Allogeneic CAR-T Research Articles

Engineering a solution for allogeneic CAR-T rejection

Engineering a solution for allogeneic CAR-T rejection

Immunosuppressant therapy averts rejection of allogeneic FKBP1A-disrupted CAR-T cells

Chimeric antigen receptor (CAR) Tcells from allogeneic donors promise "off-the-shelf" availability by overcoming challenges associated with autologous cell manufacturing. However, recipient immunologic rejection of allogeneic CAR-T cells may decrease their invivo lifespan and limit treatment efficacy. Here, we demonstrate that the immunosuppressants rapamycin and tacrolimus effectively mitigate allorejection of HLA-mismatched CAR-T cells in immunocompetent humanized mice, extending their invivo persistence to that of syngeneic humanized mouse-derived CAR-T cells. In turn, genetic knockout (KO) of FKBP prolyl isomerase 1A (FKBP1A), which encodes a protein targeted by both drugs, was necessary to confer CD19-specific CAR-T cells (19CAR) robust functional resistance to these immunosuppressants. FKBP1AKO 19CAR-T cells maintained potent invitro functional profiles and controlled invivo tumor progression similarly to untreated 19CAR-T cells. Moreover, immunosuppressant treatment averted invivo allorejection permitting FKBP1AKO 19CAR-T cell-driven B cell aplasia. Thus, we demonstrate that genome engineering enables immunosuppressant treatment to improve the therapeutic potential of universal donor-derived CAR-T cells.

Emerging Cancer Immunotherapies: Cutting-Edge Advances and Innovations in Development.

The rise in biological therapies has revolutionized oncology, with immunotherapy leading the charge through breakthroughs such as CAR-T cell therapy for melanoma and B-ALL. Modified bispecific antibodies and CAR-T cells are being developed to enhance their effectiveness further. However, CAR-T cell therapy currently relies on a costly ex vivo manufacturing process, necessitating alternative strategies to overcome this bottleneck. Targeted in vivo viral transduction offers a promising avenue but remains under-optimized. Additionally, novel approaches are emerging, such as in vivo vaccine boosting of CAR-T cells to strengthen the immune response against tumors, and dendritic cell-based vaccines are under investigation. Beyond CAR-T cells, mRNA therapeutics represent another promising avenue. Targeted delivery of DNA/RNA using lipid nanoparticles (LNPs) shows potential, as LNPs can be directed to T cells. Moreover, CRISPR editing has demonstrated the ability to precisely edit the genome, enhancing the effector function and persistence of synthetic T cells. Enveloped delivery vehicles packaging Cas9 directed to modified T cells offer a virus-free method for safe and effective molecule release. While this platform still relies on ex vivo transduction, using cells from healthy donors or induced pluripotent stem cells can reduce costs, simplify manufacturing, and expand treatment to patients with low-quality T cells. The use of allogeneic CAR-T cells in cancer has gained attraction for its potential to lower costs and broaden accessibility. This review emphasizes critical strategies for improving the selectivity and efficacy of immunotherapies, paving the way for a more targeted and successful fight against cancer.

An exploratory investigator-initiated trial via intrathecal or intracerebroventricular delivery of B7H3-specific allogeneic universal CAR-T cells in patients with recurrent high-grade gliomas.

23 Background: The MT027, developed by T-Maximum, is a B7-H3 (CD276)-directed genetically modified allogeneic T cell, targeting CD276-overexpressed tumor cells. Here, we reported a first-in-human, single-center, open-label investigator-initiated trial (IIT) via intrathecal or Intracerebroventricular delivery targeting recurrent high-grade glioma (ChiCTR2100047968). Methods: As of March 7, 2024, a total of 50 adult patients with recurrent high-grade glioma, B7H3+ expression, and KPS ≥40 were enrolled and administered at least one dose of MT027 (FAS), of whom, 32 received at least 3 doses (PPS1), 15 subjects with ≥3 doses and at least 1 efficacy visit (PPS2). 4 dose levels of 1.0, 1.5, 2.0, 2.5×107 cells per injection were administered once every 4 weeks. Results: The overall results demonstrated the favorable tolerability, safety, PK/PD characteristics, and preliminary efficacy. In FAS, the most common AE were fever and headache, without any CRS, ICANS, GvHD, or drug-related death. There were 4 cases (8%) of grade 3 AE or greater and 3 cases (6%) of SAEs. The copies of CAR in all groups reached 10000-100000 copy/ug, and persisted for > 60 days after a single dose. After multiple doses, the MT027 CAR-T cell numbers maintained at a high level (median 8850 copies /μg (range: 200-385900)) and for a long time. The levels of IL6, TNF-α and IFN-γ in CSF increased significantly and maintained for a long time. The mOS was 13.54 m (95% CI: 7.45; 19.63) and 20.73 m (95% CI: 16.12; 25.34) in PPS1 and PPS2, respectively. The 12-month OS rate was 53.30% (95%CI: 37.5%-75.7%) and 84.60% (95%CI: 67.1%-100%) in PPS1 and PPS2, respectively (historical data: 14%). The objective response rate (ORR) was 33% and the disease control rate (DCR) was 80% in PPS2. Conclusions: In patients with relapsed high-grade glioma, the intrathecal or ICV administration of MT027 cell therapy was found to be safe and well-tolerated. The toxicity of grade 3 or above was 1/5 of similar products. The pharmacokinetics and pharmacodynamics of single-dose and multiple-dose treatments were stable. MT027 exhibited longer persistence in the body of the patients, and the cell numbers and cytokine responses induced in vivo were 1-2 orders of magnitude higher than those of similar products. MT027 cell therapy demonstrated the excellent efficacy in treating relapsed high-grade glioma, with significantly prolonged overall survival and higher objective response rate compared to the historical data and similar product data. Currently, we are preparing for the IND filing in US (expected in 2024) with the recurrent glioblastoma as the first indication. Clinical trial information: ChiCTR2100047968 .

Innovative therapies for treatment of invasive fungal diseases

Invasive fungal diseases (IFD) are difficult to treat and pose a significant threat to immunocompromised individuals. Current antifungal agents face limitations, including antifungal resistance and adverse effects. This review aims to give a comprehensive overview of emerging treatment strategies.Novel drugs in development are Ibrexafungerp, an orally available triterpenoid inhibiting glucan synthesis, and Rezafungin representing the echinocandins with extended half-life and improved tissue penetration, both recently licensed for certain indications. Fosmanogepix targets glycosylphosphatidylinositol biosynthesis, while Olorofim, an orotomide, inhibits fungal nucleic acid synthesis, both currently assessed in advanced clinical trials.Immunotherapeutic approaches include immune checkpoint inhibitors to enhance immune response in immunosuppressed individuals and fungal-specific allogeneic CAR-T cell therapy. For prophylactic purpose in high-risk populations to develop IFD, monoclonal antibodies against different virulence factors of Candida spp. have been discovered but are not yet seen in clinical trials. Vaccines against distinct fungal antigens as well as pan fungal vaccines to prevent IFD are under development in preclinical stages, notably for Candida spp., Cryptococcus spp., and Aspergillus spp., however, their clinical value is still discussed.In summary, major advances to treat IFD have been observed, but challenges for their establishment in the clinical routine persist.

Allogeneic CD19-targeted CAR-T therapy in patients with severe myositis and systemic sclerosis

Allogeneic chimeric antigen receptor (CAR)-T cells hold great promise for expanding the accessibility of CAR-T therapy, whereas the risks of allograft rejection have hampered its application. Here, we genetically engineered healthy-donor-derived, CD19-targeting CAR-T cells using CRISPR-Cas9 to address the issue of immune rejection and treated one patient with refractory immune-mediated necrotizing myopathy and two patients with diffuse cutaneous systemic sclerosis with these cells. This study was registered at ClinicalTrials.gov (NCT05859997). The infused cells persisted for over 3months, achieving complete B cell depletion within 2weeks of treatment. During the 6-month follow-up, we observed deep remission without cytokine release syndrome or other serious adverse events in all three patients, primarily shown by the significant improvement in the clinical response index scores for the two diseases, respectively, and supported by the observations of reversal of inflammation and fibrosis. Our results demonstrate the high safety and promising immune modulatory effect of the off-the-shelf CAR-T cells in treating severe refractory autoimmune diseases.

An aptamer-mediated base editing platform for simultaneous knockin and multiple gene knockout for allogeneic CAR-T cells generation

Gene editing technologies hold promise for enabling the next generation of adoptive cellular therapies. Conventional gene editing platforms that rely on nuclease activity, such as Clustered regularly interspaced short palindromic repeats-CRISPR associated protein 9 (CRISPR-Cas9), allow efficient introduction of genetic modifications; however, these modifications occur via the generation of DNA double-strand breaks (DSBs) and can lead to unwanted genomic alterations and genotoxicity. Here, we apply a novel modular RNA aptamer-mediated Pin-point™ base editing platform to simultaneously introduce multiple gene knockouts and site-specific integration of a transgene in human primary T cells. We demonstrate high editing efficiency and purity at all target sites and significantly reduced frequency of chromosomal translocations compared to the conventional CRISPR-Cas9 system. Site-specific knock-in of a chimeric antigen receptor (CAR) and multiplex gene knockout are achieved within a single intervention and without the requirement for additional sequence-targeting components. The ability to perform complex genome editing efficiently and precisely highlights the potential of the Pin-point platform for application in a range of advanced cell therapies.

A CRISPR-edited allogeneic anti-CD19 CAR-T cell therapy with a PD-1 knockout (CB-010) in patients with relapsed/refractory B cell non-Hodgkin lymphoma (r/r B-NHL): Updated phase 1 results from the ANTLER trial.

7025 Background: CB-010 is an allogeneic anti-CD19 CAR-T cell therapy derived from healthy donor T cells using CRISPR hybrid RNA-DNA (chRDNA) technology. This technology is used to introduce 3 genome edits: (1) knockout of TRACto eliminate TCR expression and reduce risk of GvHD, (2) insertion of a CD19-specific CAR (scFv FMC63) into the TRAC locus, and (3) knockout of PD-1 to prevent premature CAR-T cell exhaustion and potentially enhance antitumor activity. Methods: ANTLER is a Phase 1 clinical trial (NCT04637763) with a 3+3 dose escalation phase and a dose expansion phase designed to evaluate safety, tolerability, and antitumor activity of CB-010 in patients (pts) with r/r B-NHL and determine RP2D. In dose escalation, pts must have received ≥2 prior lines of chemoimmunotherapy or had primary refractory disease to 1L therapy. Pts received lymphodepletion with sequential cyclophosphamide (60 mg/kg/day x 2 days) and fludarabine (25 mg/m2/day x 5 days) followed by a single CB-010 infusion. Results: 16 pts with r/r B-NHL (10 LBCL, 3 MCL, 2 FL with POD24, 1 MZL) received CB-010 at 40 x 106 CAR-T cells (dose level 1; N=8), 80 x 106 CAR-T cells (dose level 2; N=5), or 120 x 106 CAR-T cells (dose level 3; N=3) during dose escalation. Median age was 66 years (range 55-82). Median time since first diagnosis was 2.4 years (range 0.2-16.4). Median prior lines of therapy was 2 (range 1-8). CB-010 was generally well tolerated. No GvHD was seen. CRS occurred in 7/16 (44%) pts (no CRS grade ≥3). Median time to CRS onset was 3.5 days and median duration was 3 days. ICANS occurred in 4/16 (25%) pts (13% grade ≥3). Median time to ICANS onset was 7.5 days and median duration was 2 days. The 3 most common TEAEs grade ≥3 were thrombocytopenia (11/16; 69%), neutropenia (9/16; 56%), and anemia (8/16; 50%). One grade 3 infection (antecubital cellulitis) occurred unrelated to CB-010. After a single CB-010 infusion, 15/16 (94%) pts achieved an overall response, 11/16 (69%) achieved a CR, and 7/16 (44%) achieved a CR at ≥6 months. Median time to CR was 28 days. Among LBCL pts (n=10), 9 (90%) achieved an overall response, 7 (70%) achieved a CR, and 5 (50%) achieved a CR at ≥6 months. To date,2 pts have completed the 24-month study period with ongoing CR. Peak expansion of CB-010 occurred at days 7-10 post-infusion. T and NK cells recovered rapidly in peripheral blood (<3 weeks) after lymphodepletion, and B cells remained below the limit of quantification beyond 3 months, supporting specific targeting of B cells by CB-010. Conclusions: CB-010 showed a manageable safety profile and promising efficacy for treatment of pts with r/r B-NHL, including aggressive subtypes. The dose escalation phase is complete. Enrollment of 2L LBCL pts in dose expansion is ongoing. Initial dose expansion data at the CB-010 RP2D and translational data will be presented for the first time at the meeting. Clinical trial information: NCT04637763 .

Intracellular retention of TCRαβ/CD3 to generate novel allogeneic CAR-T cells targeting CLL1 for treating acute myelocytic leukemia.

e14532 Background: The prognosis of patients with R/R AML is poor and treatment remains challenging. Human C-type lectin-like molecule 1(CLL1) is a type II transmembrane glycoprotein that is highly expressed on AML but is absent on normal HSCs. Clinical studies have shown that autologous CLL-1 is a novel and promising target for the treatment of AML. But autologous CAR-T therapy has been complicated by long production time, high-cost and risks of manufacturing failure, and allogeneic CAR-T cells can overcome these hurdles. Methods: A novel non-gene-editing allogeneic CAR-T platform was developed on the base of intracellular retention of membrane proteins, and named ThisCART (This = TCR and/or HLA-I intracellular sequestered). CLL1-directed ThisCART cells are readily produced with a single lentiviral vector, encoding both a CLL1-targeting CAR and an anti-CD3 single chain antibody with the KDEL peptide fused to its C-termini. The surface expression of CAR and TCRαβ/CD3 was measured by flow cytometer. Specific tumor cytotoxicity was evaluated both in vitro and in vivo. Furthermore, the safety of donor derived ThisCART cells were tested in a xenogeneic GvHD model. Results: The manufacturing platform of CLL1 ThisCART was able to achieve over 150-folds of ex vivo CAR-T expansion in all batches, with the purity of products (CAR-positive/TCRαβ-negative) above 99%. In preclinical models, CLL1 ThisCART did not induce GvHD, and exhibited superior antitumor function compared to benchmark (WO2017091615A) and conventional CLL1 CAR-T cells. CLL1 ThisCART cells were readily produced to a quantity and quality supporting clinical investigation. Conclusions: CLL1 ThisCART cells based on intracellular retention of TCRαβ/CD3 complex demonstrated superior CLL1-dependent cytotoxicity and no xenogeneic GvHD in murine models. With streamlined single-vector-based production, enhanced CAR signaling and potent cytotoxicity and favored preclinical safety profile, CLL1 ThisCART warrant clinical investigation.

Intracellular retention of TCRαβ/CD3 and CD7 to generate novel allogeneic CAR-T cells targeting CD7 for treating T-cell malignancies.

e14531 Background: The treatment for patients with T-ALL/LBL who relapse after hematopoietic stem cell transplantation (HSCT) are currently restricted. CD7 is highly expressed on the surface of T-ALL/LBL T cells and CAR-T cell therapy provides a promising avenue towards remission. However, CD7-targeting immunotherapies may be compromised by T-cell fratricide. Furthermore, in addition to the long production time, high cost, and high risk of production failure, the biggest challenges of autologous CAR-T cell therapy are how to isolate a sufficient number of healthy T cells from malignant T cells. Thus, allogeneic CAR-T cells can overcome these hurdles. Methods: A novel non-gene-editing allogeneic CAR-T platform was developed on the base of intracellular retention of membrane proteins, and named ThisCART (TCR and/or HLA-I intracellular sequestered). CD7-directed ThisCART cells are readily produced with a single lentiviral vector, encoding both a CD7-targeting CAR, an anti-CD7and anti-CD3 single chain antibody with the KDEL peptide fused to its C-termini. The surface expression of CAR, TCRαβ/CD3 and CD7 was measured by flow cytometer. Specific tumor cytotoxicity was evaluated both in vitro and in vivo. Furthermore, the safety of donor derived ThisCART cells were tested in a xenogeneic GvHD model. Results: The manufacturing platform of CD7 ThisCART was able to achieve over 130-folds of ex vivo CAR-T expansion in all batches, with the purity of products (CAR-positive/CD7-negative/TCRαβ-negative) above 99%. In preclinical models, CD7 ThisCART did not induce GvHD, and exhibited superior antitumor function compared to Control T. CD7 ThisCART cells were readily produced to a quantity and quality supporting clinical investigation. Conclusions: CD7 ThisCART cells based on intracellular retention of TCRαβ/CD3 complex and CD7 demonstrated superior CD7-dependent cytotoxicity and no xenogeneic GvHD in murine models. With streamlined single-vector-based production and potent cytotoxicity and favored preclinical safety profile, CD7 ThisCART warrant clinical investigation.

The interim analysis of a first-in-human phase 1 trial of ET-901, a CRISPR edited allogeneic immune-cloaked anti-CD19 CAR-T cell therapy in patients with r/r B-NHL.

e19010 Background: Allogeneic CAR T-cell therapy faces challenges like limited persistence and host rejection. Current research has improved its viability by modifying genes like B2M, despite new challenges like NK cell targeting have emerged. Through CRISPR screening, we discovered a novel gene, named GeneX, and its role in enhancing T cell persistence against allogeneic attacks and AICD. GeneX influences glycan composition, affecting immune responses and AICD initiation. Engineered GeneXKO/TCRKO/anti-CD19 CAR T cells (ET-901) resisted allogeneic killing and maintained anti-tumor effects without causing GvHD, marking a significant advancement in CAR T-cell therapy. Methods: ET-901 is being tested in a phase 1 trial for r/r B-NHL at a single center, utilizing a 3+3 dose escalation scheme and planning for expansion at the recommended Phase 2 dose. Participants must have an ECOG status of 0–2, without a history of allo-HSCT or CAR-T therapy. The study's main goals are to assess ET-901's safety and establish the optimal Phase 2 dosage. Patients undergo a 3-day lymphodepletion with fludarabine (30-50 mg/m2/d) and cyclophosphamide (500-1000 mg/m2/d), followed by a single-dose infusion of ET-901 at escalating doses (DL1:1*10e6/kg, DL2:3*10e6/kg, and DL3:10*10e6/kg). Pharmacokinetic monitoring occurs during follow-up. Results: From September 2023, a total of six patients were enrolled in the escalation cohort, including 4 patients with LBCL and 2 with FL. In these patients (3 males), the median age was 53 years (range: 46–55 years), and the median number of prior treatment lines was 5. The median SPD was 7,650 mm2 (range: 2,700-43,400 mm2). Notably, two cases in DL2 exhibited unusual lymphoma infiltration sites: patient No.4 in the forearm muscle and patient No.5 in the spleen. Update to February 2024, we have completed the safety evaluation of Dose Level (DL) 1 and DL2. No DLTs were observed. The most common TRAEs of any grade included leukopenia (6/6), granulocytopenia (6/6), anemia (6/6), thrombocytopenia (6/6), CRS (6/6), infection (2/6), ICANS (2/6), and GvH like reaction (1/6). All patients achieved objective responses, with 2 cases of PR and 4 cases of CR (1 in DL1, 3 in DL2). The peak values of CAR+ cells count and VCN in peripheral blood were 36.0/μl (range: 14.0-48.0/μl, median: day 7), and 9.6e4 copies/μg (range: 7.7e4-1.2e5 copies/μg, median: day 7), respectively. In all patients, a second expansion of CAR-T cells was observed alongside B cell recovery. This confirms that GeneX knockout enables allo CAR-T cells to maintain long-term immune privilege while preserving their biological function. Conclusions: The study demonstrated the safety and feasibility of ET-901 in patients with r/r B-NHL. These findings highlight the potential of ET-901 as an effective therapeutic approach for improving outcomes for these patients. Clinical trial information: NCT06014073 .

A first-in-human phase 1, multicenter, open-label study of CB-012, a next-generation CRISPR-edited allogeneic anti-CLL-1 CAR-T cell therapy for adults with relapsed/refractory acute myeloid leukemia (AMpLify).

TPS6586 Background: CAR-T cell therapies have shown significant clinical benefit in treating adults with many hematologic malignancies. In acute myeloid leukemia (AML), a challenge in the development of CAR-T cell therapies has been the limitation of suitable target antigens since many are also expressed on hematopoietic stem cells (HSCs). The target antigen C-type lectin-like molecule-1 (CLL-1) has emerged as an attractive therapeutic target due to its expression on AML mature blasts and leukemic stem cells and its absence on HSCs. CB-012 is an allogeneic CAR-T cell therapy that targets CLL-1. CB-012 is derived from healthy donor T cells by using Cas12a CRISPR hybrid RNA-DNA (chRDNA) technology to introduce 5 genome edits: (1) TRAC gene knockout (KO), which eliminates T cell receptor expression to reduce the risk of graft-versus-host disease, (2) site-directed insertion of a fully human anti-CLL-1 CAR into the TRAC locus, (3) KO of PD-1 to enhance antitumor activity by reducing T cell exhaustion, (4) β2-microgobulin ( B 2M) gene KO, which eliminates HLA class I presentation to mitigate host T cell-mediated rejection, and (5) site-directed insertion of a B2M–HLA-E-peptide fusion into the B 2M locus to reduce NK cell-mediated rejection. In murine xenograft models of AML, CB-012 significantly reduced the tumor burden and increased the survival of mice bearing CLL-1+PD-L1+ tumors. Methods: CB-012 is being evaluated in a multicenter, Phase 1 clinical trial in patients with relapsed/refractory (r/r) AML. A 3+3 dose escalation design is being utilized with the primary objectives to determine the safety and tolerability of CB-012 and the recommended Phase 2 dose (RP2D). An expansion phase will follow dose escalation at the recommended dose(s) for expansion. Additional objectives include preliminary antitumor activity and pharmacokinetics. Key inclusion criteria include nonproliferative disease defined as ≤25% blasts in the bone marrow and peripheral blood, ECOG performance status ≤1, and adequate organ function. After receiving lymphodepletion therapy with cyclophosphamide (750 mg/m2/d) and fludarabine (30 mg/m2/d) administered concurrently for 3 days followed by a 2-day break, patients receive a single-dose infusion of CB-012 and are followed for safety and efficacy. The dose escalation portion of the study is actively enrolling patients. The AMpLify trial is registered at clinicaltrials.gov (NCT06128044). Clinical trial information: NCT06128044 .

Current progress of CAR-T-cell therapy for patients with multiple myeloma.

Currently available chimeric antigen receptor (CAR)-engineered T-cell therapies targeting B-cell maturation antigen (BCMA), namely, idecabtagene vicleucel and ciltacabtagene autoleucel, have shown marked efficacy against relapsed and refractory multiple myeloma. However, further improvement in CAR-T-cell function is warranted as most patients treated with these products eventually relapse due to various mechanisms such as antigen loss and T-cell dysfunction or disappearance. Strategies for improving CAR-T-cell function include targeting of dual antigens, enhancing cell longevity through genetic modification, and eliminating the immunosuppressive tumor microenvironment. Serious side effects can also occur after CAR-T-cell infusions. Although understanding of the molecular pathogenesis of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome is growing, the unique movement disorder caused by BCMA-targeted therapy is less understood, and its molecular mechanisms must be further elucidated to establish better management strategies. In this article, we will review the current status of BCMA-targeting CAR-T-cell therapy. We will also highlight progress in the development of CAR-T cells targeting other antigens, as well as universal allogeneic CAR-T cells and bispecific antibodies.

Abstract PO3-13-07: MUC1-C INTEGRATES CHRONIC ACTIVATION OF INTERFERON PATHWAYS WITH CHROMATIN REMODELING IN TREATMENT RESISTANCE OF TRIPLE-NEGATIVE BREAST CANCER

Abstract Chronic inflammation is intimately linked to cancer progression and resistance to treatment. Triple-negative breast cancer (TNBC) is a recalcitrant malignancy largely unresponsive to cytotoxic, targeted and immunotherapeutic agents. The Mucin1 (MUC1) transmembrane heterodimeric protein, which is aberrantly expressed in TNBCs, evolved in mammals to provide protection of epithelia from the external environment. With loss of homeostasis, the (i) MUC1 N-terminal (MUC1-N) subunit is shed and released into serum as detected by the CA15-3 assay, and (ii) MUC1 C-terminal (MUC1-C) subunit is activated and thereby induces inflammatory, proliferative and remodeling signaling pathways associated with wound healing. However, prolonged MUC1-C activation in settings of chronic inflammation promotes cancer progression and treatment resistance. The SWI/SNF PBAF chromatin remodeling complex includes the polybromo-1 (PBRM1) subunit and drives DNA damage resistance and immune evasion in certain cancer cells through mechanisms that remain unclear. Recent studies in TNBCs have demonstrated that MUC1-C drives intrinsic activation of type II interferon (IFN) pathway that is linked to chronic inflammation and immune evasion. In extending this work, we have found that MUC1-C activates the type I IFN pathway, which contributes to genomic instability and DNA damage tolerance in TNBC cells. Importantly, our results further demonstrate that MUC1-C interacts with interferon regulatory factor 1 (IRF1) as a key regulatory node in integrating activation of the type I and II IFN pathways. Here, we report that MUC1-C is necessary for PBRM1 expression and that it forms a nuclear complex with PBRM1 in TNBC cells. Analysis of global transcriptional (RNA-seq) and chromatin accessibility (ATAC-seq) profiles further demonstrated that MUC1-C and PBRM1 drive STAT1 and IRF1 expression by increasing chromatin accessibility of promoter-like signatures (PLS) on their respective genes. We also found that MUC1-C, PBRM1, and IRF1 increase the expression and chromatin accessibility on PLSs of the (i) type II IFN pathway IDO1 and WARS genes and (ii) type I IFN pathway RIG-I, MDA5, cGAS, STING and ISG15 genes that collectively contribute to DNA damage resistance and immune evasion. In support of these results, targeting MUC1-C in wild-type BRCA1/2 TNBC cells enhanced carboplatin-induced DNA damage and loss of self- renewal capacity. In addition, MUC1-C was necessary for DNA damage resistance, self-renewal and tumorigenicity of olaparib-resistant BRCA1-mutant TNBC cells. Analysis of TNBC clinical samples corroborated that (i) MUC1 and PBRM1 are associated with decreased responsiveness to chemotherapy and (ii) MUC1-C expression is associated with the depletion of tumor-infiltrating lymphocytes. These findings demonstrate that MUC1-C activates PBRM1, and thereby chromatin remodeling of IFN-stimulated genes that promote chronic inflammation, DNA damage resistance, and immune evasion. These findings have identified MUC1-C as a potential target for the treatment of TNBC that have limited therapeutic options. To that end, the generation of MAb 3D1 against the MUC1-C extracellular domain provided an opportunity for the development of agents that target MUC1-C on the cancer cell surface. As one example, an allogeneic anti-MUC1-C CAR T cell using MAb 3D1 sequences is undergoing Phase I evaluation for the treatment of MUC1-C-expressing cancers (NCT05239143: P-MUC1C-ALLO1 Allogeneic CAR-T Cells in the Treatment of Subjects with Advanced or Metastatic Solid Tumors). In addition, anti-MUC1-C huMAb3D1-MMAE ADCs are under development by the NCI NExT Program for IND-enabling studies and performing early phase clinical trials in patients with TNBC. Citation Format: Nami Yamashita, Yoshihiro Morimoto, Atsushi Fushimi, Rehan Ahmad, Atrayee Bhattacharya, Yuka Inoue, Henry Withers, Geoffrey Shapiro, Tomoharu Yoshizumi, Takayuki Ueno, Shinji Ohno, Mark Long, Donald Kufe. MUC1-C INTEGRATES CHRONIC ACTIVATION OF INTERFERON PATHWAYS WITH CHROMATIN REMODELING IN TREATMENT RESISTANCE OF TRIPLE-NEGATIVE BREAST CANCER [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-13-07.

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

BackgroundAdoptive cell therapy, such as chimeric antigen receptor (CAR)-T cell therapy, has improved patient outcomes for hematological malignancies. Currently, four of the six FDA-approved CAR-T cell products use the FMC63-based...

Innovative therapies for treatment of invasive fungal diseases

Invasive fungal diseases (IFD) are difficult to treat and pose a significant threat to immunocompromised individuals. Current antifungal agents face limitations, including antifungal resistance and adverse effects. This review aims to give a comprehensive overview of emerging treatment strategies.Novel drugs in development are Ibrexafungerp, an orally available triterpenoid inhibiting glucan synthesis, and Rezafungin representing the echinocandins with extended half-life and improved tissue penetration, both recently licensed for certain indications. Fosmanogepix targets glycosylphosphatidylinositol biosynthesis, while Olorofim, an orotomide, inhibits fungal nucleic acid synthesis, both currently assessed in advanced clinical trials.Immunotherapeutic approaches include immune checkpoint inhibitors to enhance immune response in immunosuppressed individuals and fungal-specific allogeneic CAR-T cell therapy. For prophylactic purpose in high-risk populations to develop IFD, monoclonal antibodies against different virulence factors of Candida spp. have been discovered but are not yet seen in clinical trials. Vaccines against distinct fungal antigens as well as pan fungal vaccines to prevent IFD are under development in preclinical stages, notably for Candida spp., Cryptococcus spp., and Aspergillus spp., however, their clinical value is still discussed.In summary, major advances to treat IFD have been observed, but challenges for their establishment in the clinical routine persist.

Abstract CT180: Phase I clinical trial of CD19CAR -T cells secreting PD-1-targeting IL-21 in advanced relapsed/refractory acute lymphoblastic leukemia

Abstract Background/Purpose: Chimeric antigen receptor (CAR) T cell therapy has shown remarkable responses in hematologic malignancies. However, suboptimal clinical outcomes have been associated with decreased expansion and persistence of adoptive transferred CAR-T cells, antigen-negative relapses, and impairment by an immunosuppressive tumor microenvironment. We previously developed CD19CAR-T cells secreting PD-1Ab21 fusion protein composed of anti-PD-1 single chain antibody and IL-21(PD-1Ab21-CD19CAR-T). This investigator-initiated clinical trial is designed to assess the safety and efficacy of the novel CAR-T cells in advanced relapsed/refractory acute Lymphoblastic leukemia (ALL). Methods: This study recruited 10 patients with advanced relapsed/refractory B-ALL and half of them relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT). All patients received fludarabine and cyclophosphamide before a single infusion of PD-1Ab21-CD19CAR-T cells at dose of 0.3, 1 or 3 x 106 cells/kg of body weight. The patients were monitored for adverse events, clinical response, as well as expansion of CAR-T and lymphocytes. Results: All five non-post-transplant patients achieved complete remission (CR), including two active CNS diseases, and three of them pursued consolidative allo-HSCT. Among the five post-transplant patients, one patient, who had undergone autologous, allogeneic CAR-T cell therapies and allo-HSCT, achieved CR and remained leukemia-free for 5 months, which was longer than the duration of remission (< 4 monthes) after allo-HSCT. The last treated patient achieved CR. Three other post-transplant patients, including two active CNS diseases, eventually died of the infection. One of the patients achieved minimal residual disease negative CR. The other two patients did not undergo laboratory evaluation, but their CNS symptoms disappeared. Once the expansion of CAR-T cells was detected, the proportion of CD8+T cell in CD3+T cells increased dramatically, rapidly reaching 77.8~91.2% and maintaining above 50% for a long time in all treated patients. Except for the three patients who died from infection, other patients experienced no or mild cytokine release syndrome (CRS) (grade ≤2). None of the patients had neurotoxic side effects. Conclusion: This study demonstrates that PD-1Ab21-secreting CAR-T cells are safe and effective therapeutic platform, even in cancer patients with CNS invasion. Our data also suggest that PD-1Ab21-secreting CAR-T therapy can activate endogenous anti-tumor CD8+ T cell responses. Citation Format: Yu Jing, Ying Li, Liping Dou, Shengjuan Zhang, Ran Tian, Guojing Wang, Xiangrui Cheng, Jitao Zhao, Hang Li, Yueyi An, Naibo Yang, Shengdian Wang. Phase I clinical trial of CD19CAR -T cells secreting PD-1-targeting IL-21 in advanced relapsed/refractory acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT180.

Abstract CT070: Solid tumor patients require higher cyclophosphamide (cy) dose than multiple myeloma (MM) patients to achieve adequate lymphodepletion (LD) necessary to enable allogeneic CAR-T expansion

Abstract Introduction: Poseida is developing innovative allogeneic T stem cell memory rich CAR-T both for hematologic malignancies (HM) and solid tumors (ST) including P-BCMA-ALLO1 which targets BCMA for MM, and P-MUC1C-ALLO1 targeting MUC1-C for epithelial-derived ST. Optimal LD for allogeneic cell therapies remains to be established. Most research has focused on HM, where patients (pts) have likely undergone HSCT and are, therefore, LD experienced in contrast to ST pts. Consequently, ST pts may require higher doses of LD chemotherapy to achieve LD depth comparable to HM pts. This study sought to compare LD with higher doses of cy across our early phase 1 trials (NCT04960579/NCT05239143) which are enrolling ST and MM pts, respectively. Methods: P-BCMA-ALLO1 and P-MUC1C-ALLO1 are 3+3 phase 1 dose escalation studies enrolling heavily pre-treated pts. LD arm S used cy 300 mg/m2 + fludarabine (flu) 30 mg/m2 × 3 days, followed by CAR-T. Alternative arms tested higher cy doses: P1 (500 mg/m2) and P2 (1,000 mg/m2), both with flu. We assessed LD depth and cellular kinetics (CK) by measuring WBC, serum IL-15, and CAR-T transcripts (qPCR). Results: By Jan 4, 2024, 42 pts received P-BCMA-ALLO1 (22 in S, 13 in P1, 7 in P2), and 30 pts received P-MUC1C-ALLO1 (19 in S, 9 in P1, 2 in P2). ST pts presented with higher baseline WBC compared to MM pts with median counts of 5.7×103 vs. 4.4×103/µL. LD was less pronounced in ST pts with a median WBC nadir of 1.1×103/µL for both S and P1. In MM pts median WBC nadir was 0.6×103 for S vs. 0.2×103 for P1. For P-BCMA-ALLO1, CK at 2×106 cells/kg dose showed a mean Cmax of 130,811 copies (cp)/µg in P2 and 6,191 in P1 compared to 170 in S. Median WBC nadir was significantly (p=0.0002) lower for P2 (0.1×103/µL) compared to S (0.6×103), with corresponding AUC0-13d values of 3.5×103/µL for P2 vs. 10×103 for S (p=0.0013). Peak serum IL-15 in P2 was 66.1 pg/mL, significantly higher than 29.7 in S (p=0.0110). In P1, there was a trend towards improved LD with median WBC nadir for P1 of 0.3×103/µL and AUC0-13d of 6.4×103/µL.P1 LD for P-MUC1C-ALLO1 did not improve CK, with WBC nadir and AUC 0-13d values comparable to S. P-MUC1C-ALLO1 CK at 2×106 cells/kg showed a mean Cmax of 692 cp/µg DNA in S, 23 in P1, and 4,200 in P2. P-MUC1C-ALLO1 pts receiving P2 achieved the deepest LD (WBC nadir: 0.1×103/µL). Peak IL-15 in ST pts was increased and delayed to day 8 in P2, compared to day 0 - 1 in S or P1. Conclusion: Increasing cy dose to 500 or 1,000 mg/m2 improves CK for P-BCMA-ALLO1 pts due to enhanced LD depth. For P-MUC1C-ALLO1 pts, increasing cy to 500 does not improve LD depth or CK compared to 300. This difference suggests the need for higher LD doses in ST pts than MM pts to achieve optimal CK. This differential need for LD chemo for these two studies is unlikely due to cellular characteristics because of similar manufacturing technology with the only difference being the binder. Citation Format: Sabrina Haag, Jeff D. Eskew, Katherine McArthur, Joanne McCaigue, Sepideh Vaziri, Samuel DePrimo, Christopher E. Martin, Catherine Gregovics, Ann Murphy, Hamid Namini, Ellen Christie, Marcela Marinez-Prieto, Rajesh Belani, Stacey Cranert, Julia Coronella, Devon Shedlock. Solid tumor patients require higher cyclophosphamide (cy) dose than multiple myeloma (MM) patients to achieve adequate lymphodepletion (LD) necessary to enable allogeneic CAR-T expansion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT070.

Abstract LB341: Clinical validation and mechanistic insights of ThisCART: A novel allogeneic platform enhancing CAR-T signaling via intracellular TCRαβ/CD3 retention

Abstract Background: Current allogeneic CAR-T cell therapies face challenges with post-infusion expansion and efficacy. In response, we developed ThisCART, a non-genetic editing, allogeneic platform that significantly enhances CAR-T cell expansion and efficacy. This is achieved through a novel approach of intracellular retention of membrane proteins, reducing surface expression of TCRαβ/CD3 complexes and HLA-I molecules. Our lead product, ThisCART19, has demonstrated superior efficacy compared to conventional AutoCART19 in preclinical and early clinical studies for B-ALL. Methods: In the clinical trial NCT04384393, we assessed the safety and efficacy of ThisCART19 in patients with B-cell malignancies. Post-lymphodepletion, participants received infusions of ThisCART19 and AutoCART19, both personalized from the patient's own T cells, in equal proportions. Safety and efficacy were the primary endpoints, evaluated on Day 28 post-infusion and throughout extended follow-up. Mechanistic insights were gained through comprehensive multi-omics studies, including RNAseq, whole-cell proteomics, and phosphoproteomics. Results: ThisCART19 showed enhanced expansion and an improved safety profile in vivo. As of 01 January 2024, Two patients diagnosed as relapse/refractory acute B cell leukemia (R/R B-ALL) were enrolled in the clinical trial. Pt1 is a 55yo male with Ph-positive B-ALL (36% blasts) who relapsed after multiagent chemotherapy and TKIs. Pt2 is a 16yo male with CNS leukemia (78.5% blasts) after multiagent chemotherapy. No DLTs or ICANS were observed. Pt1 experienced Grade 1 CRS that resolved without treatment, and Pt2 experienced Grade 2 CRS that resolved after tocilizumab and corticosteroids. Complete remission with MRD-negative status was achieved by Day 28. Pharmacodynamic analysis indicated a significant expansion of CAR-T cells, predominantly in the CAR+TCR- subset, highlighting autonomous CAR signaling enhancement. Multi-omics analysis identified upregulation in JAK-STAT, PI3K-Akt, and NFKB pathways, suggesting improved cell proliferation, survival, anti-apoptotic activity, and effector function. This molecular profiling provides a mechanistic understanding of ThisCART19A's therapeutic efficacy. Conclusion: The ThisCART platform marks a transformative advancement in allogeneic CAR-T cell therapy. By enhancing CAR signaling autonomously through a unique intracellular retention of TCRαβ/CD3 complexes, ThisCART has shown promising safety and efficacy in early clinical trials. Its potential in reshaping the treatment landscape for hematological and autoimmune disorders positions ThisCART as a crucial development in cellular therapeutics. Citation Format: Jun Li, Lei Xue, Sujun Li, Ling He, Kaichun Liu, Rong Jin, Tao Wang, Yinhang Zhang, Shanshan Chen, Yulian Gao, Dan Liu, Liyun Yang, Xingbing Wang. Clinical validation and mechanistic insights of ThisCART: A novel allogeneic platform enhancing CAR-T signaling via intracellular TCRαβ/CD3 retention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB341.

Placental circulating T cells: a novel, allogeneic CAR-T cell platform with preserved T-cell stemness, more favorable cytokine profile, and durable efficacy compared to adult PBMC-derived CAR-T

BackgroundChimeric antigen receptor (CAR)-T cell quality and stemness are associated with responsiveness, durability, and memory formation, which benefit clinical responses. Autologous T cell starting material across patients with cancer is...