Durable Remissions In Patients Research Articles

A phase 1/1b study of the IL-2 prodrug WTX-124 in patients with locally advanced or metastatic solid tumors after checkpoint inhibitor therapy: Initial results of the combination dose escalation with pembrolizumab.

2623 Background: High dose IL-2 can produce durable remissions in patients who have progressed on checkpoint inhibitors but is infrequently used due to its life-threatening toxicities such as vascular leak syndrome (VLS). WTX-124 is a half-life extended, masked cytokine (INDUKINE molecule) rationally engineered to release wild type IL-2 in tumors. We previously reported that WTX-124 is clinically active as a monotherapy at doses safely administered in the outpatient setting. Here we update the data and present initial results from the combination dose escalation with pembrolizumab (anti-PD-1; NCT05479812). Methods: In this first-in-human trial, WTX-124 is administered IV Q2W alone or with pembrolizumab 400 mg IV Q6W. Eligible patients are adults with relapsed/refractory solid tumors who have previously received standard of care checkpoint inhibitor regimens. Primary endpoints are safety and ORR; secondary endpoints are PK, PD, immunogenicity, and PFS/OS. The dose escalation is guided by a mTPI-2 study design. Results: As of January 29, 2024, 32 patients have been treated with WTX-124 in five monotherapy dose escalation cohorts (1-18 mg; N=24) and two combination cohorts (3-6 mg; N=8). The most common AEs related to WTX-124 monotherapy were arthralgias, myalgias, fatigue and pruritis. Of ten evaluable patients treated with 12 or 18 mg WTX-124 monotherapy, three had objective responses, including a confirmed CR in a patient with cutaneous squamous cell cancer and unconfirmed PRs in patients with melanoma and gastroesophageal junction cancer. On-treatment tumor biopsies showed evidence of increased lymphocyte activation and PD-L1 expression. Addition of pembrolizumab to 3-6mg WTX-124 did not change the character of AEs observed with WTX-124 monotherapy. Related AEs occurred more frequently for the combination than for 3-6mg WTX-124 monotherapy, but all were mild to moderate in severity (Gr1: 74.2%, Gr2: 25.8%) and there was no increase in the percentage of Gr2 events. No DLTs, related serious AEs, treatment discontinuations due to related toxicities, or occurrences of VLS have been observed in any patient treated to date with either WTX-124 or WTX-124/pembrolizumab. Pembrolizumab did not affect WTX-124 or IL-2 PK. WTX-124 has been escalated to 12 mg IV Q2W, the initial monotherapy dose that produced objective responses, in combination with pembrolizumab. Conclusions: WTX-124 administered as a monotherapy IV Q2W in the outpatient setting is well tolerated and clinically active in patients with relapsed/refractory solid tumors after checkpoint inhibitor therapy. Preliminary results from the ongoing combination dose escalation with pembrolizumab show no new safety signals. Updated data on safety, biomarkers, and preliminary clinical activity for the combination will be presented. Clinical trial information: NCT05479812 .

Improved CAR-T cell activity associated with increased mitochondrial function primed by galactose.

CD19 CAR-T cells have led to durable remissions in patients with refractory B-cell malignancies; nevertheless, most patients eventually relapse in the long term. Many interventions aimed at improving current products have been reported, with a subset of them focusing on a direct or indirect link to the metabolic state of the CAR-T cells. We assessed clinical products from an ongoing clinical trial utilizing CD19-28z CAR-T cells from patients with acute lymphoblastic leukemia. CAR-T clinical products leading to a complete response had significantly higher mitochondrial function (by oxygen consumption rate) irrespective of mitochondrial content. Next, we replaced the carbon source of the media from glucose to galactose to impact cellular metabolism. Galactose-containing media increased mitochondrial activity in CAR-T cells, and improved in in-vitro efficacy, without any consistent phenotypic change in memory profile. Finally, CAR-T cells produced in galactose-based glucose-free media resulted in increased mitochondrial activity. Using anin-vivo model of Nalm6 injected mice, galactose-primed CAR-T cells significantly improved leukemia-free survival compared to standard glucose-cultured CAR-T cells. Our results prove the significance of mitochondrial metabolism on CAR-T cell efficacy and suggest a translational pathway to improve clinical products.

Olutasidenib Alone or in Combination with Azacitidine Induces Durable Complete Remissions in Patients with mIDH1 Myelodysplastic Syndromes/Neoplasms (MDS)

Introduction Olutasidenib is a potent, selective, oral, small-molecule inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). Olutasidenib is approved in the US for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) based on the pivotal cohort (n=153) of a registrational Phase 1/2 trial (NCT02719574), which demonstrated a rate of complete remission (CR) or CR with partial hematologic recovery (CRh) of 35%, with a duration of response of 25.9 months. The Phase 1/2 study also enrolled patients with mIDH1 myelodysplastic syndromes/neoplasms (MDS), and here we report results from this subset of 22 patients. Methods The Phase 1/2 open-label study enrolled 332 adult patients with mIDH1 AML or intermediate-, high-, or very high-risk MDSfrom 57 centers in 9 countries. Inclusion criteria included an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and adequate liver and renal function. Patients were R/R to prior therapy or, if treatment-naïve (TN), had to be eligible for azacitidine therapy (to be enrolled in a combination therapy cohort). Olutasidenib was administered at 150 mg BID (n=3) or 100-150 QD (n=3) as monotherapy or in combination with azacitidine (n=16), given at 75 mg/mm 2 daily for 7 consecutive days, in 28-day cycles. The primary efficacy endpoint for MDS was the CR rate, based on response criteria of the International Working Group in MDS. Secondary efficacy endpoints included overall response (CR/PR/marrow CR), time to response, duration of response and safety. Results Twenty-two patients with MDS were enrolled, including 6 who received monotherapy (4 R/R and 2 TN) and 16 who received combination therapy (11 R/R and 5 TN). Baseline demographics and disease characteristics are shown in Table 1. The age ranged from 59-87 years, and 59% of the study population were male. Seven patients were treatment-naïve and 15 were R/R with 1-4 prior treatment regimens. For the pooled Phase 1 and 2 data (n=22), 6 (27%) patients achieved CR and 7 (32%) patients achieved marrow CR with no PRs, generating a 59% overall response rate. The median time to response was 2.0 months. The median duration of response was not reached (NR) at 30.1+ months ( Table 2). The overall response rate was 2/6 (33%) for monotherapy and 11/16 (69%) for combination therapy. Three of 6 patients received monotherapy at a lower dose (100-150 QD) than the approved dose level, and none responded. Of the 3 patients who received monotherapy at the approved dose level (150mg BID), 2 (66%) responded. In the 7 TN patients, the overall response rate was 86%. In the 15 R/R patients, the overall response rate was 47%. All patients with MDS experienced at least 1 treatment-emergent adverse event (TEAE). The most frequent TEAEs in the study were nausea, constipation, vomiting, thrombocytopenia, neutropenia, diarrhea, and fatigue. Grade 3 TEAEs occurred in 19/22 (86%) patients, and Grade 4 TEAEs in 9/22 (41%). The most frequent Grade 3/4 TEAEs reported were cytopenias. Grade 3 transaminitis occurred in 4 patients. Grade 3 differentiation syndrome was reported in 1 patient, who discontinued treatment after 23 days due to pneumonia, which lead to respiratory failure and death. TEAEs resulting in death occurred in 5 patients and included disease progression (3), pneumonia (1, mentioned above) and chest fungal infection (1). The overall safety profile in patients with MDS was consistent with what has been reported in patients with AML in this study (Watts, et al., Lancet Hematol, 2022; de Botton et al., Blood Adv, 2023). Conclusions Olutasidenib, both as monotherapy and in combination with azacitidine, induced durable remissions in patients with intermediate-, high-, or very high-risk MDS. Patients had varying treatment backgrounds, including treatment-naïve and up to four prior regimens. This treatment had a tolerable and manageable safety profile. These encouraging results, which warrant further investigation with a larger number of patients, show that olutasidenib has clinically meaningful activity in patients with mIDH1 MDS.

Outcomes of Allogeneic Transplantation for Adult T-Cell Leukemia/Lymphoma in Adolescents and Young Adult (AYA) and Young Patients

Introduction Allogeneic hematopoietic stem cell transplantation (allo-HSCT) provides a durable remission for patients with adult T-cell leukemia/lymphoma (ATL). Reduced-intensity regimens (RIC) have been increasingly used in ATL patients due to their old age and higher non-relapse mortality. However, the role of RIC regimen has not been fully evaluated among ATL patients aged <50 years. We here conducted a nationwide study to evaluate the prognostic impact of conditioning intensity on the post-transplant outcomes in ATL patients aged <50 years. Methods The clinical data of patients aged <50 years who underwent their first allo-HSCT between January 2001 and December 2020 were collected from the Transplant Registry Unified Management Program of the Japan Society for Hematopoietic Cell Transplantation. Cox proportional hazards regression models were used to evaluate variables potentially affecting overall survival (OS), graft-versus-host disease (GVHD)- and relapse-free survival (GRFS), and chronic GVHD-free survival (CRFS). Fine and Gray proportional hazards models were used to evaluate variables potentially affecting cumulative incidences of relapse (CIR) and non-relapse mortality (NRM). CIR and NRM were estimated using cumulative incidence curves to accommodate competing events. A two-sided P-value ≤0.05 was considered to be significant. To examine the effect modification, a threshold for P interaction <0.10 was used to indicate significant differences across prespecified subgroups. Results This study included 73 and 330 patients who were <40 years old (adolescents and young adults [AYA] patients) and 40-49 years old (young patients), respectively. In AYA patients, the median age at HSCT was 36 years (range, 20-39). RIC regimen was used in 16 out of 57 AYA patients (21.9%), and in 74 out of 330 young patients (22.4%) (P=1.000). There was no significant difference of the patient characteristics regarding comorbidity, performance status at HSCT, disease status, clinical subtype, and donor type. The estimated 3-year OS rates were 61.8% and 43.1% in AYA and young patients, respectively (P=0.005); the estimated 3-year CRFS rates were 35.8% and 22.6% in AYA and young patients, respectively (P=0.008); and the estimated 3-year GRFS rates were 26.7% and 15.1% in AYA and young patients, respectively (P=0.006). The estimated 3-year CIR were 36.3% and 39.3% in AYA and young patients, respectively (P=0.407); and the estimated 3-year NRM were 17.0% and 23.4% in AYA and young patients, respectively (P=0.113). In addition, the use of RIC regimen was associated with lower NRM than that of MAC regimen (P=0.015), but there was no significant difference of OS, CRFS, GRFS, and CIR between MAC and RIC regimens. The multivariate analyses revealed that young patients were significantly associated with worse OS (Hazard ratio (HR) [95% confidential interval], 1.62 [1.10-2.39]; P=0.015), CRFS (HR, 1.51 [1.10-2.06]; P=0.010), and GRFS (HR, 1.49 [1.11-1.99]; P=0.008) than AYA patients. The utilization of RIC regimen was significantly associated with lower NRM (HR, 0.46 [0.24-0.86]; P=0.015). To find the optimal selection of conditioning intensity (MAC vs. RIC) by patient's age, we next evaluated the effect modification. In the subgroup analysis, there was significant interaction of conditioning intensity with patient's age (P interaction=0.002) in NRM but not in OS, CRFS, GRFS, and CIR. Among AYA patients, the estimated 1-year NRM were 12.5% and 18.8% in MAC and RIC regimens, respectively (P=0.085). Among young patients, the estimated 1-year NRM were 23.5% and 8.2% in MAC and RIC regimens, respectively (P<0.001). Conclusion The present study clarified that AYA patients exhibited better post-transplant outcomes than young patients, indicating the prognostic value of patient's age in ATL patients aged <50 years. Moreover, no significant differences were observed in OS, CRFS, GRFS, and CIR between RIC and MAC regimens, but the utilization of RIC regimen would reduce the risk of non-relapse death among young patients. These facts suggested that RIC regimen could be an alternative option for ATL patients aged 40-49 years.

CD19-Directed CAR T-Cells (CD19-CAR) Combined with Acalabrutinib Achieves Durable Remissions in Patients with Relapsed or Refractory (r/r) Mantle Cell Lymphoma (MCL)

Background: MCL is an aggressive non-Hodgkin lymphoma (NHL) subtype which remains incurable despite improvements in progression free survival with consolidative autologous transplant and the introduction of novel targeted therapies [Dreyling et al. Blood 2012]. CD19-directed chimeric antigen receptor (CAR) T-cell therapy (CD19-CAR) has shown durable disease control in r/r MCL, but current standard of care products are limited by high rates of grade 3+ immune-related toxicities [Wang et al. NEJM 2020]. We hypothesized that combining a naïve/stem-memory (T N/SCM) phenotype-enriched CD19-CAR T-cell product with the selective BTK inhibitor (BTKi) acalabrutinib would attenuate the rates of severe toxicities, improve durable remission rates, and obviate the need for indefinite use of acalabrutinib in r/r MCL. Methods: We conducted a phase 1 single center, prospective clinical trial (NCT04484012) evaluating a single infusion of T N/SCM-enriched CD19.28.z.EGFRt-CAR at a target dose of either 2x10 8 (DL1) or 5x10 8 (DL2) CAR+ cells (≤20% lower dose allowed) in combination with ongoing acalabrutinib 100 mg twice daily for patients with r/r MCL after at least 1 prior line of therapy. Patients were required to undergo at least 3 months but less than 7 months of treatment with a BTKi prior to enrollment without evidence of progression and with measurable disease per Lugano criteria. All patients were switched to acalabrutinib for protocol therapy prior to lymphodepletion, and planned to continue until day 180 post CD19-CAR infusion at which time all therapy would be discontinued. We report outcomes from the dose finding portion of the study. Descriptive statistics were utilized for baseline characteristics and survival analyses were calculated utilizing the Kaplan-Meier method. Investigator-assessed response rates were based on Lugano criteria. Minimal residual disease (MRD) status was determined using either multiparameter flow cytometry (FCM) or next-generation sequencing (NGS). Results: To date, 8 patients enrolled and have received CD19-CAR (n=4 at DL1; n=4 at DL2). Manufacturing was successful in 100% of patients. Median time from leukapheresis to product infusion was 53 days (range, 41-114). Treated patients were 75% male; with a median age of 63 years (range, 38-70); and median number of prior therapies of 2 (range, 2-3). All patients had bone marrow involvement, and had high risk features including progression of disease within 24 months (n=6), relapse after autologous HCT (n=2), TP53 mutations (n=6), Ki-67 ≥30% (n=4), and/or complex karyotype (n=1). Prior to enrollment, all patients had received BTKi (n=8 acalabrutinib) for a median of 6.1 months (range, 4.5-7.3). No BTK and PLC-γ mutations were detected in patients with available samples. The combination of acalabrutinib and CD19-CAR was well tolerated; 5 patients (63%; n=1 grade 2; n=4 grade 1) had cytokine release syndrome (CRS), with no severe cases. No patients (0%) had immune effector cell associated neurotoxicity syndrome (ICANS) [Figure 1A]. No patient required corticosteroids for toxicity management, and only 2 patients (n=2/5, 40%) required tocilizumab for CRS. There were no serious adverse events (SAEs), and no treatment discontinuations due to AEs observed. The best ORR was 88% [n=6 CR (75%); n=1 PR (13%)], with median time to best response of 28 days. In those 6 patients who achieved CR, 2 patients were FCM-MRD negative (<10 -4) and 2 were NGS-MRD negative (<10 -6) (n=4/6, 67%) [Figure 1B]. After a median follow-up of 18.5 months (range, 8.3-28.9), 5 of 6 patients remain in CR, while1 patient who achieved an initial CR relapsed at 9.2 months. At 1-year post-infusion, the cumulative incidence of relapse and NRM were 30% (95% CI, 3%-67%) and 0%, respectively. The 1-year PFS and OS were 70% (95% CI: 22%-92%) and 100%, respectively. Conclusion: The combination of CD19-CAR with acalabrutinib was well tolerated and effective, yielding an ORR 88% and MRD- rate 50% in a cohort of patients with high-risk MCL. Notably, CRS events were manageable and low grade, and no ICANS was observed. Enrollment is ongoing in the expansion cohort (DL2), and additional clinical and correlative analyses will be presented at the meeting.

CD4+/CD8+ Selection of Anti-AML ENG-T Cells Affects Long-Term T-Cell Persistence in Vitro and Survival in an AML Xenograft Model

Background: Immunotherapies have shown dramatic anti-cancer efficacy in pediatric hematopoietic malignancies. Despite initial disease clearance, relapse rates are high, demanding product improvement. Manufacture of engineered cellular immunotherapies involves expansion of effector cells from patient or donor peripheral blood mononuclear cells (PBMCs) ex vivo prior to patient infusion. Expansion methods in pre-clinical studies of engineered T-cell therapies often call for activating T cells from whole PBMCs using anti-CD3 and anti-CD28 co-stimulation. However, clinical production of T-cell therapies has shifted towards selecting CD4+ and CD8+ cells prior to activation due to higher product efficacy seen in clinical trial. Many acute myeloid leukemias (AML) are CD4+, introducing the risk of blast contamination during CD4+ selection. We questioned whether CD8+ T cells alone could be used to manufacture our clinical T cell product and sought to determine how selection affected our T cells. Understanding the biological impact of manufacturing changes between pre-clinical and clinical production is imperative for clinical translation. Methods: We have engineered T cells to secrete a CD123xCD3 binding bispecific engager molecule (CD123-ENG) to treat AML. Primary T cells were isolated from PBMCs, selected with microbeads, activated, and transduced with replication incompetent retroviral vectors. Unselected T cells were compared to CD4+, CD8+, or CD4+ and CD8+ selected T cells. T-cell transduction was confirmed with flow cytometry. Expression and secretion of CD123-ENG was confirmed with ELISA. Antigen-specific T-cell activation was determined by quantifying cytokine secretion in the presence of CD123+ target cell lines. Short-term cytotoxicity was examined in vitro against CD123+ target cell lines in 18-hour bioluminescence assays. T-cell serial cytotoxicity and persistence were tracked in 10-day serial stimulation studies using an IncuCyte live cell imaging system. Cytokines present during T-cell manufacture and serial stimulation were detected and quantified with Luminex multiplex assays. Immunophenotype and exhaustion markers were analyzed using flow cytometry. In vivo anti-AML cytotoxicity and T-cell persistence were determined in an AML xenograft model. Results: In our studies, unselected, CD4+, CD8+, and CD4+/CD8+ selected CD123-ENG T cells showed no differences in activation, cytotoxicity, or immunophenotype when evaluated in short-term assays. Mice harboring human AML treated with CD4+/CD8+ selected CD123-ENG T cells had improved survival compared to mice treated with unselected and CD8+ selected CD123-ENG T cells. CD4+ T cells alone provided the best survival advantage. In addition, CD4+/CD8+ selected T cells had longer persistence when challenged by serial target cell stimulations in vitro. T cells expanded from whole PBMCs were exposed to cytokines likely to emanate from non-T cells during early manufacture. These cytokines were characteristic of those produced by myeloid cells in an inflammatory environment, and may explain functional differences observed in vivo. Conclusions: Durable anti-cancer response in patients is associated with T-cell persistence and CD4+/CD8+ pre-selection of CD123-ENG may therefore improve remission duration in patients. CD4+ and CD4+/CD8+ selected T cells provided the longest survival in vivo, dissuading us from further investigating CD8+ CD123-ENG as an AML treatment. We are actively exploring additional mechanistic determinants of the observed phenotypic differences with and without selection. Optimizing cellular immunotherapy will improve patient outcomes. It is essential that engineered cellular research products intended for clinical translation be produced by the same methods used for clinical manufacture to increase the predictive power of pre-clinical data. The use of biological correlatives to predict T-cell product function will better support successful translation. Acknowledgements: This research was funded in part by NCI Contract No. HHSN26120150003I/HHSN26100077.

Translational Control of FLT3-Mutated AML Cell Survival

Acute Myeloid Leukemia (AML) is the most common acute leukemia in adults with a five-year survival rate of ~30%. Approximately 30% of AML patients harbor an internal tandem duplication (ITD) mutation in the FMS related receptor tyrosine kinase 3 (FLT3) gene, which is an indicator of poor overall survival and a high relapse rate. These mutations cause constitutive activation of the FLT3 receptor, which amplify proliferation and survival signaling that supports leukemia progression and chemotherapy resistance. Although FLT3 inhibitors (FLT3i) improve median survival by a couple of months, and they have reduced toxicity relative to conventional chemotherapy in clinical trials, patients eventually acquire resistance and relapse. Clinical trials have revealed that AML blasts in the bone marrow (BM) were not effectively eliminated compared to AML blasts in peripheral blood, suggesting a protective role of the BM microenvironment that counteracts FLT3i therapy. A clear understanding of FLT3-mutated AML biology and how it is influenced by the microenvironment is imperative for developing new molecular approaches for improving efficacy of FLT3i-based therapies. We have discovered that BM stromal cell mediated regulation of Ataxia Telangiectasia Mutated (ATM) promotes Mammalian Target of Rapamycin Complex 1 (mTORC1) activity despite FLT3 inhibition, which maintains translation of oxidative phosphorylation genes that are critical for AML cell survival upon treatment with FLT3i [PMID: 36259537]. Key findings show that FLT3i inhibits mTOR and mTOR-dependent translation leading to cell death. However, in the presence of BM stromal factors, survival is restored upon FLT3i by regulating ATM/mTOR-dependent translation of essential phosphorylation genes to overcome FLT3i. Moreover, we demonstrated that the combination of FLT3i and mTORC1 inhibition (mTORC1i) synergistically kills human FLT3-mutated AML cells in vitro and substantially reduces tumor burden and prevents relapse in mouse models of FLT3-mutated AML. Further studies measuring translation in FLT3-mutated AML cells revealed that there are at least two different translation pathways dictated by FLT3. One of these pathways is mTOR-dependent, as expected, and the other is mTOR-independent. Additional studies have sought to characterize FLT3-controlled translation, independent of mTOR, and its importance for FLT3-mutated AML cell survival. Although highly sensitized to FLT3i, we observed that ATM/mTOR-deficient cells maintain near-normal translation and survival. Additionally, mounting evidence suggests that there are other kinases, such as CDK1, GSK3β, and p38, that drive mTOR-independent translation by phosphorylating 4E-BP1. With this knowledge, we took an unbiased approach and used O-Propargyl Puromycin (OPP)-translation assays to assess the impact of inhibitors against these kinases on translation activity in FLT3-mutated AML cell lines. This approach revealed CDK1 as a critical regulator of translation downstream of FLT3. Interestingly, myeloid progenitors reprogram to an mTOR-independent translational program requiring phosphorylation of 4E-BP1 by CDK1 [PMID: 32386556], which could be relevant for myeloid leukemias. Further corroborating my findings, RNA sequencing data suggest that FLT3 positively regulates CDK1 expression/activity, suggesting a downstream position in parallel with mTOR. In conclusion, we have uncovered a FLT3-controlled translation pathway that promotes FLT3-mutated AML cell survival independent of mTOR. Further characterization of this pathway could help predict mechanisms of resistance to FLT3 and mTOR inhibitors in AML and could identify new targets to promote more durable remissions in patients.

Lenalidomide Consolidation Improves Measurable Residual Disease (MRD) Rates and Progression Free Survival in Patients with Chronic Lymphocytic Leukemia Following Initial FCR Chemotherapy - Final Analysis of CLL6 Residuum Study of the Australian Leukaemia and Lymphoma Group (ALLG) and the French Innovative Leukemia Organization (FILO)

Introduction Eradication of MRD after first line chemoimmunotherapy (CIT) correlates with longer progression-free survival (PFS) in chronic lymphocytic leukemia (CLL) patients. Lenalidomide (LEN) has antiproliferative and immunomodulatory effects in CLL and may improve response following CIT (Buhler et al 2016; Fink et al 2017). Here we report the final analysis of the phase III, randomized, CLL6 RESIDUUM trial, that aimed to determine whether LEN improves immunophenotypic (IP) complete response (CR) rates and extends remission duration in patients with CLL who have MRD following induction CIT. Methods The CLL6 trial was a joint trial of the ALLG and the FILO. CLL patients with CIRS score <6 requiring treatment according to iwCLL received 4 to 6 cycles of fludarabine, cyclophosphamide and rituximab (FCR). After completion of treatment, patients with clinical, radiological and/or flow cytometry evidence of MRD in blood (PB) or bone marrow (BM) were randomized 1:1 to receive 2 years of 10 mg daily LEN consolidation or observation (OBS). High sensitivity (HS) MRD were scheduled at month 3, 6 and every 6 months until month 24 then every 12 months until month 72 in PB and at screening and on months 12 and 24 in BM. The primary endpoint was time to clinical disease progression, or death, from randomization. The study planned to randomize 192 patients to detect a hazard ratio of 1.94, i.e., an increase in the % of patients remaining progression free at 4 years to 70% in the LEN arm compared with 50% in the OBS arm (two-sided log rank test at alpha = 0.05, no competing risks or loss to follow up, power = 0.86). Results The study closed prematurely because of an acute lymphoblastic leukemia (ALL) warning (3 of 56 patients [5.4%]) in the CLLM1 trial (Fink et al., 2017; Fürstenau et al., 2021). Between May 2011 and January 2018, 143 patients were randomized (70 in Australia and 73 in France) to the LEN (n=71) or OBS (n=72) arms. Median age was 63 [range 41-78], and 60 [26-79] years in the LEN and OBS arms respectively, 113 patients were males. At randomization, 27 (38 %) and 23 (32%) patients were in CR, 9 (13%) and 10 (14%) in nPR, 35 (49%) and 39 (54%) in PR in LEN and OBS arms respectively. Forty-nine (69%) and 47 (65%) had PB and 56 (79%) and 58 (81%) had BM detectable MRD in LEN and OBS arm respectively. Median follow-up (FU) is 52.6 months (range 44.9-59.0; LEN 49.8 [41.9-57.1], OBS 55.59 [44.0-61.7]). Twenty-eight (39%) patients progressed in the LEN arm versus 40 (56%) in the OBS arm (χ² p=0.01), 8 died in each arm. Median PFS was 64.6 (95%CI 47.7-not reached [NR]) months in the LEN arm versus 42.4 (32.3-61.6) months in the OBS arm (p=0.039). Multivariate analysis did not identify any predictive factor of relapse. Median overall survival was not reached (NR) (77.58-NR) in the LEN arm and 107.7 (107.6-NR) months in the OBS arm. There were 118 adverse events (AE), 87 in the LEN and 31 in the OBS arms respectively, with more neutropenia (n=21 vs n=1), gastrointestinal (n=10 vs n=4), respiratory (n=9 vs n=0) nervous system (n=6 vs n=1) and musculoskeletal (n=4 vs n=1) in the LEN arm. Most of the excess of AEs in LEN arm occurred after the end of the treatment. Severe AEs were reported in 35 patients (24.5%), 24 in the LEN arm and 11 in OBS. Fifteen secondary malignancies occurred: 8 in the LEN arm; 7 in the OBS arm. Six were of hematological origin (2 Richter transformation in each arm, 1 marginal zone lymphoma in the OBS arm and 1 myelodysplastic syndrome in the LEN arm). No case of ALL occurred. HS MRD analyses were performed in 71/73 patients in the French cohort. A follow-up was available in 65/71 with a median number of 7 time-points per patients (range 3-10). Different MRD kinetics were observed. While MRD rates in OBS arm increased in 33/34 patients, LEN consolidation led to long-lasting and transient deep IP CR in 4/31 and 9/31 patients respectively, MRD rate stabilization in 10/31 patients, and MRD increase in the remaining 6/31 patients. Conclusion The CLL6 RESIDUUM study demonstrated a significant benefit of consolidation therapy with lenalidomide in CLL patients with residual disease after FCR treatment. LEN resulted in a significantly longer PFS, with no unacceptable toxicity including ALL. Although FCR is no longer considered gold standard initial CLL therapy, eradicating residual disease can remain challenging with newer targeted agents. Patients with CLL MRD following initial therapy may experience prolongation in progression free survival from LEN consolidation.

Distinct Patterns of CD4+ and CD8+ T-Cell Clonal Expansion Enable Broad Clinical Responses to Pembrolizumab + GVD in Patients with Relapsed Hodgkin Lymphoma

Introduction: Classical Hodgkin lymphoma (cHL) is characterized by immune dysregulation, with recurrent amplifications of the 9p24 locus encoding several genes including CD274 (PD-L1), PDCD1LG2 (PD-L2), and JAK2, frequent genetic and epigenetic downregulation of major histocompatibility complex (MHC)-I and (MHC)-II, and a tumor microenvironment (TME) defined by T-cell infiltration and high rates of PD-L1 expression. PD-1 blockade is highly active both as single agent and in combination with chemotherapeutic agents in relapsed/refractory (RR) cHL. However, the mechanism by which PD-1 blockade promotes clinical responses in combination with chemotherapy, and whether the mechanism of action varies based on tumor or TME-specific expression of either MHC or PD-L1 remains unclear. Methods: We previously conducted a phase II study in patients with relapsed or refractory cHL evaluating pembrolizumab in combination with gemcitabine, vinorelbine and liposomal doxorubicin (P-GVD) before proceeding to high-dose therapy and autologous hematopoietic cell transplantation (AHCT) (Moskowitz AJ et al, JCO 2021). Treatment consisted of 2 to 4 cycles of P-GVD followed by AHCT. We performed combined single-cell surface protein identification, RNA sequencing, and (T cell receptor) TCR sequencing using the 10x Genomics Single Cell Immune Profiling Platform on paired C1D1 and C3D1 peripheral blood mononuclear cells (PBMCs) from 23 patients who received P-GVD and 5 control patients with relapsed cHL treated with standard chemotherapy regimens. Expression of MHC-I, MHC-II, and PD-L1 on both Hodgkin Reed Sternberg (HRS) cells and within the TME was assessed by immunohistochemistry. Results:Of 38 evaluable pts, the complete response (CR) rate after 2 or 4 cycles of P-GVD was 95%. After a median follow-up of 40 months (range: 2-56), only 1 pt experienced relapse 23 months after AHCT and another pt died 41 months after AHCT while in remission due to unrelated causes. The estimated 40-month progression-free survival (PFS) is 96% (95% CI: 91-100). CITE-Sequencing of PBMCs across 56 samples from 28 patients revealed predominantly CD4+ T, CD8+ T, NK, and myeloid cells within the peripheral blood, with smaller proportions of hematopoietic progenitors and plasmacytoid dendritic cells. Combined RNA and TCR analysis of the T-cell compartment revealed significant pre-treatment clonal expansion of both CD4+ and CD8+ T-cells exhibiting a cytotoxic phenotype, including expression of GZMH, KLRG1, and CCL5 by CD8+ T-cells and expression of PRF1, NKG7, GNLY, FGFBP2, and GZMH by CD4+ T-cells ( Fig. 1A). Correlation of pre-treatment clonal expansion with tumor-specific MHC status demonstrated that clonal expansion of CD8+ T-cells was more robust in patients whose tumors expressed either MHC-I or MHC-II; conversely, clonal expansion of CD4+ T-cells was most robust in tumors expressing MHC-II but lacking MHC-I, suggesting cytotoxic CD4+ T-cell responses may promote anti-tumor immunity in MHC-I-deficient tumors ( Fig. 1B). Both CD4+ and CD8+ T-cell clonal expansion was highest in patients whose tumors expressed high levels of PD-L1 on stromal cells. Treatment with P-GVD did not result in further clonal expansion of either CD4+ or CD8+ T-cells but did increase expression of cytotoxic genes in pre-treatment expanded CD4+ T-cells, including NKG7 and PLEK, while downregulating negative genes of T-cell function in pre-treatment expanded CD8+ T-cells, including TNFAIP3 and DUSP1, suggesting that P-GVD promotes anti-tumor immunity in cHL by enhancing the cytotoxicity of tumor-reactive expanded CD4+ and CD8+ T-cells. Conclusions: Treatment of relapsed cHL with P- GVD resulted in durable remissions in patients undergoing AHCT. Distinct patterns of peripheral blood T-cell expansion were observed based on MHC-I and MHC-II expression on tumor cells, with CD4+ T-cell clonal expansion uniquely expanding in patients with MHC-I-deficient tumors. Further analysis of the impact of P-GVD on T-cell differentiation and function is ongoing. AcknowledgementT: Supported in part by a research grant from Investigator-Initiated Studies Program of Merck Sharp & Dohme LLC. The opinions expressed in this paper are those of the authors and do not necessarily represent those of Merck Sharp & Dohme LLC.

CD19 CAR-T cell therapy for relapsed or refractory diffuse large B cell lymphoma: Why does it fail?

Chimeric antigen receptor T (CAR-T) cell therapy is an effective treatment for relapsed or refractory diffuse large B cell lymphoma (DLBCL) with 3 CD19 targeting products now FDA-approved for this indication. However, up to 60% of patients ultimately progress or relapse following CAR-T cell therapy. Mechanisms of resistance to CAR-T cell therapy in patients with DLBCL are likely multifactorial and have yet to be fully elucidated. Determining patient, tumor and therapy-related factors that may predict an individual's response to CAR-T cell therapy requires ongoing analysis of data from clinical trials and real-world experience in this population. In this review we will discuss the factors identified to-date that may contribute to failure of CAR-T cell therapy in achieving durable remissions in patients with DLBCL.

Acute Heart Failure Is a Malignant Process: But We Can Induce Remission.

Acute heart failure is a common and increasingly prevalent condition, affecting >10 million people annually. For those patients who survive to discharge, early readmissions and death rates are >30% everywhere on the planet, making it a malignant condition. Beyond these adverse outcomes, it represents one of the largest drivers of health care costs globally. Studies in the past 2 years have demonstrated that we can induce remissions in this malignant process if therapy is instituted rapidly, at the first acute heart failure episode, using full doses of all available effective medications. Multiple studies have demonstrated that this goal can be achieved safely and effectively. Now the urgent call is for all stakeholders, patients, physicians, payers, politicians, and the public at large to come together to address the gaps in implementation and enable health care providers to induce durable remissions in patients with acute heart failure.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

AbstractBlastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

The nutritional impact of CD19-targeted CAR-T therapy versus BEAM chemotherapy for adult patients with lymphoma.

Chimeric antigen receptor T (CAR-T) cell therapy is a novel therapy demonstrating durable remissions in patients with refractory or relapsing non-Hodgkin's B-cell lymphoma. Maintaining a patient's nutritional status has been demonstrated to improve outcomes in cancer treatment. However, no studies have investigated how CAR-T therapy affects nutritional status, nor compared its impact with other cancer treatments for this patient group. The primary aim of the present study was to investigate the effect of CAR-T therapy on the prevalence of nutrition impact symptoms (NIS) and nutritional status within 30 days post-treatment of patients with lymphoma compared to a conditioning regimen for autologous haematopoetic stem cell transplant (carmustine/BCNU, Etoposide, cytarabine/Ara-C, Melphalan [BEAM] auto-haematopoetic stem cell transplant [HSCT]). Clinical notes of patients with lymphoma who underwent either CAR-T therapy or BEAM auto-HSCT between 2018 and 2021 were reviewed. Data extracted included body weight measurements and NIS, including decreased appetite, nausea, vomiting, diarrhoea, constipation, mucositis, cytokine release syndrome (CRS) and neurotoxicity at baseline and 30 ± 7 days post-treatment. In total, 129 adults with lymphoma (n = 88 CAR-T vs. n = 41 BEAM) were included. Nutritional status was assessed in both groups at baseline prior to treatment. Mean absolute weight change was significantly different between groups (3.05 kg in CAR-T, -5.9 kg in BEAM, p ≤ 0.001). This was also significant when weight loss was categorised into percentage weight loss (p = 0.01). CAR-T patients experienced a significantly lower prevalence of decreased appetite (52.3% vs. 97.6%) nausea (25% vs. 78%,) vomiting (10.2% vs. 53.7%), diarrhoea (43.2% vs. 96.7%) and mucositis (5.7% vs. 75.6%) combined across all levels of severity compared to BEAM chemotherapy (all p ≤ 0.01). CRS and neurotoxicity, which are specific side effects of CAR-T therapy, were moderately positively associated with weight loss. Weight loss, percentage weight loss and NIS were significantly reduced in CAR-T compared to BEAM treatment. However, patients who experienced neurotoxicity during treatment did have significant weight loss.

Idecabtagene Vicleucel Is Well Tolerated and Effective in Relapsed/Refractory Myeloma Patients with Prior Allogeneic Stem Cell Transplantation

BCMA-specific chimeric-antigen receptor cells have led to high response rates and durable remissions in patients with relapsed refractory multiple myeloma. However, little data are available for patients after prior allogeneic transplantation, where patient T-cells are chimeric. Our objective was to assess safety and efficacy of patient-derived donor CAR-T cell treatment in myeloma patients with prior allogeneic stem cell transplantation, in particular with regard to Graft versus Host Disease (GvHD). We demonstrate a comprehensive clinical analysis of 3 patients, who had previously received allogeneic transplantation for high-risk myeloma, treated with idecabtagene vicleucel (ide-cel) at our institution. Ide-cel was well tolerated with no clinically relevant immune effector cell-associated neurotoxicity syndrome or cytokine release syndrome observed in any patient. Importantly, no new GvHD was observed although all patients had a history of GvHD. All patients responded to treatment with at least a very good partial remission. Two patients relapsed within 6 months and one patient is still in sCR. We demonstrate that treatment with ide-cel is feasible, very well tolerated and effective in patients with relapsed/refractory multiple myeloma after prior allogeneic stem cell transplantation.

Olutasidenib in post-venetoclax patients with mIDH1 AML.

e19041 Background: Olutasidenib is a potent, selective, oral inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). Olutasidenib is FDA approved for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) based on the registrational cohort (n = 153) of the Phase 2 trial, which demonstrated a rate of complete remission (CR) or CR with partial hematologic recovery (CRh) of 35%, with a duration of response of 25.9 months. Venetoclax (VEN) in combination with a hypomethylating agent (HMA) is standard treatment for AML patients unfit for chemotherapy and has adequate efficacy in IDH1-mutated AML. The sequence of therapy following failure of a VEN-based regimen in IDH1-mutated AML has not been established. We evaluated the efficacy and safety of olutasidenib in a subset of 17 patients from the Phase 2 trial (NCT02719574) previously treated with VEN combination regimens. Methods: Adults with mIDH1 R/R AML received olutasidenib 150 mg twice daily alone (n = 15) or in combination with azacitadine (AZA) (n = 2). The primary endpoint was achievement of a CR/CRh. Secondary endpoints included time to and duration of CR+CRh and rate of transfusion independence (TI). Data cut-off for the analysis was 18 June 2021. Results: Of 17 patients with prior VEN treatment, 5 are ongoing and 12 discontinued due to progressive disease (6), adverse events (4), or withdrawal by subject (2). Median age was 73 (range 65-83). Median time since diagnosis was 19.5 months (1.2-41). Cytogenetic risk class was intermediate in 9, poor in 6, favorable in 1 and unknown in 1. Most patients had relapsed; 6 were refractory to prior treatment. The median number of prior regimens was 2 (range 1-6); 13 had prior HMA, 2 had prior olutasidenib. VEN was generally used for induction. Some patients received VEN in multiple regimens. VEN was used with azacytidine (AZA) in 8 patients, after AZA (1), and with decitabine (5), cytarabine +/- idarubicin (5), and dinaciclib (2). The best response to olutasidenib was CR/CRh in 5/17 (29.4%), of which 4 (23.5%) were CR. In the 8 patients who previously received the combination of VEN-AZA, 3 (37.5%) patients achieved a CR/CRh. Time to CR/CRh was median 2.1 months (actual: 1, 1.9, 2.1, 2.8 and 2.8). Duration of CR/CRh was median 18.5+ months (4.8, 9.0+, 18.5+, 22.6+, and 28.5+ months as of cut-off date). Other responses included CR with incomplete blood count recovery (CRi) in 2 patients, stable disease (SD) in 2, progressive disease (PD) in 3, not done (ND) in 2, not evaluable (NE) in 1 and not listed in 2. At baseline 14/17 were red blood cell (RBC) dependent, and 4 of the 14 (28%) had a 56-day period of RBC transfusion independence (TI). Ten were platelet dependent at baseline and 5 of the 10 (50%) had a 56-day period of platelet TI while receiving olutasidenib. Conclusions: Olutasidenib induced durable remissions in patients with mIDH1 R/R AML, including those failing prior treatment with a venetoclax-based regimen. Clinical trial information: NCT02719574 .

Abstract 2530: DELE1 loss and dysfunctional integrated stress signaling in TP53 mutated AML is a novel pathway for venetoclax resistance

Abstract Background: Venetoclax (ven) in combination with hypomethylating agents or low dose cytarabine leads to rapid and durable remission in patients (pts) with acute myeloid leukemia (AML) unfit for intensive chemotherapy (IC), however, pts with TP53 mutations (TP53mut) exhibit adverse prognosis. Here, we identify dysregulation of the integrated stress response (ISR) pathway in pts with TP53mut, specifically through the actions of DAP3 binding cell death enhancer 1 (DELE1) and its activating protease OMA1. Methods: RNA sequencing was performed on pre-treatment bone marrow-derived mononuclear cells (BMMCs) from pts with AML ineligible for IC across four clinical trials (NCT02993523, NCT02203773, NCT03069352, and NCT02287233). CRISPR-Cas9 editing of TP53-intact AML cell lines was used to generate TP53-/-, TP53mut, DELE1-/-, OMA1-/- and TP53/DELE1 double deficient cell lines. Quantification of BCL2 and Myeloid cell leukemia 1 (MCL1) complexes with BCL2 interacting mediator (BIM) was performed using chemiluminescence assays. A drug screen to assess viability and gene expression was performed in cells treated with ven in combination with 63 drugs. Results: In total 401 pts were included in the analyses, of which 17% harbored TP53mut and 83% were TP53wt. Analysis of genes differentially expressed (DE) between pts with TP53mut and TP53wt AML revealed 19 DE genes shared across all trials. DELE1, an ISR adaptor, was associated with genes mapping to the ISR-related eukaryotic initiation factor-α (eIF2α) in TP53mut AML BMMCs. Deletion of DELE1 or OMA1 in AML cell lines blocked eIF2α activation and induction of the transcription factor ATF4, a critical ISR effector, in response to the mitochondrial stressor FCCP, ven, and azacitidine, and resulted in ven resistance similar to that of TP53 deficient cells. All modified AML cell lines exhibited a concomitant decrease in the pro-apoptotic regulator PMAIP1, encoding NOXA, and a 14-18-fold increase in MCL1-BIM complexes following ven treatment, as well as increased MCL1 expression, compared to parental lines. Further screening of these cell lines for ven sensitizing activity revealed the BH3 mimetic S63845, which targets MCL1, as the top hit, suggesting that combined BH3 mimetics may overcome ven resistance during ISR pathway defects. As DELE1 is located on chromosome 5 (CH); the frequent loss of CH 5q among TP53mut AML may contribute to low DELE1 expression. Conclusions: These data suggest that defective ISR signaling may be a factor in TP53mut AML treatment outcome and point to DELE1 dysregulation as a driver of ISR inactivation in pts with TP53mut AML. The ISR induces the expression of NOXA, which displaces MCL1 from BIM and lowers the apoptotic threshold. Our data identify p53, DELE1, and OMA1 as regulators of NOXA expression post ven treatment and indicate that co-targeting MCL1 in pts with TP53mut AML may be beneficial to overcome ven resistance. Citation Format: David Sharon, Paul Jung, Yan Sun, Weiguo Feng, Ziping Yang, Valerie Robinson, Diya Mitra, Wei Liu, Pingping Zheng, Tamar Uziel, Lloyd Lam, Mark D. Minden, Jeremy Ross, Wellington Mendes, Jalaja Potluri, Andrew H. Wei, Marina Konopleva, Monique Dail, Brenda Chyla, PK Epling-Burnette. DELE1 loss and dysfunctional integrated stress signaling in TP53 mutated AML is a novel pathway for venetoclax resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2530.

2 - CD22 CAR T Cell Therapy Induces Durable Remissions in Patients with Large B Cell Lymphoma Who Relapse after CD19 CAR T Cell Therapy

2 - CD22 CAR T Cell Therapy Induces Durable Remissions in Patients with Large B Cell Lymphoma Who Relapse after CD19 CAR T Cell Therapy

Relapsed or refractory large B-cell lymphoma after chimeric antigen receptor T-cell therapy: Current challenges and therapeutic options.

Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy can provide durable remission in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) after failure of chemoimmunotherapy. However, patients who are refractory or relapsing after CAR-T therapy have poor outcomes. Multiple mechanisms of CAR-T therapy failure have been proposed but management of these patients remains a challenge. As CAR-T therapy moves earlier in the treatment of DLBCL, we urgently need trials focused on patients with relapse after CAR-T therapy. Recent advances in novel immunotherapies such as bispecific antibodies, antibody-drug conjugates and next-generation CAR-T therapies may provide avenues for treatment. Here we review the available data on using these drugs after failure of CAR-T therapy and provide a framework for the ideal sequencing of these novel agents.

Mesenchymal stem cell therapy in patients with Crohn’s disease — 5 year follow-up

Abstract We investigated the efficacy of combination therapy using bone marrow-derived mesenchymal stromal cells (MSC) and Infliximab (IFX) to achieve “deep remission” in patients with luminal Crohn disease (CD). Our study included 72 patients (age 19–62 years) (Ме = 29) with luminal CD. Patients in the 1st group (n = 21) received standard 5-aminosalicylic acid (5-ASA) and glucocorticosteroid therapy in combination with MSC. Patients in the 2nd group (n = 32) were prescribed anti-cytokine therapy IFX. Patients in the 3rd group (n = 19) received MSC and IFX. Clinical and immunobiological (C-reactive protein-CRP and faecal calprotectin-FCP) showed a more significant decrease of local and systemic inflammation activity in the 3rd group of patients. During a 5-year follow-up we observed longer duration of remission in patients who received MSC and IFX compared to the 1st (р = 0,04) and 2nd groups of patients (р = 0.038). Combination therapy of bone marrow-derived MSC and IFL provides “deep remission” in patients with luminal CD and has higher prognostic value for duration of CD remission period.

CAR Triggered Release of Type-1 Interferon Limits CAR T-Cell Activities by an Artificial Negative Autocrine Loop

The advent of chimeric antigen receptor (CAR) T cells expedited the field of cancer immunotherapy enabling durable remissions in patients with refractory hematological malignancies. T cells redirected for universal cytokine-mediated killing (TRUCKs), commonly referred to as "fourth generation" CAR T-cells, are designed to release engineered payloads upon CAR-induced T-cell activation. Building on the TRUCK technology, we aimed to generate CAR T-cells with a CAR-inducible artificial, self-limiting autocrine loop. To this end, we engineered CAR T-cells with CAR triggered secretion of type-1 interferons (IFNs). At baseline, IFNα and IFNβ CAR T-cells showed similar capacities in cytotoxicity and cytokine secretion compared to conventional CAR T-cells. However, under "stress" conditions of repetitive rounds of antigen stimulation using BxPC-3 pancreas carcinoma cells as targets, anti-tumor activity faded in later rounds while being fully active in destructing carcinoma cells during first rounds of stimulation. Mechanistically, the decline in activity was primarily based on type-1 IFN augmented CAR T-cell apoptosis, which was far less the case for CAR T-cells without IFN release. Such autocrine self-limiting loops can be used for applications where transient CAR T-cell activity and persistence upon target recognition is desired to avoid lasting toxicities.