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Background： CT103A, a fully human BCMA-specific chimeric antigen receptor (CAR) T-cell therapy product showed excellent safety and promising efficacy in heavily pretreated relapsed and refractory multiple myeloma (RRMM) patients in our previous report [Blood. 2021; 137 (21): 2890-2901]. The unique CAR structure containing fully human single-chain variable fragments (scFvs) may bypass the potential host anti-CAR immunogenicity and retain antitumor activity. Here we reported the safety and efficacy results of 71 patients in 1.0×10 6 CAR+ T cells/kg cohort from the ongoing phase1/2 study (ChiCTR1800018137/ ChiCTR2000033946). Notably, it was the first time that prior BCMA CAR-T exposed patients were eligible to participate in an anti-BCMA CAR-T cell trial. Methods： This phase 1/2 study of CT103A is single-arm designed and is conducted in 13 centers in China. The study enrolled RRMM patients who had received ≥ 3 lines of prior therapies containing at least a proteasome inhibitor and an immunomodulatory agent and were refractory to their last line of treatment. 1.0 × 10 6 CAR+ T cells/Kg was previously identified as recommended phase 2 dose (RP2D). Lymphodepletion with fludarabine and cyclophosphamide was performed for three consecutive days. After 1-day rest, patients received CT103A. The primary objectives of this study were to assess the safety and efficacy of CT103A at RP2D. The cellular pharmacokinetic profile of CT103A in peripheral blood was investigated by measuring CAR transgene levels using droplet digital polymerase chain reaction (ddPCR) and CAR-T cells by flow cytometry. Minimal residual disease (MRD) negativity was evaluated in bone marrow aspirate by standardized Euroflow 8-color flow cytometry with a minimum sensitivity of 10 -5 nucleated cells. Immunogenicity was assessed by MSD-based antidrug antibody (ADA) assay. Results: As of the July 15, 2021, 71 patients [59.2% male; median age 58.0 years (range 41-71)] with RRMM received CT103A (9 in phase 1a; 17 in phase 1b; 45 in phase 2). The median follow-up time was 147 days (range 31 to 1029). The treated patients had received a median of 4 (range 3-13) lines of prior therapy. 28.2% and 18.3% were previously treated with auto-HSCT and anti-CD38 antibody respectively. Notably, 18.3% had previously received CAR-T therapy. What's more, 7% of the patients had the extramedullary disease at baseline, and 76.1% had high-risk cytogenetics. The most common ≥ grade 3 treatment-related AEs were hematological toxicities. 93.0% of the patients experienced CRS, among which only 2.8% were grade 3. All CRS cases were rapidly relieved after conventional CRS intervention, including tocilizumab and steroids. The median time to CRS onset was 6 days (range 1-12) with a median duration of 4 days (range 1-27). Only one (1.4%) patient experienced grade 2 ICANS which manifested as a transiently decreased level of consciousness and soon recovered without intervention. All 71 patients were evaluable for at least one month of efficacy assessment. The median time to first response was 15 days (range 11-124). A 94.4% ORR was observed, with 50.7% ≥ CR, 26.8% VGPR, and 16.9% PR. Among them, 50 patients who have completed follow-up of 3 months achieved 96.0% ORR, with 54.0% ≥ CR, 28% VGPR, and 14% PR. For 13 patients who have previously been treated with CAR-T therapy, ORR was 76.9%, with ≥ CR rate of 38.5%，VGPR of 15.4%, and PR of 23.1%. Of the 69 patients with evaluable bone marrow aspirate, 92.8% achieved MRD-negativity with a median time to MRD-negative of 17 days (range 13-180), and among them, 75.0% (95%CI 53.1-87.6%) achieved sustained MRD negativity over six months. The expansion of CT103A reached the peak at a median of 12 days (range 5 to 29). CT103A was still detectable in 88.5% (23/26) patients at 6 months and 87.5% (14/16) patients at 12 months after infusion. The first enrolled patient remains in sCR for 34 months with significant persistence of CT103A transgene. In addition, only 2 of 71 patients were detected positive for anti-drug antibody, which was reported to be a high-risk factor for disease relapse/progression after CAR-T therapy. Conclusion: The impressive efficacy of CT103A, including time to response, overall response rate, and durability, was corroborated by robust expansion and prolonged persistence of CT103A. The expansion and clinical benefits of CT103A did not seem to be influenced by prior murine BCMA CAR-T. Disclosures No relevant conflicts of interest to declare.

Introduction Multiple issues arise for a wider application of chimeric antigen receptor (CAR) T cell therapy including manufacturing time and antigen escape. Here we report data on an anti-CD19/CD22 dual CAR-T (GC022F) therapy based on a novel manufacturing platform, from a phase I clinical study (NCT04129099) in treating patients with B-cell acute lymphoblastic leukemia (B-ALL). Methods Peripheral blood (PB) mononuclear cells were obtained by leukapheresis. T-cells were separated and transduced with lentivirus that encodes a CD19/CD22 directed 4-1BB: ζ CAR. GC022F cells were manufactured using a novel FasTCARTM platform which takes 24 hours, while the conventional CD19/CD22 dual CAR-T (GC022C) cells used as parallel control in the preclinical study were manufactured by conventional process which typically takes 9-14 days. The phase I dose escalation study was initiated to explore the safety and efficacy of GC022F in patients with B-ALL. All patients received a conditioning regimen of IV fludarabine (25mg/m2/d) and cyclophosphamide (250mg/m2/d) for 3 days prior to GC022F infusion. Results When compared with the GC022C, GC022F cells showed 1) less exhaustion as indicated by lower percentage of PD-1+LAG3+ cells following co-culturing with tumor cells, 2) younger phenotypes as demonstrated by more abundant T central memory cells (Tcm; CCR7+CD45RA+ or CD45RO+CD62L+), 3) higher expansion fold at in vitro culture, and 4) high anti-leukemia efficacy in mice model (Fig.1). Comparing in vivo efficacy of GC022F with GC022C cells at lower doses, GC022F treatment were more potent and could reduce tumor burden earlier and faster, and led to significantly prolonged overall survival of the experimental animals. From Nov. 2019 to Jun. 2020, 9 children and 1 adult with B-ALL were enrolled and infused with GC022F, 2 in low-dose (6.0×104/kg), 7 in medium dose (1.0-1.5×105/kg), 1 in high-dose (2.25×105/kg). Patients' median observation time was 99 (14-210) days on the day of cut-off. Characteristics of enrolled patients are shown in Table 1. The median age was 10 (3-48) years, and the median bone marrow (BM) blasts were 21.0 (0.1-63.5) % at enrollment. Three patients had prior CD19 CAR-T cell therapy history and one of whom had prior allogeneic hematopoietic stem cell transplantation (allo-HSCT). After infusion, the median peak of circulating CAR-T cell copy number was 2.29 ×105 copies/µg genomic DNA (0.0014-5.66), which occurred around day 14 (day10 - day 28). Importantly, GC022F persisted well in PB with a median of 2.40×105 copies/µg genomic DNA (0.75-3.98) on day 28 in 5 of 9 patients with available 4 weeks of cellular kinetics data. GC022F exerted a superior safety profile with no observed grade ≥ 3 cytokine release syndrome (CRS) and neurotoxicity in all patients. Among those 6 patients with CRS, only 1 at high dose level had grade 2 CRS; only 1 developed grade 1 neurotoxicity. After GC022F infusion, 6/6 patients with BM blasts > 5% at enrollment achieved complete remission (CR) by day 28, 5/6 with minimal residual disease (MRD)-negative CR. For those 4 patients with MRD positive disease at enrollment, 3 became MRD-negative CR by day 28, 1 had persist MRD positive disease and withdrew from the study by 2 weeks. Five of 8 MRD-negative CR patients subsequently made a choice to pursue consolidation allo-HSCT with a median time interval of 57 (48-71) days post GC022F infusion and all have remained in MRD-negative CR except 1 died from graft-versus-host disease (GVHD) and infection 143 days post GC022F infusion. Of the other 3 patients without allo-HSCT, 2 relapsed with CD19+/CD22+ disease at 12-16 weeks follow-up, including the patient with prior history of CD19 CAR-T treatment and transplant. Conclusion This study demonstrated that anti-CD19/CD22 dual CAR T-cells could be successfully manufactured by FasTCARTM technology in 24 hours, with younger and less exhausted phenotypes. Moreover, the Dual FasTCAR-T cells showed more potent efficacy in xenograft mouse model compared to the conventional dual CAR-T cells. Our clinical data demonstrate that GC022F is safe and efficacious in treating patients with CD19+CD22+ B-ALL. More data on additional patients and longer observation time are needed to further evaluate CD19/CD22 dual FasTCAR-T cell product. Disclosures Cai: Gracell Biotechnologies Ltd: Current Employment. Wang:Gracell Biotechnologies Ltd: Current Employment. Chen:Gracell Biotechnologies Ltd: Current Employment. Ye:Gracell Biotechnologies Co., Ltd.: Current Employment. He:Gracell Biotechnologies Co., Ltd.: Current Employment. Cao:Gracell Biotechnologies Ltd: Current Employment. Sersch:Gracell Biotechnologies Co., Ltd.: Current Employment.

Establishing a calculation procedure of stress and residual deformation of manhole under vehicle impact loads is meaningful for improving the design and rehabilitation of the manhole. By using corotational procedure, this paper presents formulation of a refined nonlinear 8-noded brick element. Theoretically, the element is capable of analyzing very large deformation in efficiency, and has the advantage of adopting to any kind of nonlinear material model. A rigorous continuum mechanics basis to the corotational framework is provided and a corotational kinematical model for geometrically nonlinear analysis is also derived with locking reduction in 3D brick elements.

Urban rainwater harvesting systems are widely used to solve urban water shortage. However, the initial rainwater collected from urban roads contains numerous particles that severely limit its reuse. This study designed a hydrodynamic separator on a separated sewer systems (between the rainwater collecting main pipe and intercepting main canal) to remove particulate pollutants, avoid rainwater reflux, and realize staggered regulation during flood peak. In this work, a 3D model of the hydrodynamic separator was constructed using SolidWorks software, and state-of-the-art FLUENT computational fluid dynamics was applied in fine-scale simulation of the hydrodynamic separator under complex initial conditions. Numerical tests were performed to validate the capability of the hydrodynamic separator in removing particulate pollutants under different initial conditions. The results of numerical tests showed that particle trajectories are relatively regular spirals in the hydrodynamic separator, whereas large-diameter particles feature high removal rates. Particle removal rate increased with increasing diameter-depth ratio and height difference between the overflow and inlet pipes. Considering the particle removal rate, the optimal order of angles between the overflow and inlet pipes is 90° > 150° > 60° > 120°. The parameters of the hydrodynamic separator in removing initial rainfall particulate pollutants were obtained, and a pilot-scale experiment was conducted, providing theoretical importance in reducing energy consumption of rainwater harvesting pretreatment systems.

Introduction Chimeric antigen receptor (CAR) T cell therapy targeting CD19 has demonstrated high success for B-cell acute lymphoblastic leukemia (B-ALL). Despite the initial high complete remission (CR) rate, about half of patients (pts) relapse at 1 year. CD19 antigen loss was observed in a significant number of relapsed patients. CD22 is another leukemic marker that often expressed on the surface of CD19- relapsed B-ALL blasts. We have developed a bispecific CAR construct targeting CD19 and CD22. Here we report results from a phase Ⅰ clinical trial of CD19/CD22 (GC022) dual CAR-T to evaluate the safety and feasibility of treating patients with relapsed/refractory B-ALL. Methods The CD19/CD22 dual CAR-T cells were manufactured in a cGMP facility. Patients' peripheral blood (PB) mononuclear cells were first collected, and CD3+ T cells were separated. The cells were then transfected by lentivirus encoded with CD19 CD22 bispecific scFv sequences. The CAR-T cells produced in this way contained a 4-1BB co-stimulatory signal domain. The CAR-T cells were then cultured for 8-14 days until sufficient cells were harvested for infusion. All pts received conditioning regimen of fludarabine and cyclophosphamide intravenously for 3 consecutive days with doses of 30 mg/m2/day and 250 mg/m2/day, respectively before a single infusion of CAR-T cells. The level of infused CAR-T cell proliferation in PB was analyzed by qPCR and flow cytometry. The primary end points were to evaluate feasibility and toxicity, and the secondary end points included disease response and engraftment/persistence of infused CD19/CD22 dual CAR-T cells. Results From Feb. 2019 to 23 July. 2019, 17 patients (pts) with relapsed/refractory B-ALL including 4 pts who previously treated with CD19 CAR-T cells were enrolled and pts were treated with CD19/CD22 dual CAR-T GC022 (US NIH Clinical#: NCT03825731). Four were adults, 13 pediatrics (age 1-45, Table 1). The median bone marrow (BM) blasts was 19.09 (0.36-87.82) %. Four patients received a low-dose (2.5-5×105/kg) dual CAR-T, 7 received a medium-dose (1-2.5×106/kg) and 5, a high-dose (3-5×106/kg). One patient withdrew immediately before CAR-T infusion due to his personal issue. Anti-leukemic efficacy was evaluated in 11/16 pts (5 pts have not yet reached D15). The 3/4 pts received low dose of GC022 had no response to treatment and 1 had MRD-positive CR. Seven patients who received medium dose achieved 100% CR on D15, highlighting the dose-dependent anti-leukemic activity. Six out of seven pts had MRD negative CR in this medium dose group. Five pts in high dose group have not reached the time for evaluation. No one relapsed with a median observation time of 60 (7-139) days. Cellular kinetic data was analyzed. Median peak of CAR-T copies was 1.09 (0.0022-4.98) x105 copy number/µg PB genomic DNA (Fig.1). The proliferation of medium or high dose groups was significantly better than the low dose group 3.47(0.43-4.98) x105 vs. 0.023(0.0022-0.81) x105(P=0.02) and 2.02(1.89-2.16) x105 vs. 0.023(0.0022-0.81) x105(P=0.004), (Fig.2). The peaks of IL-6, IFN-γ, IL-10, and CD25 were observed around day 7-10. Sixteen out of seventeen pts had grade 0-1 cytokine release syndrome (CRS) and only 1 patient experienced grade 2 CRS. None developed neurotoxicity. Conclusion Our study demonstrates safety and technical feasibility of CD19 and CD22 dual CAR-T in treating patients with CD19+CD22+ relapsed/refractory B-ALL. A low toxicity with dose-dependent high CR rate including pts who previously treated with CD19 CAR-T cells were observed. Longer observation time and more patients are needed to evaluate a beneficial advantage of the CD19/CD22 dual CAR-T over CD19 CAR-T product. Disclosures No relevant conflicts of interest to declare.

Introduction CD19-targeting chimeric antigen receptor (CAR) T cell therapy has demonstrated high success; however, its therapeutic potential can still be further improved. In addition, the high cost and lengthy process of CAR-T production limit its broad application. We have developed a new platform termed FasT (F) CAR-T with shortened manufacturing time to one day (plus 7 days of additional testing for regulatory requirements). Here we report results from a pre-clinical study of FasT (F) CAR-T (GC007F) and a phase Ⅰ clinical trial to assess the safety and feasibility of treating patients with CD19+ relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). Methods In this study, a second generation of CD19-directed CAR-T was manufactured using the FasT CAR-T platform. Peripheral blood (PB) mononuclear cells were obtained by leukapheresis either from healthy donors for the pre-clinical study or from patients undergoing the clinical trial. T cells were separated and used for CAR-T generation. A xenograft mouse model was used to determine the efficacy of GC007F in vivo. Conventional (C) CAR-T derived from the same healthy donor were also made and tested in parallel for comparison. Between Feb. 2019 and July 2019, 10 adolescent and adult patients with CD19+ relapsed/refractory B-ALL were enrolled in a feasibility trial for CD19 FasT CAR-T (www.clinicaltrials.gov, NCT03825718). FasT CAR-T cells for all patients were successfully manufactured. All patients received a conditioning regimen of IV fludarabine (30mg/m2/d) and cyclophosphamide (250mg/m2/d) for 3 days followed by a single infusion of CAR-T cells. Six patients received a low-dose 6.5 (5.86-7.04) x104/kg of FasT CAR-T, 2 received a medium-dose 1 (1-1.16) x105/kg, and 1, a high-dose 1.56x105/kg. The primary end points of the study were to evaluate feasibility and toxicity, and the secondary end points included disease response and engraftment/persistence of infused FasT CAR-T cells. Results This preclinical study has demonstrated several significant improvements of CD19-directed F CAR-T over C CAR-T: 1) 5-30 fold superior expansion capability (p For the phase Ⅰ clinical trial, the median observation period was 86 days (37-166 days). The median percentage of pre-treatment bone marrow (BM) blasts was 9.05% (0.19-32.5%). On day 15 after CAR-T cell infusion, 10/10 (100%) cases achieved complete remission (CR) or CR with incomplete count recovery (CRi) and 9/10 (90%) had minimal residual disease (MRD)-negative CR. Four of ten patients had a good blood count recovery on day 15. The number further increased to 6/10 on day 30. Patient F15 had rapidly growing disease in that his PB blasts increased from 1% on enrollment to 7% immediately before CAR-T cells infusion, and increased to 77% on day 7 post infusion. Notwithstanding the rapid disease progression, the patient achieved MRD-positive CR on day 15 with residual 0.06% BM blasts. Five of ten patients were bridged into allogeneic hematopoietic stem cell transplantation (allo-HSCT). All 10 patients have remained in CR thus far. After CAR-T infusion, the level of infused CD19 FasT CAR-T cells in PB was analyzed by qPCR and flow cytometry. Superior in vivo proliferation and persistence were detected regardless of the infused CAR-T doses. The median peak level was reached on day 7 (7-10) with 2.1(0.22-5.2) x105 copy/µg PB genomic DNA (Fig. 2) and the median CAR-T expression ratio was 44.5 (13.6-69.5) %. The peaks of IL6, IFNγ, IL10, and CD25 were observed around day 7. Despite the achievement of a very high CR rate, 9/10 had grade 1 cytokine release syndrome (CRS) and only 1 patient experienced grade 3 CRS. None developed neurotoxicity. Conclusion This study has demonstrated that FasT CAR-T cells with superior expansion capability and younger/less exhausted phenotypes can be generated rapidly. This first-in-human clinical study showed that FasT CAR-T is safe and highly effective for treating patients with B-ALL. Disclosures No relevant conflicts of interest to declare.

Due to the greater additional stress of prestressing, many serious problems - such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking frequently occurred in the prestress tensioning process of medium or short span prestressed concrete beam bridge. To solve these problems, a new type of twice prestress technology was innovatively proposed in this work. Through theoretical and experimental comparison between this new structure and the traditional prestressed structure, it was found that the application of prestressing twice can significantly improve the mechanical and deformational performance of the low height beam in the construction process and also for long-term use. In addition, a theoretical solution to calculate creep strain and deformation due to twice prestressed with respect to time t were derived in this paper. Finally, the work concluded that this new structure will make it a bright application perspective for the medium and short span prestressed beam bridge to control the deformations. (A)