Third-party fecal microbiota transplantation for high-risk treatment-naïve acute GVHD of the lower GI tract

ABSTRACT

Disruption of the intestinal microbiome is observed with acute graft-versus-host disease (GVHD) of the lower gastrointestinal (LGI) tract, and fecal microbiota transplantation (FMT) has successfully cured steroid-refractory cases. In this open-label, single-arm, pilot study, third-party, single-donor FMT was administered in combination with systemic corticosteroids to participants with high-risk acute LGI GVHD, with a focus on treatment-naïve cases. Participants were scheduled to receive 1 induction dose (15 capsules per day for 2 consecutive days), followed by 3 weekly maintenance doses, consisting of 15 capsules per dose. The primary end point of the study was feasibility, which would be achieved if ≥80% of participants able to swallow ≥40 of the 75 scheduled capsules. Ten participants (9 treatment-naïve; 1 steroid-refractory) were enrolled and treated. The study met the primary end point, with 9 of 10 participants completing all eligible doses. Organ-specific LGI complete response rate at day 28 was 70%. Initial clinical response was observed within 1 week for all responders, and clinical responses were durable without recurrent LGI GVHD in complete responders. Exploratory analyses suggest that alpha diversity increased after FMT. Although recipient microbiome composition never achieved a high degree of donor similarity, expansion of donor-derived species and increases in tryptophan metabolites and short-chain fatty acids were observed within the first 7 days after FMT. Investigation into the use of microbiome-targeted interventions earlier in the treatment paradigm for acute LGI GVHD is warranted. This trial was registered at www.ClinicalTrials.gov as #NCT04139577.

Stealth transgenes enable CAR-T cells to evade host immune responses

BACKGROUND

Adoptive cell therapy, such as chimeric antigen receptor (CAR)-T cell therapy, has improved patient outcomes for hematological malignancies. Currently, four of the six FDA-approved CAR-T cell products use the FMC63-based αCD19 single-chain variable fragment, derived from a murine monoclonal antibody, as the extracellular binding domain. Clinical studies demonstrate that patients develop humoral and cellular immune responses to the non-self CAR components of autologous CAR-T cells or donor-specific antigens of allogeneic CAR-T cells, which is thought to potentially limit CAR-T cell persistence and the success of repeated dosing.

METHODS

In this study, we implemented a one-shot approach to prevent rejection of engineered T cells by simultaneously reducing antigen presentation and the surface expression of both Classes of the major histocompatibility complex (MHC) via expression of the viral inhibitors of transporter associated with antigen processing (TAPi) in combination with a transgene coding for shRNA targeting class II MHC transactivator (CIITA). The optimal combination was screened in vitro by flow cytometric analysis and mixed lymphocyte reaction assays and was validated in vivo in mouse models of leukemia and lymphoma. Functionality was assessed in an autologous setting using patient samples and in an allogeneic setting using an allogeneic mouse model.

RESULTS

The combination of the Epstein-Barr virus TAPi and an shRNA targeting CIITA was efficient and effective at reducing cell surface MHC classes I and II in αCD19 'stealth' CAR-T cells while retaining in vitro and in vivo antitumor functionality. Mixed lymphocyte reaction assays and IFNγ ELISpot assays performed with T cells from patients previously treated with autologous αCD19 CAR-T cells confirm that CAR T cells expressing the stealth transgenes evade allogeneic and autologous anti-CAR responses, which was further validated in vivo. Importantly, we noted anti-CAR-T cell responses in patients who had received multiple CAR-T cell infusions, and this response was reduced on in vitro restimulation with autologous CARs containing the stealth transgenes.

CONCLUSIONS

Together, these data suggest that the proposed stealth transgenes may reduce the immunogenicity of autologous and allogeneic cellular therapeutics. Moreover, patient data indicate that repeated doses of autologous FMC63-based αCD19 CAR-T cells significantly increased the anti-CAR T cell responses in these patients.

Clinical Outcomes and Toxicity in Older Adults Receiving Chimeric Antigen Receptor T Cell Therapy

Chimeric antigen receptor T cell therapy (CAR-T) has transformed the treatment landscape for adults with relapsed/refractory hematologic malignancies, but few studies have examined outcomes in older adults. We aimed to evaluate clinical outcomes and treatment toxicity in older adults receiving CAR-T for hematologic malignancies and to describe outcomes and toxicities in older adults age 75+ years compared to those age 65 to 74 years. We conducted a retrospective analysis of 141 adult patients age 65+ years (46.1% age 75+ years) who received commercial CAR-T at Massachusetts General Hospital between December 2017 and June 2023. We abstracted clinical outcomes from a review of the electronic health record, including (1) toxicity (ie, cytokine release syndrome [CRS] and immune effector cell-associated neurotoxicity syndrome [ICANS]); (2) health care utilization; (3) overall survival (OS); and (4) event-free survival (EFS). We analyzed the association of age (65 to 74 years versus 75+ years) with toxicity and health care utilization using the Mann-Whitney U test for continuous variables and the Fisher exact test for categorical variables. We examined the association of age with OS and EFS using multivariable Cox regression, controlling for covariates. The median patient age was 77 years (range, 75 to 91 years) in the 75+ year group and 69 years (ranges, 65 to 74 years) in the 65 to 74 year group. There were no statistically significant differences between the 75+ year group and the 65 to 74 year group in the rates of CRS (75.4% versus 84.2%; P = .21), grade 3+ CRS (1.5% versus 6.6%; P = .24), ICANS (38.5% versus 48.7%; P = .24), grade 3+ ICANS (16.9% versus 21.1%; P = .49), or infections (23.1% versus 29.0%; P = .45). There were no significant between-group differences in hospital readmissions within 30 days of CAR-T (10.8% versus 21.1%; P = .11), intensive care unit admissions within 30 days of CAR-T (7.7% versus 9.2%; P = 1.000), or median hospital length of stay (13 days versus 14 days; P = .29) among age groups. In a multivariable Cox regression analysis controlling for CAR-T product, Eastern Cooperative Oncology Group Performance Status, lactate dehydrogenase level, bridging therapy use, and history of deep venous thromboembolism, age 75+ years was not associated with OS (hazard ratio [HR], .95; P = .86) or EFS (HR, 1.28; P = .30). We identified favorable OS and toxicity outcomes across age categories in older adults receiving CAR-T for B cell non-Hodgkin lymphoma or multiple myeloma, underscoring that age alone is not a contraindication for CAR-T.

Intraventricular CARv3-TEAM-E T Cells in Recurrent Glioblastoma

In this first-in-human, investigator-initiated, open-label study, three participants with recurrent glioblastoma were treated with CARv3-TEAM-E T cells, which are chimeric antigen receptor (CAR) T cells engineered to target the epidermal growth factor receptor (EGFR) variant III tumor-specific antigen, as well as the wild-type EGFR protein, through secretion of a T-cell-engaging antibody molecule (TEAM). Treatment with CARv3-TEAM-E T cells did not result in adverse events greater than grade 3 or dose-limiting toxic effects. Radiographic tumor regression was dramatic and rapid, occurring within days after receipt of a single intraventricular infusion, but the responses were transient in two of the three participants. (Funded by Gateway for Cancer Research and others; INCIPIENT ClinicalTrials.gov number, NCT05660369.).

Second Primary Malignancies After Commercial CAR T Cell Therapy: Analysis of FDA Adverse Events Reporting System (FAERS)

Second primary malignancies (SPMs) were reported in 536 out of 12,394 (4.3%) adverse event reports following CAR T cell therapies in the FDA Adverse Event Reporting System (FAERS). Myeloid and T-cell neoplasms were disproportionately more frequently reported, warranting further follow-up.

Optimization of a flow cytometry test for routine monitoring of B cell maturation antigen targeted CAR in peripheral blood

Chimeric antigen receptor (CAR) modified T cell therapies targeting BCMA have displayed impressive activity in the treatment of multiple myeloma. There are currently two FDA licensed products, ciltacabtagene autoleucel and idecabtagene vicleucel, for treating relapsed and refractory disease. Although correlative analyses performed by product manufacturers have been reported in clinical trials, there are limited options for reliable BCMA CAR T detection assays for physicians and researchers looking to explore it as a biomarker for clinical outcome. Given the known association of CAR T cell expansion kinetics with toxicity and response, being able to quantify BCMA CAR T cells routinely and accurately in the blood of patients can serve as a valuable asset. Here, we optimized an accurate and sensitive flow cytometry test using a PE-conjugated soluble BCMA protein, with a lower limit of quantitation of 0.19% of CD3+ T cells, suitable for use as a routine assay for monitoring the frequency of BCMA CAR T cells in the blood of patients receiving either ciltacabtagene autoleucel or idecabtagene vicleucel.

Current and emerging pharmacotherapies for cytokine release syndrome, neurotoxicity, and hemophagocytic lymphohistiocytosis-like syndrome due to CAR T cell therapy

INTRODUCTION

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of multiple hematologic malignancies. Engineered cellular therapies now offer similar hope to transform the management of solid tumors and autoimmune diseases. However, toxicities can be serious and often require hospitalization.

AREAS COVERED

We review the two chief toxicities of CAR T therapy, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and the rarer immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome. We discuss treatment paradigms and promising future pharmacologic strategies. Literature and therapies reviewed were identified by PubMed search, cited references therein, and review of registered trials.

EXPERT OPINION

Management of CRS and ICANS has improved, aided by consensus definitions and guidelines that facilitate recognition and timely intervention. Further data will define optimal timing of tocilizumab and corticosteroids, current foundations of management. Pathophysiologic understanding has inspired off-label use of IL-1 receptor antagonism, IFNγ and IL-6 neutralizing antibodies, and janus kinase inhibitors, with data emerging from ongoing clinical trials. Further strategies to reduce toxicities include novel pharmacologic targets and safety features engineered into CAR T cells themselves. As these potentially curative therapies are used earlier in oncologic therapy and even in non-oncologic indications, effective accessible strategies to manage toxicities are critical.

Metabolic parameters predict survival and toxicity in chimeric antigen receptor T-cell therapy-treated relapsed/refractory large B-cell lymphoma

CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for patients with relapsed/refractory large B-cell lymphoma (LBCL). However, data available concerning the impact of the prognostic value of quantitative 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) parameters on the CAR T-related outcomes and toxicities are limited. Therefore, we aimed to evaluate the predictive value of pre- and post-CAR T metabolic parameters on survival and toxicities following CAR T-cell therapy. Fifty-nine patients with PET/CT scans done pre-and post-CAR T infusion were retrospectively identified and analyzed in a single institution database of LBCL patients treated with commercial CD19-targeted CAR T-cell therapy. The median follow-up was 10.7 months [interquartile range (IQR): 2.6-25.5 months]. The overall response (complete response-CR and partial response) and CR rates post-CAR T were 76% (n = 45) and 53% (n = 31), respectively. On univariate analysis, low pre-CAR T total lesion glycolysis (TLG) and metabolic tumor volume (MTV) predicted improved overall response post-CAR T (OR = 4.7, p = 0.01, OR = 9.5, p = 0.03, respectively) and CR post-CAR T (OR = 12.4, p = 0.0004, OR = 10.9, p = 0.0001, respectively). High TLG pre-CAR T was correlated with cytokine release syndrome (CRS, OR = 3.25, p = 0.04). High MTV pre-CAR T was correlated with developing immune effector cell neurotoxicity syndrome (ICANS) events (OR = 4.3, p = 0.01), and high SUV pre-CAR T was associated with grade 3-4 neurological events (OR = 12, p = 0.01). High MTV/TLG/SUVmax post-CAR T were significantly associated with inferior Overall survival (OS). On multivariate analysis, high TLG pre-CAR T (HR = 2.4, p = 0.03), age ≥60 (HR = 2.7, p = 0.03), and bulky disease (≥5 cm) at the time of apheresis (HR = 2.5, p = 0.02) were identified to be independent prognostic factors for inferior PFS. High MTV post-CAR T was identified as the most prognostic factor associated with inferior OS.

Neurotoxicity and management of primary and secondary central nervous system lymphoma after adoptive immunotherapy with CD19-directed chimeric antigen receptor T-cells

BACKGROUND

Chimeric antigen receptor (CAR) T-cells targeting CD19 have been established as a leading engineered T-cell therapy for B-cell lymphomas; however, data for patients with central nervous system (CNS) involvement are limited.

METHODS

We retrospectively report on CNS-specific toxicities, management, and CNS response of 45 consecutive CAR T-cell transfusions for patients with active CNS lymphoma at the Massachusetts General Hospital over a 5-year period.

RESULTS

Our cohort includes 17 patients with primary CNS lymphoma (PCNSL; 1 patient with 2 CAR T-cell transfusions) and 27 patients with secondary CNS lymphoma (SCNSL). Mild ICANS (grade 1-2) was observed after 19/45 transfusions (42.2%) and severe immune effector cell-associated neurotoxicity syndrome (ICANS) (grade 3-4) after 7/45 transfusions (15.6%). A larger increase in C-reactive protein (CRP) levels and higher rates of ICANS were detected in SCNSL. Early fever and baseline C-reactive protein levels were associated with ICANS occurrence. CNS response was seen in 31 cases (68.9%), including a complete response of CNS disease in 18 cases (40.0%) which lasted for a median of 11.4 ± 4.5 months. Dexamethasone dose at time of lymphodepletion (but not at or after CAR T-cell transfusion) was associated with an increased risk for CNS progression (hazard ratios [HR] per mg/d: 1.16, P = .031). If bridging therapy was warranted, the use of ibrutinib translated into favorable CNS-progression-free survival (5 vs. 1 month, HR 0.28, CI 0.1-0.7; P = .010).

CONCLUSIONS

CAR T-cells exhibit promising antitumor effects and a favorable safety profile in CNS lymphoma. Further evaluation of the role of bridging regimens and corticosteroids is warranted.

Clinical efficacy and safety of chimeric antigen receptor T-cell therapy for mantle cell lymphoma with secondary central nervous system involvement

Data describing outcomes of chimeric antigen receptor (CAR) T-cell therapy in patients with secondary central nervous system (SCNS) involvement of mantle cell lymphoma (MCL) are limited. We identified 10 patients with MCL and SCNS involvement treated with anti-CD19 CAR T-cell therapy at three US academic centres. Frequent objective responses were observed in the CNS (86%) and systemically (90%), and the 1-year progression-free survival was 47%. Seven patients developed immune-effector-cell-associated-neurotoxicity-syndrome (n = 2 Grade 1, n = 5 Grade 3). Our results suggest that anti-CD19 CAR T-cell therapy in this setting is feasible and additional data regarding neurotoxicity in this population may be warranted.

Radiation therapy as a bridging and salvage strategy in patients with relapsed or refractory multiple myeloma undergoing BCMA-targeted CAR T-cell therapy

Radiation therapy (RT) may play an important role prior to and following BCMA-targeted CAR T-cell therapy in multiple myeloma (MM). We report a series of 13 patients: 5 patients received bridging RT pre-CAR T, 4 patients received salvage RT post-CAR T failure, and 4 patients received both. There was no worsening of CAR-T- or RT-related toxicities. The RT in-field local control rate was 100%, with a median follow-up after each RT course of 7.3 months. RT as a bridging and salvage strategy is safe, feasible, and offers excellent local control in MM patients treated with CAR T-cell therapy.

Anti-TACI single and dual-targeting CAR T cells overcome BCMA antigen loss in multiple myeloma

Chimeric Antigen Receptor (CAR) T cells directed to B cell maturation antigen (BCMA) mediate profound responses in patients with multiple myeloma, but most patients do not achieve long-term complete remissions. In addition, recent evidence suggests that high-affinity binding to BCMA can result in on-target, off-tumor activity in the basal ganglia and can lead to fatal Parkinsonian-like disease. Here we develop CAR T cells against multiple myeloma using a binder to targeting transmembrane activator and CAML interactor (TACI) in mono and dual-specific formats with anti-BCMA. These CARs have robust, antigen-specific activity in vitro and in vivo. We also show that TACI RNA expression is limited in the basal ganglia, which may circumvent some of the toxicities recently reported with BCMA CARs. Thus, single-targeting TACI CARs may have a safer toxicity profile, whereas dual-specific BCMA-TACI CAR T cells have potential to avoid the antigen escape that can occur with single-antigen targeting.

Salvage radiotherapy in relapsed/refractory large B-cell lymphoma after failure of CAR T-cell therapy

Despite the success of CD19-targeted chimeric antigen receptor (CAR T)-cell therapy in patients with relapsed/refractory large B-cell lymphoma (LBCL), there is a need for effective salvage strategies post-CAR T-cell therapy failure. We conducted a multi-institutional retrospective study of patients who relapsed following CAR T-cell therapy (axicabtagene ciloleucel [axi-cel] or tisagenlecleucel [tisa-cel]) and received salvage therapies (radiation therapy [RT] alone, systemic therapy alone, or combined modality therapy [CMT]). A total of 120 patients with post-CAR T relapsed LBCL received salvage therapies (RT alone, 25 patients; CMT, 15 patients; systemic therapy alone, 80 patients). The median follow-up from CAR T-cell infusion was 10.2 months (interquartile range, 5.2-20.9 months). Failure occurred in previously involved sites prior to CAR T-cell therapy in 78% of patients (n=93). A total of 93 sites were irradiated in 54 patients who received any salvage RT post-CAR T failure. The median dose/fractionation were 30 Gy (range, 4-50.4 Gy) and 10 fractions (range, 1-28 fractions). The 1-year local control rate for the 81 assessable sites was 84%. On univariate analysis, the median overall survival (OS) from the start date of RT was significantly higher among patients who received comprehensive RT versus focal RT (19.1 months vs. 3.0 months; P=<0.001). Twenty-three of 29 patients who received comprehensive RT had limited-stage disease. Among these, there was no difference in median OS among the patients who received RT alone versus those who received RT followed by additional therapies (log-rank P=0.2). On multivariate survival analysis, achieving PR or CR post-CAR T (hazard ratio =0.5; 95% confidence interval: 0.3-0.9; P=0.01) was independently associated with superior OS. Our findings suggest that RT can provide local control for LBCL relapsed post-CAR T-cell therapy, particularly in patients with limited-stage relapsed disease treated with comprehensive RT.

Automated detection of immune effector cell-associated neurotoxicity syndrome via quantitative EEG

OBJECTIVE

To develop an automated, physiologic metric of immune effector cell-associated neurotoxicity syndrome among patients undergoing chimeric antigen receptor-T cell therapy.

METHODS

We conducted a retrospective observational cohort study from 2016 to 2020 at two tertiary care centers among patients receiving chimeric antigen receptor-T cell therapy with a CD19 or B-cell maturation antigen ligand. We determined the daily neurotoxicity grade for each patient during EEG monitoring via chart review and extracted clinical variables and outcomes from the electronic health records. Using quantitative EEG features, we developed a machine learning model to detect the presence and severity of neurotoxicity, known as the EEG immune effector cell-associated neurotoxicity syndrome score.

RESULTS

The EEG immune effector cell-associated neurotoxicity syndrome score significantly correlated with the grade of neurotoxicity with a median Spearman's R2 of 0.69 (95% CI of 0.59-0.77). The mean area under receiving operator curve was greater than 0.85 for each binary discrimination level. The score also showed significant correlations with maximum ferritin (R2 0.24, p = 0.008), minimum platelets (R2 -0.29, p = 0.001), and dexamethasone usage (R2 0.42, p < 0.0001). The score significantly correlated with duration of neurotoxicity (R2 0.31, p < 0.0001).

INTERPRETATION

The EEG immune effector cell-associated neurotoxicity syndrome score possesses high criterion, construct, and predictive validity, which substantiates its use as a physiologic method to detect the presence and severity of neurotoxicity among patients undergoing chimeric antigen receptor T-cell therapy.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.

Biomarkers and cardiovascular outcomes in chimeric antigen receptor T-cell therapy recipients

AIMS

Chimeric antigen receptor T-cell therapy (CAR-T) harnesses a patient's immune system to target cancer. There are sparse existing data characterizing death outcomes after CAR-T-related cardiotoxicity. This study examines the association between CAR-T-related severe cardiovascular events (SCE) and mortality.

METHODS AND RESULTS

From a multi-centre registry of 202 patients receiving anti-CD19 CAR-T, covariates including standard baseline cardiovascular and cancer parameters and biomarkers were collected. Severe cardiovascular events were defined as a composite of heart failure, cardiogenic shock, or myocardial infarction. Thirty-three patients experienced SCE, and 108 patients died during a median follow-up of 297 (interquartile range 104-647) days. Those that did and did not die after CAR-T were similar in age, sex, and prior anthracycline use. Those who died had higher peak interleukin (IL)-6 and ferritin levels after CAR-T infusion, and those who experienced SCE had higher peak IL-6, C-reactive protein (CRP), ferritin, and troponin levels. The day-100 and 1-year Kaplan-Meier overall mortality estimates were 18% and 43%, respectively, while the non-relapse mortality (NRM) cumulative incidence rates were 3.5% and 6.7%, respectively. In a Cox model, SCE occurrence following CAR-T was independently associated with increased overall mortality risk [hazard ratio (HR) 2.8, 95% confidence interval (CI) 1.6-4.7] after adjusting for age, cancer type and burden, anthracycline use, cytokine release syndrome grade ≥ 2, pre-existing heart failure, hypertension, and African American ancestry; SCEs were independently associated with increased NRM (HR 3.5, 95% CI 1.4-8.8) after adjusting for cancer burden.

CONCLUSION

Chimeric antigen receptor T-cell therapy recipients who experience SCE have higher overall mortality and NRM and higher peak levels of IL-6, CRP, ferritin, and troponin.

Paving the Road for Chimeric Antigen Receptor T Cells: American Society for Transplantation and Cellular Therapy 80/20 Task Force Consensus on Challenges and Solutions to Improving Efficiency of Clinical Center Certification and Maintenance of Operations for Commercially Approved Immune Effector Cell Therapies

As the number and type of regulatory authority-approved cellular therapies grow, clinical treatment centers face a heavy burden of duplicative documentation around initial qualification, ongoing auditing, and reporting, with overlapping requirements from each manufacturer to ensure safe use of their specific product, which in the United States are stipulated under individual Food and Drug Administration (FDA) Biologic License Applications. The American Society for Transplantation and Cellular Therapy (ASTCT) convened the 80/20 Task Force to consider challenges and potential solutions to these issues. The Task Force proposed that 80% of manufacturers' requirements for onboarding and ongoing operations of commercially available products could be standardized and streamlined. Task Force members interviewed dozens of stakeholders, including clinicians at large academic medical centers already using commercial and investigational immune effector cell (IEC) products, regulators, members of accrediting bodies and professional cellular therapy societies, and manufacturers of IEC therapies for oncologic indications. In November 2021, the Task Force organized and led virtual discussions in a public forum and at a private ASTCT 80/20 Workshop at the online AcCELLerate Forum, a cellular-therapy stakeholders' meeting organized by the ASTCT, National Marrow Donor Program (NMDP), and Center for International Blood and Marrow Transplant Research (CIBMTR). At the workshop, approximately 60 stakeholders worked to identify and prioritize common challenges in onboarding and maintenance of operations at clinical sites for commercial FDA-approved and future IEC therapies and ways to streamline the process. It was agreed that standardization would improve efficiency of onboarding, allowing more cost-effective, sustainable growth of approved IEC therapies at treatment centers, and facilitate wider access while maintaining safety and clinical success. This early but extensive survey of stakeholders resulted in 5 overarching suggestions for both established and emerging treatment centers: (1) eliminate duplication in accreditation and auditing of clinical sites; (2) define expectations for the education about and management of CAR-T therapy toxicities to potentially replace product-specific REMS programs; (3) streamline current REMS education, testing, and data reporting; (4) standardize information technology (IT) platforms supporting enrollment, clinical site-manufacturer communication, and logistics of maintaining chain of identity/chain of custody across multiple transportation steps; and (5) encourage the use of universal nomenclature by cell therapy manufacturers. Future discussions need to engage a broader range of stakeholders, including administrators, pharmacists, nurses, data coordinators, surgeons, pathologists, and those developing promising cellular therapies for solid tumors, as well as teams from smaller academic or community cancer center settings. Continued collaboration with stakeholders outside of clinical sites will include accrediting bodies/auditors, established and emerging cell therapy companies, software developers, professional societies, and the patients who receive these therapies. Active dialog with government regulators remains essential. Such joint efforts are critical as the number of IEC therapies for myriad oncologic and nononcologic indications grows.

Phase 1 study of CART-ddBCMA for the treatment of subjects with relapsed and refractory multiple myeloma

Relapsed and refractory multiple myeloma (RRMM) is a plasma cell neoplasm defined by progressively refractory disease necessitating chronic and increasingly intensive therapy. Despite recent advances, limited treatment options exist for RRMM. This single-arm, open label phase 1 study aimed to evaluate the safety of novel B-cell maturation antigen (BCMA)-targeting chimeric antigen receptor (CAR) T construct that leverages a completely synthetic antigen-binding domain (CART-ddBCMA), which was specifically engineered to reduce immunogenicity and improve CAR cell surface stability. Thirteen patients ≥18 years with RRMM who received at least 3 prior regimens of systemic therapy were enrolled in the study. Patients received a single dose of 100 × 106 CART-ddBCMA (DL1) or 300 × 106 CART-ddBCMA (DL2) following standard lymphodepleting chemotherapy. The primary endpoints of the study were to evaluate the incidence of treatment emergent adverse events, including dose-limiting toxicities, and establish a recommended phase 2 dose. Results showed that CART-ddBCMA was well tolerated and demonstrated a favorable toxicity profile. Only 1 case of grade ≥3 cytokine release syndrome and 1 case of immune effector cell-associated neurotoxicity were reported; both were at DL2 and were manageable with standard treatment. No atypical neurological toxicities and Parkinson disease-like movement disorders were observed. The maximum tolerated dose was not reached. All infused patients responded to CART-ddBCMA, and 9/12 (75%) patients achieved complete response/stringent complete response. Responses deepened over time, and at the time of last data-cut (median follow-up 56 weeks), 8/9 (89%) evaluable patients achieved minimal residual disease negativity. In conclusion, the findings demonstrate the safety of CART-ddBCMA cells and document durable responses to CART-ddBCMA in patients with RRMM. This trial was registered at www.clinicaltrials.gov as #NCT04155749.

Perception of prognosis, quality of life, and distress in patients receiving chimeric antigen receptor T-cell therapy

BACKGROUND

Chimeric antigen receptor (CAR) T-cell is potentially curative therapy for patients with hematologic malignancies but can cause life-threatening toxicities. Data on perceptions of prognosis and psychological distress are lacking.

METHODS

The authors conducted a cross-sectional study of patients receiving CAR-T. Before hospitalization for CAR-T, patients completed assessments of quality of life (QOL) (Functional Assessment of Cancer Therapy-General), anxiety and depression symptoms (Hospital Anxiety and Depression Scale) and post-traumatic stress disorder symptoms (Post-Traumatic Stress Checklist). Patients also completed the Prognostic Awareness Impact Scale (PAIS), which measures three domains: cognitive understanding of prognosis, emotional coping with prognosis, and adaptive response.

RESULTS

A total of 71.8% (102 of 142) of eligible patients were enrolled. A total of 34% of patients reported that their oncologist said their cancer is curable and 64% reported there was >50% chance of cure. Overall, 26%, 30%, and 21% of patients reported clinically significant depression, anxiety, and posttraumatic stress disorder (PTSD) symptoms, respectively. We found no association between patients' cognitive understanding of prognosis and QOL or mood. Higher emotional coping with prognosis was associated with better QOL (Β = 0.72; SE = 0.10; p = <.001) and lower depression (Β = -0.17; SE = 0.02; p = <.001), anxiety (Β = -0.21; SE = 0.02; p = <.001), and PTSD (Β = -0.43; SE = 0.06; p = <.001) symptoms. Higher adaptive response was associated with better QOL (Β = 0.19; SE = 0.09; p = .028) and lower depression (Β = -0.05; SE = 0.02; p = .023), anxiety (Β = -0.09; SE = 0.02; p = <.001), and PTSD (Β = -0.19; SE = 0.05; p = <.001) symptoms.

CONCLUSIONS

Patients undergoing CAR-T report overly optimistic perception of their prognosis and have high rates of psychological distress. Higher emotional coping with prognosis and adaptive response were associated with better QOL and less psychological distress, underscoring the need to develop interventions to promote coping with this treatment.

PLAIN LANGUAGE SUMMARY

Patients undergoing chimeric antigen receptor T-cell therapy experience report overly optimistic perceptions of their prognosis and have high rates of psychological distress. Notably, higher emotional coping with prognosis and adaptive response were associated with better quality of life and less psychological distress.

Dose-response correlation for CAR-T cells: a systematic review of clinical studies

The potential of chimeric antigen receptor (CAR) T cells to successfully treat hematological cancers is widely recognized. Multiple CAR-T cell therapies are currently under clinical development, with most in early stage, during which dose selection is a key goal. The objective of this review is to address the question of dose-dependent effects on response and/or toxicity from available CAR-T cell clinical trial data. For that purpose, systematic literature review of studies published between January 2010 and May 2022 was performed on PubMed and Embase to search clinical studies that evaluated CAR-T cells for hematological cancers. Studies published in English were considered. Studies in children (age <18 years), solid tumors, bispecific CAR-T cells and CAR-T cell cocktails were excluded. As a result, a total of 74 studies met the inclusion criteria. Thirty-nine studies tested multiple dose levels of CAR-T cells with at least >1 patient at each dose level. Thirteen studies observed dose-related increase in disease response and 23 studies observed dose-related increase in toxicity across a median of three dose levels. Optimal clinical efficacy was seen at doses 50-100 million cells for anti-CD19 CAR-T cells and >100 million cells for anti-BCMA CAR-T cells in majority of studies. The findings suggest, for a given construct, there exists a dose at which a threshold of optimal efficacy occurs. Dose escalation may reveal increasing objective response rates (ORRs) until that threshold is reached. However, when ORR starts to plateau despite increasing dose, further dose escalation is unlikely to result in improved ORR but is likely to result in higher incidence and/or severity of mechanistically related adverse events.

Tandem chimeric antigen receptor (CAR) T cells targeting EGFRvIII and IL-13Rα2 are effective against heterogeneous glioblastoma

Background

Chimeric antigen receptor (CAR) T cells have achieved remarkable responses in patients with hematological malignancies; however, the potential of this therapeutic platform for solid tumors like glioblastoma (GBM) has been limited, due in large part to the targeting of single antigens in a heterogeneous disease. Strategies that allow CAR T cells to engage multiple antigens concomitantly may broaden therapeutic responses and mitigate the effects of immune escape.

Methods

Here we have developed a novel, dual-specific, tandem CAR T (TanCART) cell with the ability to simultaneously target both EGFRvIII and IL-13Rα2, two well-characterized tumor antigens that are frequently found on the surface of GBM cells but completely absent from normal brain tissues. We employed both standard immunological assays and multiple orthotopic preclinical models including patient-derived xenograft to demonstrate efficacy of this approach against heterogeneous tumors.

Results

Tandem CAR T cells displayed enhanced cytotoxicity in vitro against heterogeneous GBM populations, including patient-derived brain tumor cultures (P < .05). Compared to CAR T cells targeting single antigens, dual antigen engagement through the tandem construct was necessary to achieve long-term, complete, and durable responses in orthotopic murine models of heterogeneous GBM, including patient-derived xenografts (P < .05).

Conclusions

We demonstrate that TanCART is effective against heterogeneous tumors in the brain. These data lend further credence to the development of multi-specific CAR T cells in the treatment of GBM and other cancers.

Association of bridging therapy utilization with clinical outcomes in patients receiving chimeric antigen receptor (CAR) T-cell therapy

Background

Chimeric antigen receptor (CAR) T-cell therapy recipients may receive bridging therapy while awaiting product manufacturing to control disease. Yet, data are lacking regarding the impact of bridging therapy use on clinical outcomes.

Methods

We conducted a retrospective analysis of 235 patients who received CAR T-cell therapy at two tertiary care centers from February 2016 to December 2019. We abstracted clinical outcomes from review of the electronic health record including (1) overall response; (2) complete response (CR); (3) progression-free survival (PFS); (4) overall survival (OS); and (5) toxicity (cytokine release syndrome (CRS) and neurotoxicity). We assessed the association of bridging therapy use with overall response rate (ORR) and CR rate using multivariable logistic regression and with PFS and OS using multivariable Cox regression controlling for covariates. We analyzed the association of bridging therapy use with CRS and neurotoxicity using Fisher’s exact test.

Results

Patients’ median age was 63.1 years (range: 19–82), and the majority were men (144/235, 61.3%). Most patients received axicabtagene ciloleucel (192/235, 81.7%), and the most common lymphoma subtype was diffuse large B-cell lymphoma or grade 3B follicular lymphoma (107/235, 45.5%). Overall, 39.4% (93/236) received bridging therapy. Bridging therapy regimens included systemic chemotherapy (48/92, 52.2%), corticosteroids (25/92, 27.2%), radiation (9/92, 9.8%), and other systemic therapies (10/92, 10.9%). In multivariable Cox regression, bridging therapy use was associated with OS (HR: 1.97, p=0.004) but not PFS (HR: 1.18, p=0.449). In multivariable logistic regression, bridging therapy use was not associated with ORR (OR: 0.69, p=0.391) or CR rate (OR: 0.96, p=0.901). We did not identify an association of bridging therapy use with grade 3+ CRS (p=0.574) or grade 3+ neurotoxicity (p=0.748).

Conclusions

We identified that bridging therapy use is not associated with differences in ORR, CR rate, or PFS but is associated with worse OS. These data suggest bridging therapy may be a surrogate for additional poor prognostic factors leading to inferior OS and underscore the need for novel bridging therapy regimens to optimize outcomes in this patient population.

Abstract 3575: Differential dynamics of response at single cell resolution between axi-cel and tisa-cel CAR-T therapy in refractory B-cell lymphomas

Chimeric Antigen Receptor (CAR)-T cell therapy has revolutionized the treatment of hematologic malignancies. Approximately half of patients with refractory large B-cell lymphomas achieve durable responses from CD19-targeting CAR-T treatment, across the commercially available CAR-T products with differing designs. Known failure mechanisms such as antigen loss account for only a fraction of cases without durable responses, and this knowledge gap has limited advances in CAR-T engineering and optimal targeting to patients.

We hypothesized that characterization of the transcriptional programs and temporal evolution of CAR-T and host immune cell populations could provide novel insights into the basis of clinical response to CAR-T cell therapy for B cell lymphoma. We performed 10X single-cell RNA sequencing on serial samples collected from 32 individuals with high grade B cell lymphoma treated with the two first FDA-approved CD19 CAR-T products: axicabtagene ciloleucel (axi-cel, utilizing a CD28z costimulatory domain) and tisagenlecleucel (tisa-cel, with a 4-1BB domain). We analyzed 106 samples, including pre-infusion blood samples, infusion product, and post-infusion T cells sorted by flow cytometry into CAR+ and CAR- populations. Analyzing 602,577 single-cell transcriptomes, we discerned major differences in the dynamics of response of the two products. Tisa-cel responders showed dramatic expansion of CD8+ T cells at day 7 after infusion, which represented less than 10% of cells in the product. Conversely, CD8+ T cells in products of non-responders failed to expand to the same degree post-infusion and had a more effector- than memory-like T cell phenotype. In one tisa-cel–treated patient who had no CD8+ T cell expansion after initial infusion and relapsed at 6 months post-infusion, re-treatment with a second dose of the same product led to a durable response and was associated with greater CD8+ T cell expansion as well as a shift in CD4+ T phenotype from cytotoxic to helper. In contrast, axi-cel responders had pre-expanded effector populations distributed more heterogeneously among CD4+ and CD8+ T cells. Finally, we identified nominal elevations in CAR-T regulatory cells (CAR-Tregs) among both axi-cel and tisa-cel non-responders in our dataset, which we confirmed in an external dataset. These small increases in CAR-Tregs were sufficient to uniformly suppress conventional CAR-T cell expansion and drive late relapses in an in vivo mouse model of lymphoma after treatment with CARs with either CD28z or 4-1BB co-stimulatory domains. In summary, this represents the largest CAR-T scRNAseq cohort established thus far and provides important insights into (i) the temporal dynamics of a successful CAR-T response, (ii) the molecular phenotypes of CAR-T cells with different costimulatory domains, and (iii) the capacity for small increases in CAR-Tregs to drive relapse.

Citation Format: Nicholas J. Haradhvala, Mark B. Leick, Katie Maurer, Satyen Gohil, Rebecca C. Larson, Estelle Yao, Matthew J. Frigault, Shuqiang Li, Kenneth J. Livak, Kahn Rhrissorrakrai, Filippo Utro, Chaya Levovitz, Raquel A. Jacobs, Kara Slowik, Brian P. Danysh, Laxmi Parida, Catherine J. Wu, Gad Getz, Marcela V. Maus. Differential dynamics of response at single cell resolution between axi-cel and tisa-cel CAR-T therapy in refractory B-cell lymphomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3575.

Phase 1 study of CART-ddBCMA in relapsed or refractory multiple myeloma

8003

Background: Chimeric Antigen Receptor (CAR) T cell therapies targeting B-cell maturation antigen (BCMA) have demonstrated benefit in patients (pts) with relapsed and/or refractory Multiple Myeloma (RRMM). CART-ddBCMA is an autologous anti-BCMA CAR T cell therapy that utilizes a novel, synthetic binding domain, called a D-Domain, instead of a typical scFv binder. The objective of this first-in-human trial is to assess the safety and efficacy of CART-ddBCMA. Methods: This is a Phase 1, multi-center, open label, dose escalation trial for pts with RRMM who have received ≥3 prior regimens or are triple-refractory. After apheresis, bridging therapy is allowed during manufacturing. Pts receive fludarabine and cyclophosphamide (30/300 mg/m2/day) days -5 to -3 and CART-ddBCMA infusion on day 0. Dose escalation was performed at 100 (DL1) and 300 (DL2) x 106 (± 20%) CAR+T cells, followed by expansion of DL1. The primary endpoint is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Additional endpoints are depth and duration of response (IMWG Criteria), minimal residual disease (MRD, clonoSEQ), progression-free (PFS) and overall survival (OS). Pts with 1- and 3-months follow-up were eligible for safety and efficacy analysis, respectively. Results: As of January 25, 2022, 25 pts received CART-ddBCMA, with median age 66 (range: 44-76), after a median of 5 prior lines of therapy (3-16), including 10 (40%) with extramedullary disease (EMD). Median follow-up was 9.8 (2-23.7) months. Overall, 25 pts (19 DL1; 6 DL2) were evaluable for safety and 24 (18 DL1; 6 DL2) for efficacy analysis. All pts experienced CRS, but only 1 pt (in DL2) had grade (gr) 3 CRS. All other CRS cases were gr ≤2, with no cases of gr ≥3 CRS in DL1. Four pts experienced ICANS (2, gr ≤2; 2, gr 3), with 1 gr 3 case in each of DL1 (5%) and DL2 (17%). Standard management resulted in resolution of CRS/ICANS within 30 days in all cases without sequelae. The ORR = 100%, sCR/CR rate = 67%, and ≥VGPR rate = 88%. Conversion to CR/sCR has occurred with longer follow-up, as late as month 9 in this trial. At time of data-cut 5 pts in DL1 with PR/VGPR have < 9 months follow-up, with 4 (of 4 evaluable) negative at ≥10-5 for MRD. Overall, 17 of 20 (85%) evaluable pts have achieved best MRD response of ≥10-5. In the dose escalation pts (i.e., those with longest follow-up, n = 12), the ORR and CR/sCR rate was 100% and 75%, respectively, despite 58% (7/12) EMD in this group. Of the first 6 pts dosed in DL1, 4 (67%) continue in ongoing sCR beyond 18 months, including 3 with EMD. Median duration of response, PFS and OS were not evaluable at the time of data-cut because 19 of 24 evaluable pts (79%) remain in ongoing response. Conclusions: CART-ddBCMA administration, to date, has demonstrated clinical activity, including 100% ORR with rates of CR/sCR and ≥VGPR of 67% and 88%, respectively. Durable responses beyond 18 months have been observed, including in pts with EMD. Clinical trial information: NCT04155749.

Non-cleavable hinge enhances avidity and expansion of CAR-T cells for acute myeloid leukemia

Chimeric antigen receptor (CAR) T cell therapy is effective in lymphoid malignancies, but there has been limited data in myeloid cancers. Here, we start with a CD27-based CAR to target CD70 ("native") in acute myeloid leukemia (AML), and we find modest efficacy in vivo, consistent with prior reports. We then use orthogonal approaches to increase binding on both the tumor and CAR-T cell sides of the immune synapse: a pharmacologic approach (azacitidine) to increase antigen density of CD70 in myeloid tumors, and an engineering approach to stabilize binding of the CAR to CD70. To accomplish the latter, we design a panel of hinge-modified regions to mitigate cleavage of the extracellular portion of CD27. Our CD8 hinge and transmembrane-modified CD70 CAR-T cells are less prone to cleavage, have enhanced binding avidity, and increased expansion, leading to more potent in vivo activity. This enhanced CD70-targeted CAR is a promising candidate for further clinical development.

Safety and efficacy of tisagenlecleucel in primary CNS lymphoma: a phase 1/2 clinical trial

CD19-directed chimerical antigen receptor T-cell (CAR-T) products have gained US Food and Drug Administration approval for systemic large B-cell lymphoma. Because of concerns about potential immune cell-associated neurotoxicity syndrome (ICANS), patients with primary central nervous system (CNS) lymphoma (PCNSL) were excluded from all pivotal CAR-T studies. We conducted a phase 1/2 clinical trial of tisagenlecleucel in a highly refractory patients with PCNSL and significant unmet medical need. Here, we present results of 12 relapsed patients with PCNSL who were treated with tisagenlecleucel and followed for a median time of 12.2 months (range, 3.64-23.5). Grade 1 cytokine release syndrome was observed in 7/12 patients (58.3%), low-grade ICANS in 5/12 (41.6%) patients, and only 1 patient experienced grade 3 ICANS. Seven of 12 patients (58.3%) demonstrated response, including a complete response in 6/12 patients (50%). There were no treatment-related deaths. Three patients had ongoing complete remission at data cutoff. Tisagenlecleucel expanded in the peripheral blood and trafficked to the CNS. Exploratory analysis identified T-cell, CAR T, and macrophage gene signatures in cerebrospinal fluid following infusion when compared with baseline. Overall, tisagenlecleucel was well tolerated and resulted in a sustained remission in 3/7 (42.9%) of initial responders. These data suggest that tisagenlecleucel is safe and effective in this highly refractory patient population. This trial was registered at www.clinicaltrials.gov as #NCT02445248.

Phase 1 Clinical Trial Evaluating the Safety and Anti-Tumor Activity of ADP-A2M10 SPEAR T-Cells in Patients With MAGE-A10+ Head and Neck, Melanoma, or Urothelial Tumors

Background

ADP-A2M10 specific peptide enhanced affinity receptor (SPEAR) T-cells are genetically engineered autologous T-cells that express a high-affinity melanoma-associated antigen (MAGE)-A10-specific T-cell receptor (TCR) targeting MAGE-A10-positive tumors in the context of human leukocyte antigen (HLA)-A*02. ADP-0022-004 is a phase 1, dose-escalation trial to evaluate the safety and anti-tumor activity of ADP-A2M10 in three malignancies (https://clinicaltrials.gov: NCT02989064).

Methods

Eligible patients were HLA-A*02 positive with advanced head and neck squamous cell carcinoma (HNSCC), melanoma, or urothelial carcinoma (UC) expressing MAGE-A10. Patients underwent apheresis; T-cells were isolated, transduced with a lentiviral vector containing the MAGE-A10 TCR, and expanded. Patients underwent lymphodepletion with fludarabine and cyclophosphamide prior to receiving ADP-A2M10. ADP-A2M10 was administered in two dose groups receiving 0.1×10⁹ and >1.2 to 6×10⁹ transduced cells, respectively, and an expansion group receiving 1.2 to 15×10⁹ transduced cells.

Results

Ten patients (eight male and two female) with HNSCC (four), melanoma (three), and UC (three) were treated. Three patients were treated in each of the two dose groups, and four patients were treated in the expansion group. The most frequently reported adverse events grade ≥3 were leukopenia (10), lymphopenia (10), neutropenia (10), anemia (nine), and thrombocytopenia (five). Two patients reported cytokine release syndrome (one each with grade 1 and grade 3), with resolution. Best response included stable disease in four patients, progressive disease in five patients, and not evaluable in one patient. ADP-A2M10 cells were detectable in peripheral blood from patients in each dose group and the expansion group and in tumor tissues from patients in the higher dose group and the expansion group. Peak persistence was greater in patients from the higher dose group and the expansion group compared with the lower dose group.

Conclusions

ADP-A2M10 has shown an acceptable safety profile with no evidence of toxicity related to off-target binding or alloreactivity in these malignancies. Persistence of ADP-A2M10 in the peripheral blood and trafficking of ADP-A2M10 into the tumor was demonstrated. Because MAGE-A10 expression frequently overlaps with MAGE-A4 expression in tumors and responses were observed in the MAGE-A4 trial (NCT03132922), this clinical program closed, and trials with SPEAR T-cells targeting the MAGE-A4 antigen are ongoing.

Phase I clinical trial evaluating the safety and efficacy of ADP-A2M10 SPEAR T cells in patients with MAGE-A10+ advanced non-small cell lung cancer

Background

ADP-A2M10 specific peptide enhanced affinity receptor (SPEAR) T cells (ADP-A2M10) are genetically engineered autologous T cells that express a high-affinity melanoma-associated antigen A10 (MAGE-A10)-specific T-cell receptor (TCR) targeting MAGE-A10⁺ tumors in the context of human leukocyte antigen (HLA)-A*02. ADP-0022-003 was a phase I dose-escalation trial that aimed to evaluate the safety and antitumor activity of ADP-A2M10 in non-small cell lung cancer (NSCLC) (NCT02592577).

Methods

Eligible patients were HLA-A*02 positive with advanced NSCLC expressing MAGE-A10. Patients underwent apheresis; T cells were isolated, transduced with a lentiviral vector containing the TCR targeting MAGE-A10, and expanded. Patients underwent lymphodepletion with varying doses/schedules of fludarabine and cyclophosphamide prior to receiving ADP-A2M10. ADP-A2M10 were administered at 0.08–0.12×10⁹ (dose group 1), 0.5–1.2×10⁹ (dose group 2), and 1.2–15×10⁹ (dose group 3/expansion) transduced cells.

Results

Eleven patients (male, n=6; female, n=5) with NSCLC (adenocarcinoma, n=8; squamous cell carcinoma, n=3) were treated. Five, three, and three patients received cells in dose group 1, dose group 2, and dose group 3/expansion, respectively. The most frequently reported grade ≥3 adverse events were lymphopenia (n=11), leukopenia (n=10), neutropenia (n=8), anemia (n=6), thrombocytopenia (n=5), and hyponatremia (n=5). Three patients presented with cytokine release syndrome (grades 1, 2, and 4, respectively). One patient received the highest dose of lymphodepletion (fludarabine 30 mg/m² on days –5 to –2 and cyclophosphamide 1800 mg/m² on days −5 to −4) prior to a second infusion of ADP-A2M10 and had a partial response, subsequently complicated by aplastic anemia and death. Responses included: partial response (after second infusion; one patient), stable disease (four patients), clinical or radiographic progressive disease (five patients), and not evaluable (one patient). ADP-A2M10 were detectable in peripheral blood and in tumor tissue. Peak persistence was higher in patients who received higher doses of ADP-A2M10.

Conclusions

ADP-A2M10 demonstrated an acceptable safety profile and no evidence of toxicity related to off-target binding or alloreactivity. There was persistence of ADP-A2M10 in peripheral blood as well as ADP-A2M10 trafficking into the tumor. Given the discovery that MAGE-A10 and MAGE-A4 expression frequently overlap, this clinical program closed as trials with SPEAR T cells targeting MAGE-A4 are ongoing.

Single-center experience using anakinra for steroid-refractory immune effector cell-associated neurotoxicity syndrome (ICANS)

In addition to remarkable antitumor activity, chimeric antigen receptor (CAR) T-cell therapy is associated with acute toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Current treatment guidelines for CRS and ICANS include use of tocilizumab, a monoclonal antibody that blocks the interleukin (IL)-6 receptor, and corticosteroids. In patients with refractory CRS, use of several other agents as third-line therapy (including siltuximab, ruxolitinib, anakinra, dasatinib, and cyclophosphamide) has been reported on an anecdotal basis. At our institution, anakinra has become the standard treatment for the management of steroid-refractory ICANS with or without CRS, based on recent animal data demonstrating the role of IL-1 in the pathogenesis of ICANS/CRS. Here, we retrospectively analyzed clinical and laboratory parameters, including serum cytokines, in 14 patients at our center treated with anakinra for steroid-refractory ICANS with or without CRS after standard treatment with tisagenlecleucel (Kymriah) or axicabtagene ciloleucel (Yescarta) CD19-targeting CAR T. We observed statistically significant and rapid reductions in fever, inflammatory cytokines, and biomarkers associated with ICANS/CRS after anakinra treatment. With three daily subcutaneous doses, anakinra did not have a clear, clinically dramatic effect on neurotoxicity, and its use did not result in rapid tapering of corticosteroids; although neutropenia and thrombocytopenia were common at the time of anakinra dosing, there were no clear delays in hematopoietic recovery or infections that were directly attributable to anakinra. Anakinra may be useful adjunct to steroids and tocilizumab in the management of CRS and/or steroid-refractory ICANs resulting from CAR T-cell therapies, but prospective studies are needed to determine its efficacy in these settings.

False-positive HIV testing in patients receiving lentivirus-based chimeric antigen receptor T-cell therapy: A case report, review of the literature and proposed recommendations

There are emerging reports of false positive HIV nucleic acid testing in patients who have received novel lentivirus-based chimeric antigen receptor T-cell (CAR-T) therapies. Herein, we report such a case, review the current state of the science on HIV-1 RNA diagnostics, highlight the potential for lentivirus-based CAR-T cell therapy cross-reactivity, and offer recommendations for HIV diagnostic testing in patients undergoing this mode of therapy.

Blockade or deletion of IFNg reduces macrophage activation without compromising CAR-T function in hematologic malignancies

Chimeric antigen receptor T cells (CAR-T) induce impressive responses in patients with hematologic malignancies but can also trigger cytokine release syndrome (CRS), a systemic toxicity caused by activated CAR-T and innate immune cells. Although interferon-gamma (IFNg) production serves as a potency assay for CAR T cells, its biologic role in conferring responses in hematologic malignancies is not established. Here we show that pharmacologic blockade or genetic knockout of IFNg reduced immune checkpoint protein expression with no detrimental effect on anti-tumor efficacy against hematologic malignancies in vitro or in vivo. Furthermore, IFNg blockade reduced macrophage activation to a greater extent than currently used cytokine antagonists in immune cells from healthy donors and serum from CAR-T treated lymphoma patients who developed CRS. Collectively, these data show that IFNg is not required for CAR-T efficacy against hematologic malignancies, and blocking IFNg could simultaneously mitigate cytokine-related toxicities while preserving persistence and anti-tumor efficacy.

Immune checkpoint inhibitors for cancer and venous thromboembolic events

BACKGROUND

Immune checkpoint inhibitors (ICIs) are widely used cancer treatments. There are limited data on the risk for developing venous thromboembolism (VTE) among patients on an ICI.

METHODS

This was a retrospective study of 2854 patients who received ICIs at a single academic centre. VTE events, defined as a composite of deep vein thrombosis or pulmonary embolism, were identified by individual chart review and blindly adjudicated using standard imaging criteria. A self-controlled risk-interval design was applied with an 'at-risk period' defined as the two-year period after and the 'control period', defined as the two-year before treatment. The hazard ratio (HR) was calculated using a fixed-effect proportional hazards model.

RESULTS

Of the 2854 patients, 1640 (57.5%) were men; the mean age was 64 ± 13 years. The risk for VTE was 7.4% at 6 months and 13.8% at 1 year after starting an ICI. The rate of VTE was > 4-fold higher after starting an ICI (HR 4.98, 95% CI 3.65-8.59, p < 0.001). There was a 5.7-fold higher risk for deep vein thrombosis (HR 5.70, 95% CI 3.79-8.59, p < 0.001) and a 4.75-fold higher risk for pulmonary embolism (HR 4.75, 95% CI 3.20-7.10, p < 0.001). Comparing patients with and without a VTE event, a history of melanoma and older age predicted lower risk of VTE, while a higher Khorana risk score, history of hypertension and history of VTE predicted higher risk.

CONCLUSIONS

The rate of VTE among patients on an ICI is high and increases after starting an ICI.

Allogeneic transplantation after PD-1 blockade for classic Hodgkin lymphoma

Anti-PD-1 monoclonal antibodies yield high response rates in patients with relapsed/refractory classic Hodgkin lymphoma (cHL), but most patients will eventually progress. Allogeneic hematopoietic cell transplantation (alloHCT) after PD-1 blockade may be associated with increased toxicity, raising challenging questions about the role, timing, and optimal method of transplantation in this setting. To address these questions, we assembled a retrospective cohort of 209 cHL patients who underwent alloHCT after PD-1 blockade. With a median follow-up among survivors of 24 months, the 2-year cumulative incidences (CIs) of non-relapse mortality and relapse were 14 and 18%, respectively; the 2-year graft-versus-host disease (GVHD) and relapse-free survival (GRFS), progression-free survival (PFS), and overall survival were 47%, 69%, and 82%, respectively. The 180-day CI of grade 3-4 acute GVHD was 15%, while the 2-year CI of chronic GVHD was 34%. In multivariable analyses, a longer interval from PD-1 to alloHCT was associated with less frequent severe acute GVHD, while additional treatment between PD-1 and alloHCT was associated with a higher risk of relapse. Notably, post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis was associated with significant improvements in PFS and GRFS. While awaiting prospective clinical trials, PTCy-based GVHD prophylaxis may be considered the optimal transplantation strategy for this patient population.

Hypoxemic Respiratory Failure Following Ruxolitinib Discontinuation in Allogeneic Hematopoietic Cell Transplantation Recipients

Ruxolitinib, a selective inhibitor of Janus kinases 1 and 2, is increasingly being used in allogeneic hematopoietic cell transplantation (HCT) recipients following its approval by the U.S. Food and Drug Administration for the treatment of steroid-refractory acute graft-versus-host disease. Although there is extensive experience using ruxolitinib for patients with myeloproliferative neoplasms, the biologic effects and clinical implications of its dosing, tapering, and discontinuation for allogeneic HCT recipients are incompletely characterized. We describe three allogeneic HCT recipients who developed acute hypoxemic respiratory failure within 3 months of ruxolitinib discontinuation. Radiographic findings included marked bilateral ground-glass opacities. Systemic corticosteroids and reinitiation of ruxolitinib resulted in rapid clinical improvement in all three patients. All three patients achieved a significant clinical response, with decrease in oxygen requirement and improvement in radiographic changes. Given the increasing use of ruxolitinib in allogeneic HCT recipients, there is significant impetus to characterize the biologic and clinical effects resulting from discontinuation of ruxolitinib, to better tailor treatment plans and prevent potential adverse effects.

Immunomodulation as Treatment for Severe Coronavirus Disease 2019: A Systematic Review of Current Modalities and Future Directions

In severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, viral load peaks early and declines quickly after symptom onset. Severe coronavirus disease 2019 (COVID-19) is marked by aberrant innate and adaptive immune responses with an abnormal cytokine profile and multiorgan system dysfunction that persists well after viral clearance. A purely antiviral treatment strategy may therefore be insufficient, and antiviral agents have not shown a benefit later in the illness course. A number of immunomodulatory strategies are being tested, including corticosteroids, cytokine and anticytokine therapies, small molecule inhibitors, and cellular therapeutics. To date, the only drug to show a mortality benefit for COVID-19 in a randomized, controlled trial is dexamethasone. However, there remains uncertainty about which patients may benefit most and about longer-term complications, including secondary infections. Here, we review the immune dysregulation of severe COVID-19 and the existing data behind various immunomodulatory strategies, and we consider future directions of study.

Patient with Lobular Carcinoma of the Breast and Activating AKT1 E17K Variant

OBJECTIVE

To present the characteristics of the AKT1E117K gene variant and a description of the clinical application in a patient with metastatic breast cancer.

RESULTS

63 y/o woman with Stage IV Invasive lobular carcinoma at diagnosis was treated with Palbociclib and aromatase inhibitors (AI). At progression, tissue was sent for comprehensive genomic profiling to Foundation Medicine (FM) which revealed AKT1E17K mutation. In lieu of available clinical data within the patient's tumor type (HR+ HER2- breast cancer), extrapolated data from the Flatiron Health-FM (FH-FMI) Clinico-genomic Database (CGDB) was discussed at our Molecular Tumor Board (MTB). After multidisciplinary discussion, the consensus recommendation was to start treatment with the combination of mTOR inhibitor everolimus, and AI, exemestane. Patient tolerated treatment without major side effects. By the second clinical visit the patient's breast showed signs of improvement. PET/CT showed diminished left axillary uptake, decreased right paratracheal lymph node PET avidity, and stable bone disease consistent with a partial response. The most recent office visit in January 2021, breast exam revealed a normal-appearing skin with only faint erythema. All other skin lesions have resolved. Although, the role of AKT1 variant described here is not well defined and therapeutic significance of M-Tor inhibitors not established in metastatic breast cancers, comprehensive approach to this case unraveled new and successful therapeutic option in this patient.

CONCLUSION

This demonstrates that applying available Precision Medicine tools like MTB and real world data sets from patient populations with similar clinical and genomic profiles may provide more options for treatment.

Phase 1 Study of CART-ddBCMA, a CAR-T therapy utilizing a novel synthetic binding domain, for the treatment of subjects with relapsed and refractory multiple myeloma

8015

Background: CART-ddBCMA is an autologous CAR-T cell therapy encoding a novel non-scFv synthetic binding domain targeting BCMA with a 4-1BB costimulatory motif and CD3-zeta T-cell activation domain. The novel binding domain is based on a computationally-derived triple-helix protein scaffold that is small (73 amino acids), stable, engineered to reduce immunogenicity, and can be modified to bind alternative targets. Methods: ARC-101 (NCT04155749), ARM 1 (CART-ddBCMA) is a Phase 1, multi-center, open-label, dose escalation trial enrolling subjects who have received ≥3 prior regimens, including proteasome inhibitor(s), immuno-modulatory agent(s), and anti-CD38 antibody, or are triple-refractory. Subjects undergo lymphodepletion with fludarabine and cyclophosphamide, then receive CART-ddBCMA as a single infusion. Planned dose levels are 100, 300, and up to 900 x 106 CAR+ T cells. The primary endpoint is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Secondary endpoints include clinical response per IMWG criteria, MRD, DOR, PFS, OS, and CAR-T cell kinetics. Results: As of 29 Jan 2021, 10 subjects received CART-ddBCMA, 9 subjects were evaluable, and 1 subject was pending assessment. Median age was 66 years [min:max 54 to 75]. 6 subjects received 100 x 106 CAR+ T cells, and 4 subjects received 300 x 106 CAR+ T cells. Median CAR+ expression was 74.5% (min:max 61-87%) of total T cells. Of the evaluable subjects, median follow-up after cell infusion was 208 days (min:max 45 to 355+ days), 9/9 subjects were penta-refractory, 1 subject was also refractory to BCMA-directed ADC. 8/9 had high-risk cytogenetics (1 subject’s sample not evaluable), and 6/9 subjects had extramedullary disease. No DLTs were reported. Per ASTCT Consensus Grading (Lee et al, 2019), 8 subjects developed G1/2 CRS, 1 subject in the higher dose cohort developed G3 CRS that rapidly resolved with tocilizumab. 1 subject developed G2 ICANS which rapidly resolved with intervention. 7 subjects received tocilizumab; 3 received dexamethasone. ORR was 100% (9/9) per IMWG criteria including 4 sCR, 1 VGPR, and 4 PR. 1 subject with PR relapsed and was retreated. All other subjects have ongoing responses; observations included sFLC normalization and elimination of detectable bone marrow disease by Month 1. Ongoing responses for subjects not yet achieving CR continue to deepen. 7 subjects were evaluable by MRD of which 5 are MRD-negative, and 2 are pending results. CAR-T cell expansion, as measured by vector transgene copies per microgram genomic DNA was observed in all patients. Conclusions: Early efficacy results are encouraging, with 9/9 (100%) ORR and manageable toxicities. 8/9 responses are ongoing and responses continue to deepen. These data are encouraging in high-risk subjects with penta-refractory myeloma. Subjects continue to be enrolled and treated. Clinical trial information: NCT04155749.

Detection of CAR-T19 cells in peripheral blood and cerebrospinal fluid: An assay applicable to routine diagnostic laboratories

BACKGROUND

Chimeric antigen receptor-modified T-cells targeting CD19 (CAR-T19) are licensed for treating relapsed/refractory diffuse large B-cell lymphoma and B-acute lymphoblastic leukemia. Predicting treatment responses and toxicity (e.g., cytokine release syndrome and neurotoxicity) remains a big challenge. CAR-T19 monitoring could increase our understanding of treatment responses and be of relevance to patient management. A robust method for accurate CAR-T19 detection is therefore extremely desirable.

METHODS

An assay that uses fluorochrome-conjugated human recombinant soluble CD19 was tested against two commercially available CAR-T19 therapies and a CAR-T19 cell line developed in-house. Precision, concordance, and analyte stability were tested using peripheral blood obtained from CAR-T19-treated patients and controls.

RESULTS

The assay showed good accuracy, and had a limit of blank for whole blood samples of 0.13%. Reproducibility and inter-operator concordance were satisfactory (CVs <15%). The assay distinguished CAR-T19 from reactive T-cells in cerebrospinal fluid (CSF) from patients with suspected immune effector cell-associated neurotoxicity syndrome (ICANS), and was adapted to study memory T-cell compartments in treated patients.

CONCLUSION

The assay enabled routine monitoring of CAR-T19 in blood and CSF samples. Despite profound cytopenia in many lymphoma patients, results were obtained regularly from only 4 ml of blood. The assay can be adapted easily to characterize the memory and exhaustion status of CAR-T19 and native T-cells. Importantly, it does not rely on CAR construct specificity; thus, it can be used to detect any CD19-targeted CAR cell. Finally, our validation process can serve as a blueprint for other fluorochrome proteins used to detect CAR cells.