Outcomes with low dose anti-thymocyte globulin based graft versus host disease prophylaxis after mismatched unrelated donor allogeneic hematopoietic cell transplantation.

BACKGROUND: Anti-thymocyte globulin (ATG) based graft versus host disease (GVHD) prophylaxis is widely used for mismatched unrelated donor allogeneic hematopoietic cell transplantation (HCT) although optimal dose remains unclear. Although recent literature suggested improved outcomes with PTCy-based regimens when compared to ATG-based regimens these studies used doses of ATG ≥5 mg/kg. Thus, we analyzed outcomes of HLA 9/10 MMUD allogeneic HCTs using lower-dose ATG-based regimens at our center. METHODS: We retrospectively analyzed outcomes of HLA 9/10 MMUD allogeneic HCTs using lower dose ATG-based regimens for all adults undergoing allogeneic HCT at The Ottawa Hospital from 2015 to 2022. Data regarding demographics, conditioning regimen, dose of ATG, rates of GVHD, duration of remission, and survival, were collected and analyzed. RESULTS: Seventy-seven (n = 77) patients (males 62.3%; median age 50 years) underwent allogeneic HCT from MMUD. Majority(81%; n = 63) received 2.5 mg/kg of rabbit ATG and remaining 18.2% (n = 14) received 4.5 mg/kg. Grade II-IV acute GVHD occurred in 24.7% (n = 19) while any chronic GVHD occurred in 32.5% (n = 25) patients. After a median follow-up of 21 months, relapse occurred in 28.6% of patients. Two-year OS, GRFS, CIR, and NRM were 60.6%, 45.3%, 16.9%, and 18.2% respectively. Dose of ATG (2.5 mg/kg vs. 4.5 mg/kg) was not associated with outcomes in either univariate or multivariate analyses. CONCLUSIONS: When compared to published studies using ATG doses ≥5 mg/kg, GVHD prophylaxis using lower dose ATG may potentially lead to improved outcomes in patients undergoing MMUD allogeneic HCT. Further studies are needed to directly compare lower dose ATG to PTCy-based regimens to determine ideal GVHD prophylaxis for these patients.

Economic Evaluations of Chimeric Antigen Receptor T-Cell Therapies for Hematologic and Solid Malignancies: A Systematic Review.

OBJECTIVES: This study aimed to systematically review evidence on the cost-effectiveness of chimeric antigen receptor T-cell (CAR-T) therapies for patients with cancer. METHODS: Electronic databases were searched in October 2022 and updated in September 2023. Systematic reviews, health technology assessments, and economic evaluations that compared costs and effects of CAR-T therapy in patients with cancer were included. Two reviewers independently screened studies, extracted data, synthesized results, and critically appraised studies using the Philips checklist. Cost data were presented in 2022 US dollars. RESULTS: Our search yielded 1809 records, 47 of which were included. Most of included studies were cost-utility analysis, published between 2018 and 2023, and conducted in the United States. Tisagenlecleucel, axicabtagene ciloleucel, idecabtagene vicleucel, ciltacabtagene autoleucel, lisocabtagene maraleucel, brexucabtagene autoleucel, and relmacabtagene autoleucel were compared with various standard of care chemotherapies. The incremental cost-effectiveness ratio (ICER) for CAR-T therapies ranged from $9424 to $4 124 105 per quality-adjusted life-year (QALY) in adults and from $20 784 to $243 177 per QALY in pediatric patients. Incremental cost-effectiveness ratios were found to improve over longer time horizons or when an earlier cure point was assumed. Most studies failed to meet the Philips checklist due to a lack of head-to-head comparisons and uncertainty surrounding CAR-T costs and curative effects. CONCLUSIONS: CAR-T therapies were more expensive and generated more QALYs than comparators, but their cost-effectiveness was uncertain and dependent on patient population, cancer type, and model assumptions. This highlights the need for more nuanced economic evaluations and continued research to better understand the value of CAR-T therapies in diverse patient populations.

A Discussion with Dr. Natasha Kekre, Hematologist and Clinician Scientist.

[Figure: see text] Dr. Natasha Kekre has been appointed to the Department of Medicine in the Division of Hematology, within the Transplant and Cellular Therapy Program at The Ottawa Hospital since 2015. She is also a scientist within the Ottawa Hospital Research Institute and an associate professor of medicine at the University of Ottawa. She completed her Bachelor's in Science at the University of Windsor then obtained her medical degree from the University of Ottawa. She trained at the University of Ottawa in Internal Medicine and Hematology, then did fellowship in stem cell transplantation at Dana Farber Cancer Institute in Boston, MA with a Masters in Public Health from Harvard University. Her research is focused on developing early phase clinical trials and moving home grown therapeutic strategies from the lab to patients in the clinic. She has collaborated with scientists and physicians across Canada to build a Canadian CAR-T cell platform (chimeric antigen receptor T cells are immune cells engineered to kill cancer cells), bringing this exciting new therapy to Canadian patients.

Discovery and preclinical development of a therapeutically active nanobody-based chimeric antigen receptor targeting human CD22.

Chimeric antigen receptor (CAR) T cell therapies targeting B cell-restricted antigens CD19, CD20, or CD22 can produce potent clinical responses for some B cell malignancies, but relapse remains common. Camelid single-domain antibodies (sdAbs or nanobodies) are smaller, simpler, and easier to recombine than single-chain variable fragments (scFvs) used in most CARs, but fewer sdAb-CARs have been reported. Thus, we sought to identify a therapeutically active sdAb-CAR targeting human CD22. Immunization of an adult Llama glama with CD22 protein, sdAb-cDNA library construction, and phage panning yielded >20 sdAbs with diverse epitope and binding properties. Expressing CD22-sdAb-CAR in Jurkat cells drove varying CD22-specific reactivity not correlated with antibody affinity. Changing CD28- to CD8-transmembrane design increased CAR persistence and expression in vitro. CD22-sdAb-CAR candidates showed similar CD22-dependent CAR-T expansion in vitro, although only membrane-proximal epitope targeting CD22-sdAb-CARs activated direct cytolytic killing and extended survival in a lymphoma xenograft model. Based on enhanced survival in blinded xenograft studies, a lead CD22sdCAR-T was selected, achieving comparable complete responses to a benchmark short linker m971-scFv CAR-T in high-dose experiments. Finally, immunohistochemistry and flow cytometry confirm tissue and cellular-level specificity of the lead CD22-sdAb. This presents a complete report on preclinical development of a novel CD22sdCAR therapeutic.

Cyclophosphamide-glucocorticoids versus lenalidomide-dexamethasone as treatment for multiple myeloma at first relapse after autologous stem cell transplantation - a retrospective analysis

ABSTRACT There have been significant improvements in therapeutic options for relapsed multiple myeloma (MM) over the past two decades, with many novel agents including proteasome inhibitors, immunomodulatory agents, and more recently monoclonal antibodies demonstrating efficacy in this setting. However, there is a paucity of real-world data comparing outcomes seen in patients treated with novel agents as opposed to older agents. We report a historical single center cohort of patients diagnosed with myeloma between the years 1991-2012 in order to explore possible differences in outcomes. A total of 139 patients who underwent stem cell transplantation were included in our study. In our study, 88 patients were treated with cyclophosphamide and steroids alone at relapse whereas 51 patients were treated with Len-Dex. In the multivariate analysis, TTNT was shorter for patients who received Cyclo compared to Len-Dex (HR = 1.74; 95% CI, 1.01-2.99; p = 0.04); however, we could not detect an overall survival benefit (HR = 1.20; 95% CI 0.63-2.29; p = 0.57). Adverse event rates were similar in the two groups. In this retrospective single center analysis, Len-Dex was associated with longer TTNT compared with Cyclo at first relapse following autoSCT in MM; however its effect on overall survival in this setting was less clear.

The impact of multiple myeloma induction therapy on hematopoietic stem cell mobilization and collection: 25-year experience

ABSTRACT While first-line induction therapy for patients with multiple myeloma has changed over the years, autologous hematopoietic stem cell transplantation still plays a significant role, improving both depth of response and progression-free survival of myeloma patients. Our 25-year experience in mobilizing hematopoietic stem and progenitor cells for 472 transplant-eligible myeloma patients was retrospectively reviewed. Patients were stratified according to the remission induction therapy received, and the outcomes were compared among the cohorts that received vincristine, adriamycin and dexamethasone (VAD) (n = 232), bortezomib and dexamethasone (BD) (n = 86), cyclophosphamide, bortezomib and dexamethasone (CyBorD) (n = 82) and other regimens (n = 67). Cyclophosphamide plus granulocyte colony-stimulating factor was the predominant mobilization regimen given. A greater number of CD34+ cells (9.9 × 10E6/kg, p = 0.026) was collected with less hospital admissions in BD patients (13%, p = 0.001), when compared to those receiving VAD (7.5 × 10E6/kg, 29%), CyBorD (7.6 × 10E6/kg, 19%), or other regimens (7.9 × 10E6/kg, 36%). Induction therapy did not influence the overall rate of unscheduled visits or the length of hospitalization because of complications following mobilization. The myeloma response was not significantly deepened following the cyclophosphamide administered for mobilization. This analysis demonstrates the importance of monitoring the impact of initial treatment on downstream procedures such as stem cell mobilization and collection.