated with longer survival compared to non-transplant treatments and may be the preferred approach in a subset of patients with relapsed AML/MDS after HSCT1.

Point-of-care CAR T-cell therapy as salvage strategy for out-of-specification tisagenlecleucel

Tisagenlecleucel (tisa-cel) is an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for patients with relapsed/refractory large B-cell lymphoma. Outcomes of patients with out-of-commercial specification (OOS) CAR T products are not well characterized. We therefore assessed 37 adult patients who underwent leukapheresis for tisa-cel therapy in a single center. In nine (24%) patients, manufactured tisa-cel was considered OOS. Three of them (33%) received tisa-cel after institutional review board approval; 2/9 (22%) did not receive tisa-cel due to disease progression; and 4/9 (44%) received academic point-of-care (POC) CAR T-cell as salvage therapy, at a median of 35 days following OOS notification. Three of those four patients achieved a complete response. In univariate analysis, risk factors for OOS were ≥ 4 prior therapies or previous bendamustine exposure. In conclusion, we report high OOS incidence of 24% in real-life setting. Forty-four percent of those patients received POC CAR T-cell as salvage therapy.

Immunogenicity and safety of the BNT162b2 mRNA COVID-19 vaccine in haematopoietic stem cell transplantation recipients

The immunogenicity and safety of Pfizer‐BioNTech BNT162b2 mRNA vaccine in allogeneic haematopoietic stem cell transplantation (HSCT) recipients are unknown. We prospectively followed 152 HSCT recipients who were at least six months following transplantation and with no active acute graft‐versus‐host disease (GVHD). Blood samples were taken 2–4 weeks after the second vaccination and analyzed for receptor‐binding domain (RBD) antibodies and neutralizing antibodies (NA). 272 immunocompetent healthcare workers served as controls. At a median of 28 days after the second vaccination, 118 patients (77·6%) developed RBD immunoglobulin G (IgG) with a geometric mean titre (GMT) of 2·61 [95% CI (confidence interval), 2·16–3·16]. In the control group 269/272 (98·9%) developed RBD IgG, with a GMT of 5·98 (95% CI 5·70–6·28), P < 0·0001. The GMT of NA in HSCT recipients and controls was 116·0 (95% CI 76·5–175·9), and 427·9 (95% CI 354·3–516·7) respectively (P < 0001). Multivariate logistic regression analysis revealed that HSCT recipients with no chronic GVHD and no immunosuppressive therapy at the time of vaccination had significantly higher levels of NA following the second vaccination. Adverse events were minimal and were less common than in healthy controls. In conclusion; the BNT162b2 mRNA vaccination is safe and effective in HSCT recipients, especially those who are immunosuppression‐free. A significant fraction developed protecting NA.

Complete Remission with Incomplete Blood Count Recovery Is a Strong Predictor of Nonrelapse Mortality in Acute Myeloid Leukemia Patients Undergoing Allogeneic Stem Cell Transplantation

INTRODUCTION

Achievement of an initial complete remission (CR) following induction chemotherapy is tightly correlated with survival in acute myeloid leukemia (AML) patients, yet patients in CR with incomplete hematologic recovery (CRi) still experience improved outcomes compared with nonresponding patients. Whether CRi predicts prognosis in patients referred to an allogeneic stem cell transplantation (allo-SCT) is incompletely defined. In this analysis, we evaluated whether clinical outcomes of transplanted AML patients in CR and CRi were significantly different.

METHODS

A retrospective single-center analysis of all de novo AML patients who underwent an allo-SCT between 2001 and 2015. The cohort included all adult patients with AML who underwent a first allo-SCT either in first or second CR or CRi at the time of transplantation.

RESULTS

The study cohort included 186 CR patients and 44 CRi patients. In univariate analysis, CRi was associated with inferior 3-year survival and 3-year nonrelapse mortality (NRM) compared to CR (41 vs. 62%; p = 0.022 and 27 vs. 10%; p = 0.006, respectively). In multivariate analysis, CRi was associated with decreased rates of survival (hazard ratio [HR] 2.01; 95% CI, 1.24-3.25; p = 0.005) and NRM (HR, 3.5; 95% CI, 1.6-7.8; p = 0.002).

CONCLUSION

CRi in transplanted AML patients is potentially a potent predictor of increased NRM and survival.

Immune imitation of tumor progression after anti-CD19 chimeric antigen receptor T cells treatment in aggressive B-cell lymphoma

We present three patients with aggressive non-Hodgkin's B-cell lymphoma (NHL) who received anti-CD19 chimeric antigen receptor T (CAR T) cells therapy after failure of several lines of chemotherapy that developed pseudo-progression. One-week clinical and radiological findings were consistent with tumor progression. Positron emission tomography-computed tomography (PET-CT) at 1 month post CAR T cells administration was consistent with treatment response. The rapid tumor growth and subsequent resolution are suggestive of tumor pseudo-progression mediated secondary to infiltration and immune activation of CAR T cells. Overall, 56 adult patients with NHL were enrolled in a phase 1b/2 in house clinical study with CD19 CAR T cells. Out of them 22/56 patients progressed as per PET-CT the 1 month post CAR T cells. In 14 patients, signs of progression started 7-10 days after CAR T cells infusion. In 11/14 patients, it was true progression, while in 3 it was pseudo-progression. Additional studies are warranted to describe the extent of this phenomenon and evaluate correlation with the CAR T activity and long-term disease control.

A phase II study of bisantrene in patients with relapsed/refractory acute myeloid leukemia

OBJECTIVES

To determine the current role of bisantrene, an anthracene with anthracycline-like activity which was shown in earlier studies to be effective therapy in relapsed/refractory acute myeloid leukemia with no discernible cardiotoxicity, in the treatment of patients with R/R AML.

METHODS

This phase 2, single-center study (NCT03820908) enrolled adult R/R AML to receive bisantrene (250 mg/m² daily for 7 days) which was administered via an intravenous infusion over 2 hours on days 1-7. Disease assessment included routine blood work and bone marrow studies.

RESULTS

In all, 10 patients were enrolled with a median of 3 lines of prior therapy including seven patients who had relapsed following allogeneic stem cell transplantation. The most frequently reported grade ≥3 treatment-attributed hematologic AE was thrombocytopenia, whereas the most frequently reported grade ≥3 treatment-attributed non-hematologic AE was mucositis. Of the 10 patients, one (10%) achieved a complete remission and three patients achieved a partial remission resulting in an overall response rate of 40%. Next-generation sequencing of patient samples identified a wide array of mutations associated with activated signaling, splicing, and epigenetic modification.

CONCLUSIONS

In view of the observed low toxicity, a follow-up study combining bisantrene with complementary anti-leukemic therapy is planned.

Treatment with anti CD19 chimeric antigen receptor T cells after antibody-based immunotherapy in adults with acute lymphoblastic leukemia

PURPOSE OF THE STUDY

The prognosis of patients with relapsed/refractory precursor B-acute lymphoblastic leukemia (ALL) is dismal. Antibody-based therapies, such as blinatumomab or inotuzumab ozogamycin (IO) have led to improved outcomes. The impact of prior immunotherapy on chimeric antigen receptor (CAR) T-Cell therapeutic efficacy and toxicity is unknown.

METHODS

We describe a case series of ALL patients with prior exposure to blinatumomab or IO, who were treated with anti-CD19 CAR T cells with CD28 co-stimulatory domain (NCT02772198). We then review the literature on CAR-T post antibody-based therapy with either antibodies.

RESULTS

Five adult patients with B-ALL were included. Three had active disease, and two were in morphological complete remission (CR) with minimal residual disease (MRD+). Therapy before CAR-T included blinatumomab (3/5 [60 %]) and IO (3/5 [60 %]), with one patient receiving both. One patient experienced severe cytokine release syndrome and central nervous system toxicity and subsequently died. At 28 days following treatment, two patients achieved CR with MRD negativity, and two had an MRD + CR. Two patients received allogeneic hematopoietic stem cell transplantation. At a median of 10 months (range, 5-26, three out of the four patients are still in CR, and one relapsed. The literature review identified a deficiency on data on the influence of blinatumumab and IO on outcomes post CAR-T therapy.

CONCLUSIONS

CD19 CAR T-cell therapy after treatment with blinatumomab and/or IO in patients with relapsed/refractory B-ALL is feasible and results in promising response rates in this case series. Future trails should specifically address outcomes in this population.

A simplified method for detection of N-terminal valine adducts in patients receiving treosulfan

RATIONALE

Treosulfan is a substance that is being studied as part of the conditioning regimen given prior to allogeneic stem cell transplantation in patients with hematological malignancies. It is known to decompose into 1,2:3,4-diepoxybutane (DEB) under physiologic conditions. In this study, we investigate whether N-terminal valine adducts can be utilized to monitor differences in DEB formation of patients receiving treosulfan as part of the conditioning regimen for transplantation.

METHODS

Blood samples were collected from a group of 14 transplant recipients and analyzed for N,N-(2,3-dihydroxy-1,4-butadiyl)valine (pyr-Val) and 2,3,4-trihydroxybutylvaline (THB-Val) adducts as biomarkers for drug uptake and metabolism before treosulfan treatment and 6 days after treatment.

RESULTS

A new direct injection liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated prior to clinical analysis. The assay precision was determined by 3 replicate analyses on 3 individual days using control globin spiked with known amounts of pyr-Val and THB-Val. The intra- and inter-day precision coefficients of variance (CVs) and accuracy were < 10% and 15%, respectively. In clinical specimens, the means ± SD of pyr-Val and THB-Val background were 0.29 ± 0.10 pmol/g HB and 5.17 ± 1.7 pmol/g HB, respectively.

CONCLUSIONS

These values are similar to those found previously. Treosulfan treatment leads to a significant increase in pyr-Val and THB-Val adducts in each patient (Student's t-test p <0.0001). The mean ± SD amounts of adduct formed were 245.3 ± 89.6 and 210 ± 78.5 pmol/g globin for pyr-Val and THB-Val, respectively. Importantly, these results show that this direct injection method can quantitate both background and treosulfan-induced pyr-Val and THB-Val N-terminal valine globin adducts in humans.

Baseline Renal Function and Albumin are Powerful Predictors for Allogeneic Transplantation-Related Mortality

Biomarkers measured in blood chemistry before allogeneic hematopoietic stem cell transplantation (HSCT) may reflect patients' physiological status. We hypothesized that selected markers are predictive for nonrelapse mortality (NRM) following transplantation and could contribute to risk assessment. We investigated the value of pre-HSCT albumin, estimated glomerular filtration rate (eGFR), and alkaline phosphatase (AlkP) in predicting NRM. We retrospectively analyzed clinical and laboratory data from 1217 patients receiving a first HSCT in 2 European centers between 2003 and 2015. Transplantation indications and conditioning regimens were diverse. Patients had a median age of 55 years and hematopoietic cell transplantation comorbidity index (HCT-CI) scores of 0 (24%), 1 to 2 (39%), and ≥3 (37%). Cutoffs of eGFR <60 mL/min, albumin <3.5 g/dL, and AlkP >180 IU/L corresponded with 8.8%, 8.3%, and 6.5% of the patients, respectively. eGFR and albumin were associated with increased risk and higher cumulative incidence of day-100, 1-year, and 2-year NRM, both as continuous or categorized variables. A similar pattern was observed for AlkP, except for day-100 NRM. In multivariable analyses, eGFR and albumin were consistently among the top risk factors for early and late-term NRM, abrogating the role of age. Prediction models for day-100, 1-year, and 2-year NRM based only on HCT-CI resulted in c-statistics of .565, .575, and .577, respectively. Addition of both biomarkers increased c-statistics for day-100, 1-year, and 2-year NRM to .651, .633, and .624, respectively. Albumin and eGFR are prognostic biomarkers for NRM after HSCT and improve the discriminative power of the HCT-CI.

Immunological effects of nilotinib prophylaxis after allogeneic stem cell transplantation in patients with advanced chronic myeloid leukemia or philadelphia chromosome-positive acute lymphoblastic leukemia

Allogeneic stem cell transplantation remains the standard treatment for resistant advanced chronic myeloid leukemia and Philadelphia chromosome–positive acute lymphoblastic leukemia. Relapse is the major cause of treatment failure in both diseases. Post-allo-SCT administration of TKIs could potentially reduce relapse rates, but concerns regarding their effect on immune reconstitution have been raised. We aimed to assess immune functions of 12 advanced CML and Ph+ ALL patients who received post-allo-SCT nilotinib. Lymphocyte subpopulations and their functional activities including T-cell response to mitogens, NK cytotoxic activity and thymic function, determined by quantification of the T cell receptor (TCR) excision circles (TREC) and TCR repertoire, were evaluated at several time points, including pre-nilotib-post-allo-SCT, and up to 365 days on nilotinib treatment. NK cells were the first to recover post allo-SCT. Concomitant to nilotinib administration, total lymphocyte counts and subpopulations gradually increased. CD8 T cells were rapidly reconstituted and continued to increase until day 180 post SCT, while CD4 T cells counts were low until 180−270 days post nilotinib treatment. T-cell response to mitogenic stimulation was not inhibited by nilotinib administration. Thymic activity, measured by TREC copies and surface membrane expression of 24 different TCR Vβ families, was evident in all patients at the end of follow-up after allo-SCT and nilotinib treatment. Finally, nilotinib did not inhibit NK cytotoxic activity. In conclusion, administration of nilotinib post allo-SCT, in attempt to reduce relapse rates or progression of Ph+ ALL and CML, did not jeopardize immune reconstitution or function following transplantation.

Second Malignancies after Hematopoietic Stem Cell Transplantation

OPINION STATEMENT

Second malignancies are a rare but well-defined late complication after autologous and allogeneic hematopoietic stem-cell transplantation (SCT). Solid malignancies occur in up to 15% of patients 15 years after SCT with myeloablative conditioning, with no plateau in the incidence rates. They are responsible for 5-10% of late deaths after SCT. The incidence is increased with advanced age at SCT. The major risk factors are the use of total body irradiation, which is associated with adenocarcinomas and with chronic graft-versus-host disease which is associated with squamous cell cancers. There is less data on the incidence of second malignancies after reduced-intensity conditioning, but it may not be lower. The types of solid tumors reported in excess include melanoma and other skin cancers; cancers of the oral cavity and head and neck, brain, liver, uterine cervix, thyroid, breast, lung; and possibly gastrointestinal cancers. Therapy-related myeloid neoplasms (t-MN) are more common after autologous SCT and may be related mostly to pre-transplant therapies. Post-transplant lymphoproliferative disease is donor-cell-derived lymphoma that is more common after allogeneic SCT with T-cell depletion or intensive immune-suppression state. Second malignancies are most often treated similarly to the standard therapy for similar malignancies. Lifelong cancer screening and prevention interventions are required for all transplantation survivors.

Missing HLA C group 1 ligand in patients with AML and MDS is associated with reduced risk of relapse and better survival after allogeneic stem cell transplantation with fludarabine and treosulfan reduced toxicity conditioning

Reduced-toxicity conditioning with fludarabine and treosulfan is a dose-intensive regimen with enhanced anti-leukemia effect and acceptable toxicity in AML/MDS. HLA-C regulates natural-killer (NK) cell function by inhibiting Killer immunoglobulin-like receptors (KIR) and is divided into C1 and C2 epitopes. The missing-ligand theory suggests that missing recipient KIR ligands drives NK-alloreactivity after SCT, in the absence of HLA-mismatch by activating unlicensed donor NK cells. We analyzed SCT outcomes in 203 patients with AML/MDS, median age 58 years, given SCT from matched-siblings (n = 97) or matched-unrelated donors (n = 106), using two treosulfan doses (total 36 or 42 g/m² ). 34% expressed one HLA-C group 1 allele (C1C1), 19% one HLA-C group 2 allele (C2C2), and 48% both KIR ligands (C1C2). Median follow-up was 48 months. 5-year relapse, nonrelapse mortality (NRM) and leukemia-free survival (LFS) rates were 38%, 27%, and 36%, respectively. Relapse rates were 43%, 45%, and 26% in patients expressing C1C1, C1C2, and C2C2 ligands, respectively (P = .03). Multivariate-analysis identified chemo-refractory disease (HR 3.1, P = .003), poor cytogenetics (HR 1.7, P = .08), female donor to male recipient (HR 0.4, P = .01) and C2C2 ligands (HR 0.4, P = .04) as independent factors predicting relapse. HLA-C ligands were not associated with GVHD or NRM. LFS was 33%, 30%, and 46%, respectively (P = .07). Chemorefractory disease (HR 3.1, P = .0004) and C2C2 group ligand (HR 0.6, P = .06) independently predicted LFS. Treosulfan dose did not predict any SCT outcome. In conclusion, missing HLA-C group 1 ligand is associated with reduced relapse risk, similar NRM and improved LFS, after HLA-matched SCT with treosulfan conditioning in AML/MDS.

Isolated Extramedullary Relapse of Acute Leukemia after Allogeneic Stem Cell Transplantation: Different Kinetics and Better Prognosis than Systemic Relapse

Allogeneic stem cell transplantation (SCT) is curative treatment in patients with acute leukemia and myelodysplastic syndrome. However, recurrent disease is the major cause of treatment failure. Isolated extramedullary relapse (iEMR) after SCT is relatively rare and not well characterized. We performed a retrospective analysis of 566 consecutive patients with acute myeloid leukemia (n = 446) and acute lymphoblastic leukemia (ALL; n = 120) after SCT to study the incidence, risk factors, treatment options, and outcome of iEMR. The 5-year cumulative incidence of bone marrow relapse (BMR) and iEMR was 41.0% and 5.8%, respectively. iEMR occurred significantly later than BMR at 10 and 4 months, respectively (P < .001). Diagnosis of ALL (HR, 2.6; P = .05), poor cytogenetics (HR, 2.1; P = .06), and prior extramedullary disease (HR, 3.8; P = .002) were independent factors predicting iEMR. Acute and chronic graft-versus-host disease (GVHD) reduced the risk of BMR but did not protect against iEMR. Most patients with iEMR received systemic treatment combined with local radiation and donor lymphocyte infusions when feasible. The 3-year survival after relapse was 8.5% and 30.1% after BMR and iEMR, respectively (P = .002). Patients with a first iEMR continued to have recurrent EMRs, and only a minority progressed to BMR. Second iEMR was also common after first BMR and associated with longer survival than second BMR. iEMR is more frequent in patients with ALL and prior extramedullary disease. It occurs later than BMR and more commonly in patients with chronic GVHD, suggesting less effective graft-versus-leukemia effect in extramedullary sites. Second iEMR is common after a first iEMR but also after a first BMR. Long-term survival is feasible with aggressive treatment.

The combination of cyclosporine and mycophenolate mofetil is less effective than cyclosporine and methotrexate in the prevention of acute graft-versus host disease after stem-cell transplantation from unrelated donors

Acute graft-versus-host disease (GVHD) is the major treatment-related complication after stem-cell transplantation (SCT) from unrelated-donors. Several GVHD prophylaxis regimens have been explored, but no regimen has shown superiority. We analyzed transplantation outcomes in 472 consecutive unrelated-donor SCT recipients, using cyclosporine/methotrexate (MTX, n = 314) or cyclosporine/mycophenolate-mofetil (MMF, n = 158) for GVHD prophylaxis. Neutrophil engraftment was faster after MMF, days 11 and 14, respectively (P = .001). Acute GVHD grade II-IV and III-IV occurred in 47% and 28% after MMF compared to 27% and 12% after MTX, respectively (P < .001). Nonrelapse mortality (NRM) was 44% and 24%, respectively (P < .001). Death associated with GVHD occurred in 25% and 8% (P < .0001), while other NRM causes occurred in 19% and 16%, respectively (P = .39). Relapse mortality was similar. Overall survival was better after MTX, 40% and 29%, respectively (P = .006). However, this difference had only borderline significance when adjusting for differences in patient characteristics (HR, 1.3, P = .08). To minimize potential selection bias we analyzed outcomes on the basis of an intention-to-treat like analysis. During the years 2008-2009, the leading GVHD prophylaxis regimen for unrelated-donor SCT included MMF (89% of transplants). During the other periods, MTX was used predominantly (82% of transplants). The two periods were otherwise well-matched. Acute GVHD occurred more often in 2008-2009. Death associated with GVHD occurred more often, while other NRM causes occurred less often resulting in similar NRM and overall survival. In conclusion, cyclosporine/MMF is associated with faster engraftment and possibly with less organ toxicity than cyclosporine/MTX. However, it is associated with increased rates of acute GVHD and GVHD-associated deaths.

Plerixafor (Mozobil): A Stem Cell-Mobilizing Agent for Transplantation in Lymphoma Patients Predicted to Be Poor Mobilizers - A Pilot Study

Autologous hematopoietic stem cell transplantation is the standard therapy for refractory/relapsed aggressive lymphoma. The initial step of the procedure involves mobilization and collection of hematopoietic stem cells. G-CSF fails to achieve mobilization in 15-25% of lymphoma patients. Plerixafor is a novel CXCR4 antagonist that can promote mobilization. It has been used successfully in patients after the failure of G-CSF. It is reasonable to test whether plerixafor should become the mobilizing agent of choice in patients expected to exhibit difficulties in mobilization. We initiated a study to assess the use of plerixafor as a first-line stem cell mobilizer in 20 elderly or heavily pretreated patients with non-Hodgkin or Hodgkin lymphoma. The minimum defined CD34+ cell dose of ≥2 × 106 cells/kg was achieved by 90% of the patients, and for 83% of them with one apheresis procedure. The target CD34+ dose of ≥5 × 106 cells/kg was achieved by 70% of the patients. The median number of circulating CD34+ cells before and after plerixafor was 14.4 and 42.8 cells/μl, respectively. The post-plerixafor adverse events were mild. All patients promptly engrafted after high-dose chemotherapy treatment. We conclude that plerixafor administration is safe and efficient for upfront mobilization in lymphoma patients predicted to be poor mobilizers.

Monoclonal antibody-based immunotherapy for multiple myeloma

Multiple myeloma (MM) is a life-threatening hematological malignancy. High-dose chemotherapy followed by autologous stem cell transplantation is a relatively effective treatment, but disease recurrence remains a major obstacle. Allogeneic transplantation may result in durable responses and cure due to antitumor immunity mediated by donor lymphocytes. However, morbidity and mortality related to graft-versus-host disease remain a challenge. Recent advances in understanding the interaction between the immune system of the patient and the malignant cells are influencing the design of clinically more efficient study protocols for MM. This review will focus on MM antigens and their specific antibodies. These monoclonal antibodies are an attractive therapeutic tool for MM humoral immunotherapy, with most promising preclinical results.