Safety and Toxicity Profiles of CAR T Cell Therapy in Non-Hodgkin Lymphoma: A Systematic Review and Meta-Analysis

BACKGROUND

The application of CD19-directed chimeric antigen receptor T (CAR T) cell therapy has improved outcomes for thousands of patients with non-Hodgkin B cell lymphoma (NHL). The toxicities associated with various CAR T cell products, however, can be severe and difficult to anticipate.

METHODS

In this systematic review and meta-analysis, we set out to determine whether there are measurable differences in common toxicities, including cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS), cytopenias, and infections, between CAR T products that are commercially available for the treatment of NHL.

RESULTS

After a stringent study selection process, we used a cohort of 1364 patients enrolled in 15 prospective clinical trials investigating the use of axicabtagene ciloleucel (axi-cel), lisocabtagene maraleucel (liso-cel), and tisagenlecleucel (tisa-cel). We found that the rates of CRS and ICANS were significantly higher with axi-cel as compared to both liso-cel and tisa-cel. Conversely, we demonstrated that rates of all-grade and severe neutropenia were significantly greater with liso-cel. Febrile neutropenia and all-grade infection rates did not differ significantly between products though rates of severe infection were increased with axi-cel.

CONCLUSIONS

Overall, this study serves as the first to delineate toxicity profiles associated with various available CAR T products. By better understanding associated toxicities, it may become possible to tailor therapies towards individual patients and anticipate the development of toxicities at earlier stages.

Primary central nervous system post-transplant lymphoproliferative disorder after allogeneic stem cell transplantation: a case report

Purpose

Primary central nervous system, diffuse large B-cell lymphoma, post-transplant lymphoproliferative disorder in the cerebellopontine angle after an allogeneic stem cell transplantation has never been reported in the literature. Typically, diffuse large B-cell lymphoma is non-polyploid. We report the first case of a patient with polyploid post-transplant lymphoproliferative disorder in the cerebellopontine angle who presented with back pain.

Case presentation

A 45-year-old man with a history of nodular sclerosing classic Hodgkin lymphoma stage IIB treated with systemic chemotherapy, external radiation and autologous stem cell transplant and double umbilical cord allogeneic transplant presented with several weeks of back pain. He was found to have a small right cerebellopontine angle mass thought to be consistent with a meningioma. Patient presented again two weeks later with acute onset of severe headache, right sided ptosis, right facial numbness, weakness and possible seizure event. Repeat MRI scans showed an interval and significant increase of the right cerebellopontine angle lesion. Biopsy of the cerebellopontine angle lesion was planned with suspicion of lymphoma. Intraoperative pathology consultation findings were not consistent with an acoustic neuroma, meningioma, or epidermoid cyst. Lymphoma could not be definitively identified by intra-operative frozen section. However, it was suspected, and a portion of fresh specimen was submitted for flow cytometry analysis. A near total resection of the tumor and decompression of the brainstem was achieved. Final pathologic analysis was positive for post-transplant lymphoproliferative disorder, monomorphic type, diffuse large B-cell lymphoma, non-germinal center B-cell type, EBV+, post-transplant (allogeneic stem cell) setting (post-transplant lymphoproliferative disorder (PTLD), monomorphic type, diffuse large B-cell lymphoma, non-germinal center B-cell type (non-GCB), EBV-positive under pre-2022 WHO terminology). The patient began a high-dose methotrexate-based regimen (the MATRIX regimen).

Conclusions

Our case illustrates an unusual presentation of post-transplant lymphoproliferative disorder in the cerebellopontine angle in a patient with a remote history of allogeneic stem cell transplantation. It demonstrates the importance of keeping primary central nervous system post-transplant lymphoproliferative disorder on the differential for patients who present with back pain or headache that have a history of allogeneic stem cell transplant.

Efficacy and Toxicity of CD19 Chimeric Antigen Receptor T Cell Therapy for Lymphoma in Solid Organ Transplant Recipients: A Systematic Review and Meta-Analysis

The safety and efficacy of chimeric antigen receptor (CAR) T cell therapy in solid organ transplant recipients is poorly understood, given the paucity of available data in this patient population. There is a theoretical risk of compromising transplanted organ function with CAR T cell therapy; conversely, organ transplantation-related immunosuppression can alter the function of CAR T cells. Given the prevalence of post-transplantation lymphoproliferative disease, which often can be difficult to treat with conventional chemoimmunotherapy, understanding the risks and benefits of delivering lymphoma-directed CAR T cell therapy in solid organ transplant recipients is of utmost importance. We sought to determine the efficacy of CAR T cell therapy in solid organ transplant recipients as well as the associated adverse effects, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and compromised solid organ transplant function. We conducted a systematic review and meta-analysis of adult recipients of solid organ transplant who received CAR T cell therapy for non-Hodgkin lymphoma. Primary outcomes included efficacy, defined as overall response (OR), complete response (CR), progression-free survival, and overall survival, as well as rates of CRS and ICANS. Secondary outcomes included rates of transplanted organ loss, compromised organ function, and alterations to immunosuppressant regimens. After a systematic literature review and 2-reviewer screening process, we identified 10 studies suitable for descriptive analysis and 4 studies suitable for meta-analysis. Among all patients, 69% (24 of 35) achieved a response to CAR T cell therapy, and 52% (18 of 35) achieved a CR. CRS of any grade occurred in 83% (29 of 35), and CRS grade ≥3 occurred in 9% (3 of 35). Sixty percent of the patients (21 of 35) developed ICANS, and 34% (12 of 35) developed ICANS grade ≥3. The incidence of any grade 5 toxicity among all patients was 11% (4 of 35). Fourteen percent of the patients (5 of 35) experienced loss of the transplanted organ. Immunosuppressant therapy was held in 22 patients but eventually restarted in 68% of them (15 of 22). Among the studies included in the meta-analysis, the pooled OR rate was 70% (95% confidence interval [CI], 29.2% to 100%; I2 = 71%) and the pooled CR rate was 46% (95% CI, 25.4% to 67.8%; I2 = 29%). The rates of any grade CRS and grade ≥3 CRS were 88% (95% CI, 69% to 99%; I2 = 0%) and 5% (95% CI, 0% to 21%; I2 = 0%), respectively. The rates of any grade ICANS and ICANS grade ≥3 were 54% (95% CI, 9% to 96%; I2 = 68%) and 40% (95% CI, 3% to 85%; I2 = 63%), respectively. The efficacy of CAR T cell therapy in solid organ transplant recipients is comparable to that in the general population as reported in prior investigational studies, with an acceptable toxicity profile in terms of CRS, ICANS, and transplanted organ compromise. Further studies are needed to determine long-term effects on organ function, sustained response rates, and best practices peri-CAR T infusion period in this patient population.

Acute hemolytic anemia after hematopoietic stem cell transplantation: An unusual invader

69-year-old man with a history of diffuse large B-cell lymphoma (DLBCL) presented with severe acute hemolytic anemia 27 months after an autologous hematopoietic stem cell transplantation. Bone marrow aspirate revealed intracellular micro-organisms (arrows) located within the cytoplasm of red blood cells confirming the diagnosis of severe babesiosis.

Reducing central-line associated bloodstream infections (CLABSIs) through patient accountability contracts: A pilot project for patients on Weill Cornell Medicine (WCM) bone marrow transplant (BMT) service

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Background: Patients with cancer whom develop Central Line Associated Blood Stream Infections (CLABSIs) have increased mortality rates ranging from 12% to 40%. Transplant patients are particularly at risk due to cytotoxic chemotherapy regimens and/or graft-versus-host disease with risk for translocation of oral and gut flora to the bloodstream. At Weill Cornell Medicine, we had 102 CLABSIs in 2021, 25 (25%) of which attributed to patients in oncology units. The Bone Marrow Transplant (BMT) Unit, had 10 of the 25 (40%), 2.05 CLABSIs per 1000 central line inpatient days with a CLABSI standardized infection ratio (SIR) of 1.26 (above goal of 1). Methods: Our SMART aim was to reduce the number and rate of CLABSI events on the BMT unit by 10% from February 1, 2022 – June 30, 2022 by educating patients on preventive strategies and implementing a patient central-line maintenance “contract.” We had previously optimized evidence-based nursing interventions for CLABSI prevention which included adherence to central line maintenance best practices, weekly device rounds with Infection, Protection & Control to monitor compliance with dressing changes and IV tubing, annual CLABSI prevention competencies, peer-to-peer validation of blood culture lab draws, weekly quality-improvement huddles and interdisciplinary root cause analysis discussions for CLABSI events. Patient noncompliance with daily recommendations for central line care was identified as a possible CLABSI risk factor that was not previously addressed in the bundle. Newly-developed patient education and a “contract” was incorporated into the BMT admission process. Results: The BMT CLABSI patient education and contract was initiated with all new patients admitted to unit in February 1, 2022. Since starting, the BMT unit CLABSI SIR has decreased from 1.26 to 0.6, and from a CLABSI rate per 1000 central lines days of 2.05 to 0.97. Conclusions: Engaging patients in their own care of the central lines can significantly reduce overall risk of central line infections. Patients have positively responded to this pilot project. We have translated educational materials and contracts to other languages and are considering expansion into other units.

Adenovirus viremia after in vivo T-cell depleted allo-transplant in adults: low lymphocyte counts are associated with uncontrolled viremia and fatal outcomes

The incidence of adenovirus viremia and the role of screening in preventing adenovirus disease in adult transplant recipients are not well defined. Between January 2017 and May 2020, 262 allogeneic transplants were performed using in vivo T-cell depletion. Adenovirus viremia was found in 59 patients for a cumulative incidence of 10% by one hundred days and 23% (95% CI 20-26%) by one year. There was a higher incidence of viremia associated with cord blood transplant (p = .04). No other patient, donor or transplant characteristics were identified that predicted for viremia. In 47 patients (80%), viremia remained well below 200,000 copies/mL and resolved. Twelve patients developed high level viremia. Treatment with antivirals and in some cases adoptive cell therapy, was often ineffective and only two survived. Low lymphocyte count at initial detection of adenovirus viremia was the best predictor of uncontrolled disease.

High-dose lenalidomide and melphalan as conditioning for autologous stem cell transplantation in relapsed or refractory multiple myeloma

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Background: Autologous stem cell transplantation (ASCT) remains a standard of care of eligible patients with multiple myeloma, despite the many novel therapies introduced over the past decade. High dose melphalan (HDM) is the only approved regimen to date. Lenalidomide (LEN) is an oral immunomodulatory drug which has become the backbone of myeloma therapy from induction through salvage and maintenance. Early studies noted a dose response relationship, and found myelosuppression to be the dose limiting toxicity. We previously reported on our phase 1 study of high dose lenalidomide (HDLEN) with HDM in conditioning for ASCT, where no DLT was noted up to 350mg PO daily of LEN. Here we report the phase 2 data of patients undergoing ASCT with combination conditioning regimen. Methods: 50 patients with relapsed/refractory multiple myeloma (RRMM) underwent ASCT using HDLEN+HDM conditioning. HDLEN was dosed at 350mg PO daily from day -5 to day -1 and HDM was dosed 100mg/m2 on days -2 and -1. TPatients were heavily pre-treated: 32% had prior HDM-ASCT, 96% had received prior lenalidomide, and 42% prior pomalidomide; 40% prior anti-CD38 mAB. Of note, 68% entered the study with progressive disease at time of enrollment. Results: Overall response rate was 96%, with 80% being ≥VGPR. Median progression free survival (PFS) was noted at 14.3 months, while overall survival (OS) was 68.2 months. PFS was similar when patients were stratified by prior ASCT, depth of response at enrollment, or presence of high risk FISH. Toxicities were mostly hematologic (100% neutropenia and thrombocytopenia, 90% anemia), GI (88% diarrhea, 72% nausea, 42% vomiting) and metabolic (30-96% derangement in electrolytes), and similar to historical controls receiving HDM alone. Second malignancies were noted in 2 patients. Conclusions: HDLEN/HDM is a well tolerated and effective conditioning regimen for ASCT in patients with RRMM. This regimen merits further investigation as ASCT is likely to remain an integral part of the treatment of RRMM patients, yet few advancements have been made to this modality. HDLEN may be particularly useful in patients with high risk disease and those progressing after multiple lines of therapy. HDLEN added little toxicity to HDM and SPMs were not more frequent than expected per SEER database for patients in this age range. Clinical trial information: NCT01054196. [Table: see text]

Impact of a Multiplexed Polymerase Chain Reaction Panel on Identifying Diarrheal Pathogens in Hematopoietic Cell Transplant Recipients

BACKGROUND

Diarrhea is common and associated with substantial morbidity among hematopoietic cell transplant (HCT) recipients, but the etiology is often not identified. Multiplexed polymerase chain reaction (PCR) assays increase the detection of diarrheal pathogens, but the impact of this technology in this population has not been evaluated.

METHODS

Our center replaced stool cultures and other conventional microbiologic methods with the FilmArray Gastrointestinal Panel (GI PCR) in June 2016. We reviewed all adult patients who received an HCT from June 2014-May 2015 (pre-GI PCR, n = 163) and from June 2016-May 2017 (post-GI PCR, n = 182) and followed them for 1 year after transplantation. Clostridioides difficile infection was diagnosed by an independent PCR test in both cohorts.

RESULTS

The proportion of patients with ≥1 identified infectious diarrheal pathogen increased from 25% to 37% after implementation of GI PCR (P = .01). Eight patients (5%) in the pre-GI PCR cohort tested positive for a pathogen other than C. difficile versus 49 patients (27%) in the post-GI PCR cohort (P < .001). The most common non-C. difficile diarrheal pathogens in the post-GI PCR cohort were enteropathogenic Escherichia coli (n = 14, 8%), norovirus (n = 14, 8%), and Yersinia enterocolitica (n = 7, 4%). The percentage of diarrheal episodes with an identified infectious etiology increased from 14% to 23% (P = .001). Median total costs of stool testing per patient did not increase (pre: $473; post: $425; P = .25).

CONCLUSIONS

Infectious etiologies of diarrhea were identified in a higher proportion of HCT recipients after replacing conventional stool testing with a multiplexed PCR assay, without an increase in testing costs.

Sequential intensive chemotherapy followed by autologous or allogeneic transplantation for refractory lymphoma

We evaluate the safety of bendamustine as a bridge to stem cell transplantation (SCT) in patients with relapsed/refractory lymphoma and residual disease after salvage therapy. Thirty-four subjects without complete responses (CR) received bendamustine 200 mg/m²/day for 2 days followed 14 days later by SCT. Sixteen subjects in partial remission (PR) with maximal FDG-PET SUVs ≤8 prior to bendamustine received autologous SCT, while 13 with suboptimal responses were allografted. Five subjects did not proceed to transplant. No bendamustine toxicities precluded transplantation and no detrimental effect on engraftment or early treatment-related mortality (TRM) was attributable to bendamustine. At 1 year, 75% of auto-recipients and 31% of allo-recipients were alive with CR. Two subjects in the autologous arm developed therapy-related myeloid neoplasia (t-MN). In conclusion, a bendamustine bridge to SCT can be administered without early toxicity to patients with suboptimal responses to salvage chemotherapy. However this approach may increase the risk of t-MN. (NCT02059239).Supplemental data for this article is available online at here.

Hematology and oncology clinical care during the coronavirus disease 2019 pandemic

New York City has been at the epicenter of the coronavirus disease 2019 (COVID-19) pandemic that has already infected over a million people and resulted in more than 70,000 deaths as of early May 2020 in the United States alone. This rapid and enormous influx of patients into the health care system has had profound effects on all aspects of health care, including the care of patients with cancer. In this report, the authors highlight the transformation they underwent within the Division of Hematology and Medical Oncology as they prepared for the COVID-19 crisis in New York City. Under stressful and uncertain conditions, some of the many changes they enacted within their division included developing a regular line of communication among division leaders to ensure the development and implementation of a restructuring strategy, completely reconfiguring the inpatient and outpatient units, rapidly developing the ability to perform telemedicine video visits, and creating new COVID-rule-out and COVID-positive clinics for their patients. These changes allowed them to manage the storm while minimizing the disruption of important continuity of care to their patients with cancer. The authors hope that their experiences will be helpful to other oncology practices about to experience their own individual COVID-19 crises.

Outcomes of Allogeneic Stem Cell Transplant for Elderly Patients with Hematologic Malignancies

Reduced-intensity conditioning (RIC) regimens, improved HLA matching, and better supportive care allow allogeneic stem cell transplant (alloSCT) to be offered to older patients. Only a small percentage of eligible patients between ages 65 and 74 years actually undergo alloSCT, and comprehensive outcome data from the aging population are still lacking. We examined the outcome of older patients who underwent alloSCT using melphalan-based RIC for hematologic malignancies at our institution. We identified 125 patients older than 65 years (median, 69; range, 66 to 77) who underwent matched related donor, matched unrelated donor, or combined haploidentical/umbilical cord alloSCT between 2012 through November, 2017. Among them, 52 (41.6%) and 70 (56%) had, respectively, intermediate and high/very high Center for International Blood and Marrow Transplant Research (CIBMTR) disease risk index (DRI). One hundred six patients (85%) received fludarabine/melphalan-based RIC regimen with either antithymocyte globulin (ATG) or alemtuzumab. The median time to neutrophil engraftment was 13 days (range, 8 to 37) and platelet engraftment 17 days (range, 9 to 169). The cumulative incidence of nonrelapse mortality was 11.5% at 100 days and 30.1% and 34.8% at 1 and 2 years, respectively. The cumulative incidence of relapse was 35% and 40% at 1 and 2 years. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) at day 100 and 6 months was 29.5% and 34.5%, and chronic GVHD at 6, 12, and 24 months was 2.5%, 5.2%, and 6.3%, respectively. With a median follow-up of 32 months, the 1-, 2-, and 3-year progression-free survival (PFS) was 34.6%, 24.4%, and 16.5%, respectively. The graft GVHD-free survival was 24.6%, 16.1%, and 9.3%, respectively. The 1-, 2-, and 3-year overall survival (OS) was 44.5%, 30.7%, and 26.5%, respectively. In multivariable analysis, low albumin was predictive of poor PFS and OS and high hematopoietic cell transplantation-specific comorbidity index, and CIBMTR DRI was predictive of worse graft GVHD-free survival. Among long-term survivors the median Karnofsky performance status was 80. Older patients, even when referred with advanced disease, can benefit from melphalan-based alloSCT with HLA-matched or alternative donor sources without discernible impact of donor source on outcome. Using alemtuzumab- or ATG-based in vivo T cell depletion, the incidence of chronic GVHD is extremely low. Performance status in survivors is excellent. Better predictors for outcome in this patient population need to be identified.

2695. Pneumocystis jirovecii Pneumonia in the Era of Effective Prophylaxis Following Hematopoietic Stem Cell Transplant

Background

Pneumocystis jirovecii pneumonia is an uncommon and life-threatening disease that can occur following hematopoietic stem cell transplantation (HSCT). Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis greatly reduces the incidence of PJP. We aim to determine what factors contribute to the development of PJP following HSCT where TMP-SMX prophylaxis is widely used.

Methods

We performed a single-center, retrospective case series of HSCT recipients from January 1, 2012 to December 31, 2018. Subjects had clinical symptoms and radiographic evidence for PJP along with at least one positive Pneumocystis test obtained from bronchoalveolar lavage (BAL) including direct fluorescence antibody (DFA), quantitative polymerase chain reaction (qPCR), cytology, and pathology.

Results

1111 subjects underwent HSCT; of whom, 25 (2.2%) met inclusion criteria and were treated for PJP. 6 were autologous and 19 were allogeneic HSCT recipients (1.23% and 3.05% of total autologous and allogeneic HSCT, respectively). All allogeneic HSCT recipients received in-vivo T-cell depletion. Median duration from autologous and allogeneic HSCT to PJP diagnosis were 138 days (range 20 to 348) and 346 days (range 41 to 771), respectively. PJP qPCR was positive in all samples tested (n = 20, range < 84 to 14900). DFA was positive in 6 (28%). Death from pneumonia occurred in 2 subjects; 11 (44%) required ICU stay, and 7 (27%) required intubation. At diagnosis, 3 subjects had relapse of underlying disease and 10 were on immunosuppression. 12 were on PJP prophylaxis (autologous HSCT n = 3), the most common of which was atovaquone (n = 5); only 2 subjects were on TMP-SMX. Cytomegalovirus (CMV) viremia was detected in 9 subjects (36%) prior to PJP diagnosis; 4 had pulmonary CMV coinfection. In total, 17 subjects (68%) had one of the above risk factors for PJP. Median total lymphocyte count and % lymphocytes were 5.1 × 10³ cells/μL (range 1.4 to 38.5 × 10³ cells/μL) and 9.6% (range 1.1 to 29.5%), respectively.

Conclusion

PJP is an uncommon (2.2% of the study population) complication of HSCT while receiving PJP prophylaxis and in the absence of disease relapse, CMV reactivation, or ongoing immunosuppression. Presentation is often delayed in this population; a high degree of clinical suspicion should prompt diagnostic evaluation using a combination of laboratory tests on BAL fluid.

Disclosures

All authors: No reported disclosures.

Haploidentical vs haplo-cord transplant in adults under 60 years receiving fludarabine and melphalan conditioning

Haplo-identical transplant with posttransplant cyclophosphamide (haplo) and umbilical cord blood transplant supported by third-party CD34 cells (haplo-cord) are competing approaches to alternative donor transplant. We compared, in adults younger than age 60 years, the outcomes of 170 haplo at 1 institution with that of 137 haplo-cord at 2 other institutions. All received reduced intensity conditioning with fludarabine and melphalan ± total body irradiation. GVHD prophylaxis for haplo consisted of cyclophosphamide, tacrolimus, and mycophenolate, whereas haplo-cord received antithymocyte globulin, tacrolimus, and mycophenolate. Haplo transplant used mostly bone marrow, and peripheral blood stem cells were used in haplo-cord transplants. Haplo-cord were older and had more advanced disease. Haplo-cord hastened median time to neutrophil (11 vs 18 days, P = .001) and platelet recovery (22 vs 25 days, P = .03). At 4 years, overall survival (OS) was 50% for haplo-cord vs 49% for haplo. Progression-free survival (PFS) was 40% for haplo-cord vs 45% for haplo. In multivariate analysis, the disease risk index was significant for OS (hazard ratio, 1.8; 95% confidence interval, 1.48-2.17; P = .00) and PFS. Total body irradiation was associated with decreased recurrence and improved PFS, age >40 with increased nonrelapse mortality. The type of transplant had no effect on OS, PFS, relapse, or nonrelapse mortality. Cumulative incidence of grade 2-4 acute graft-versus-host disease (GVHD) by day 100 was 16% after haplo-cord vs 33% after haplo (P < .0001), but grade 3-4 GVHD was similar. Chronic GVHD at 1 year was 4% after haplo-cord vs 16% after haplo (P < .0001). Haplo or haplo-cord results in similar and encouraging outcomes. Haplo-cord is associated with more rapid neutrophil and platelet recovery and lower acute and chronic GVHD. Institutional review board authorization for this retrospective study was obtained at each institution. Some patients participated in trials registered at www.clinicaltrials.gov as #NCT01810588 and NCT01050946.

Adoptive Immunotherapy with Cord Blood for the Treatment of Refractory Acute Myelogenous Leukemia: Feasibility, Safety, and Preliminary Outcomes

Adoptive immunotherapy has shown efficacy in patients with relapsed/refractory acute myelogenous leukemia (AML). We conducted a prospective evaluation of cord blood (CB)-based adoptive cell therapy following salvage chemotherapy in patients with AML or myelodysplastic syndrome (MDS) and describe the safety and early outcomes of this approach. To enhance the antileukemic effect, we selected CB units (CBUs) with a shared inherited paternal antigen (IPA) and/or noninherited maternal antigen (NIMA) match with the recipients. Furthermore, the CBUs had total nucleated cell (TNC) dose <2.5 × 10⁷/kg and were at least 4/6 HLA-matched with the patients; a higher allele-level match was preferred. Heavily pretreated adult patients with AML/MDS were enrolled. CBU searches were performed for 50 patients. CBUs with shared IPA targets were identified for all, and CBUs with NIMA matches were found for 80%. Twenty-one patients underwent treatment (AML, primary induction failure, n = 8; refractory relapse, n = 10, including 7 recipients of previous allogeneic HSCT; blast crisis chronic myelogenous leukemia, n = 1; MDS, n = 2). Most received combination chemotherapy; those not fit for intensive treatment received a hypomethylating agent. Response was defined as <10% residual blasts in hypocellular bone marrow at approximately 2 weeks after treatment. Ten of the 19 evaluable patients responded, including 5 of the 7 recipients of previous transplant. Response was seen in 4 of 4 patients with full CBU-derived chimerism, 2 of 2 of those with partial, low-level chimerism and 4 of 12 of the recipients with no detectable CBU chimerism. The most common adverse events were infections (bacterial, n = 5; viral, n = 2; fungal, n = 5). Grade IV acute graft-versus-host disease (GVHD) developed in 2 patients with full CBU chimerism; 2 other patients had grade 1 skin GVHD. A total of 11 patients died, 7 from disease recurrence and 4 from infections (1 early death; the other 3 in remission at the time of death). Overall, 12 patients proceeded to allogeneic HSCT; of those, 7 had responded to treatment, 3 had not (and had received additional therapy), and 2 had persistent minimal residual disease. In conclusion, the use of CB as adoptive immunotherapy in combination with salvage chemotherapy for patients with refractory AML/MDS is feasible, can induce disease control, can serve as a bridge to allogeneic HSCT, and has an acceptable incidence of adverse events. Alloreactivity was enhanced through the selection of CBUs targeting a shared IPA and/or NIMA match with the patients. CBUs with lower cell doses, already available in the CB bank and unlikely to be adequate grafts for adult transplants, can be used for cell therapy within a short time frame.

Bortezomib and Immune Globulin Have Limited Effects on Donor-Specific HLA Antibodies in Haploidentical Cord Blood Stem Cell Transplantation: Detrimental Effect of Persistent Haploidentical Donor-Specific HLA Antibodies

Donor-specific HLA antibodies (DSAs) have been associated with an increased risk of graft failure. To decrease DSA levels and reduce the risk of graft failure in haploidentical cord blood transplantation recipients, we studied the effect of bortezomib (BTZ) and i.v. immune globulin (IVIG) pretransplantation. Between 2012 and 2016, 14 patients with a DSA level >2000 mean fluorescence intensity (MFI) to 1 or more mismatched HLA alleles of haploidentical donors, cord blood donors, or both were treated with BTZ and IVIG. Fourteen patients received a median of 4 doses (range, 2 to 8 doses) of BTZ 1.3 mg/m² and a median total IVIG of 2 g/kg before transplantation. Only 2 of 14 patients attained a reduction in MFI to <2000 with this combination. After additional IVIG (n = 8), rituximab (n = 4), and/or plasmapheresis (n = 11), 12 of 14 patients were desensitized to a DSA level <2000 MFI at the time of engraftment. All obtained initial hematopoietic reconstitution, and no DSA rebound phenomenon was observed. Responders with DSA MFI <2000 to the haploidentical donor by transplantation engrafted at a rate comparable to that of historical controls, whereas engraftment in nonresponders took 3 times as long. BTZ and IVIG alone do not appear sufficient to rapidly induce DSA desensitization, and persistent DSAs to a haploidentical donor lead to delayed count recovery. Our data suggest that additional pretreatment with BTZ and IVIG in combination with the conditioning regimen may help abrogate the rebound phenomenon observed with plasmapheresis.

Final results from a defibrotide treatment-IND study for patients with hepatic veno-occlusive disease/sinusoidal obstruction syndrome

Hepatic veno‐occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life‐threatening complication of haematopoietic stem cell transplant (HSCT) conditioning and chemotherapy. Defibrotide is approved for treatment of hepatic VOD/SOS with pulmonary or renal dysfunction [i.e., multi‐organ dysfunction (MOD)] after HSCT in the United States and severe VOD/SOS after HSCT in patients aged older than 1 month in the European Union. Defibrotide was available as an investigational drug by an expanded‐access treatment programme (T‐IND; NCT00628498). In the completed T‐IND, the Kaplan–Meier estimated Day +100 survival for 1000 patients with documented defibrotide treatment after HSCT was 58·9% [95% confidence interval (CI), 55·7–61·9%]. Day +100 survival was also analysed by age and MOD status, and post hoc analyses were performed to determine Day +100 survival by transplant type, timing of VOD/SOS onset (≤21 or >21 days) and timing of defibrotide treatment initiation after VOD/SOS diagnosis. Day +100 survival in paediatric patients was 67·9% (95% CI, 63·8–71·6%) and 47·1% (95% CI, 42·3–51·8%) in adults. All patient subgroups without MOD had higher Day +100 survival than those with MOD; earlier defibrotide initiation was also associated with higher Day +100 survival. The safety profile of defibrotide in the completed T‐IND study was similar to previous reports.

Safety and efficacy of plerixafor dose escalation for the mobilization of CD34+ hematopoietic progenitor cells in patients with sickle cell disease: interim results

Gene therapy for sickle cell disease is limited by the yield of hematopoietic progenitor cells that can be harvested for transduction or gene editing. We therefore performed a phase I dose-escalation study of the hematopoietic progenitor cell mobilizing agent plerixafor to evaluate the efficacy and safety of standard dosing on peripheral blood CD34⁺ cell mobilization. Of 15 patients enrolled to date, only one was chronically transfused and ten were on hydroxyurea. Of eight patients who achieved a CD34⁺ cell concentration >30 cells/μL, six were on hydroxyurea. There was no clear dose response to increasing plerixafor dosage. There was a low rate of serious adverse events; two patients developed vaso-occlusive crises, at the doses of 80 μg/kg and 240 μg/kg. Hydroxyurea may have contributed to the limited CD34⁺ mobilization by affecting baseline peripheral blood CD34 counts, which correlated strongly with peak peripheral blood CD34 counts. Plerixafor administration did not induce significant increases in the fraction of activated neutrophils, monocytes, or platelets. However, increased neutrophils positive for activated β2 integrin and Mac-1 were associated with serious adverse events. In summary, plerixafor was well tolerated but did not achieve consistent CD34⁺ cell mobilization in this cohort of patients, most of whom were being actively treated with hydroxyurea and only one was chronically transfused. The study will continue with escalation of the dose of plerixafor and modification of hydroxyurea administration. Clinicaltrials.gov identifier: NCT02193191.

Reduced-Intensity Allogeneic Transplant for Acute Myeloid Leukemia and Myelodysplastic Syndrome Using Combined CD34-Selected Haploidentical Graft and a Single Umbilical Cord Unit Compared with Matched Unrelated Donor Stem Cells in Older Adults

Haplo/cord transplantation combines an umbilical cord blood (UCB) graft with CD34-selected haploidentical cells and results in rapid hematopoietic recovery followed by durable UCB engraftment. We compared outcomes of transplants in older patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndromes (MDS) who received either HLA-matched unrelated donor (MUD) cells or haplo/cord grafts. Between 2007 and 2013, 109 adults ages 50 and older underwent similar reduced-intensity conditioning with fludarabine and melphalan and antibody-mediated T cell depletion for AML (n = 83) or high-risk MDS (n = 26) followed by either a MUD (n = 68) or haplo/cord (n = 41) graft. Patient characteristics were similar for each graft source except for more minority patients receiving a haplo/cord transplant (P = .01). One half of the AML patients were not in remission. Two-year progression-free survival (PFS), overall survival (OS), and graft-versus-host disease-free relapse-free survival were 38%, 48%, and 32.1% for MUD and 33%, 48%, and 33.8% for haplo/cord transplants (P = .62 for PFS; P = .97 for OS; P= .84), respectively. Acute grades II to IV and chronic graft-versus-host-disease rates did not differ at 19.5% and 4.9% in haplo/cord compared with 25% and 7.4% after MUD (P = .53 and P = .62, respectively). Multivariate analysis confirmed no significant differences in transplant outcomes by donor type. Haplo/cord reduced-intensity transplantation achieves similar outcomes relative to MUD in older AML and MDS patients, making this a promising option for those without matched donors.

Validating and implementing the use of an infusion pump for the administration of thawed hematopoietic progenitor cells-a single-institution experience

BACKGROUND

Direct thaw and administration of previously cryopreserved peripheral blood stem cell products is a commonly used practice and should be performed rapidly to reduce cellular damage caused by dimethyl sulfoxide exposure. Cells are typically thawed at the bedside and infused by gravity through a high-flow-rate central venous catheter. An existing nontunneled catheter is occasionally used instead and often results in a slower infusion rate. To ensure expedient and consistent infusions, we validated and implemented the use of an infusion pump for thawed peripheral blood stem cells.

STUDY DESIGN AND METHODS

Validation was performed in two phases: in vitro simulation and in vivo clinical assessment. Total nucleated cell recovery and viability plus progenitor cell viability and potency were compared in vitro between two cryopreserved peripheral blood stem cell units that were either passed through a preset infusion pump or drained by gravity. The infusion rate, adverse events, and engraftment times were retrospectively compared between patients who received infusions by infusion pump (n = 35) and by gravity (n = 38).

RESULTS

No significant differences were observed in vitro between the infusion methods for all measured variables. Overall infusion rates were similar in vivo for both groups but were significantly lower for patients who had nontunneled catheters that delivered the infusion by gravity. The time to neutrophil and platelet engraftment was similar for both groups.

CONCLUSION

This is the first study to assess the use of an infusion pump for stem cell transplant. The use of an infusion pump for peripheral blood stem cell infusion is safe, provides a reliable and consistent infusion method, and can mitigate the effect of the type of venous access line used.

Granulocyte Colony-Stimulating Factor Use after Autologous Peripheral Blood Stem Cell Transplantation: Comparison of Two Practices

Administration of granulocyte colony-stimulating factor (G-CSF) after autologous peripheral blood stem cell transplantation (PBSCT) is generally recommended to reduce the duration of severe neutropenia; however, data regarding the optimal timing of G-CSFs post-transplantation are limited and conflicting. This retrospective study was performed at NewYork-Presbyterian/Weill Cornell Medical Center between November 5, 2013, and August 9, 2016, of adult inpatient autologous PBSCT recipients who received G-CSF empirically starting on day +5 (early) versus on those who received G-CSF on day +12 only if absolute neutrophil count (ANC) was <0.5 × 10⁹/L (ANC-driven). G-CSF was dosed at 300 µg in patients weighing <75 kg and 480 µg in those weighing ≥75 kg. One hundred consecutive patients underwent autologous PBSCT using either the early (n = 50) or ANC-driven (n = 50) G-CSF regimen. Patient and transplantation characteristics were comparable in the 2 groups. In the ANC-driven group, 24% (n = 12) received G-CSF on day +12 and 60% (n = 30) started G-CSF earlier due to febrile neutropenia or at the physician's discretion, 6% (n = 3) started after day +12 at the physician's discretion, and 10% (n = 5) did not receive any G-CSF. The median start day of G-CSF therapy was day +10 in the ANC-driven group versus day +5 in the early group (P < .0001). For the primary outcome, the median time to neutrophil engraftment was 12 days (interquartile range [IQR] 11-13 days) in the early group versus 13 days (IQR, 12-14 days) in the ANC-driven group (P = .07). There were no significant between-group differences in time to platelet engraftment, 1-year relapse rate, or 1-year overall survival. The incidence of febrile neutropenia was 74% in the early group versus 90% in the ANC-driven group (P = .04); however, there was no significant between-group difference in the incidence of positive bacterial cultures or transfer to the intensive care unit. The duration of G-CSF administration until neutrophil engraftment was 6 days in the early group versus 3 days in the ANC-driven group (P < .0001). The median duration of post-transplantation hospitalization was 15 days (IQR, 14-19 days) in the early group versus 16 days (IQR, 15-22 days) in the ANC-driven group (P = .28). Our data show that early initiation of G-CSF (on day +5) and ANC-driven initiation of G-CSF following autologous PBSCT were associated with a similar time to neutrophil engraftment, length of stay post-transplantation, and 1-year overall survival.

A Phase I Trial of High-Dose Lenalidomide and Melphalan as Conditioning for Autologous Stem Cell Transplantation in Relapsed or Refractory Multiple Myeloma

Autologous stem cell transplantation (ASCT) conditioned with high-dose chemotherapy has long been established as the standard of care for eligible patients with newly diagnosed multiple myeloma. Despite recent therapeutic advances, high-dose melphalan (HDM) remains the chemotherapy regimen of choice in this setting. Lenalidomide (LEN) in combination with low-dose dexamethasone is recognized as a standard of care for patients with relapsed or refractory multiple myeloma (RRMM), and there is growing support for the administration of LEN as maintenance therapy post-ASCT. In view of the above, the present phase I clinical trial was designed to evaluate the safety and tolerability of high-dose LEN (HDLEN) in patients with RRMM, and to determine the maximum tolerated dose of HDLEN when added to HDM before ASCT. Despite administering HDLEN at doses of up to 350 mg/day, the maximum tolerated dose could not be determined, owing to an insufficient number of dose-limiting toxicities in the 21 patients enrolled in the trial. Conditioning with HDLEN plus HDM was associated with a favorable tolerability profile. Adverse events following ASCT were as expected with HDM. Median progression-free and overall survival were 10 months and 22 months, respectively, in this population of heavily pretreated patients. Our findings suggest that HDLEN in combination with HDM may offer significant potential as a conditioning regimen before ASCT in patients with RRMM. These preliminary findings are now being evaluated further in an ongoing phase II clinical trial.

Defibrotide for Patients with Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome: Interim Results from a Treatment IND Study

Hepatic veno-occlusive disease, or sinusoidal obstruction syndrome (VOD/SOS), is a serious and potentially fatal complication of conditioning for hematopoietic stem cell transplantation (HSCT) or of chemotherapy regimens alone. Defibrotide is a complex mixture of single-stranded polydeoxyribonucleotides that is approved in the United States for treating hepatic VOD/SOS with renal or pulmonary dysfunction post-HSCT and in the European Union, Israel, and South Korea for treating severe hepatic VOD/SOS post-HSCT. Defibrotide was previously available in the United States as an investigational drug through a treatment protocol (treatment IND) study. Interim results of that large, treatment IND study of patients with VOD/SOS and with or without multiorgan dysfunction (MOD; also known as multiorgan failure) are presented here. Defibrotide was administered i.v. at 6.25 mg/kg every 6 hours (25 mg/kg/day), with a recommended treatment duration of at least 21 days. Enrolled patients (n = 681) were diagnosed with VOD/SOS based on Baltimore or modified Seattle criteria or liver biopsy analysis. Among the 573 HSCT recipients, 288 (50.3%; 95% confidence interval [CI], 46.2% to 54.4%) were alive at day +100 post-HSCT. Day +100 survival for the pediatric (≤16 years) and adult (>16 years) subgroups was 54.5% (95% CI, 49.1% to 60.0%; n = 174 of 319) and 44.9% (95% CI, 38.8% to 51.0%; n = 114 of 254), respectively. In the MOD subgroup, 159 of 351 patients (45.3%; 95% CI, 40.1% to 50.5%) of patients were alive at day +100 post-HSCT. Treatment with defibrotide was generally well tolerated, and drug-related toxicities were consistent with previous studies. Adverse events were reported in 69.6% of safety-evaluable patients (399 of 573). Other than VOD/SOS and associated MOD symptoms, the most commonly reported treatment-emergent adverse event was hypotension (13.8%). Day +100 survival results observed in this trial were consistent with results seen in previous trials of defibrotide for VOD/SOS in adult and pediatric patients. These data support the potential benefit of defibrotide in treating a VOD/SOS patient population that includes those with and without MOD.

Cord blood chimerism and relapse after haplo-cord transplantation

Haplo-cord stem cell transplantation combines the infusion of CD34 selected hematopoietic progenitors from a haplo-identical donor with an umbilical cord blood (UCB) graft from an unrelated donor and allows faster count recovery, with low rates of disease recurrence and chronic graft-versus-host disease (GVHD). But the contribution of the umbilical cord blood graft to long-term transplant outcome remains unclear. We analyzed 39 recipients of haplo-cord transplants with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), engrafted and in remission at 2 months. Median age was 66 (18-72) and all had intermediate, high, or very-high risk disease. Less than 20% UCB chimerism in the CD33 lineage was associated with an increased rate of disease recurrence (54% versus 11% p < 0.0001) and decrease in one year progression-free (20% versus 55%, p = 0.004) and overall survival (30% versus 62%, p = 0.02). Less than 100% UCB chimerism in the CD3 lineage was associated with increase rate of disease recurrence (46% versus 12%, p = 0.007). Persistent haplo-chimerism in the CD3 lineage was associated with an increased rate of disease recurrence (40% versus 15%, p = 0.009) Chimerism did not predict for treatment related mortality. The cumulative incidence of acute GVHD by day 100 was 43%. The cumulative incidence of moderate/severe chronic GVHD was only 5%. Engraftment of the umbilical cord blood grafts provides powerful graft-versus-leukemia (GVL) effects which protect against disease recurrence and is associated with low risk of chronic GVHD. Engraftment of CD34 selected haplo-identical cells can lead to rapid development of circulating T-cells, but when these cells dominate, GVL-effects are limited and rates of disease recurrence are high.

Early human herpes virus type 6 reactivation in umbilical cord blood allogeneic stem cell transplantation

Human herpes virus type 6 can reactivate in patients after allogeneic stem cell transplantation and has been associated with serious sequelae such as delayed engraftment and an increased risk of developing acute graft-versus-host disease (GVHD). This study investigated human herpes virus type 6 (HHV-6) reactivation within 60 days of transplantation in stem cell transplants utilizing single umbilical cord blood, double umbilical cord blood, or umbilical cord blood plus haploidentical stem cells. Of 92 patients, 60 (65%) had HHV-6 reactivation. Reactivation was not significantly influenced by any patient characteristics, disease characteristics, or by stem cell source (umbilical cord blood only versus haploidentical plus umbilical cord blood). We did not observe any impact of HHV-6 reactivation on neutrophil or platelet count recovery or on relapse-free survival. HHV-6 reactivation was associated with subsequent development of prerelapse acute GVHD (HR = 3.00; 95% CI, 1.4 to 6.4; p = 0.004).

DAS181 for Treatment of Parainfluenza Virus Infections in Hematopoietic Stem Cell Transplant Recipients at a Single Center

Parainfluenza virus (PIV) causes severe respiratory infections in hematopoietic stem cell transplant (HSCT) recipients. Currently, no effective therapies are available. DAS181 is a novel antiviral agent that inhibits attachment of PIV to respiratory cells, but clinical data on the use of DAS181 for PIV infection are limited to case reports. We report the clinical manifestations and outcomes of 16 HSCT recipients who received DAS181 daily for the treatment of PIV infection through a compassionate-use protocol or a single-arm clinical trial. Of the 16 patients (clinical trial: 9; compassionate use: 7), 13 were allogeneic HSCT recipients and 8 had graft-versus-host disease. PIV types were 3 (n = 7), 4 (n = 5), 1 (n = 3), and type 3 and 4 coinfection (n = 1). Fourteen patients had pneumonia. All patients presented with cough, 14 had dyspnea, 11 had hypoxia, and 8 had a fever. Patients received 5 to 10 days of treatment. Nine patients (56%) had a complete clinical response after DAS181 therapy and 4 (25%) had a partial response. The 3 patients without a clinical response had coinfections with other pathogens. Of the 7 patients with virologic and spirometric data, 5 had >1-log reduction in nasopharyngeal swab PIV viral load and 4 had improved forced expiratory volumes by the end of treatment. Three patients (19%) died within 30 days and 2 of these deaths were related to PIV infection. Our data suggest that DAS181 may be an effective therapy for PIV pneumonia in HSCT recipients. Randomized placebo-controlled trials are needed to better evaluate its efficacy.

Reduced intensity haplo plus single cord transplant compared to double cord transplant: improved engraftment and graft-versus-host disease-free, relapse-free survival

Umbilical cord blood stem cell transplants are commonly used in adults lacking HLA-identical donors. Delays in hematopoietic recovery contribute to mortality and morbidity. To hasten recovery, we used co-infusion of progenitor cells from a partially matched related donor and from an umbilical cord blood graft (haplo-cord transplant). Here we compared the outcomes of haplo-cord and double-cord transplants. A total of 97 adults underwent reduced intensity conditioning followed by haplo-cord transplant and 193 patients received reduced intensity conditioning followed by double umbilical cord blood transplantation. Patients in the haplo-cord group were more often from minority groups and had more advanced malignancy. Haplo-cord recipients received fludarabine-melphalan-anti-thymocyte globulin. Double umbilical cord blood recipients received fludarabine-cyclophosphamide and low-dose total body irradiation. In a multivariate analysis, haplo-cord had faster neutrophil (HR=1.42, P=0.007) and platelet (HR=2.54, P<0.0001) recovery, lower risk of grade II-IV acute graft-versus-host disease (HR=0.26, P<0.0001) and chronic graft-versus-host disease (HR=0.06, P<0.0001). Haplo-cord was associated with decreased risk of relapse (HR 0.48, P=0.001). Graft-versus-host disease-free, relapse-free survival was superior with haplo-cord (HR 0.63, P=0.002) but not overall survival (HR=0.97, P=0.85). Haplo-cord transplantation using fludarabine-melphalan-thymoglobulin conditioning hastens hematopoietic recovery with a lower risk of relapse relative to double umbilical cord blood transplantation using the commonly used fludarabine-cyclophosphamide-low-dose total body irradiation conditioning. Graft-versus-host disease-free and relapse-free survival is significantly improved. Haplo-cord is a readily available graft source that improves outcomes and access to transplant for those lacking HLA-matched donors. Trials registered at clinicaltrials.gov identifiers 00943800 and 01810588.

Comparison of Subcutaneous versus Intravenous Alemtuzumab for Graft-versus-Host Disease Prophylaxis with Fludarabine/Melphalan-Based Conditioning in Matched Unrelated Donor Allogeneic Stem Cell Transplantation

The objective of this study was to compare infusion-related reactions and outcomes of using subcutaneous (subQ) alemtuzumab versus intravenous (i.v.) alemtuzumab as graft-versus-host disease (GVHD) prophylaxis for matched unrelated donor stem cell transplantations. Outcomes include incidence of cytomegalovirus (CMV)/Epstein-Barr (EBV) viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, time to engraftment, relapse rate, and survival. We conducted a retrospective study of all adult matched unrelated donor stem cell transplantations patients who received fludarabine/melphalan with subQ or i.v. alemtuzumab in combination with tacrolimus as part of their conditioning for unrelated donor transplantation at New York-Presbyterian/Weill Cornell Medical Center from January 1, 2012 to March 21, 2014. Alemtuzumab was administered at a total cumulative dose of 100 mg (divided over days −7 to −3). Forty-six patients received an unrelated donor stem cell transplantation with fludarabine/melphalan and either subQ (n = 26) or i.v. (n = 20) alemtuzumab in combination with tacrolimus. Within the evaluable population, 130 subQ and 100 i.v. alemtuzumab doses were administered. For the primary outcome, ≥grade 2 infusion-related reactions occurred in 11 (8%) versus 25 (25%) infusions in the subQ and i.v. cohorts, respectively (P = .001). Overall, 12 injections (9%) in the subQ arm versus 26 infusions (26%) in the i.v. arm experienced an infusion-related reaction of any grade (P = .001). There were no significant differences between the subQ and i.v. arms in rates of reactivation of CMV/EBV, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, relapse, or survival. Subcutaneous administration of alemtuzumab for GVHD prophylaxis was associated with fewer infusion-related reactions compared with i.v. administration in the SCT setting. Incidences of acute and chronic GVHD were similar between both arms. There was also no difference in reactivation of CMV/EBV viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, relapse, or survival.

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We conducted a retrospective comparison of intravenous versus subcutaneous administration of alemtuzumab for graft-versus-host disease prophylaxis in unrelated donor transplant recipients.

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We observed a significant reduction in grade ≥ 2 infusion-related reactions after subcutaneous injections. The incidences of acute and chronic graft-versus-host disease were similar. There was no difference in incidence of viral reactivation or fatal bacterial infections.

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There was no difference in 30-day mortality or 1-year overall survival between the 2 arms.

A novel hematopoietic progenitor cell mobilization and collection algorithm based on preemptive CD34 enumeration

BACKGROUND

The collection of autologous peripheral blood (PB) stem cells can be challenging in the subgroup of patients deemed "poor mobilizers" with granulocyte-colony-stimulating factor. Plerixafor, a CXCR-4 antagonist, is an alternative mobilizing agent, but is costly, and the optimal mobilization algorithm has yet to be determined.

STUDY DESIGN AND METHODS

To address the question we developed a protocol measuring PB CD34 on Day 4 of mobilization. We examined 26 patients before initiating the protocol versus 24 patients after initiation.

RESULTS

Significant differences (p ≤ 0.05) included fewer days of collection (1.25 days vs. 2.42 days), lower total blood volume processed (25.9 L vs. 57.2 L), lower total product volume (324 mL vs. 691 mL), lower RBC content (9 mL vs. 18 mL), and lower granulocyte percentage per collection (35% vs. 11%). There were no significant differences between the two groups in demographics, baseline platelet count, total CD34, or CD34/kg harvested.

CONCLUSION

Use of a protocol to assess PB CD34 1 day before collection allows for preemptive administration of plerixafor to augment mobilization. Subsequently, days of collection and processed blood volume are reduced while there is less RBC and granulocyte contamination in the collected stem cell product.

Abstract CT413: Lutetium-177-labeled anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 (177Lu-J591) for metastatic non-prostate solid tumors

Introduction: PSMA is a non-secreted cell-surface protein that is expressed by the neovascular endothelium of most solid tumors (but not by vascular endothelium of normal tissue), making it a candidate for vascular-targeted therapy. The purpose of this study was to define the change in tumor perfusion and cellularity after 177Lu-J591 therapy in patients (pts) with advanced non-prostate solid tumors and PSMA expression as determined by radionuclide imaging (with 111In-J591) and/or by immunohistochemistry (IHC). Of note, radiolabeled J591 is hepatically cleared (negating accurate assessment of liver metastases by J591 imaging).

Methods: In this pilot study, following confirmation of PSMA expression by 111In-J591 imaging and/or IHC of tumor neovasculature), 14 pts in 2 cohorts received 177Lu-J591 therapy (7 received a single dose at 70 mCi/m2; 7 received 2 fractionated doses at 35 mCi/m2 each). Pts underwent dynamic contrast enhanced (DCE)-MRI and diffusion weighted imaging (DWI) at baseline, then repeated at 1, 4, 8, and 12 wks post treatment to evaluate tumor perfusion (DCE-MRI) and cellularity (Apparent Diffusion Coefficient (ADC) values from DWI). Values were compared with paired t-testing using Wilcoxon signed-rank test for significance.

Results: Among the 14 treated pts, tumor types included: lung (5), bladder (2), pancreas (2), colon, GE junction, renal, ovarian carcinomas and melanoma (1 each). Median age was 61.5 with a median of 3 prior therapies including 5 with prior anti-angiogenic agents; 8 pts received prior radiation. Metastatic sites included: bone, lymph nodes, liver, lung, brain, other. 11 of 14 pts had PSMA expression confirmed by imaging, 3 additional by IHC of archival tumor tissue (with liver metastases).

DCE-MRI demonstrated that treatment significantly affected tumor perfusion, with decreased perfusion at the 1-wk (n=11, p=0.03) and 4-wk (n=6, p=0.01) post 177Lu-J591 time points. Compared to baseline, DCE slope was lower than baseline at 1 wk (p=0.045) and 4-wk (p=0.02). Week 8 (n=4) was non-significant for both % change and DCE slope and only 2 pts completed the wk 12 time point.

In evaluation of cellularity, 5 of 9 pts had an increase in ADC at either the 1- or 4-wk time point (1 stable, 3 decreased). However, paired comparisons at individual time points were non-significant.

Conclusion: Anti-PSMA radioimmunotherapy targeting tumor neovasculature is feasible using 177Lu-J591 and can alter tumor perfusion and cellularity, including in those with prior exposure to anti-angiogenic therapy and/or radiation. Refinement in patient selection with improved imaging (anti-PSMA immuno-PET) is ongoing.

Citation Format: Orrin Pail, Gurveen Kaur, Jonathan Dyke, Yuliya Jhanwar, Paul Christos, Allyson Ocean, Manish Shah, Tsiporah Shore, Bryan Schneider, Ronald Scheff, Himisha Beltran, Douglas Ballon, Brian Robinson, David M. Nanus, Neil H. Bander, Scott T. Tagawa. Lutetium-177-labeled anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 (177Lu-J591) for metastatic non-prostate solid tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT413. doi:10.1158/1538-7445.AM2014-CT413

Hematopoietic transplant-associated thrombotic microangiopathy: case report and review of diagnosis and treatments

Transplant-associated thrombotic microangiopathy (TA-TMA) refers to inflammatory and thrombotic diseases of the microvasculature characterized by hemolytic anemia, thrombocytopenia, and evidence of organ damage, particularly acute renal failure. This syndrome occurs in 10% to 20% of patients with allogeneic hematopoietic stem cell transplants (HSCTs). It is much less frequent in the autologous setting. TA-TMAs present diagnostic challenges because they may not clearly fall into one of the categories of the 2 major TMAs: atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP). In addition, complications of the transplant itself, including infection, graft-versus-host disease, and disseminated intravascular coagulation, as well as the side effects of immunosuppressive drugs, can mimic a TMA. Because the pathophysiology of TA-TMA is poorly understood, current treatment options are suboptimal, and the condition carries a very high mortality rate. In 3 recent case summaries, the median acute response rate to plasma exchange was as high as 55%, but this therapy failed to alter underlying disease pathology and had little impact on overall mortality, which was approximately 80%. Indeed, the vast majority of TA-TMA patients lack suppression of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity to less than 5% to 10% of normal and do not have a complete response to plasma exchange, characteristics indicating that a TTP-like disorder is not involved. Recent advances in the treatment of aHUS may offer a therapeutic option in the aHUS-like TMAs associated with HSCTs. These issues are discussed in the context of a patient recently evaluated and treated at our institution; the case serves to illustrate the difficulties associated with the diagnosis and treatment of TA-TMA.

Hematopoietic stem-cell transplantation for advanced systemic mastocytosis

PURPOSE

Advanced systemic mastocytosis (SM), a fatal hematopoietic malignancy characterized by drug resistance, has no standard therapy. The effectiveness of allogeneic hematopoietic stem-cell transplantation (alloHCT) in SM remains unknown.

PATIENTS AND METHODS

In a global effort to define the value of HCT in SM, 57 patients with the following subtypes of SM were evaluated: SM associated with clonal hematologic non-mast cell disorders (SM-AHNMD; n = 38), mast cell leukemia (MCL; n = 12), and aggressive SM (ASM; n = 7). Median age of patients was 46 years (range, 11 to 67 years). Donors were HLA-identical (n = 34), unrelated (n = 17), umbilical cord blood (n = 2), HLA-haploidentical (n = 1), or unknown (n = 3). Thirty-six patients received myeloablative conditioning (MAC), and 21 patients received reduced-intensity conditioning (RIC).

RESULTS

Responses in SM were observed in 40 patients (70%), with complete remission in 16 patients (28%). Twelve patients (21%) had stable disease, and five patients (9%) had primary refractory disease. Overall survival (OS) at 3 years was 57% for all patients, 74% for patients with SM-AHNMD, 43% for those with ASM, and 17% for those with MCL. The strongest risk factor for poor OS was MCL. Survival was also lower in patients receiving RIC compared with MAC and in patients having progression compared with patients having stable disease or response.

CONCLUSION

AlloHCT was associated with long-term survival in patients with advanced SM. Although alloHCT may be considered as a viable and potentially curative therapeutic option for advanced SM in the meantime, given that this is a retrospective analysis with no control group, the definitive role of alloHCT will need to be determined by a prospective trial.

A phase 1 study of bendamustine and melphalan conditioning for autologous stem cell transplantation in multiple myeloma

Bendamustine has efficacy in multiple myeloma with a toxicity profile limited to myelosuppression. We hypothesized that adding bendamustine to autologous stem cell transplant conditioning in myeloma would enhance response without significant additional toxicity. We conducted a phase 1 trial adding escalating doses of bendamustine to the current standard conditioning of melphalan 200 mg/m(2). Twenty-five subjects were enrolled into 6 cohorts. A maximum tolerated dose was not encountered and the highest dose level cohort of bendamustine 225 mg/m(2) + melphalan 200 mg/m(2) was expanded to further evaluate safety. Overall, there was no transplant related mortality and only one grade 4 dose-limiting toxicity was observed. Median number of days to neutrophil and platelet engraftment were 11 (range, 9 to 14) and 13 (range, 10 to 21), respectively. Disease responses at day +100 posttransplantation were progression in 5 (21%), partial response in 1 (4%), very good partial response in 7 (33%), complete response in 1 (4%), and stringent complete response in 9 (38%). Six patients (24%) with pre-existing high-risk disease died from progressive myeloma during study follow-up, all at or beyond 100 days after autologous stem cell transplant. Bendamustine up to a dose of 225 mg/m(2) added to autologous stem cell transplantation conditioning with high-dose melphalan in patients with multiple myeloma did not exacerbate expected toxicities.

Avoiding pitfalls in bone marrow engraftment analysis: a case study highlighting the weakness of using buccal cells for determining a patient's constitutional genotype after hematopoietic stem cell transplantation

BACKGROUND AIMS

An accurate and reliable assessment of bone marrow engraftment (BME) after hematopoietic stem cell transplantation (HSCT) is based on the ability to distinguish between recipient and donor cells at selected polymorphic short tandem repeat (STR) DNA loci. Buccal cells are an important source of DNA for determining the recipient's constitutional genotype, particularly in patients transplanted before the STR evaluation.

METHODS

Genomic DNA was extracted from the recipient buccal cells and from isolated CD3+ (T-cell lymphocyte) and CD33+ (myelocyte) cells after HSCT. BME analysis was performed using a STR-based polymerase chain reaction amplification method followed by fragment-size analysis for assessing the recipient-derived or donor-derived composition of cell lineage-specific peripheral blood DNA.

RESULTS

We identified three cases of complete buccal epithelial cell engraftment after HSCT detected by BME analysis, potentially leading to misinterpretation of testing results if these cells were used as the sole source for determining the recipient's genotype.

CONCLUSIONS

These cases suggest that complete engraftment of buccal epithelial cells may be a common finding in patients receiving HSCT, drawing attention to important issues such as the type of samples used for determining a patient's constitutional genotype that may confound testing results. This study also highlights the need for careful interpretation of the BME testing results in the context of the clinical findings.