Phase 1 Study of ROR1 Specific CAR T Cells in Advanced Hematopoietic and Epithelial Malignancies

PURPOSE

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed in hematopoietic and epithelial cancers but has limited expression on normal adult tissues. This phase 1 study evaluated the safety of targeting ROR1 with autologous T-lymphocytes engineered to express a ROR1 chimeric antigen receptor (CAR). Secondary objectives evaluated persistence, trafficking, and antitumor activity of CAR T cells.

PATIENTS & METHODS

Twenty-one patients with ROR1+ tumors received CAR T cells at one of four dose levels (DL): 3.3x105/1x106/3.3x106/1x107 cells/kg, administered after lymphodepletion with Cyclophosphamide/Fludarabine (Cy/Flu) or Oxaliplatin/Cyclophosphamide (Ox/Cy). Cohort A included patients with chronic lymphocytic leukemia (CLL, n=3); cohort B included patients with triple-negative breast cancer (TNBC, n=10) or non-small-cell lung cancer (NSCLC, n=8). A second infusion was administered to one patient in cohort A with residual CLL in the marrow and three patients in cohort B with stable disease after first infusion.

RESULTS

Treatment was well tolerated apart from one dose limiting toxicity at DL4 in a patient with advanced NSCLC. Two of the three (67%) CLL patients showed robust CAR T expansion and a rapid antitumor response. In patients with NSCLC and TNBC, CAR T cells expanded to variable levels, infiltrated tumor poorly, and one of eighteen patients (5.5%) achieved partial response by RECIST 1.1.

CONCLUSION

ROR1 CAR T cells were well tolerated in most patients. Antitumor activity was observed in CLL but was limited in TNBC and NSCLC. Immunogenicity of the CAR and lack of sustained tumor infiltration were identified as limitations.

Histone marks identify novel transcription factors that parse CAR-T subset-of-origin, clinical potential and expansion

Chimeric antigen receptor-modified T cell (CAR-T) immunotherapy has revolutionised blood cancer treatment. Parsing the genetic underpinnings of T cell quality and CAR-T efficacy is challenging. Transcriptomics inform CAR-T state, but the nature of dynamic transcription during activation hinders identification of transiently or minimally expressed genes, such as transcription factors, and over-emphasises effector and metabolism genes. Here we explore whether analyses of transcriptionally repressive and permissive histone methylation marks describe CAR-T cell functional states and therapeutic potential beyond transcriptomic analyses. Histone mark analyses improve identification of differences between naïve, central memory, and effector memory CD8 + T cell subsets of human origin, and CAR-T derived from these subsets. We find important differences between CAR-T manufactured from central memory cells of healthy donors and of patients. By examining CAR-T products from a clinical trial in lymphoma (NCT01865617), we find a novel association between the activity of the transcription factor KLF7 with in vivo CAR-T accumulation in patients and demonstrate that over-expression of KLF7 increases in vitro CAR-T proliferation and IL-2 production.  In conclusion, histone marks provide a rich dataset for identification of functionally relevant genes not apparent by transcriptomics.

HA-1-targeted T-cell receptor T-cell therapy for recurrent leukemia after hematopoietic stem cell transplantation

ABSTRACT

Relapse is the leading cause of death after allogeneic hematopoietic stem cell transplantation (HCT) for leukemia. T cells engineered by gene transfer to express T cell receptors (TCR; TCR-T) specific for hematopoietic-restricted minor histocompatibility (H) antigens may provide a potent selective antileukemic effect post-HCT. We conducted a phase 1 clinical trial using a novel TCR-T product targeting the minor H antigen, HA-1, to treat or consolidate treatment of persistent or recurrent leukemia and myeloid neoplasms. The primary objective was to evaluate the feasibility and safety of administration of HA-1 TCR-T after HCT. CD8+ and CD4+ T cells expressing the HA-1 TCR and a CD8 coreceptor were successfully manufactured from HA-1-disparate HCT donors. One or more infusions of HA-1 TCR-T following lymphodepleting chemotherapy were administered to 9 HCT recipients who had developed disease recurrence after HCT. TCR-T cells expanded and persisted in vivo after adoptive transfer. No dose-limiting toxicities occurred. Although the study was not designed to assess efficacy, 4 patients achieved or maintained complete remissions following lymphodepletion and HA-1 TCR-T, with 1 patient still in remission at >2 years. Single-cell RNA sequencing of relapsing/progressive leukemia after TCR-T therapy identified upregulated molecules associated with T-cell dysfunction or cancer cell survival. HA-1 TCR-T therapy appears feasible and safe and shows preliminary signals of efficacy. This clinical trial was registered at ClinicalTrials.gov as #NCT03326921.

Detecting HLA loss of heterozygosity within a standard diagnostic sequencing workflow for prognostic and therapeutic opportunities

To enable interrogation of tumor HLA LOH as a clinical diagnostic for precision oncology, we developed and validated an assay that detects HLA LOH within the context of an FDA-approved clinical diagnostic test, Tempus xT CDx. Validation was conducted via: (1) analytical evaluation of 17 archival patient samples and 42 cell line admixtures and (2) independent clinical evaluation of LOH prevalence in the HLA-A gene (HLA-A LOH) across 10,982 patients. To evaluate the prognostic relevance of HLA-A LOH we assessed 256 immunotherapy-treated non-small cell lung cancer (NSCLC) patients. To determine the feasibility of prospectively identifying and enrolling HLA-A LOH patients into a clinical trial, we established BASECAMP-1 (NCT04981119). We observed a positive predictive agreement of 97% and a negative predictive agreement of 100% in samples with ≥ 40% tumor purity. We observed HLA-A LOH in 16.1% of patients (1771/10,982), comparable to previous reports. HLA-A LOH was associated with longer survival among NSCLC adenocarcinoma patients (HR = 0.60, 95% CI [0.37, 0.96], p = 0.032) with a trend towards shorter survival among squamous cell patients (HR = 1.64, 95% CI [0.80, 3.41], p = 0.183). In 20 months, we prospectively screened 1720 subjects using the Tempus AWARE program, identifying 26 HLA-A*02 LOH patients at 8 sites, with 14 (54%) enrolled into BASECAMP-1. In conclusion, we developed and validated an investigational assay that detects tumor HLA LOH within an FDA-approved clinical diagnostic test, enabling HLA LOH utilization in diagnostic, prognostic, and therapeutic applications.

PD-L1+ macrophage and tumor cell abundance and proximity to T cells in the pretreatment large B-cell lymphoma microenvironment impact CD19 CAR-T cell immunotherapy efficacy

CD19-targeted chimeric antigen receptor T-cell (CAR-T) immunotherapy has transformed the management of relapsed/refractory large B-cell lymphoma (LBCL), yet durable remissions are observed in less than half of treated patients. The tumor microenvironment (TME) is a key and understudied factor impacting CD19 CAR-T therapy outcomes. Using NanoString nCounter transcriptome profiling (n = 24) and multiplex immunohistochemistry (mIHC, n = 15), we studied the TME in pretreatment biopsies from patients with LBCL undergoing CD19 CAR-T therapy. Patients who achieved complete response (CR) after CAR-T therapy demonstrated higher expression of genes associated with T-cell trafficking and function, whereas those who did not achieve CR had higher expression of genes associated with macrophages and T-cell dysfunction. Distinct patterns of immune infiltration and fibrosis in the TME were associated with CAR-T therapy outcomes, and these findings were corroborated using artificial intelligence-assisted image analyses. Patients who achieved CR had a lower proportion of the biopsy occupied by an interspersed immune infiltrate and a higher proportion of hypocellular/fibrotic regions. Furthermore, mIHC revealed lower density of CD4+ T cells and higher densities of both macrophages and tumor cells expressing PD-L1 in non-CR patients. Spatial analysis revealed that PD-1+ T cells were in close proximity to PD-L1+ macrophages or PD-L1+ tumor cells in patients who did not compared to those who did achieve CR after CAR-T therapy. These findings suggest that morphologic patterns in the TME and engagement of the PD-1/PD-L1 axis in pretreatment biopsies may impact CD19 CAR-T immunotherapy response in patients with LBCL.

Long-term Remissions Following CD20-Directed Chimeric Antigen Receptor-Adoptive T-cell Therapy

Chimeric antigen receptor (CAR) T-cell therapy produces high response rates in refractory B-cell non-Hodgkin lymphoma, but long-term data are minimal to date. In this study, we present long-term follow-up of a pilot trial testing a CD20-targeting third-generation CAR in patients with relapsed B-cell lymphomas following cyclophosphamide-only lymphodepletion. Two of the three patients in the trial, with mantle cell lymphoma and follicular lymphoma, had remissions lasting more than 7 years, though they ultimately relapsed. The absence of B-cell aplasia in both patients suggested a lack of functional CAR T-cell persistence, leading to the hypothesis that endogenous immune responses were responsible for these long-term remissions. Correlative immunologic analyses supported this hypothesis, with evidence of new humoral and cellular antitumor immune responses proximal to clinical response time points. Collectively, our results suggest that CAR T-cell therapy may facilitate epitope spreading and endogenous immune response formation in lymphomas. Significance: Two of three patients treated with CD20-targeted CAR T-cell therapy had long-term remissions, with evidence of endogenous antitumor immune response formation. Further investigation is warranted to develop conditions that promote epitope spreading in lymphomas.

qPCR assay for detection of Woodchuck Hepatitis Virus Post-Transcriptional Regulatory Elements from CAR-T and TCR-T cells in fresh and formalin-fixed tissue

As adoptive cellular therapies become more commonplace in cancer care, there is a growing need to monitor site-specific localization of engineered cells-such as chimeric antigen receptor T (CAR-T) cells and T-cell receptor T (TCR-T) cells-in patients' tissues to understand treatment effectiveness as well as associated adverse events. Manufacturing CAR-T and TCR-T cells involves transduction with viral vectors commonly containing the WPRE gene sequence to enhance gene expression, providing a viable assay target unique to these engineered cells. Quantitative PCR (qPCR) is currently used clinically in fresh patient tissue samples and blood with target sequences specific to each immunotherapy product. Herein, we developed a WPRE-targeted qPCR assay that is broadly applicable for detection of engineered cell products in both fresh and archival formalin-fixed paraffin embedded (FFPE) tissues. Using both traditional PCR and SYBR Green PCR protocols, we demonstrate the use of this WPRE-targeted assay to successfully detect two CAR-T cell and two TCR-T cell products in FFPE tissue. Standard curve analysis reported a reproducible limit of detection at 100 WPRE copies per 20μL PCR reaction. This novel and inexpensive technique could provide better understanding of tissue abundance of engineered therapeutic T cells in both tumor and second-site toxicity tissues and provide quantitative assessment of immune effector cell trafficking in archival tissue.

Cytomegalovirus (CMV) Reactivation and CMV-Specific Cell-Mediated Immunity After Chimeric Antigen Receptor T-Cell Therapy

BACKGROUND

The epidemiology of cytomegalovirus (CMV) after chimeric antigen receptor-modified T-cell immunotherapy (CARTx) is poorly understood owing to a lack of routine surveillance.

METHODS

We prospectively enrolled 72 adult CMV-seropositive CD19-, CD20-, or BCMA-targeted CARTx recipients and tested plasma samples for CMV before and weekly up to 12 weeks after CARTx. We assessed CMV-specific cell-mediated immunity (CMV-CMI) before and 2 and 4 weeks after CARTx, using an interferon γ release assay to quantify T-cell responses to IE-1 and pp65. We tested pre-CARTx samples to calculate a risk score for cytopenias and infection (CAR-HEMATOTOX). We used Cox regression to evaluate CMV risk factors and evaluated the predictive performance of CMV-CMI for CMV reactivation in receiver operator characteristic curves.

RESULTS

CMV was detected in 1 patient (1.4%) before and in 18 (25%) after CARTx, for a cumulative incidence of 27% (95% confidence interval, 16.8-38.2). The median CMV viral load (interquartile range) was 127 (interquartile range, 61-276) IU/mL, with no end-organ disease observed; 5 patients received preemptive therapy based on clinical results. CMV-CMI values reached a nadir 2 weeks after infusion and recovered to baseline levels by week 4. In adjusted models, BCMA-CARTx (vs CD19/CD20) and corticosteroid use for >3 days were significantly associated with CMV reactivation, and possible associations were detected for lower week 2 CMV-CMI and more prior antitumor regimens. The cumulative incidence of CMV reactivation almost doubled when stratified by BCMA-CARTx target and use of corticosteroids for >3 days (46% and 49%, respectively).

CONCLUSIONS

CMV testing could be considered between 2 and 6 weeks in high-risk CARTx recipients.

Three-year follow-up analysis of axicabtagene ciloleucel in relapsed/refractory indolent non-Hodgkin lymphoma (ZUMA-5)

ABSTRACT

Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory (R/R) follicular lymphoma (FL). Approval was supported by the phase 2, multicenter, single-arm ZUMA-5 study of axi-cel for patients with R/R indolent non-Hodgkin lymphoma (iNHL; N = 104), including FL and marginal zone lymphoma (MZL). In the primary analysis (median follow-up, 17.5 months), the overall response rate (ORR) was 92% (complete response rate, 74%). Here, we report long-term outcomes from ZUMA-5. Eligible patients with R/R iNHL after ≥2 lines of therapy underwent leukapheresis, followed by lymphodepleting chemotherapy and axi-cel infusion (2 × 106 CAR T cells per kg). The primary end point was ORR, assessed in this analysis by investigators in all enrolled patients (intent-to-treat). After median follow-up of 41.7 months in FL (n = 127) and 31.8 months in MZL (n = 31), ORR was comparable with that of the primary analysis (FL, 94%; MZL, 77%). Median progression-free survival was 40.2 months in FL and not reached in MZL. Medians of overall survival were not reached in either disease type. Grade ≥3 adverse events of interest that occurred after the prior analyses were largely in recently treated patients. Clinical and pharmacokinetic outcomes correlated negatively with recent exposure to bendamustine and high metabolic tumor volume. After 3 years of follow-up in ZUMA-5, axi-cel demonstrated continued durable responses, with very few relapses beyond 2 years, and manageable safety in patients with R/R iNHL. The ZUMA-5 study was registered at www.clinicaltrials.gov as #NCT03105336.

Two-year follow-up of lisocabtagene maraleucel in relapsed or refractory large B-cell lymphoma in TRANSCEND NHL 001

ABSTRACT

Lisocabtagene maraleucel (liso-cel) demonstrated significant efficacy with a manageable safety profile as third-line or later treatment for patients with relapsed or refractory (R/R) large B-cell lymphoma (LBCL) in the TRANSCEND NHL 001 study. Primary end points were adverse events (AEs), dose-limiting toxicities, and objective response rate (ORR) per independent review committee. Key secondary end points were complete response (CR) rate, duration of response (DOR), progression-free survival (PFS), and overall survival (OS). After 2-year follow-up, patients could enroll in a separate study assessing long-term (≤15 years) safety and OS. Liso-cel-treated patients (N = 270) had a median age of 63 years (range, 18-86 years) and a median of 3 prior lines (range, 1-8) of systemic therapy, and 181 of them (67%) had chemotherapy-refractory LBCL. Median follow-up was 19.9 months. In efficacy-evaluable patients (N = 257), the ORR was 73% and CR rate was 53%. The median (95% confidence interval) DOR, PFS, and OS were 23.1 (8.6 to not reached), 6.8 (3.3-12.7), and 27.3 months (16.2-45.6), respectively. Estimated 2-year DOR, PFS, and OS rates were 49.5%, 40.6%, and 50.5%, respectively. In the 90-day treatment-emergent period (N = 270), grade 3 to 4 cytokine release syndrome and neurological events occurred in 2% and 10% of patients, respectively. The most common grade ≥3 AEs in treatment-emergent and posttreatment-emergent periods, respectively, were neutropenia (60% and 7%) and anemia (37% and 6%). Liso-cel demonstrated durable remissions and a manageable safety profile with no new safety signals during the 2-year follow-up in patients with R/R LBCL. These trials were registered at www.ClinicalTrials.gov as #NCT02631044 and #NCT03435796.

Timing of anti-PD-L1 antibody initiation affects efficacy/toxicity of CD19 CAR T-cell therapy for large B-cell lymphoma

ABSTRACT

More than half of the patients treated with CD19-targeted chimeric antigen receptor (CAR) T-cell immunotherapy for large B-cell lymphoma (LBCL) do not achieve durable remission, which may be partly due to PD-1/PD-L1-associated CAR T-cell dysfunction. We report data from a phase 1 clinical trial (NCT02706405), in which adults with LBCL were treated with autologous CD19 CAR T cells (JCAR014) combined with escalating doses of the anti-PD-L1 monoclonal antibody, durvalumab, starting either before or after CAR T-cell infusion. The addition of durvalumab to JCAR014 was safe and not associated with increased autoimmune or immune effector cell-associated toxicities. Patients who started durvalumab before JCAR014 infusion had later onset and shorter duration of cytokine release syndrome and inferior efficacy, which was associated with slower accumulation of CAR T cells and lower concentrations of inflammatory cytokines in the blood. Initiation of durvalumab before JCAR014 infusion resulted in an early increase in soluble PD-L1 (sPD-L1) levels that coincided with the timing of maximal CAR T-cell accumulation in the blood. In vitro, sPD-L1 induced dose-dependent suppression of CAR T-cell effector function, which could contribute to inferior efficacy observed in patients who received durvalumab before JCAR014. Despite the lack of efficacy improvement and similar CAR T-cell kinetics early after infusion, ongoing durvalumab therapy after JCAR014 was associated with re-expansion of CAR T cells in the blood, late regression of CD19+ and CD19- tumors, and enhanced duration of response. Our results indicate that the timing of initiation of PD-L1 blockade is a key variable that affects outcomes after CD19 CAR T-cell immunotherapy for adults with LBCL.

Factors associated with long-term outcomes of CD19 CAR T-cell therapy for relapsed/refractory CLL

High response rates have been reported after CD19-targeted chimeric antigen receptor-modified (CD19 CAR) T-cell therapy for relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), yet the factors associated with duration of response in this setting are poorly characterized. We analyzed long-term outcomes in 47 patients with R/R CLL and/or Richter transformation treated on our phase 1/2 clinical trial of CD19 CAR T-cell therapy with an updated median follow-up of 79.6 months. Median progression-free survival (PFS) was 8.9 months, and the 6-year PFS was 17.8%. Maximum standardized uptake value (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.07-1.23; P < .001) and bulky disease (≥5 cm; HR, 2.12; 95% CI, 1.06-4.26; P = .034) before lymphodepletion were associated with shorter PFS. Day +28 complete response by positron emission tomography-computed tomography (HR, 0.13; 95% CI, 0.04-0.40; P < .001), day +28 measurable residual disease (MRD) negativity by multiparameter flow cytometry (HR, 0.08; 95% CI, 0.03-0.22; P < .001), day +28 MRD negativity by next-generation sequencing (HR, 0.21; 95% CI, 0.08-0.51; P < .001), higher peak CD8+ CAR T-cell expansion (HR, 0.49; 95% CI; 0.36-0.68; P < .001), higher peak CD4+ CAR T-cell expansion (HR, 0.47; 95% CI; 0.33-0.69; P < .001), and longer CAR T-cell persistence (HR, 0.56; 95% CI, 0.44-0.72; P < .001) were associated with longer PFS. The 6-year duration of response and overall survival were 26.4% and 31.2%, respectively. CD19 CAR T-cell therapy achieved durable responses with curative potential in a subset of patients with R/R CLL. This trial was registered at www.clinicaltrials.gov as #NCT01865617.

Bortezomib and Vorinostat Therapy as Maintenance Therapy Post-Autologous Transplant for Non-Hodgkin's Lymphoma Using R-BEAM or BEAM Transplant Conditioning Regimen

INTRODUCTION

The success of autologous stem cell transplantation (ASCT) for treating non-Hodgkin's lymphoma (NHL) is limited by its high relapse rates. To reduce the risk of relapse, additional maintenance therapy can be added post-transplant. In a non-transplant setting at the time of initiation of this study, both bortezomib and vorinostat had been studied alone or in combination for some NHL histology and showed some clinical activity. At our center, this combination therapy post-transplant for multiple myeloma showed acceptable toxicity. Therefore, it seemed reasonable to study this combination therapy post-ASCT for NHL.

METHODS

NHL patients underwent conditioning for ASCT with rituximab, carmustine, etoposide, cytarabine, melphalan/carmustine, etoposide, cytarabine, melphalan. After recovery from the acute transplant-related toxicity, combination therapy with IV bortezomib and oral vorinostat (BV) was started and was given for a total of 12 (28-day) cycles.

RESULTS

Nineteen patients received BV post-ASCT. The most common toxicities were hematologic, gastrointestinal, metabolic, fatigue, and peripheral neuropathy. With a median follow-up of 10.3 years, 11 patients (58%) are alive without disease progression and 12 patients (63%) are alive.

CONCLUSIONS

BV can be given post-ASCT for NHL and produces excellent disease-free and overall survival rates.

Lisocabtagene maraleucel in chronic lymphocytic leukaemia and small lymphocytic lymphoma (TRANSCEND CLL 004): a multicentre, open-label, single-arm, phase 1-2 study

BACKGROUND

Patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma for whom treatment has failed with both Bruton tyrosine kinase (BTK) inhibitor and venetoclax have few treatment options and poor outcomes. We aimed to evaluate the efficacy and safety of lisocabtagene maraleucel (liso-cel) at the recommended phase 2 dose in patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma.

METHODS

We report the primary analysis of TRANSCEND CLL 004, an open-label, single-arm, phase 1-2 study conducted in the USA. Patients aged 18 years or older with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma and at least two previous lines of therapy, including a BTK inhibitor, received an intravenous infusion of liso-cel at one of two target dose levels: 50 × 106 (dose level 1) or 100 × 106 (dose level 2, DL2) chimeric antigen receptor-positive T cells. The primary endpoint was complete response or remission (including with incomplete marrow recovery), assessed by independent review according to the 2018 International Workshop on Chronic Lymphocytic Leukemia criteria, in efficacy-evaluable patients with previous BTK inhibitor progression and venetoclax failure (the primary efficacy analysis set) at DL2 (null hypothesis of ≤5%). This trial is registered with ClinicalTrials.gov, NCT03331198.

FINDINGS

Between Jan 2, 2018, and June 16, 2022, 137 enrolled patients underwent leukapheresis at 27 sites in the USA. 117 patients received liso-cel (median age 65 years [IQR 59-70]; 37 [32%] female and 80 [68%] male; 99 [85%] White, five [4%] Black or African American, two [2%] other races, and 11 [9%] unknown race; median of five previous lines of therapy [IQR 3-7]); all 117 participants had received and had treatment failure on a previous BTK inhibitor. A subset of patients had also experienced venetoclax failure (n=70). In the primary efficacy analysis set at DL2 (n=49), the rate of complete response or remission (including with incomplete marrow recovery) was statistically significant at 18% (n=9; 95% CI 9-32; p=0·0006). In patients treated with liso-cel, grade 3 cytokine release syndrome was reported in ten (9%) of 117 (with no grade 4 or 5 events) and grade 3 neurological events were reported in 21 (18%; one [1%] grade 4, no grade 5 events). Among 51 deaths on the study, 43 occurred after liso-cel infusion, of which five were due to treatment-emergent adverse events (within 90 days of liso-cel infusion). One death was related to liso-cel (macrophage activation syndrome-haemophagocytic lymphohistiocytosis).

INTERPRETATION

A single infusion of liso-cel was shown to induce complete response or remission (including with incomplete marrow recovery) in patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma, including patients who had experienced disease progression on a previous BTK inhibitor and venetoclax failure. The safety profile was manageable.

FUNDING

Juno Therapeutics, a Bristol-Myers Squibb Company.

γ-Secretase inhibitor in combination with BCMA chimeric antigen receptor T-cell immunotherapy for individuals with relapsed or refractory multiple myeloma: a phase 1, first-in-human trial

BACKGROUND

γ-Secretase inhibitors (GSIs) increase B cell maturation antigen (BCMA) density on malignant plasma cells and enhance antitumour activity of BCMA chimeric antigen receptor (CAR) T cells in preclinical models. We aimed to evaluate the safety and identify the recommended phase 2 dose of BCMA CAR T cells in combination with crenigacestat (LY3039478) for individuals with relapsed or refractory multiple myeloma.

METHODS

We conducted a phase 1, first-in-human trial combining crenigacestat with BCMA CAR T-cells at a single cancer centre in Seattle, WA, USA. We included individuals aged 21 years or older with relapsed or refractory multiple myeloma, previous autologous stem-cell transplant or persistent disease after more than four cycles of induction therapy, and Eastern Cooperative Oncology Group performance status of 0-2, regardless of previous BCMA-targeted therapy. To assess the effect of the GSI on BCMA surface density on bone marrow plasma cells, participants received GSI during a pretreatment run-in, consisting of three doses administered 48 h apart. BCMA CAR T cells were infused at doses of 50 × 106 CAR T cells, 150 × 106 CAR T cells, 300 × 106 CAR T cells, and 450 × 106 CAR T cells (total cell dose), in combination with the 25 mg crenigacestat dosed three times a week for up to nine doses. The primary endpoints were the safety and recommended phase 2 dose of BCMA CAR T cells in combination with crenigacestat, an oral GSI. This study is registered with ClinicalTrials.gov, NCT03502577, and has met accrual goals.

FINDINGS

19 participants were enrolled between June 1, 2018, and March 1, 2021, and one participant did not proceed with BCMA CAR T-cell infusion. 18 participants (eight [44%] men and ten [56%] women) with multiple myeloma received treatment between July 11, 2018, and April 14, 2021, with a median follow up of 36 months (95% CI 26 to not reached). The most common non-haematological adverse events of grade 3 or higher were hypophosphataemia in 14 (78%) participants, fatigue in 11 (61%), hypocalcaemia in nine (50%), and hypertension in seven (39%). Two deaths reported outside of the 28-day adverse event collection window were related to treatment. Participants were treated at doses up to 450 × 106 CAR+ cells, and the recommended phase 2 dose was not reached.

INTERPRETATIONS

Combining a GSI with BCMA CAR T cells appears to be well tolerated, and crenigacestat increases target antigen density. Deep responses were observed among heavily pretreated participants with multiple myeloma who had previously received BCMA-targeted therapy and those who were naive to previous BCMA-targeted therapy. Further study of GSIs given with BCMA-targeted therapeutics is warranted in clinical trials.

FUNDING

Juno Therapeutics-a Bristol Myers Squibb company and the National Institutes of Health.

Anakinra for Refractory Cytokine Release Syndrome or Immune Effector Cell-Associated Neurotoxicity Syndrome after Chimeric Antigen Receptor T Cell Therapy

Chimeric antigen receptor-engineered (CAR)-T cell therapy remains limited by significant toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The optimal management of severe and/or refractory CRS/ICANS remains ill-defined. Anakinra has emerged as a promising agent based on preclinical data, but its safety and efficacy in CAR-T therapy recipients are unknown. The primary objective of this study was to evaluate the safety of anakinra to treat refractory CRS and ICANS after CAR-T therapy. The secondary objective was to evaluate the impact of key treatment-, patient-, and disease-related variables on the time to CRS/ICANS resolution and treatment-related mortality (TRM). We retrospectively analyzed the outcomes of 43 patients with B cell or plasma cell malignancies treated with anakinra for refractory CRS or ICANS at 9 institutions in the United States and Spain between 2019 and 2022. Cause-specific Cox regression was used to account for competing risks. Multivariable cause-specific Cox regression was used to estimate the effect of anakinra dose on outcomes while minimizing treatment allocation bias by including age, CAR-T product, prelymphodepletion (pre-LD) ferritin, and performance status. Indications for anakinra treatment were grade ≥2 ICANS with worsening or lack of symptom improvement despite treatment with high-dose corticosteroids (n = 40) and grade ≥2 CRS with worsening symptoms despite treatment with tocilizumab (n = 3). Anakinra treatment was feasible and safe; discontinuation of therapy because of anakinra-related side effects was reported in only 3 patients (7%). The overall response rate (ORR) to CAR-T therapy was 77%. The cumulative incidence of TRM in the whole cohort was 7% (95% confidence interval [CI], 2% to 17%) at 28 days and 23% (95% CI, 11% to 38%) at 60 days after CAR-T infusion. The cumulative incidence of TRM at day 28 after initiation of anakinra therapy was 0% in the high-dose (>200 mg/day i.v.) recipient group and 47% (95% CI, 20% to 70%) in the low-dose (100 to 200 mg/day s.c. or i.v.) recipient group. The median cumulative incidence of CRS/ICANS resolution from the time of anakinra initiation was 7 days in the high-dose group and was not reached in the low-dose group, owing to the high TRM in this group. Univariate Cox modeling suggested a shorter time to CRS/ICANS resolution in the high-dose recipients (hazard ratio [HR], 2.19; 95% CI, .94 to 5.12; P = .069). In a multivariable Cox model for TRM including age, CAR-T product, pre-LD ferritin level, and pre-LD Karnofsky Performance Status (KPS), higher anakinra dose remained associated with lower TRM (HR, .41 per 1 mg/kg/day increase; 95% CI, .17 to .96; P = .039. The sole factor independently associated with time to CRS/ICANS resolution in a multivariable Cox model including age, CAR-T product, pre-LD ferritin and anakinra dose was higher pre-LD KPS (HR, 1.05 per 10% increase; 95% CI, 1.01 to 1.09; P = .02). Anakinra treatment for refractory CRS or ICANS was safe at doses up to 12 mg/kg/day i.v. We observed an ORR of 77% after CAR-T therapy despite anakinra treatment, suggesting a limited impact of anakinra on CAR-T efficacy. Higher anakinra dose may be associated with faster CRS/ICANS resolution and was independently associated with lower TRM. Prospective comparative studies are needed to confirm our findings.

Anti-HLA antibodies in recipients of CD19 versus BCMA-targeted CAR T-cell therapy

Antibodies against foreign human leukocyte antigen (HLA) molecules are barriers to successful organ transplantation. B cell-depleting treatments are used to reduce anti-HLA antibodies but have limited efficacy. We hypothesized that the primary source for anti-HLA antibodies is long-lived plasma cells, which are ineffectively targeted by B cell depletion. To study this, we screened for anti-HLA antibodies in a prospectively enrolled cohort of 49 patients who received chimeric antigen receptor T-cell therapy (CARTx), targeting naïve and memory B cells (CD19-targeted, n = 21) or plasma cells (BCMA-targeted, n = 28) for hematologic malignancies. Longitudinal samples were collected before and up to 1 year after CARTx. All individuals were in sustained remission. We identified 4 participants with anti-HLA antibodies before CD19-CARTx. Despite B cell depletion, anti-HLA antibodies and calculated panel reactive antibody scores were stable for 1 year after CD19-CARTx. Only 1 BCMA-CARTx recipient had pre-CARTx low-level anti-HLA antibodies, with no follow-up samples available. These data implicate CD19neg long-lived plasma cells as an important source for anti-HLA antibodies, a model supported by infrequent HLA sensitization in BCMA-CARTx subjects receiving previous plasma cell-targeted therapies. Thus, plasma cell-targeted therapies may be more effective against HLA antibodies, thereby enabling improved access to organ transplantation and rejection management.

Prospective BASECAMP-1 experience in patients with gastrointestinal (GI) cancer: Identifying patients with human leukocyte antigen (HLA) loss of heterozygosity (LOH) for a future therapeutic trial exploiting LOH as a tumor vulnerability

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Background: Metastatic colorectal (CRC), pancreatic (PANC), and gastroesophageal cancers are the leading causes of GI cancer–related mortality (5-y survival: 15%, 3%, and 5%-6%, respectively) (ACS 2022). HLA LOH is a recurrent mechanism of immune escape observed in 15%-20% of GI cancers (Hecht R., ASCO GI 2022). The Tmod platform is a logic-gated chimeric antigen receptor (CAR) T-cell modular system, comprising a carcinoembryonic antigen (CEA)- or mesothelin (MSLN)-targeting CAR activator and a separate HLA-A*02-targeting blocker receptor. Both in vitro/in vivo, Tmod CAR T therapy kills cells with HLA-A*02 LOH (tumor) without harming cells with retained HLA-A*02 expression (normal). However, HLA-A*02 LOH can only be therapeutically exploited if patients are identifiable through a feasible and timely clinical workflow. Methods: We established a biobanking protocol (BASECAMP-1, NCT04981119) to determine whether HLA-A*02 LOH patients can be prospectively identified. Patients with CRC, PANC, or non-small cell lung cancer (NSCLC), and a high risk for incurable relapse, were screened first using a standard HLA assay. Heterozygous HLA-A*02 positive tumor samples were then assessed for LOH using a bioinformatic algorithm applied via the Tempus xT platform. Results: As of Sep 1, 2022, 83 patients were consented at 4 institutions. HLA status was obtained from 70 patients and 28 were identified as HLA-A*02:01 heterozygous (40%; expected frequency based on USA NMDP data, 27.6%). LOH results were available for 16 patients; 4 LOH-positive patients were identified (25%, 2 PANC, 2 NSCLC). The LOH assay sensitivity declines below a tumor purity of 40% (Hecht R., ASCO GI 2022). Six patients had a tumor purity of 20% (all with PANC, a tumor known for high stromal content), limiting possible LOH detection. The impact of tumor purity on LOH sensitivity was highlighted in a patient with a low initial sample tumor purity (30%) that resulted in a 41% probability of HLA-A*02:01 LOH (below positive threshold). A second sample with a higher tumor purity (70%), obtained from formalin-fixed, paraffin-embedded sections, resulted in a 92% probability of HLA-A*02:01 LOH (positive). Conclusions: BASECAMP-1 prospective identification of HLA-A*02 LOH is feasible in the real-world setting. The frequencies of the HLA-A*02 allele and of HLA-A*02 LOH in this cohort mirrored expected population frequencies. LOH results can be obtained within a clinically feasible workflow and timeframe, although samples with a < 40% tumor purity have a reduced sensitivity for LOH detection, an issue recurrently observed in patients with PANC. The BASECAMP-1 strategy enables prospective identification of appropriate patients for future therapeutic clinical trials using Tmod CEA and MSLN logic-gated CAR T cells. Clinical trial information: NCT04981119 .

Predictors of response to axicabtagene-ciloleucel CAR T cells in aggressive B cell lymphomas: A real-world study

Chimeric antigen receptor T-cell (CAR T) therapy has shown promising efficacy in relapsed and refractory diffuse large B cell lymphoma (DLBCL). While most patients undergo CAR T infusion with active disease, the impact of some clinical variables, such as responsiveness to the pre-CAR T chemotherapy on the response to CAR T, is unknown. In this single-institution study, we studied the impact of several pre-CAR T variables on the post-CAR outcomes. Sixty patients underwent apheresis for axicabtagene-ciloleucel (axi-cel) and 42 of them (70.0%) had primary refractory disease. Bridging therapy between apheresis and lymphodepletion was given in 34 patients (56.7%). After axi-cel, the overall response rate was 63.3%. Responsiveness to the immediate pre-CAR T therapy did not show a significant association with response to axi-cel, progression-free (PFS) or overall (OS) survival. Multivariable analysis determined that bulky disease before lymphodepletion was independently associated with inferior outcomes, and patients that presented with high-burden disease unresponsive to immediate pre-CAR T therapy had a dismal outcome. This data supports proceeding with treatment in CAR T candidates regardless of their response to immediate pre-CAR T therapy. Interim therapeutic interventions should be considered in patients who have known risk factors for poor outcomes (bulky disease, high LDH).

Predictors of cytopenias after treatment with axicabtagene ciloleucel in patients with large B-cell lymphoma

Cytopenias are important but less studied adverse events following chimeric antigen receptor-engineered T cell (CAR-T) therapy. In our analysis of patients with large cell lymphoma who received axicabtagene ciloleucel (axi-cel), we sought to determine the rate and risk factors of clinically significant short term cytopenias defined as grade ≥3 neutropenia, anemia, or thrombocytopenia, or treatment with growth factors or blood product transfusions between days 20-30 after axi-cel. Fifty-three pts received axi-cel during the study period and severe cytopenias were observed in 32 (60%) pts. Significant cytopenias were more common in non-responders (stable or progressive disease) vs. responders (partial or complete response) (100% vs. 70%; p = .01). In the multivariable model, platelet transfusion within a month before leukapheresis, number of red blood cell and platelet transfusions between leukapheresis to lymphodepletion, pre-lymphodepletion absolute neurophil count, pre-lymphodepletion lactate dehydrogenase, and number of dexamethasone treatments after CAR-T were significantly associated with severe cytopenias after axi-cel.

Impact of CD19 CAR T-cell product type on outcomes in relapsed or refractory aggressive B-NHL

CD19-targeted chimeric antigen receptor-engineered (CD19 CAR) T cells are novel therapies showing great promise for patients with relapsed or refractory (R/R) aggressive B-cell non-Hodgkin lymphoma (B-NHL). Single-arm studies showed significant variations in outcomes across distinct CD19 CAR T-cell products. To estimate the independent impact of the CAR T-cell product type on outcomes, we retrospectively analyzed data from 129 patients with R/R aggressive B-NHL treated with cyclophosphamide and fludarabine lymphodepletion followed by either a commercially available CD19 CAR T-cell therapy (axicabtagene ciloleucel [axicel] or tisagenlecleucel [tisacel]), or the investigational product JCAR014 on a phase 1/2 clinical trial (NCT01865617). After adjustment for age, hematopoietic cell transplantation-specific comorbidity index, lactate dehydrogenase (LDH), largest lesion diameter, and absolute lymphocyte count (ALC), CAR T-cell product type remained associated with outcomes in multivariable models. JCAR014 was independently associated with lower cytokine release syndrome (CRS) severity compared with axicel (adjusted odds ratio [aOR], 0.19; 95% confidence interval [CI]; 0.08-0.46), with a trend toward lower CRS severity with tisacel compared with axicel (aOR, 0.47; 95% CI, 0.21-1.06; P = .07). Tisacel (aOR, 0.17; 95% CI, 0.06-0.48) and JCAR014 (aOR, 0.17; 95% CI, 0.06-0.47) were both associated with lower immune effector cell-associated neurotoxicity syndrome severity compared with axicel. Lower odds of complete response (CR) were predicted with tisacel and JCAR014 compared with axicel. Although sensitivity analyses using either positron emission tomography- or computed tomography-based response criteria also suggested higher efficacy of axicel over JCAR014, the impact of tisacel vs axicel became undetermined. Higher preleukapheresis LDH, largest lesion diameter, and lower ALC were independently associated with lower odds of CR. We conclude that CD19 CAR T-cell product type independently impacts toxicity and efficacy in R/R aggressive B-NHL patients.