CD8+ T-cell Differentiation and Dysfunction Inform Treatment Response in Acute Myeloid Leukemia.

The interplay between T-cell states of differentiation, dysfunction, and treatment response in acute myeloid leukemia (AML) remains unclear. Here, we leveraged a multimodal approach encompassing high-dimensional flow cytometry and single-cell transcriptomics and found that early memory CD8+ T cells are associated with therapy response and exhibit a bifurcation into two distinct terminal end states. One state is enriched for markers of activation, whereas the other expresses NK-like and senescence markers. The skewed clonal differentiation trajectory towards CD8+ senescence was also a hallmark indicative of therapy resistance. We validated these findings by generating an AML CD8+ single-cell atlas integrating our data and other independent datasets. Finally, our analysis revealed that an imbalance between CD8+ early memory and senescent-like cells is linked to AML treatment refractoriness and poor survival. Our study provides crucial insights into the dynamics of CD8+ T-cell differentiation and advances our understanding of CD8+ T-cell dysfunction in AML.

CD38 deletion of human primary NK cells eliminates daratumumab-induced fratricide and boosts their effector activity.

Multiple myeloma (MM) is a plasma cell neoplasm that commonly expresses CD38. Daratumumab (DARA), a human monoclonal antibody targeting CD38, has significantly improved the outcome of patients with relapsed or refractory MM, but the response is transient in most cases. Putative mechanisms of suboptimal efficacy of DARA include downregulation of CD38 expression and overexpression of complement inhibitory proteins on MM target cells as well as DARA-induced depletion of CD38high natural killer (NK) cells resulting in crippled antibody-dependent cellular cytotoxicity (ADCC). Here, we tested whether maintaining NK cell function during DARA therapy could maximize DARA-mediated ADCC against MM cells and deepen the response. We used the CRISPR/Cas9 system to delete CD38 (CD38KO) in ex vivo expanded peripheral blood NK cells. These CD38KO NK cells were completely resistant to DARA-induced fratricide, showed superior persistence in immune-deficient mice pretreated with DARA, and enhanced ADCC activity against CD38-expressing MM cell lines and primary MM cells. In addition, transcriptomic and cellular metabolic analysis demonstrated that CD38KO NK cells have unique metabolic reprogramming with higher mitochondrial respiratory capacity. Finally, we evaluated the impact of exposure to all-trans retinoic acid (ATRA) on wild-type NK and CD38KO NK cell function and highlighted potential benefits and drawbacks of combining ATRA with DARA in patients with MM. Taken together, these findings provide proof of concept that adoptive immunotherapy using ex vivo expanded CD38KO NK cells has the potential to boost DARA activity in MM.

Shortened-Duration Immunosuppressive Therapy after Nonmyeloablative, Related HLA-Haploidentical or Unrelated Peripheral Blood Grafts and Post-Transplantation Cyclophosphamide.

With post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis, nonmyeloablative (NMA) HLA-haploidentical (haplo) and HLA-matched blood or marrow transplantation (BMT) have comparable outcomes. Previous reports have shown that discontinuation of immunosuppression (IS) as early as day 60 after infusion of a bone marrow (BM) haplo allograft with PTCy is feasible. There are certain diseases in which peripheral blood (PB) may be favored over BM, but given the higher rates of GVHD with PB, excessive GVHD is of increased concern. We report a completed, prospective single-center trial of stopping IS at days 90 and 60 after NMA PB stem cell transplantation (PBSCT). Between 12/2015-7/2018, 117 consecutive patients with hematologic malignancies associated with higher rates of graft failure after NMA conditioned BMT and PTCy, received NMA PB allografts on trial. The primary objective of this study was to evaluate the safety and feasibility of reduced-duration IS (from day 5 through day 90 in the D90 cohort and through day 60 in the D60 cohort). Of the 117 patients (median age, 64 years; range, 22 to 78 years), the most common diagnoses were myelodysplastic syndrome (33%), acute myelogenous leukemia (with minimal residual disease or arising from an antecedent disorder) (32%), myeloproliferative neoplasms (19%), myeloma (9%), and chronic lymphoblastic leukemia (7%). Shortened IS was feasible in 75 patients (64%) overall. Ineligibility for shortened IS resulted most commonly from GVHD (17 patients), followed by early relapse (11 patients), nonrelapse mortality (NRM) (7 patients), patient/ physician preference (4 patients) or graft failure (3 patients). Of the 57 patients in the D90 cohort, 33 (58%) stopped IS early as planned, and among the 60 patients in the D60 cohort, 42 (70%) stopped IS early as planned. The graft failure rate was 2.6%. After IS cessation, the median time to diagnosis of grade II-IV acute GVHD was 21 days in the D90 cohort and 32 days in the D60 cohort, with almost all cases developing within 40 days. Approximately one-third of these patients resumed IS. All outcome measures were similar in the 2 cohorts and our historical outcomes with 180 days of IS. The cumulative incidence of grade III-IV acute GVHD was low, 2% in the D90 cohort and 7% in the D60 cohort. The incidence of severe chronic GVHD at 2 years was 9% in the D90 cohort and 5% in the D60 cohort. The 2-year overall survival was 67% for both the D90 and D60 cohorts. The 2-year progression-free survival was 47% for the D90 cohort and 52% for the D60 cohort, and the GVHD-free, relapse-free survival was <35% for both cohorts. These data suggest that reduced-duration IS in patients undergoing NMA PBSCT with PTCy is feasible and has an acceptable safety profile. © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Thrombotic Microangiopathy after Post-Transplantation Cyclophosphamide-Based Graft-versus-Host Disease Prophylaxis.

Transplant-associated thrombotic microangiopathy (taTMA) is a systemic vascular illness associated with significant morbidity and mortality, resulting from a convergence of risk factors after allogeneic blood or marrow transplantation (alloBMT). The diagnosis of taTMA has been a challenge, but most criteria include an elevated lactate dehydrogenase (LDH), low haptoglobin, and schistocytes on peripheral blood smear. We performed a retrospective review of the 678 consecutive adults who received high-dose post-transplantation cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis between January 1, 2015, and August 31, 2018. In April 2016, we initiated a monitoring program of weekly LDH and haptoglobin measurements and blood smears when those 2 parameters were both abnormal on all of our adult patients undergoing alloBMT for hematologic malignancies. During the entire period, the 1-year cumulative incidence of taTMA was 1.4% (95% confidence interval, 0.5% to 2.3%). Eight patients were taking tacrolimus at the time of diagnosis, and 1 was not on any immunosuppression. Eight of 9 patients (89%) were hypertensive. Four patients had invasive infections at the time of diagnosis, 4 patients required renal replacement therapy, and 5 of 9 patients were neurologically impaired. Eculizumab was given to 6 patients (0.9%), of whom 2 died and 4 recovered with resolution of end-organ dysfunction. The paucity of events made the determination of risk factors difficult; however, the low incidence of taTMA in this cohort may be related to the limited use of myeloablative conditioning regimens, low incidence of severe GVHD, and use of PTCy. PTCy-based GVHD prophylaxis appears to be associated with a low incidence of severe taTMA.

Development of Grade II Acute Graft-versus-Host Disease Is Associated with Improved Survival after Myeloablative HLA-Matched Bone Marrow Transplantation using Single-Agent Post-Transplant Cyclophosphamide.

Post-transplant cyclophosphamide (PTCy) can be used as the sole immunosuppression after myeloablative conditioning (MAC) for HLA-matched bone marrow transplantation (BMT). However, the effects of graft-versus-host disease (GVHD) with this platform are undefined. We retrospectively analyzed 298 consecutive adult patients with hematologic malignancies who engrafted after MAC HLA-matched sibling donor (MSD; n = 187) or HLA-matched unrelated donor (MUD; n = 111) T-cell-replete BMT with PTCy 50 mg/kg on days +3 and +4. After MSD and MUD BMT, 35% and 57% of patients, respectively, developed grade II acute GVHD (aGVHD) by 100 days, 11% and 14% grade III to IV aGVHD by 100 days, and 9% and 16% chronic GVHD (cGVHD) by 1 year. In landmark analyses at 100 days after HLA-matched BMT, 4-year overall survival (OS) and progression-free survival (PFS) were 57% (95% confidence interval [CI], .49 to .67) and 40% (95% CI, .31 to .51) in patients without grades II to IV aGVHD, and 68% (95% CI, .59 to .78) and 54% (95% CI, .44 to .65) in patients with grade II aGVHD. In adjusted time-dependent multivariable analyses, grade II aGVHD was associated with improved OS (hazard ratio, .58; 95% CI, .37 to .89; P = .01) and PFS (hazard ratio, .50; 95% CI, .34 to .74; P < .001) after HLA-matched BMT with PTCy. The ability of PTCy to limit grades III to IV aGVHD and cGVHD while maintaining grade II aGVHD may contribute to its effectiveness, and further attempts to reduce aGVHD may be detrimental.

Severe Cytokine Release Syndrome after Haploidentical Peripheral Blood Stem Cell Transplantation.

Inflammatory cytokines released by activated lymphocytes and innate cells in the context of cellular therapy can cause fever, vasodilatation, and end-organ damage, collectively known as cytokine release syndrome (CRS). CRS can occur after allogeneic blood or marrow transplantation, but is especially prevalent after HLA-haploidentical (haplo) peripheral blood transplantation (PBT). We reviewed charts of all patients who underwent haplo-PBT between October 1, 2013, and September 1, 2017 and graded CRS in these patients. A total of 146 consecutive patients who underwent related haplo-PBT were analyzed. CRS occurred in 130 patients (89%), with most cases of mild severity (grade 0 to 2). Severe CRS (grade 3 to 5) occurred in 25 patients (17%). In this group with severe CRS, 13 patients had encephalopathy, 12 required hemodialysis, and 11 were intubated. Death from the immediate complications of CRS occurred in 6 patients (24% of the severe CRS group and 4% of the entire haplo-PBT cohort). The cumulative probability of nonrelapse mortality (NRM) was 38% at 6 months for the patients with severe CRS and 8% (121 of 146) in patients without severe CRS. In conclusion, CRS occurs in nearly 90% of haplo-PBTs. Older haplo-PBT recipients (odds ratio [OR], 2.4; 95% confidence interval [CI], .83 to 6.75; P = .11) and those with a history of radiation therapy (OR, 3.85; 95% CI, 1.32 to 11.24; P = .01) are at increased risk of developing severe CRS. Although most recipients of haplo-PBT develop CRS, <20% experience severe complications. The development of severe CRS is associated with a significantly increased risk of NRM.

Low immunosuppressive burden after HLA-matched related or unrelated BMT using posttransplantation cyclophosphamide.

The intensive and prolonged immunosuppressive therapy required to prevent or treat graft-versus-host disease (GVHD) after allogeneic blood or marrow transplantation (alloBMT) puts patients at substantial risk for life-threatening infections, organ toxicity, and disease relapse. Posttransplantation cyclophosphamide (PTCy) can function as single-agent GVHD prophylaxis after myeloablative, HLA-matched related (MRD), or HLA-matched unrelated (MUD) donor T-cell-replete bone marrow allografting, obviating the need for additional prophylactic immunosuppression. However, patients who develop GVHD require supplemental treatment. We assessed the longitudinal requirement for immunosuppressive therapy in 339 patients treated with this transplantation platform: 247 receiving busulfan/cyclophosphamide (BuCy) conditioning (data collected retrospectively) and 92 receiving busulfan/fludarabine (BuFlu) conditioning (data collected prospectively). Approximately 50% of MRD patients and 30% of MUD patients never required immunosuppression beyond PTCy. In patients requiring further immunosuppression, typically only 1 to 2 agents were required, and the median durations of systemic pharmacologic immunosuppression for the BuCy MRD, BuFlu MRD, BuCy MUD, and BuFlu MUD groups all were 4.5 to 5 months. For these 4 groups, 1-year probabilities of being alive and off all systemic immunosuppression were 61%, 53%, 53%, and 51% and 3-year probabilities were 53%, 48%, 49%, and 56%, respectively. These data suggest that PTCy minimizes the global immunosuppressive burden experienced by patients undergoing HLA-matched alloBMT.

Grade II Acute Graft-versus-Host Disease and Higher Nucleated Cell Graft Dose Improve Progression-Free Survival after HLA-Haploidentical Transplant with Post-Transplant Cyclophosphamide.

Compared with standard graft-versus-host disease (GVHD) prophylaxis platforms, post-transplantation cyclophosphamide (PTCy) after T cell-replete HLA-haploidentical (haplo) bone marrow transplantation (BMT) reduces the risk of grades III to IV acute (a) and chronic (c) GVHD, but maintains similar rates of grade II aGVHD. Given that mild GVHD has been associated with reduced treatment failure in HLA-matched BMT, we evaluated the risk factors for and effects of GVHD on survival in 340 adults with hematologic malignancies who engrafted after nonmyeloablative haplo-BMT with PTCy, mycophenolate mofetil, and tacrolimus. The cumulative incidence at 100 days of grade II and grades III to IV aGVHD were 30% (95% confidence interval [CI], 25% to 35%) and 2% (95% CI, 1% to 4%), respectively. The 1-year cumulative incidence of cGVHD was 10% (95% CI, 7% to 13%). In landmark analyses at 100 days, the 4-year probabilities of overall survival (OS) and progression-free survival (PFS) were, 48% (95% CI, 41% to 56%) and 39% (95% CI, 32% to 47%) for patients without grades II to IV aGVHD, compared with 63% (95% CI, 53% to 73%) and 59% (95% CI, 50% to 71%) for patients with grade II aGVHD (P = .05 and P = .009). In multivariable modeling, when compared with patients who never experienced GVHD, the hazard ratio (HR) for OS and PFS in patients with grade II aGVHD was .78 (95% CI, .54 to 1.13; P = .19) and .69 (95% CI, .48 to .98; P = .04). Higher nucleated cell graft dose was also associated with improved OS (HR, .88; 95% CI, .78 to 1.00; P = .05) and PFS (HR, .89; 95% CI, .79 to 1.0; P = .05) and decreased risk of grades III to IV aGVHD (subdistribution HR, .66; 95% CI, .46 to .96; P = .03). PTCy reduces grades III to IV aGVHD and cGVHD, but retains similar incidence of grade II aGVHD, the development of which improves PFS. Higher nucleated cell graft dose goals may also improve survival after nonmyeloablative haplo-BMT with PTCy.

Shortened-Duration Tacrolimus after Nonmyeloablative, HLA-Haploidentical Bone Marrow Transplantation.

With post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis, nonmyeloablative HLA-haploidentical (NMA haplo) and HLA-matched blood or marrow transplantation (BMT) have comparable outcomes. Early discontinuation of immunosuppression may reduce the risk of relapse and improve immune reconstitution, but may increase the risk of GVHD. We conducted a prospective trial of NMA haplo BMT for patients with hematologic malignancies (median age, 61 years), evaluating the safety of early discontinuation of tacrolimus. All patients received T cell-replete bone marrow followed by high-dose PTCy, mycophenolate mofetil, and tacrolimus. Tacrolimus was prespecified to stop without taper at day +90, +60, or +120, contingent on having ≥5% donor T cells, no relapse, and no grade II-IV acute or significant chronic GVHD. Safety stopping rules were based on ≥5% graft failure, ≥10% nonrelapse mortality (NRM), or a ≥20% combined incidence of severe acute and chronic GVHD from the tacrolimus stop date through day +180. Of the 47 patients in the day +90 arm, 23 (49%) stopped tacrolimus as planned. Of the 55 patients in the day +60 arm, 38 (69%) stopped as planned. Safety stopping criteria were not met. In both arms, at day +180, the probability of grade II-IV acute GVHD was <40%, that of grade III-IV acute GVHD was <8%, and that of NRM was <5%. The 1-year probabilities of chronic GVHD and NRM were <15% and <10%, respectively, in both arms. The 1-year GVHD-free relapse-free survival was higher in the day 60 arm. Thus, stopping tacrolimus as early as day +60 is feasible and carries acceptable risks after NMA haplo BMT with PTCy. This approach may facilitate post-transplantation strategies for relapse reduction.

Early Fever after Haploidentical Bone Marrow Transplantation Correlates with Class II HLA-Mismatching and Myeloablation but Not Outcomes.

Noninfectious fevers are common early after T cell-replete HLA haploidentical (haplo) peripheral blood transplants and have been associated with cytokine release syndrome and overall mortality. However, less is known regarding the incidence and associations of early fever after bone marrow transplantation (BMT) with post-transplant cyclophosphamide (PTCy). We hypothesized that early fever would be associated with myeloablative conditioning (MAC), because of its relative increase in tissue damage augmenting antigen presentation and class II HLA-mismatching because of recognition of antigen-presenting cells by CD4+ T cells. In 672 recipients of MAC HLA-matched related donor (MRD) (n = 183), MAC HLA-matched unrelated donor (MUD) (n = 115), MAC haplo (n = 79), or nonmyeloablative (NMA) haplo (n = 295) T cell-replete BMT with PTCy, we retrospectively analyzed early noninfectious fever defined as temperature of ≥38.3°C once or ≥38.0°C twice or more on days 1 to 6. Fever occurred in 13% after MAC MRD, 23% after MAC MUD, 44% after NMA haplo, and 84% after MAC haplo BMT (P < .0001). Survival outcomes did not differ between patients with and without early fever. In NMA haplo BMT, mismatch in the graft-versus-host direction at HLA-DRB1 or -DPB1 (but not HLA-A, -B, -Cw, or -DQB1) was associated with early fever compared with no mismatches at these loci (P < .0001 and P = .02, respectively). In multivariable modeling, -DRB1 or -DPB1 mismatch and higher CD3+ graft cell dose were significantly associated with early fever. Early fever is more common after haplo compared with HLA-matched BMT. Fever is associated with myeloablation, -DRB1 or -DPB1 mismatching, and higher CD3+ graft cell dose but not survival.

Haploidentical Bone Marrow Transplantation with Post-Transplant Cyclophosphamide Using Non-First-Degree Related Donors.

Outcomes of nonmyeloablative (NMA) haploidentical (haplo) blood or marrow transplant (BMT) with post-transplantation cyclophosphamide (PTCy) using non-first-degree relatives are unknown. We evaluated 33 consecutive adult patients (median age, 56 years) with hematologic malignancies who underwent NMA haplo T cell-replete BMT with PTCy at Johns Hopkins using second- or third-degree related donors. Donors consisted of 10 nieces (30%), 9 nephews (27%), 7 first cousins (21%), 5 grandchildren (15%), and 2 uncles (6%). Thirty-one patients (94%) reached full donor chimerism by day 60. The estimated cumulative incidence (CuI) of grades II to IV acute graft-versus-host disease (aGVHD) at day 180 was 24% (90% confidence interval [CI], 9% to 38%). Only 1 patient experienced grades III to IV aGVHD. At 1 year the CuI of chronic GVHD was 10% (90% CI, 0% to 21%). The CuI of nonrelapse mortality at 1 year was 5% (90% CI, 0% to 14%). At 1 year the probability of relapse was 31% (90% CI, 12% to 49%), progression-free survival 64% (90% CI, 48% to 86%), and overall survival 95% (90% CI, 87% to 100%). The 1-year probability of GVHD-free, relapse-free survival was 57% (90% CI, 41% to 79%). NMA haplo BMT with PTCy from non-first-degree relatives is an acceptably safe and effective alternative donor platform, with results similar to those seen with first-degree relatives.

PD-1 blockade with nivolumab in relapsed or refractory Hodgkin's lymphoma.

BACKGROUND: Preclinical studies suggest that Reed-Sternberg cells exploit the programmed death 1 (PD-1) pathway to evade immune detection. In classic Hodgkin's lymphoma, alterations in chromosome 9p24.1 increase the abundance of the PD-1 ligands, PD-L1 and PD-L2, and promote their induction through Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling. We hypothesized that nivolumab, a PD-1-blocking antibody, could inhibit tumor immune evasion in patients with relapsed or refractory Hodgkin's lymphoma. METHODS: In this ongoing study, 23 patients with relapsed or refractory Hodgkin's lymphoma that had already been heavily treated received nivolumab (at a dose of 3 mg per kilogram of body weight) every 2 weeks until they had a complete response, tumor progression, or excessive toxic effects. Study objectives were measurement of safety and efficacy and assessment of the PDL1 and PDL2 (also called CD274 and PDCD1LG2, respectively) loci and PD-L1 and PD-L2 protein expression. RESULTS: Of the 23 study patients, 78% were enrolled in the study after a relapse following autologous stem-cell transplantation and 78% after a relapse following the receipt of brentuximab vedotin. Drug-related adverse events of any grade and of grade 3 occurred in 78% and 22% of patients, respectively. An objective response was reported in 20 patients (87%), including 17% with a complete response and 70% with a partial response; the remaining 3 patients (13%) had stable disease. The rate of progression-free survival at 24 weeks was 86%; 11 patients were continuing to participate in the study. Reasons for discontinuation included stem-cell transplantation (in 6 patients), disease progression (in 4 patients), and drug toxicity (in 2 patients). Analyses of pretreatment tumor specimens from 10 patients revealed copy-number gains in PDL1 and PDL2 and increased expression of these ligands. Reed-Sternberg cells showed nuclear positivity of phosphorylated STAT3, indicative of active JAK-STAT signaling. CONCLUSIONS: Nivolumab had substantial therapeutic activity and an acceptable safety profile in patients with previously heavily treated relapsed or refractory Hodgkin's lymphoma. (Funded by Bristol-Myers Squibb and others; ClinicalTrials.gov number, NCT01592370.).

The immunotherapy era of myeloma: monoclonal antibodies, vaccines, and adoptive T-cell therapies.

The treatment of multiple myeloma has evolved significantly over the last decades from primarily alkylator-based chemotherapeutic agents with minimal efficacy to the introduction of more effective agents including immune modulators and proteasome inhibitors, which have changed the landscape of therapy for this disease. We are now entering a new era that will increasingly integrate immunotherapy into standard treatment. This review discusses the current immune-based strategies currently approved, as well as various immune approaches being actively investigated including monoclonal antibodies, checkpoint inhibitors, vaccines, and adoptive T-cell therapies.

Allogeneic Blood or Marrow Transplantation with Post-Transplantation Cyclophosphamide as Graft-versus-Host Disease Prophylaxis in Multiple Myeloma.

Allogeneic blood or marrow transplantation (alloBMT) may lead to long-term disease control in patients with multiple myeloma (MM). However, historically, the use of alloBMT in MM has been limited by its high nonrelapse mortality (NRM) rates, primarily from graft-versus-host disease (GVHD). We previously demonstrated that post-transplantation cyclophosphamide (PTCy) decreases the toxicities of both acute and chronic GVHD after alloBMT. Here, we examine the impact of PTCy in patients with MM undergoing alloBMT at Johns Hopkins Hospital. From 2003 to 2011, 39 patients with MM underwent bone marrow or peripheral blood alloBMT from HLA-matched related/unrelated or haploidentical related donors after either myeloablative or nonmyeloablative conditioning. Post-transplantation GVHD prophylaxis consisted of cyclophosphamide (50 mg/kg) on days +3 and +4 with or without mycophenolate mofetil and tacrolimus. Engraftment was detected in 95% of patients, with neutrophil and platelet recovery at a median of 15 and 16 days, respectively. The cumulative incidences of acute grades 2 to 4 and grades 3 and 4 GVHD were .41 and .08, respectively, and no cases of grade 4 acute GVHD were observed. The cumulative incidence of chronic GVHD was .13. One patient succumbed to NRM. All cases of chronic GVHD involved extensive disease and 60% of these patients received systemic therapy with complete resolution. After alloBMT, the overall response rate was 62% with complete, very good partial, and partial response rates of 26%, 21%, and 15%, respectively. The median progression-free survival was 12 months and was associated with the depth of response but not cytogenetic risk. The estimated cumulative incidence of relapse was .46 (95% confidence interval [CI], .3 to .62) at 1 year and .56 (95% CI, .41 to .72) at 2 years. At last follow-up, 23% of patients remain without evidence of disease at a median follow-up of 10.3 years after alloBMT. The median overall survival was 4.4 years and the 5-year and 10-year overall survival probabilities were 49% (95% CI, 35% to 67%) and 43% (95% CI, 29% to 62%), respectively. The use of PTCy after alloBMT for MM is feasible and results in low NRM and GVHD rates. The safety of this approach may allow the development of novel post-transplantation maintenance strategies to improve long-term disease control.

Major Histocompatibility Mismatch and Donor Choice for Second Allogeneic Bone Marrow Transplantation.

Large alternative donor pools provide the potential for selecting a different donor for a second allogeneic (allo) bone or marrow transplant (BMT). As HLA disparity may contribute to the graft-versus-tumor effect, utilizing new mismatched haplotype donors may potentially improve the antitumor activity for relapsed hematologic malignancies despite a previous alloBMT. Data from patients who received a second alloBMT for relapsed hematologic malignancies at Johns Hopkins were analyzed. Outcomes were compared between patients who received a second allograft with the same MHC composition and those who received an allograft with a new mismatched haplotype. Loss of heterozygosity analysis was performed for patients with acute myeloid leukemia (AML) whose first allograft was haploidentical. Between 2005 and 2015, 40 patients received a second BMT for a relapsed hematologic malignancy. The median follow-up is 750 (range, 26 to 2950) days. The median overall survival (OS) in the cohort is 928 days (95% confidence interval [CI], 602 to not reached [NR]); median event-free survival (EFS) for the cohort is 500 days (95% CI, 355 to NR). The 4-year OS is 40% (95% CI, 25% to 64%), and the 4-year EFS is 36% (95% CI, 24% to 55%). The cumulative incidence of nonrelapsed mortality by 2 years was 27% (95% CI, 13% to 42%). The cumulative incidence of grade 3 to 4 acute graft-versus-host disease (GVHD) at 100 days was 15% (95% CI, 4% to 26%); the cumulative incidence of extensive chronic GVHD at 2 years was 22% (95% CI, 9% to 36%). The median survival was 552 days (95% CI, 376 to 2950+) in the group who underwent transplantation with a second allograft that did not harbor a new mismatched haplotype, while it was not reached in the group whose allograft contained a new mismatched haplotype (hazard ratio [HR], .36; 95% CI, .14 to .9; P = .02). EFS was also longer in the group who received an allograft containing a new mismatched haplotype, (NR versus 401 days; HR, .50; 95% CI, .22 to 1.14; P = .09). Although the allograft for this patient's second BMT contained a new mismatched haplotype, AML nevertheless relapsed a second time. Second BMTs are feasible and provide a reasonable chance of long-term survival. An allograft with a new mismatched haplotype may improve outcomes after second BMTs for relapsed hematologic malignancies.

Impaired B cell immunity in acute myeloid leukemia patients after chemotherapy.

BACKGROUND: Changes in adaptive immune cells after chemotherapy in adult acute myeloid leukemia (AML) may have implications for the success of immunotherapy. This study was designed to determine the functional capacity of the immune system in adult patients with AML who have completed chemotherapy and are potential candidates for immunotherapy. METHODS: We used the response to seasonal influenza vaccination as a surrogate for the robustness of the immune system in 10 AML patients in a complete remission post-chemotherapy and performed genetic, phenotypic, and functional characterization of adaptive immune cell subsets. RESULTS: Only 2 patients generated protective titers in response to vaccination, and a majority of patients had abnormal frequencies of transitional and memory B-cells. B-cell receptor sequencing showed a B-cell repertoire with little evidence of somatic hypermutation in most patients. Conversely, frequencies of T-cell populations were similar to those seen in healthy controls, and cytotoxic T-cells demonstrated antigen-specific activity after vaccination. Effector T-cells had increased PD-1 expression in AML patients least removed from chemotherapy. CONCLUSION: Our results suggest that while some aspects of cellular immunity recover quickly, humoral immunity is incompletely reconstituted in the year following intensive cytotoxic chemotherapy for AML. The observed B-cell abnormalities may explain the poor response to vaccination often seen in AML patients after chemotherapy. Furthermore, the uncoupled recovery of B-cell and T-cell immunity and increased PD-1 expression shortly after chemotherapy might have implications for the success of several modalities of immunotherapy.

Risk-stratified outcomes of nonmyeloablative HLA-haploidentical BMT with high-dose posttransplantation cyclophosphamide.

Related HLA-haploidentical blood or marrow transplantation (BMT) with high-dose posttransplantation cyclophosphamide (PTCy) is being increasingly used because of its acceptable safety profile. To better define outcomes of nonmyeloablative (NMA) HLA-haploidentical BMT with PTCy, 372 consecutive adult hematologic malignancy patients who underwent this procedure were retrospectively studied. Risk-stratified outcomes were evaluated using the refined Disease Risk Index (DRI), developed to stratify disease risk across histologies and allogeneic BMT regimens. Patients received uniform conditioning, T-cell-replete allografting, then PTCy, mycophenolate mofetil, and tacrolimus. Six-month probabilities of nonrelapse mortality and severe acute graft-versus-host disease were 8% and 4%. With 4.1-year median follow-up, 3-year probabilities of relapse, progression-free survival (PFS), and overall survival (OS) were 46%, 40%, and 50%, respectively. By refined DRI group, low (n = 71), intermediate (n = 241), and high/very high (n = 60) risk groups had 3-year PFS estimates of 65%, 37%, and 22% (P < .0001), with corresponding 3-year OS estimates of 71%, 48%, and 35% (P = .0001). On multivariable analyses, the DRI was statistically significantly associated with relapse, PFS, and OS (each P < .001). This analysis demonstrates that the DRI effectively risk stratifies recipients of NMA HLA-haploidentical BMT with PTCy and also suggests that this transplantation platform yields similar survivals to those seen with HLA-matched BMT.

Comparable composite endpoints after HLA-matched and HLA-haploidentical transplantation with post-transplantation cyclophosphamide.

Composite endpoints that not only encompass mortality and relapse, but other critical post-transplant events such as graft-versus-host disease, are being increasingly utilized to quantify survival without significant morbidity after allogeneic blood or marrow transplantation. High-dose, post-transplantation cyclophosphamide reduces severe graft-versus-host disease with allogeneic marrow transplantation, making composite endpoints after this management particularly interesting. We retrospectively analyzed 684 adults with hematologic malignancies who received T-cell-replete bone marrow grafts and cyclophosphamide after myeloablative HLA-matched related (n=192) or unrelated (n=120), or non-myeloablative HLA-haploidentical (n=372) donor transplantation. The median follow up was 4 (range, 0.02-11.4) years. Graft-versus-host disease-free, relapse-free survival was defined as the time after transplantation without grade III-IV acute graft-versus-host disease, chronic graft-versus-host disease requiring systemic treatment, relapse, or death. Chronic graft-versus-host disease-free, relapse-free survival was defined as the time after transplantation without moderate or severe chronic graft-versus-host disease, relapse, or death. One-year graft-versus-host disease-free, relapse-free survival and chronic graft-versus-host disease-free, relapse-free survival estimates were, respectively, 47% (95% CI: 41-55%) and 53% (95% CI: 46-61%) after myeloablative HLA-matched related, 42% (95% CI: 34-52%) and 52% (95% CI: 44-62%) after myeloablative HLA-matched unrelated, and 45% (95% CI: 40-50%) and 50% (95% CI: 45-55%) after non-myeloablative HLA-haploidentical donor transplantation. In multivariable models, there were no differences in graft-versus-host disease-free, or chronic graft-versus-host disease-free, relapse-free survival after either myeloablative HLA-matched unrelated or non-myeloablative HLA-haploidentical, compared with myeloablative HLA-matched related donor transplantation. Although limited by inclusion of dissimilar cohorts, we found that post-transplantation cyclophosphamide-based platforms yield comparable composite endpoints across conditioning intensity, donor type, and HLA match.

Growth differentiating factor 15 enhances the tumor-initiating and self-renewal potential of multiple myeloma cells.

Disease relapse remains a major factor limiting the survival of cancer patients. In the plasma cell malignancy multiple myeloma (MM), nearly all patients ultimately succumb to disease relapse and progression despite new therapies that have improved remission rates. Tumor regrowth indicates that clonogenic growth potential is continually maintained, but the determinants of self-renewal in MM are not well understood. Normal stem cells are regulated by extrinsic niche factors, and the tumor microenvironment (TME) may similarly influence tumor cell clonogenic growth and self-renewal. Growth differentiation factor 15 (GDF15) is aberrantly secreted by bone marrow stromal cells (BMSCs) in MM. We found that GDF15 is produced by BMSCs after direct contact with plasma cells and enhances the tumor-initiating potential and self-renewal of MM cells in a protein kinase B- and SRY (sex-determining region Y)-box-dependent manner. Moreover, GDF15 induces the expansion of MM tumor-initiating cells (TICs), and changes in the serum levels of GDF15 were associated with changes in the frequency of clonogenic MM cells and the progression-free survival of MM patients. These findings demonstrate that GDF15 plays a critical role in mediating the interaction among mature tumor cells, the TME, and TICs, and strategies targeting GDF15 may affect long-term clinical outcomes in MM.

Single-agent GVHD prophylaxis with posttransplantation cyclophosphamide after myeloablative, HLA-matched BMT for AML, ALL, and MDS.

High-dose, posttransplantation cyclophosphamide (PTCy) reduces severe graft-versus-host disease (GVHD) after allogeneic blood or marrow transplantation (alloBMT), but the impact of PTCy on long-term, disease-specific outcomes is unclear. We conducted a retrospective study of 209 consecutive adult patients transplanted for acute myeloid leukemia (AML, n = 138), myelodysplastic syndrome (n = 28), or acute lymphoblastic leukemia (ALL, n = 43) using PTCy as sole GVHD prophylaxis after myeloablative conditioning and HLA-matched-related or -unrelated T-cell-replete allografting. At alloBMT, 30% of patients were not in morphologic complete remission. The cumulative incidences of grades II to IV and III to IV acute GVHD at 100 days and chronic GVHD at 2 years were 45%, 11%, and 13%, respectively. Forty-three percent of patients did not require immunosuppression for any reason beyond PTCy. At 3 years, relapse cumulative incidence was 36%, disease-free survival was 46%, survival free of disease and chronic GVHD was 39%, and overall survival was 58%. Lack of remission at alloBMT, adverse cytogenetics, and low allograft nucleated cell dose were associated with inferior survival for AML patients. Minimal residual disease but not t(9;22) was associated with inferior outcomes for ALL patients. The ability to limit posttransplantation immunosuppression makes PTCy a promising transplantation platform for the integration of postgrafting strategies to prevent relapse.