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Despite the success of antiretroviral therapy (ART) for people living with HIV, lifelong treatment is required and there is no cure. HIV can integrate in the host genome and persist for the life span of the infected cell. These latently infected cells are not recognized as foreign because they are largely transcriptionally silent, but contain replication-competent virus that drives resurgence of the infection once ART is stopped. With a combination of immune activators, neutralizing antibodies, and therapeutic vaccines, some nonhuman primate models have been cured, providing optimism for these approaches now being evaluated in human clinical trials. In vivo delivery of gene-editing tools to either target the virus, boost immunity or protect cells from infection, also holds promise for future HIV cure strategies. In this Review, we discuss advances related to HIV cure in the last 5 years, highlight remaining knowledge gaps and identify priority areas for research for the next 5 years. An effective and scalable cure strategy is a top priority for the HIV research field; this Review discusses recent advances, knowledge gaps, and priority research areas for the next 5 years.

Chimeric antigen receptor (CAR) T cells targeting CD19 are a breakthrough treatment for relapsed, refractory B cell malignancies1–5. Despite impressive outcomes, relapse with CD19− disease remains a challenge. We address this limitation through a first-in-human trial of bispecific anti-CD20, anti-CD19 (LV20.19) CAR T cells for relapsed, refractory B cell malignancies. Adult patients with B cell non-Hodgkin lymphoma or chronic lymphocytic leukemia were treated on a phase 1 dose escalation and expansion trial (NCT03019055) to evaluate the safety of 4-1BB–CD3ζ LV20.19 CAR T cells and the feasibility of on-site manufacturing using the CliniMACS Prodigy system. CAR T cell doses ranged from 2.5 × 105–2.5 × 106 cells per kg. Cell manufacturing was set at 14 d with the goal of infusing non-cryopreserved LV20.19 CAR T cells. The target dose of LV20.19 CAR T cells was met in all CAR-naive patients, and 22 patients received LV20.19 CAR T cells on protocol. In the absence of dose-limiting toxicity, a dose of 2.5 × 106 cells per kg was chosen for expansion. Grade 3–4 cytokine release syndrome occurred in one (5%) patient, and grade 3–4 neurotoxicity occurred in three (14%) patients. Eighteen (82%) patients achieved an overall response at day 28, 14 (64%) had a complete response, and 4 (18%) had a partial response. The overall response rate to the dose of 2.5 × 106 cells per kg with non-cryopreserved infusion (n = 12) was 100% (complete response, 92%; partial response, 8%). Notably, loss of the CD19 antigen was not seen in patients who relapsed or experienced treatment failure. In conclusion, on-site manufacturing and infusion of non-cryopreserved LV20.19 CAR T cells were feasible and therapeutically safe, showing low toxicity and high efficacy. Bispecific CARs may improve clinical responses by mitigating target antigen downregulation as a mechanism of relapse. A new bispecific CAR T cell product targeting the CD20 and CD19 antigens demonstrates an excellent safety profile and high clinical efficacy in patients with B cell non-Hodgkin lymphoma and chronic lymphocytic leukemia.

Anti-CD19 chimeric antigen receptor T (CAR-T) cells have demonstrated activity against relapsed/refractory lymphomas. Cytokine release syndrome (CRS) and immune effector cell – associated neurotoxicity syndrome (ICANS) are well-known complications. Tocilizumab, a monoclonal antibody targeting the interleukin-6 (IL-6) receptor was administered 1 hour prior to infusion of anti-CD19 CAR-T cells with CD3ζ/4-1BB costimulatory signaling used to treat non-Hodgkin lymphoma patients. Relapsed/refractory lymphoma patients treated with anti-CD19 CAR-T cells were included in this analysis. Cytokine plasma levels were measured by electrochemiluminescence before lymphodepleting chemotherapy, prior to infusion and then on days 2, 4,6, and 14 days after treatment. Twenty patients were treated. Cell products included locally manufactured anti-CD19 CAR-T (n=18) and tisagenlecleucel (n=2). There were no adverse events attributed to tocilizumab. Ten patients had grade 1–2 CRS at a median of 4 (range 3-7) days. There were no cases of grade ≥3 CRS. Five patients had ICANS, grade 1 (n=4) and grade 4 (n=1). Laboratory studies obtained prior to lymphodepleting chemotherapy were comparable between patients with and without CRS, except for interleukin (IL)-15 plasma concentrations. patients with CRS had higher post-infusion ferritin and C reactive protein, with more marked increases in inflammatory cytokines, including IL-6, IL-15, IFN-γ, fractalkine and MCP-1. Fifteen patients (75%) achieved CR and 2 (10%), PR. One-year OS and PFS estimates were 83% and 73%. Prophylactic tocilizumab was associated with low CRS incidence and severity. There were no adverse events associated with tocilizumab, no increase in frequency or severity of ICANS and excellent disease control and overall survival.

Chimeric antigen receptor T cell (CAR-T cell) therapy is known to produce durable remissions in the treatment of CD19+relapsed/refractory B cell malignancies. Nonetheless, a significant portion of patients receiving the therapy experience poor outcomes in the acute response for unknown reasons. Given the decreased expansion and persistence of CD8 CAR-T cells in poor outcome groups, this failure may be attributed to CAR-T cell dysfunction. However, a comparison of the post-infusion transcriptional profiles and phenotypes between CAR-T cells of poor and favorable response groups has not been performed. Here, we employed single cell RNA sequencing and protein surface marker profiling of serial CAR-T cell blood samples from patients with CD19+relapsed/refractory non-Hodgkin’s lymphoma (NHL) to reveal CAR-T cell evolution, identify biomarkers of response, and test for evidence of exhaustion in CAR-T cells of poor responders. At the transcriptional and protein levels, we note the evolution of a majority of CAR-T cells toward a non-proliferative and highly-differentiated state. In poor outcome patients, we observed a more marked enrichment of an exhaustion profile as compared to favorable outcome patients. Lastly, we identified the checkpoint receptor TIGIT (T cell immunoreceptor with Ig and ITIM domains) as a novel prognostic biomarker and potential driver of CAR-T cell exhaustion. Altogether, we provide evidence of CAR-T cell dysfunction marked by TIGIT expression driving poor response in NHL patients.

INTRODUCTION GBM has median survival of 12 months despite current SOC therapy. The most important mechanism of TMZ resistance is the O6-methylguanine-DNA methyltransferase (MGMT) gene. The MGMT inhibitor O6-benzylguanine (BG) demonstrated efficacy in depleting MGMT but approach led to unacceptable bone marrow toxicity and has thus been abandoned. We hypothesized that chemoprotection of hematopoietic HPC with an MGMT mutant (MGMT-P140K) characterized by normal methyltransferase activity, coupled with low affinity for BG would maximize anti-tumor response while enabling patients to tolerate TMZ & BG dose escalation with minimal toxicity. A phase I trial was performed to test this hypothesis. METHODS 10 adults with newly diagnosed MGMT unmethylated, IDH-1 WT, GBM underwent standard surgery and radiation, followed by transplantation with autologous CD34+ HPC transfected with MGMT-P140K using a lentiviral vector. We tested tolerance and efficacy of three different paradigms for conditioning bone marrow and re-infusion of HPC. RESULTS Treatment was moderately toxic with 3/10 patients suffering grade 3–4 hematologic toxicity; no high grade non-hematologic toxicity was observed. Viral transduction rates ranged from 3–75% and were clearly improved in Arm III utilizing BCNU conditioning and intra-patient dose escalation of TMZ/O6GB. In patients tolerating 3 cycles or more, P140K-MGMT gene markings in peripheral blood and bone marrow cells increased 3-26-fold with only mild (Grade 2–3) myelosuppression consistent with chemo-protection as hypothesized. Median PFS and OS was 24 and 33 months respectfully, and three patients in Arm III were progression free at 36 months with one progression free at 48 months. OS exceeded RPA & Nomogram predicted survival by 3.6-fold, suggesting clinical benefit. Viral insertion site analysis demonstrate no clonal dominance. CONCLUSIONS P140K-MGMT transfected HPC enables TMZ/ BG dose escalation with acceptable toxicity and increased survival in a small cohort of selected patients. A U-01 funded phase II study is ongoing at UH and NIH.

Chimeric antigen receptor T cells (CAR-T cell) targeting CD19 are effective against several subtypes of CD19-expressing hematologic malignancies. Centralized manufacturing has allowed rapid expansion of this cellular therapy, but it may be associated with treatment delays due to the required logistics. We hypothesized that point of care manufacturing of CAR-T cells on the automated CliniMACS Prodigy® device allows reproducible and fast delivery of cells for the treatment of patients with non-Hodgkin’s lymphoma. Here we describe cell manufacturing results and characterize the phenotype and effector function of CAR-T cells used in a phase I/II study. We utilized a lentiviral vector delivering a second-generation CD19 CAR construct with 4-1BB costimulatory domain and TNFRSF19 transmembrane domain. Our data highlight the successful generation of CAR-T cells at numbers sufficient for all patients treated, a shortened duration of production from twelve to eight days followed by fresh infusion into patients, and the detection of CAR-T cells in patient circulation up to one-year post-infusion.

Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent effects in relapsed and/or refractory pre-B cell acute lymphoblastic leukemia (B-ALL), but antigen loss is a frequent cause of resistance to CD19-targeted immunotherapy. CD22 is also expressed in most cases of B-ALL and is usually retained following CD19 loss. We report results from a phase 1 trial testing a new CD22-targeted CAR (CD22-CAR) in 21 children and adults, including 17 who were previously treated with CD19-directed immunotherapy. Dose-dependent antileukemic activity was observed, with complete remission obtained in 73% (11/15) of patients receiving ≥1 × 106 CD22-CAR T cells per kg body weight, including 5 of 5 patients with CD19dim or CD19- B-ALL. Median remission duration was 6 months. Relapses were associated with diminished CD22 site density that likely permitted CD22+ cell escape from killing by CD22-CAR T cells. These results are the first to establish the clinical activity of a CD22-CAR in B-ALL, including leukemia resistant to anti-CD19 immunotherapy, demonstrating potency against B-ALL comparable to that of CD19-CAR at biologically active doses. Our results also highlight the critical role played by antigen density in regulating CAR function.

INTRODUCTION: Anti-CD19 chimeric antigen receptor T (CAR-T) cells have demonstrated activity against relapsed/refractory lymphomas. Cytokine release syndrome (CRS) and CAR-T related encephalopathy syndrome (CRES/ICANS) are well-known complications of CAR-T cell therapy. Tocilizumab, a humanized monoclonal antibody targeting the interleukin 6 (IL-6) receptor, is approved for treatment of CRS. Our institutional standard was modified to administer prophylactic tocilizumab before infusion CAR-T cell products. We present the outcomes of subjects treated with locally manufactured antiCD19 CAR-T cells (TNFRSF19 transmembrane domain, CD3Zeta/4-1BB costimulatory signaling) with and without prophylactic tocilizumab. METHODS: Relapsed / refractory (r/r) lymphoma patients (pts) treated with anti-CD19 CAR-T cells at our institution were included. Baseline demographic and clinical characteristics, as well as laboratory results were obtained from our Hematologic Malignancies and Stem Cell Therapy Database. Prior to institution of prophylactic tocilizumab, pts received this agent only if they presented evidence of CRS grade 2 or higher. In May 2019, our institutional practice changed to provide tocilizumab 8mg/kg, 1 hour prior to infusion of CAR-T cell product. CRS was measured according to the ASTCT Consensus Grading, whereas CRES was measured using the CARTOX-10 criteria. Comparisons between groups were done with the Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables. RESULTS: Twenty-three relapsed / refractory lymphoma pts were treated with antiCD19 CAR-T cells; 15 pts received prophylactic tocilizumab. Median follow up was 312 days (range 64 - 679) days. Baseline characteristics are listed in table 1. Both groups were similar: There were no statistically differences in the rate of bulky, refractory disease, prior ASCT or number or prior lines of therapy. Baseline lymphocyte counts, C - reactive protein (CRP) and were also comparable between groups (Table 2). We did not observe immune adverse reactions to tocilizumab infusion. There were no differences in the incidence of cytopenias or infectious complications between groups. CRS of any grade was observed in 6/8 (75%) of pts without prophylactic tocilizumab vs. 6/15 (40%) in pts treated with prophylactic tocilizumab (p = 0.23), whereas CRS grade >1 was observed in 5 pts (62.5%) without prophylactic tocilizumab and in 3 pts (20%) treated with prophylactic tocilizumab (p = 0.02). There was no significant difference in the incidence of all grade CRES (no prophylaxis, 3/8 [38%] pts; prophylaxis 5/15 [30%] pts, p = 0.2969). There was a statistically significant difference in the peak CRP and peak ferritin without difference in the peak lymphocyte count after CAR-T infusion (Table 2, Figure 1). Patients given prophylactic tocilizumab had higher IL-6 plasma concentrations on day 2 after infusion (Figure 2). Complete response was observed in 4/8 (50%) pts without prophylactic tocilizumab vs. 12/15 (80%) pts with prophylactic tocilizumab (p = 0.18). All pts had detectable Anti-CD19 CAR-T cells on day 30, both groups had peak CAR-T expansion on day 14, with no statistically significant differences in expansion rates between groups. All evaluable subjects have had CAR-T persistence on days 60, 90, 180, and 365. CONCLUSIONS: Use of prophylactic tocilizumab prior to infusion of antiCD19 CAR-T cells is associated with reduced incidence of severe CRS and decreased levels of clinical laboratory markers of inflammation, despite increases in plasma concentration of IL-6. This decreased rate of grade ≥2 CRS is not associated with impaired disease control and did not result in increased rates of neurologic toxicity. Prophylactic tocilizumab does not appear to affect CAR-T cell expansion or persistence. Figure 1 Disclosures Caimi: ADC therapeutics: Other: Advisory Board, Research Funding; Celgene: Speakers Bureau; Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Verastem: Other: Advisory Board; Kite pharmaceuticals: Other: Advisory Board. Worden:Lentigen, a Miltenyi biotec company: Current Employment. Kadan:Lentigen, a Miltenyi biotec company: Current Employment. Orentas:Lentigen Technology, a Miltenyi Biotec Company: Research Funding. Dropulic:Lentigen, a Miltenyi Biotec Company: Current Employment, Patents & Royalties: CAR-T immunotherapy. de Lima:Celgene: Research Funding; Pfizer: Other: Personal fees, advisory board, Research Funding; Kadmon: Other: Personal Fees, Advisory board; Incyte: Other: Personal Fees, advisory board; BMS: Other: Personal Fees, advisory board. OffLabel Disclosure: Use of tocilizumab as prophylaxis for CRS is not approved, whereas use for treatment is approved and on label.

Background Patients (pts) with rapidly progressive lymphoma and urgent need for therapy have worse prognosis and may not be able to receive CAR-T cells. Decreasing apheresis to infusion time can make CAR-T cells available to this patient population. We present the results of a phase I trial using rapid on-site CAR-T manufacture for relapsed/refractory B cell non Hodgkin lymphoma (NHL). Methods Adult pts with CD19+ B NHL who failed ≥ 2 lines of therapy were enrolled. Autologous T cells were transduced with a lentiviral vector (Lentigen Technology, Inc) encoding antiCD19 binding motif, CD8 linker and TNFRS19 transmembrane region, and 4-lBB/CD3z costimulatory domains. GMP compliant manufacture was done using CliniMACS Prodigy, in a 12 day culture. Dose escalation was done using 3+3 design, with 3 dose levels (0.5, 1 and 2 × 106 CAR-T cells/kg). Lymphodepletion was done with cyclophosphamide (60mg/kg × 1) and fludarabine (25mg/m2/d × 3). Results As of September 30, 2019, 14 pts were enrolled and treated. Table 1 lists baseline characteristics. 12 pts had refractory NHL, 6 had bulky disease and 9 had symptomatic disease at the time of lymphocyte collection. CAR-T cell product manufacture was successful in all pts. Median transduction rate was 48% [range 29-62] with median culture expansion of 41-fold [range 30-79]. All pts received their infusion of antiCD19 CAR-T cells. CAR-T cell doses were 0.5 × 106/kg (n = 4) and 1 × 106/kg (n = 10). Median apheresis to infusion time was 13 days [range 13–20]. CAR-T persistence, based on vector sequence, peaked in peripheral blood MNCs between days 14-21. All evaluable subjects had persistent CAR-Ts on PCR measurements done on days 30, 60 and 90. CAR-T cell dose did not have an impact in the time to peak in vivo CAR-T cell expansion or in the rate of CAR-T cell persistence (fig 1). Six pts experienced CRS. Five pts had grade 1 – 2 CRS and 1 pt died on day 8 due to CRS. Two pts presented grade 4 CRES, resolved after corticosteroids. No other grade ≥3 non-hematologic toxicity was observed. The most common non – hematologic toxicity was fatigue (n=7). Hematologic toxicity was common, with grade ≥ 3 neutropenia observed in all pts. Among 12 evaluable pts, 8 have achieved complete response (CR) and two had partial response (PR). Two pts did not respond. The CR rate was 67% and overall response rate was 83%. Three pts have died, causes of death include progressive disease (n=2) and CRS (n=1). After a median follow up 4.5 months (range 1 – 14) all responding pts are alive; 1 pt relapsed 6 months after treatment with CD19+ disease and entered CR after antiCD19 antibody drug immunoconjugate. Conclusions AntiCD19 CAR-T cells with TNFRS19 transmembrane domain have potent clinical activity. The short manufacture times achieved by local CAR-T cell manufacture enables treatment of a very high risk NHL population that would otherwise not be able to receive CAR-T products due to rapidly progressive disease.

Introduction Anti CD19 CAR T-cell therapy is a breakthrough immunotherapeutic approach for relapsed, refractory B-cell malignancies. Despite initial excitement, long term progression free survival with single antigen targeted CD19 CAR T-cells range from 30-40% in aggressive B-cell NHL. Loss of target due to selective pressure against CD19 can lead to antigen downregulation and development of a CD19-negative clonal population. To overcome this resistance mechanism, we recently completed a Phase 1 anti-CD19, anti-CD20 (LV20.19) CAR T-cell trial demonstrating the safety of 2.5x10e6 cells/kg dose in patients with relapsed, refractory B-cell lymphomas (in press in Nature Medicine). We report below single cell cytokine studies from final LV20.19 CAR T-cell products using the Isoplexis single-cell proteomics device. Methods LV20.19 CAR T-cells were manufactured onsite using the CliniMACS Prodigy device on a fixed 14-day manufacturing platform with IL-2 for cell expansion (NCT03019055). Isoplexis cytokine analysis was limited to the cohort of patients treated at goal dose of 2.5x10e6 cells/kg (n=16). Leftover LV20.19 CAR T-cells from the original product were thawed, CD4 and CD8 T cells were enriched by immunomagnetic sorting, and the T-cell subsets separately stimulated with CD19-engineered K562 stimulators overnight. The stimulated cells were loaded onto single-cell, Adaptive Immune Isocode chips, and the chips read for 18 hours in an Isolight instrument to assess single-cell production of 32 individual cytokines. Isospeak software was used to analyze the single-cell data. Results 15 patients had adequate samples for analysis. Results were stratified by response (complete responders (CR) versus partial responders (PR) or progressive disease (PD)). The Isoplexis device was utilized to generate a polyfunctional (i.e., ability to produce more that 1 cytokine) index score (PSI) that has been previously reported (Rossi et al. Blood 2018) to correlate with CAR T-cell treatment outcomes. At Day 28 after LV20.19 CAR T-cell therapy, there were 11 CR patients and 4 PR/PD patients. CD4+ LV20.19 CAR T-cells from complete responders had a non-statistically significant decreased PSI score versus CD4+ cells from PR/PD patients (Figure 1A, p=0.38). The PSI score among CD8+ T-cells was similar (p=0.71) (Figure 1A). The increased PSI score among CR patients' CD4+ LV20.19 CAR T-cells was driven primarily by cells producing effector (IFNg and TNFb) cytokines. On a singular cytokine level, compared to PR/PD patient cells, CR patient CAR T-cells produced significantly higher levels of CCL-11, GM-CSF and IL-17A (Figure 1B; p Conclusion CD4+ LV20.19 CAR T-cells in responding patients trended towards a higher PSI than non-responding patients. At the single cell level, differences in the PSI among CD4+ LV20.19 CAR T-cells from responding patients were driven primarily by a few cytokines including IL-17A, CCL11, GM-CSF, IFNg, and TNFb, which may be key to clinical response. While our results are limited by sample size and only 4 PR/PD patients in this cohort, identification of cytokines correlating with response will allow selective modulation to improve clinical outcomes while limiting CRS. Ongoing studies with LV20.19 CAR T-cells will further delineate the role of IL-17A, GM-CSF and CCL-11 production as potential biomarkers of clinical response with bispecific CAR T-cell products. Disclosures Johnson: Cell Vault: Research Funding; Miltenyi Biotec: Research Funding. Fenske:Medical College of Wisconsin: Current Employment. Hamadani:Sanofi Genzyme, AstraZeneca: Speakers Bureau; Janssen R&D; Incyte Corporation; ADC Therapeutics; Celgene Corporation; Pharmacyclics, Omeros, AbGenomics, Verastem, TeneoBio: Consultancy; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Takeda Pharmaceutical Company; Spectrum Pharmaceuticals; Astellas Pharma: Research Funding. Dropulic:Lentigen, a Miltenyi Biotec Company: Current Employment, Patents & Royalties: CAR-T immunotherapy. Schneider:Lentigen, a Miltenyi Biotec Company: Current Employment, Patents & Royalties. Hari:GSK: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy; BMS: Consultancy; Amgen: Consultancy. Shah:Miltenyi Biotec: Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Incyte: Consultancy; TG Therapeutics: Consultancy; Verastim: Consultancy; Lily: Consultancy, Honoraria; Cell Vault: Research Funding; Kite Pharma: Consultancy, Honoraria.

Background & Aim Current approved CAR-T cell manufacturing employs off-site production, a labor-intensive process that requires several weeks and involves shipping back and forth to the production site. This production model may limit availability and accessibility to CAR-T cells and delay treatment for patient (pt) s with rapidly progressive disease. To address these limitations, we utilized the Miltenyi CliniMACS Prodigy, a GMP-compliant device, to produce CAR-T cells on-site for a first-in-human bi-specific CD19/20 (LV20.19) CAR-T Phase I trial. Methods, Results & Conclusion CAR-T cells were manufactured within our Cell Therapy Laboratory, an ISO7 facility. Pt's mononuclear cell apheresis was collected and loaded onto the Prodigy to isolate CD4/CD8 T cells. The T cells were suspended in TexMACS supplemented with human AB serum and IL-2, activated with TransACT, and then transduced by LV20.19 the next day. Culture wash and feedings were done during the production process, and the final cell product was harvested at day 14. The process was automated with limited machine/operator interactions. CAR-T expression was assessed by protein L staining. CAR-T cells were either administered fresh or cryopreserved for later infusion. Dose was escalated in a 3+3 manner from 2.5e+5 cells/kg to a target dose of 2.5e+6 cells/kg. CAR-T cells have been successfully generated for 11/11 enrolled pts thus far with no manufacture failures, and all products met release criteria. Median T cell recovery from the apheresis products was 59.5% with a median CD3+ purity of 97.2% (Figure 1). Final product CAR expression was at a median of 17.6%. A median of 4.7e+8 CAR T cells was obtained at harvest, exceeding the required target dose. CAR-T cells contained both CD4 and CD8 T cells with higher CD4 content. The majority of CAR-T cells showed an effector-memory phenotype. CAR-T cells were able to kill CD19+/20+ target cells and produced IFN-gin response to antigens. Among the 11 treated pts 8 received fresh CAR-T cells and 3 received CAR-T cells after cryopreservation. As no DLTs were observed at the 3 dose levels, a dose of 2.5e+6 cells/kg has been selected for further expansion. Clinical response shows 6 pts have achieved a CR at Day +28 with a duration of response between 2 to 14 months. In summary, initial results demonstrated feasibility for point-of-care manufacturing of bispecific LV20.19CAR-T cells with safe and promising efficacy in treating heavily pretreated pts with R/R B-cell NHL, which warrants further investigations.

Malignant melanoma incidence has been increasing for over 30 years, and despite promising new therapies, metastatic disease remains difficult to treat. We describe preliminary results from a Phase I clinical trial (NCT01586403) of adoptive cell therapy in which three patients received autologous CD4+ and CD8+ T cells transduced with a lentivirus carrying a tyrosinase-specific TCR and a marker protein, truncated CD34 (CD34t). This unusual MHC Class I-restricted TCR produces functional responses in both CD4+ and CD8+ T cells. Parameters monitored on transduced T cells included activation (CD25, CD69), inhibitory (PD-1, TIM-3, CTLA-4), costimulatory (OX40), and memory (CCR7) markers. For the clinical trial, T cells were activated, transduced, selected for CD34t+ cells, then re-activated, and expanded in IL-2 and IL-15. After lymphodepleting chemotherapy, patients were given transduced T cells and IL-2, and were followed for clinical and biological responses. Transduced T cells were detected in the circulation of three treated patients for the duration of observation (42, 523, and 255 days). Patient 1 tolerated the infusion well but died from progressive disease after 6 weeks. Patient 2 had a partial response by RECIST criteria then progressed. After progressing, Patient 2 was given high-dose IL-2 and subsequently achieved complete remission, coinciding with the development of vitiligo. Patient 3 had a mixed response that did not meet RECIST criteria for a clinical response and developed vitiligo. In two of these three patients, adoptive transfer of tyrosinase-reactive TCR-transduced T cells into metastatic melanoma patients had clinical and/or biological activity without serious adverse events.

Background: Salvage regimens for chemorefractory aggressive lymphoma achieve response rates of approximately 30%. Anti-CD19 CAR-T cells have demonstrated anti-lymphoma activity, but patients (pts) with rapidly progressive disease and urgent need for therapy have worse prognosis and many are not able to receive CAR-T cells in time. Decreasing the time from apheresis to infusion can make CAR-T cells available to pts with rapid progression of their disease. We present the results of a phase I clinical trial using on-site CAR-T manufacture for treatment of relapsed / refractory (r/r) B cell non Hodgkin lymphoma (NHL). Methods: Adult pts with r/r CD19+ B cell lymphomas who failed ≥ 2 lines of therapy were enrolled. Autologous T cells were transduced with a lentiviral vector (Lentigen Technology, Inc, LTG1563) encoding an anti-CD19 binding motif, CD8 linker and tumor necrosis receptor superfamily 19 (TNFRS19) transmembrane region, and 4-lBB/CD3z intracellular signaling domains. GMP-compliant manufacture was done using CliniMACS Prodigy, in a 12-day culture. Dose escalation was conducted according to a 3+3 design. Lymphodepletion was done with cyclophosphamide (60mg/kg x 1) and fludarabine (25mg/m2/d x 3). Cytokine release syndrome (CRS) and CAR-T related encephalopathy syndrome (CRES) were graded using the Lee and CARTOX criteria, respectively. Results: As of July 30, 2019 , 12 pts were enrolled and treated. Baseline characteristics are listed in table 1. 10/12 pts were refractory to the prior line of therapy, 5 had bulky disease and 9 had symptomatic disease at the time of lymphocyte collection. CAR-T cell product manufacture was successful in all pts. Median transduction rate was 48% [range 29-62] with and median culture expansion of 43-fold [range 30-79]. High dimensional flow cytometry showed the infused CD4 and CD8 CAR-T cells express a central memory and transition to memory - like profile, with enrichment for CD27 and high CCR7 expression. In addition, a subset of CD4 and CD8 CAR-T cells expressed effector transcription factors T-BET and GATA3 while CD4 CAR-T clusters express low levels of immune checkpoint blockers PD-1 and BTLA. All enrolled pts received their infusion of anti-CD19 CAR-T cells. CAR-T cell doses were 0.5 x 106/kg (n = 4) and 1 x 106/kg (n = 8). Median apheresis to infusion time was 13 days [range 13-20], 10 products were infused fresh. CAR-T persistence, based on vector sequence, peaked in peripheral blood MNCs between days 14-21. All responding subjects have had CAR-T persistence on follow up PCR measurements (range 1 - 12 months). CAR-T cell dose did not have an impact in the time to peak in vivo CAR-T cell expansion or in the rate of CAR-T cell persistence. Five pts experienced CRS. Grade 1 - 2 CRS was observed in 4 pts; whereas 1 pt died as a consequence of severe CRS in the context of bulky disease. Pharmacologic interventions for CRS included tocilizumab (n = 5), siltuximab (n = 2) and corticosteroids (n = 2). Two subjects presented grade 4 CRES with resolution after corticosteroids, no other grade ≥3 non-hematologic toxicity was observed. The most common all grade non - hematologic toxicity was fatigue, observed in 6 subjects. Hematologic toxicity was common, with grade ≥ 3 neutropenia observed in all subjects, with 4 subjects presenting grade 3 neutropenia without fever beyond day 30. Among 11 pts evaluable for response, 8 pts have achieved complete response (CR) and one had partial response (PR). Two pts did not respond. For the intention to treat population (n=12), the CR rate was 67% and overall response rate (ORR) was 75%. Overall response rates were equal between both dose levels (75%), but CR rates were higher in pts treated with 1 x 106 CAR-T cells (75% vs. 50%). Two pts have died, causes of death include progressive disease (n=1) and CRS (n=1). After a median follow up 3 months (range 1 - 12) all responding pts are alive; 1 subject relapsed 6 months after treatment with CD19+ disease and entered CR after anti-CD19 antibody drug immunoconjugate treatment. Conclusions: In this phase 1 study, second generation anti-CD19 CAR-T cells with TNFRS19 transmembrane domain have potent clinical activity. The short manufacture times achieved by local CAR-T cell manufacture with the CliniMACS Prodigy enables treatment of a very high risk NHL population that would otherwise not be able to receive CAR-T products due to rapidly progressive disease. Disclosures Caimi: ADC Therapeutics: Research Funding; Celgene: Speakers Bureau; Genentech: Research Funding. Schneider:Lentigen Technology, A Miltenyi Biotec Company: Employment. Bakalarz:Genentech: Speakers Bureau. Kruger:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology, A Miltenyi Biotec Company: Employment. Kadan:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Malek:Adaptive: Consultancy; Janssen: Speakers Bureau; Amgen: Speakers Bureau; Celgene: Consultancy; Takeda: Consultancy; Sanofi: Consultancy; Medpacto: Research Funding. Metheny:Takeda: Speakers Bureau; Incyte: Speakers Bureau. Dropulic:Lentigen Technology, A Miltenyi Biotec Company: Employment. OffLabel Disclosure: Clinical Trial of on - site manufactured CAR-T cells. This manufacturing process is under research.

Introduction Chimeric Antigen Receptor modified T (CAR-T) cell therapies have revolutionized the relapsed, refractory B cell malignancy landscape. Due to the complex steps involved with cell production, some third-party companies require T cells to be cryopreserved prior to shipping, while most manufacturers deliver modified CAR-T cells to the treating center in a cryopreserved state. This is vastly different to the approach taken with traditional cell based therapies, specifically allogeneic transplant (allo-HCT), an immunological treatment that relies on a graft-versus-tumor (GVT) effect to prevent disease relapse. Historically, "fresh" stem cells were felt to be superior to cryopreserved products due to concerns that cryopreservation may damage T cells and other mononuclear cells delaying engraftment and limiting GVT reactivity. As a result, in clinical practice most allo-HCT products are still given as fresh infusions without cryopreservation. In a Phase 1 clinical trial evaluating the safety of a bispecific anti-CD19, anti-CD20 CAR (LV20.19CAR), CAR-T cells were produced in a point-of-care fashion utilizing the CliniMACS Prodigy device. Local manufacturing allowed flexibility to administer either fresh LV20.19CAR-T cells without cryopreservation, or if indicated, thawed CAR-T cells post-cryopreservation. Methods Patients (pts) were treated on a Phase 1 dose escalation + expansion trial (NCT03019055) to demonstrate safety of 41BB/CD3z LV20.19CAR-modified T cells for adults with relapsed, refractory B cell NHL including DLBCL, MCL, FL, and CLL. The starting dose was 2.5x10^5 cells/kg with a target dose of 2.5x10^6 cells/kg. All pts received low dose fludarabine (30 mg/m2) x 3 days +cyclophosphamide (500 mg/m2) x 1 day for lymphodepletion. In the Phase 1 dose-escalation cohorts, pts received fractionated CAR-T cells over two days (30% on Day 0 and 70% on Day+1), while expansion cohort pts received CAR-T cells as a single infusion. The goal for all pts was to infuse fresh CAR-T cell prior to cryopreservation, however, CAR-T cell could be cryopreserved and infused at a later date for clinical / logistical reasons. Results A total of 20 pts received LV20.19CAR T cell therapy (Table 1). Fourteen pts received fresh CAR-T cells immediately post-harvest, 5 pts received post-thaw CAR-T cells, and 1 patient received a mixed fresh/cryopreserved product and was not included in this analysis. Reasons for cryopreserved administration was delay due to active infection (N=3), patient preference (N=1), and unexplained neutropenia (N=1). Among 19 evaluable pts, the CR rate (79% vs 40%), mean ferritin, mean CRP, and incidence of CRS and neurotoxicity were all higher in the fresh infusion group (Table 1), but not statistically significant. In terms of LV20.19 CAR-T product characteristics, mean cell viability at infusion was 93% for the fresh infusion group versus 63% for cryopreserved pts (p Conclusions Cryopreservation is known to diminish cell viability and increase clinical costs associated with freezing and storage. To date, there is limited clinical data evaluating outcomes of pts receiving fresh CAR-T cells compared to thawed CAR-T cells post-cryopreservation. Although it is presumed that in-vivo CAR-T cell activity is comparable in both scenarios, among our pts, both cell viability and in-vivo expansion favored pts who received a fresh infusion. Unlike third-party CAR-T cell products where viability is unknown at the time of infusion, we adjusted the final dose to accommodate decreased cell viability. CR rates and incidence of CRS and NTX were higher among fresh infused pts suggesting greater in-vivo activity, although findings were not statistically significant, partially a result of the small sample size. While our findings are limited by small numbers in each cohort and variability in cell dose and diagnosis, these data suggest that cryopreservation of CAR-T cells may impact clinical responses and is a logistical step that needs further investigation. Disclosures Shah: Cell Vault: Consultancy, Equity Ownership; Oncosec: Equity Ownership; Lentigen: Honoraria, Research Funding; Exelexis: Equity Ownership; Geron: Equity Ownership; Celgene: Other: Advisory Board; Incyte: Consultancy; Oncosec: Equity Ownership; Kite Pharma: Other: Advisory Board. Zhu:Miltenyi Biotec: Research Funding. Schneider:Lentigen Technology, A Miltenyi Biotec Company: Employment. Krueger:Lentigen Technology, A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology, A Miltenyi Biotec Company: Employment. Hamadani:Sanofi Genzyme: Research Funding, Speakers Bureau; Otsuka: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Takeda: Research Funding; Celgene: Consultancy; Janssen: Consultancy; Pharmacyclics: Consultancy; Merck: Research Funding; Medimmune: Consultancy, Research Funding. Dropulic:Lentigen Technology, A Miltenyi Biotec Company: Employment. Hari:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Amgen: Research Funding; Spectrum: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding; Cell Vault: Equity Ownership; AbbVie: Consultancy, Honoraria. Johnson:Miltenyi Biotec: Research Funding; Cell Vault: Equity Ownership.

2062 Background: GBM is the most common malignant brain tumor with a median survival of 15 months despite surgery and radio-chemotherapy. The most important mechanism of TMZ resistance is the O6-methylguanine-DNA methyltransferase (MGMT) gene which repairs temozolamide-induced DNA methylation. The MGMT inhibitor O6-benzylguanine (BG) demonstrated efficacy in depleting MGMT and maximizing tumor response in early phase clinical trials. However, MGMT expression is also low in hematopoietic cells, so this approach led to unacceptable bone marrow toxicity and thus has been abandoned. We hypothesized that chemoprotection of hematopoietic HPC with an MGMT mutant (MGMT-P140K) characterized by normal methyltransferase activity, coupled with low affinity for BG would maximize anti-tumor response while enabling patients to tolerate TMZ & BG dose escalation with minimal toxicity. A phase I trial was performed to test this hypothesis. Methods: 10 adults with newly diagnosed MGMT unmethylated, IDH-1 WT, GBM underwent standard surgery and radiation, followed by transplantation with autologous CD34+ HPC engineered to express MGMT-P140K using a lentiviral vector. We tested tolerance and efficacy of three different paradigms for conditioning bone marrow and re-infusion of HPC. To assess chemo-protection, patients’ blood counts and transgene marking were monitored during and after treatment, as was toxicity, response, and progression-free and overall survival. Results: Treatment was moderately toxic with 3/10 patients suffering grade 3-4 hematologic toxicity; no high grade non-hematologic toxicity was observed . Viral transduction rates ranged from 3-75% and were clearly improved in Arm III utilizing BCNU conditioning and intra-patient dose escalation of TMZ/O6GB. In patients tolerating 3 cycles or more, P140K-MGMT gene markings in peripheral blood and bone marrow cells increased 3-26-fold with only mild (Grade 2-3) mylosuppression consistent with chemo-protection as hypothesized. Median PFS and OS was 22 and 31 months respectfully, and three patients in Arm III are healthy and progression free at 36-39 months. OS exceeded RPA predicted survival by 3.3-fold suggesting clinical benefit. Viral insertion site analysis demonstrate lack of clonal dominance. Conclusions: P140K-MGMT transfected HPC enables TMZ/ BG dose escalation with acceptable toxicity and increased survival in a small cohort of selected patients. A phase II study is ongoing. Clinical trial information: NCT01269424.

2510 Background: Anti-CD19 CAR-T cell therapy is a breakthrough treatment (tx) for patients (pts) with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL). Despite impressive outcomes, non-response and relapse with CD19 negative disease remain challenges. Through dual B-cell antigen targeting of CD20 and CD19, with a first-in-human bispecific lentiviral CAR-T cell (LV20.19CAR), we aim to improve response rates while limiting CD19 negative relapse. Methods: Pts were treated on a Phase 1 dose escalation + expansion trial (NCT03019055) to demonstrate safety of a 41BB/CD3z LV20.19CAR T cell for adults with R/R B-cell NHL. Safety was assessed by incidence of dose limiting toxicities (DLTs) within 28 days post-infusion. Starting dose was 2.5 x 10^5 cells/kg with a target dose of 2.5 x 10^6 cells/kg. All pts received fludarabine+cyclophosphamide for lymphodepletion. Results: 11 pts have completed tx to date. 9 pts in dose escalation and 2 pts in expansion phase. Median age was 54 years (46-67) and histology included DLBCL = 5 pts, MCL = 4 pts, and CLL = 2 pts. In dose escalation, 3 pts were treated at 2.5 x 10^5 cells/kg, 3 pts at 7.5 x 10^5 cells/kg, and 3 pts at 2.5 x 10^6 cells/kg with no DLTs. As a result, 2.5 x 10^6 cells/kg was selected for expansion. In terms of safety, 6 pts developed Grade 1-2 cytokine release syndrome (CRS) and 3 pts had Grade 1-2 neurotoxicity (NTX). No patient had grade 3-4 CRS or NTX and none required ICU level care. 4 pts required 1-2 doses of tocilizumab for CRS. The day 28 overall response rate (ORR) for all pts was 82% (6/11 = complete response (CR) and 3/11 = partial response). All CR pts remain in remission, the longest > 1 year. All progressing pts underwent repeat biopsy, and all retained either CD19 or CD20 positivity. Additional pts are being enrolled in the expansion phase and updated data will be presented. Conclusions: Phase 1 results from the LV20.19 CAR T clinical trial demonstrate that infusion of 2.5 x 10^6 cells/kg is safe for further investigation with no DLTs among treated pts. Down-regulation of target antigens was not identified as a mechanism of resistance in progressing pts. With limited toxicity and encouraging ORR, dual targeted LV20.19CAR T cells merits further investigation. Clinical trial information: NCT03019055.

2539 Background: AntiCD19 CAR-T cells have shown encouraging anti-lymphoma activity. Decreasing the time from apheresis to CAR-T infusion can make this therapy available to pts with rapid progression. We present the interim results of a phase I clinical trial using on-site CAR-T manufacture. Methods: Adult pts with r/r CD19+ B cell lymphomas who failed ≥ 2 lines of therapy were enrolled. Autologous T cells were transduced with a lentiviral vector (Lentigen Technology, Inc,LTG1563) encoding an antiCD19 binding motif, CD8 linker and TNFRSF19 transmembrane region, and 4-lBB/CD3z domains. GMP-compliant manufacture was done using CliniMACS Prodigy, in a 12-day culture. Dose levels were 0.5, 1 and 2 x 106 CAR-T cells/kg. Lymphodepletion was done with cyclophosphamide (60mg/kg x 1) and fludarabine (25mg/m2/d x 3). Results: 7 pts (4 women, 3 men) were enrolled. Median age was 60y [range 43-69]. Diagnoses were DLBCL (n = 3) PMBCL, follicular lymphoma (FL), transformed FL, and transformed lymphoplasmacytic lymphoma; with a median of 4 previous treatments. Six pts had symptomatic refractory disease. CAR-T cell product manufacture was successful in all pts. Mean transduction rate was 44% [range 29-57]. CAR-T cell doses were 0.5 x 106/kg (n = 3) and 1 x 106/kg (n = 4). Median apheresis to infusion time was 13 days [range 13–20], 5 products were infused fresh. CAR-T persistence based on vector sequence, peaked in peripheral blood MNCs between days 14-21. Five pts are evaluable for safety. CRS grade 1 - 2 (Lee) occurred in 4 pts; with 3 requiring treatment. Grade 4 CRES (CARTOX-10) occurred in 1 pt, with resolution after corticosteroids; considered a DLT as it lasted more than 72 hours. No treatment-related mortality has occurred. 4/5 evaluable pts have achieved complete response. One pt did not respond and died. After a median follow up 3 months, all responding pts are alive and 1 relapsed 6 mo after treatment. Conclusions: Second generation antiCD19 CAR-T cells with TNFRS19 transmembrane domain have clinical activity against refractory NHL. Short manufacture time achieved by local CAR-T cell manufacture with the CliniMACS Prodigy enables treatment of a very high risk NHL population. Clinical trial information: NCT03434769.

Adoptive cell therapy with autologous CAR-T cells has induced remarkable responses in patients with treatment-refractory hematologic malignancies, but limitations exist with off-site commercial CAR-T production: (1) manufacturing can take several weeks and requires shipping patient cells; (2) off-site manufacturing limits treatment options for patients with rapidly progressive disease; (3) high cost of the products may limit their availability. To address these challenges, we used the fully automated Miltenyi CliniMACS Prodigy GMP-compliant device to manufacture autologous CAR-T cells for a Phase I trial (NCT03019055) evaluating a first-in-human bi-specific CAR that targets CD19 and CD20 (CD20.19 CAR). Using reagents from Miltenyi Biotec, production was performed within the Medical College of Wisconsin (MCW) Cell Therapy Laboratory. Manufacturing time was 14 days, and production was as follows. First, peripheral blood mononuclear cells (MNC) collected from patients by apheresis were loaded onto the Prodigy, and CD4 and CD8 T cells enriched by positive immunomagnetic selection. The T cells were cultured in 200 U/mL IL-2, and TransACT reagent was added to stimulate the T cells in the Prodigy cell culture chamber. Next day, lentiviral vector expressing anti-CD19 and anti-CD20 (in tandem) with CD3z and 4-1BB stimulatory domains was added to the cells. Culture washes and feedings were done on days 5, 6, 8, 10 and 12 of manufacture, and final products harvested on day 14. Eligible patients either received fresh CAR-T cells, or cells that had been cryopreserved and administered on a later date. CAR-T cell products have been successfully generated for all 8 patients enrolled thus far on the Phase 1 clinical trial with no production failures, and all products passed release criteria for infusion. Three patients received cryopreserved product and 5 patients received fresh product. Average T cell recovery from the apheresis cell products was 66.0% (56.0-76.0%), and the enriched T cells were 94.3% CD3+ (87.8-97.4%) (Table 1). Protein L staining of the final cell products indicated 19.6% average CD20.19 CAR expression. Patient CAR-T cells were able to kill CD19+ and CD20+ target cells in vitro and produce IFNg upon antigen stimulation. An average yield of 5.27e+8 CAR T cells was obtained at harvest, exceeding the required cell dose for all patients. The CAR-T cells were comprised of both CD4 and CD8 T cells, with greater percentages of CD4 T cells. The majority of T cells (avg. 83.2%) had an effector-memory phenotype. In summary, we have successfully demonstrated feasibility for point-of-care CAR-T cell production for clinical use from patient apheresis products utilizing the CliniMACS Prodigy device. A major clinical advantage of CAR-T cells generated on-site is flexibility in treatment, with either immediate (i.e., fresh) or later (cryopreserved/thaw) infusion, dependent on patient need.

Reference standards are important tools for the calibration of medical products and procedures. They are particularly important when dosing and potency are critical parameters for patient safety and product efficacy.1 Reference standards benefit the field by fostering best practices for the manufacturing and testing of safe and efficacious medicinal products. As the first commercial gene therapy products are now reaching market approval in the United States,2,3 there is increased discussion of the need to generate reference standards for the industry.

Background: CAR-T cell therapy directed against the CD19 antigen is a breakthrough treatment for patients (pts) with relapsed/refractory (R/R) B-cell NHL. Despite impressive outcomes, not all pts respond and many that respond still relapse. Affordability and accessibility are further considerations that limit current commercial models of CAR-T products. Commercial CAR-T manufacturing is complex, time consuming, and expensive with a supply chain starting at the treating center with apheresis of mononuclear cells, cryopreservation, and shipping to and from a centralized third-party manufacturing site. We addressed these limitations in a Phase 1 clinical trial evaluating a first-in-human bispecific tandem CAR-T cell directed against both CD19 and CD20 (CAR-20.19-T) antigens for pts with R/R B-cell NHL. Through dual targeting we hope to improve response rates and durability of response while limiting antigen escape. We eliminated third party shipping logistics utilizing the CliniMACS Prodigy, a compact tabletop device that allows for automated manufacturing of CAR-T cells within a GMP compliant environment within the hospital. Most materials and reagents used to produce the CAR-T cell product were single-sourced from the device manufacturer. Methods: Phase 1 (NCT03019055), single center, dose escalation + expansion study to demonstrate feasibility and safety of locally manufactured second generation 41BB + CD3z CAR-20.19-T cells via the CliniMACS Prodigy. Feasibility was measured by ability to generate a target CAR-20.19-T cell dose for a minimum of 75% of subjects. Safety was assessed by the presence of dose limiting toxicities (DLTs) through 28 days post-infusion. Dose was escalated in a 3+3 fashion with a starting dose of 2.5 x 10^5 cells/kg, a target DLT rate CAR-T production was set for a 14-day manufacturing process. Day 8 in-process testing was performed to ensure quality and suitability of CAR-T cells for a potential fresh infusion. On Day 10, pts eligible for a fresh CAR-T infusion initiated lymphodepletion (LDP) chemotherapy with fludarabine 30 mg/m2 x 3 days and cyclophosphamide 500 mg/m2 x 1 day, and cells were administered after harvest on Day 14. Pts ineligible for fresh infusion received cryopreserved product and LDP was delayed accordingly. Results: 6 pts have been enrolled and treated with CAR-20.19-T cells: 3 pts at 2.5 x 10^5 cells/kg and 3 pts at 7.5 x 10^5 cells/kg. Median age was 53 years (48-62). Underlying disease was MCL in 3 pts, DLBCL in 2 pts, and CLL in 1 patient. Baseline data and prior treatments are listed in Table 1. CAR-T production was successful in all runs and all pts received their target dose. Three pts received fresh CAR-T cells and 3 pts received CAR-T cells after cryopreservation. To date there are no DLTs to report. No cases of Grade 3/4 cytokine release syndrome (CRS) or neurotoxicity (NTX) were observed. One patient had Grade 2 CRS and Grade 2 NTX requiring intervention. The other had self-limited Grade 1 CRS and Grade 1 NTX. Median time to development of CRS was Day +11 post-infusion. All pts had neutrophil recovery (ANC>0.5 K/µL) by Day 28. Response at Day 28 (Table 2) is as follows: 2/6 pts achieved a complete response (CR), 2/6 achieved a partial response (PR), and 2/6 had progressive disease (PD). One subject with a PR subsequently progressed at Day 90. The 3 pts who did progress all underwent a repeat biopsy, and all retained either CD19 or CD20 positivity. Pts are currently being enrolled at the target dose (2.5 x 10^6 cells/kg) and updated results will be provided at ASH. Conclusions: Dual targeted anti-CD19 and anti-CD20 CAR-T cells were successfully produced for all pts demonstrating the feasibility of a point-of-care manufacturing process via the CliniMACS Prodigy device. With no DLTs or Grade 3-4 CRS or NTX to report, and 2/6 heavily pre-treated pts remaining in CR at 3 and 9 months respectively our approach represents a feasible and promising alternative to existing CAR-T models and costs. Down-regulation of both target antigens was not identified in any patient following CAR-T infusion, and in-process studies suggest that a shorter manufacturing timeline is appropriate for future trials (10 days). Disclosures Shah: Juno Pharmaceuticals: Honoraria; Lentigen Technology: Research Funding; Oncosec: Equity Ownership; Miltenyi: Other: Travel funding, Research Funding; Geron: Equity Ownership; Exelexis: Equity Ownership. Zhu:Lentigen Technology Inc., A Miltenyi Biotec Company: Research Funding. Schneider:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Krueger:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Hamadani:Sanofi Genzyme: Research Funding, Speakers Bureau; Merck: Research Funding; Janssen: Consultancy; MedImmune: Consultancy, Research Funding; Cellerant: Consultancy; Celgene Corporation: Consultancy; Takeda: Research Funding; Ostuka: Research Funding; ADC Therapeutics: Research Funding. Johnson:Miltenyi: Research Funding. Dropulic:Lentigen, A Miltenyi Biotec company: Employment. Orentas:Lentigen Technology Inc., A Miltenyi Biotec Company: Other: Prior Employment. Hari:Takeda: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Kite Pharma: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Amgen Inc.: Research Funding; Sanofi: Honoraria, Research Funding.

Adoptive cell therapy with autologous CAR-T cells has induced remarkable responses in patients with treatment-refractory hematologic malignancies, which has led to FDA approvals for two CAR-T products. However, limitations exist with commercial CAR-T centralized production: (1) off-site manufacturing can take several weeks and requires shipping from and to the treating facility; (2) off-site manufacturing limits treatment options for progressing patients; (3) high cost of the commercial products may limit their availability. To address these challenges, we used the fully automated Miltenyi CliniMACS Prodigy device, a GMP-compliant closed system, to manufacture autologous CAR-T cells for a Phase I trial (NCT03019055) evaluating a first-in-human bi-specific CAR that targets CD19 and CD20 (CD20.19 CAR). CAR-T manufacturing was performed exclusively using the CliniMACS Prodigy device and reagents obtained from Miltenyi Biotec. Production was performed within the Medical College of Wisconsin (MCW) Cell Therapy Laboratory, an ISO7 air handling environment. Manufacturing was set at 14 days, and production was as follows. First, peripheral blood mononuclear cells (MNC) were collected by apheresis, with a collection goal of 4 blood volumes to eliminate risk of a low CD3 yield in heavily pre-treated patients. Next, MNC were loaded onto the Prodigy, and CD4 and CD8 T cells enriched by positive immunomagnetic selection. To start the culture process, enriched T cells were suspended in TexMACS medium supplemented with 3% human AB serum and 200 U/mL IL-2, and TransACT reagent was added to stimulate the T cells in the Prodigy cell culture chamber. The following day (day 1), lentiviral vector expressing anti-CD19 and anti-CD20 (in tandem) with CD3ζ and 4-1BB stimulatory domains was added to the stimulated cells. Culture washes and feedings were done on days 5, 6, 8, 10 and 12 of manufacture, and final products harvested on Day 14. Protein L staining was used to detect expression of CD20.19 CAR on the T cells. On Day 14, eligible patients received fresh CAR-T cells, while for others the product was cryopreserved and administered on a later date. To date, the MCW Cell Therapy Laboratory has successfully generated CAR-T cell products for all 6 patients enrolled thus far on the Phase 1 clinical trial with no production failures (Table 1). Three patients received cryopreserved product and 3 patients received fresh product. The enriched T cells were 94.3% CD3+ (87.8-97.4%), and average T cell recovery from the apheresis cell products was 65.2% (54.2-80.0%). Protein L staining indicated 20.8% average CD20.19 CAR expression. Patient CAR-T cells were able to kill CD19+ and CD20+ target cells in vitro and produce IFN-gamma in response to the same target cells. An average yield of 5.9e+8 (4.3-7.9e+8) CAR T cells was obtained at harvest, which exceeded the required cell dose for all patients. The CAR-T cells were comprised of both CD4 and CD8 T cells, with higher expression on CD4 T cells; average CAR-T CD4:CD8 ratio on the final products was 2.8. The majority of T cells (average of 81.5%) had an effector-memory phenotype. In-process testing performed on Day 8 of manufacturing demonstrated sufficient numbers of CAR-T cells needed for patient infusions were already present, and that the CAR-T cells only expanded an additional 1.9 to 3.5-fold between Days 8 and 14. In conclusion, we have successfully demonstrated feasibility for point-of-care CAR-T cell production for clinical use from patient apheresis products utilizing the CliniMACS Prodigy device. Time to production was efficient (14 days), and patient-derived CAR-T cell products were reproducibly generated in a standard cell processing laboratory within an academic medical center. A major clinical advantage of CAR-T cells generated on-site is the flexibility in treatment. Patients can receive cells either immediately (i.e., fresh) or the cells can be cryopreserved for later infusion if the patient is not able to receive fresh cells. Based on our results, we intend to decrease the cell processing time to 10 days. Disclosures Zhu: Lentigen Technology Inc., A Miltenyi Biotec Company: Research Funding. Shah:Juno Pharmaceuticals: Honoraria; Oncosec: Equity Ownership; Geron: Equity Ownership; Exelexis: Equity Ownership; Miltenyi: Other: Travel funding, Research Funding; Lentigen Technology: Research Funding. Schneider:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Keever-Taylor:Medical College of Wisconsin: Research Funding. Dropulic:Lentigen, A Miltenyi Biotec company: Employment. Orentas:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Hari:Bristol-Myers Squibb: Consultancy, Research Funding; Amgen Inc.: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Kite Pharma: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding. Johnson:Miltenyi: Research Funding.

Introduction CD19 CAR-T cell products were recently approved as therapy for advanced B-cell lineage malignancies. The predominant manufacturing model for this type of therapy is a centralized industrial-type production process. An attractive model of CAR-T cell production and delivery to the patient is via a point-of care-manufacturing process. We report on first cases of implementation of this approach in a setting of compassionate use program. Patients and methods Four patients with relapsed/refractory B-cell lineage malignancies were eligible for compassionate use of CD19 CAR-T cell therapy. Three patients, median age 15 years, had relapsed B-cell lineage acute lymphoblastic leukemia (B-ALL) after haploidentical hematopoietic stem cell transplantation (HSCT). Bone marrow disease burden at therapy start was 12%, 74% and 0,159. The patient with low minimal residual disease (MRD) in the bone marrow had skeletal involvement with multiple lymphomatous mass lesions. One patient had refractory primary mediastinal B-cell lymphoma (PMBCL). The CliniMACS Prodigy T cell transduction (TCT) process was used to produce CD19 CAR-T cells from patient-derived leukapheresis product. Automatic production included CD4/CD8 selection, CD3/CD28 stimulation with MACS GMP T Cell TransAct, transduction with lentiviral (second generation CD19.4-1BB zeta) vector (Lentigen, Miltenyi Biotec company) and expansion over 12 days in the presence of TexMACS GMP Medium supplemented with MACS GMP IL-7/IL-15 combination. Final product was administered without cryopreservation to the patients after fludarabine/cyclophosphamide preconditioning. All patients received prophylactic tocilizumab 1 hour before CAR-T cell infusion at 8mg/kg. Results All production cycles were successful. Median transduction efficacy achieved was 57%(52-63). Median expansion of T cells was x26(24-43). CD4/CD8 ratio in the final product was 0,750,22-6). All final products passed the in-process and quality controls. The cell products were administered at a dose of 1*106/kg of CAR-T cells. No immediate infusion reactions were reported. In 2 cases mild cytokine release syndrome (CRS) was diagnosed. In one case mild CAR-T cell related encephalopathy developed. In one case additional dose of tocilizumab and one dose of dexamethasone were administered to control CRS and encephalopathy. All patients survived to the point of response evaluation. In 3 cases CAR-T cell expansion was detected to a maximum 25%. MRD-negative responses detected by flow cytometry and PCR were achieved in 2 cases with bone marrow involvement. In two cases with prominent mass lesions an objective response was documented. In the patient with 74% blast in bone marrow at start of therapy, neither CAR-T cell expansion nor leukemia response were documented. Details of therapy and response are summarized in table 1. Conclusion Production of CAR-T cells with the CliniMACS Prodigy TCT process is a feasible and an attractive option that provides a point-of-care manufacturing approach to enable rapid delivery of CAR-T cells to patients in need. Robustness and consistency of this approach provides a solid basis for multi-center academic trials in the field of adoptive cell therapy. Table 1. Table 1. Disclosures Dropulic: Lentigen, A Miltenyi Biotec company: Employment. Shneider:Lentigen, A Miltenyi Biotec company: Employment. Orentas:Lentigen, A Miltenyi Biotec company: Employment. Alex:Miltenyi Biotec: Employment. Essl:Miltenyi Biotec: Employment.

The recent successes of adoptive T-cell immunotherapy for the treatment of hematologic malignancies have highlighted the need for manufacturing processes that are robust and scalable for product commercialization. Here we review some of the more outstanding issues surrounding commercial scale manufacturing of personalized-adoptive T-cell medicinal products. These include closed system operations, improving process robustness and simplifying work flows, reducing labor intensity by implementing process automation, scalability and cost, as well as appropriate testing and tracking of products, all while maintaining strict adherence to Current Good Manufacturing Practices and regulatory guidelines. A decentralized manufacturing model is proposed, where in the future patients' cells could be processed at the point-of-care in the hospital.

Introduction Chimeric Antigen Receptor T (CAR-T) cells redirected against tumor antigens are an effective therapy for B cell malignancies refractory to standard treatments. The production of patient-derived CAR-T cells is complicated and thus far is limited to institutions with experienced researchers and expensive GMP facilities, or to those invited to participate in industry sponsored clinical trials. The outsourcing of CAR T-cell production to third party vendors where cells are collected locally, shipped to the manufacturing site, and then sent back to the institution for infusion can be both costly and timely. As a result, CAR-T cell therapies are not widely available and only patients with means to travel to participating sites and with disease that is stable enough to wait the 2-3 months needed to collect and produce CAR-T cells are eligible for these treatments. At our instution we have explored the use of the CliniMACS® Prodigy (Miltenyi Biotec, Inc) for the production of CAR-T cells. The CliniMACS® Prodigy is an automated device that can be used for cell processing within a closed GMP-compliant system. Using the CAR-T system that includes software, specialized tubing sets, and optimized reagents we demonstrate the processing of CAR-T cells, with similar characteristics to those produced in a more traditional manner, in a closed system that is suitable for clinical use without the need for a clean room manufacturing facility. Methods In collaboration with Miltenyi Biotec, we obtained pre-release and final versions of the CliniMACS® Prodigy TCT process software and the TS520 tubing set that allows for cell enrichment, transduction, wash steps, and expansion all within a single set. Starting material was MNC cells recovered from a leukoreduction system chamber (LRSC) used during platelet collections by apheresis. Materials and reagents included MACS CD4 & CD8 reagents for cell enrichment, TransAct CD3/CD28 reagent for activation, lentiviral CD8 TM-41BB-CD3 zeta-cfrag vectors with either CD19 or CD20/CD19 Ab chains (Lentigen Technology Inc., A Miltenyi Biotec Company), TexMACS culture medium-3% HS-IL2, and PBS/EDTA buffer for wash steps. For two experiments, cells after CD4/CD8 enrichment were activated and transduced in 6 well plates and expanded after day 5 in G-Rex gas permerable devices. Total time for line preparation was 14±1 days. Transduction was measured by Protein L expression using flow cytometry. Line function was measured in 51Cr Release assays and by intracellular cytokine production. Results Starting cells were washed free of platelets and enriched for CD4+ and CD8+ cells using the Prodigy device. We achieved consistent high levels purity (99±3%) and good recovery (51.0±6%) of CD4+ and CD8+ cells (N=5). The enriched cells were 90±12% CD3+. The approximately 10% non-T cells were CD8+ NK cells, that were largely eliminated after cell activation through CD3/CD28 and expansion. A controlled number of 1 x 10E8 cells enriched for CD4+ plus CD8+ cells were retained in the Prodigy and in 2 experiments a smaller fraction of cells was cultured in 6 well plates for activation and initial transduction. Three preparations were conducted in the Prodigy, one using the CD19 vector and two with the CD19+CD20 vector. Transduction efficiency ranged from 21%-46% of total T cells with a modest preference for CD4+ cells. Expansion ranged from 26-40 fold and all of the lines recognized CD19 and/or CD20 targets based on 51Cr release assays or IFN-gamma production. The paired lines generated on the Prodigy versus manual methods showed similar overall transduction, phenotype, and function as shown in the figure for one representative preparation. Conclusions CAR-T cells generated in the Prodigy were similar to those prepared using manual methods in both phenotype and function. This process is timely, requiring 14 days for generation of the target CAR-T cell dose, and does not require outsourcing to third party vendors. All of the Prodigy CAR-T cell preparations met criteria for clinical use in our upcoming Phase I clinical trial. The ability to produce CAR-T cells suitable for clinical use in an entirely closed system without the need for a clean room should allow more centers and patients access to this novel form of immunotherapy. Disclosures Shah: Oncosec: Equity Ownership; Exelixis: Equity Ownership; Geron: Equity Ownership. Orentas:Lentigen Technology, Inc.: Employment. Dropulic:Lentigen Technology Inc. A Miltenyi Biotec Company: Employment. Hari:Merck: Research Funding; BMS: Honoraria.

The field of possible application of mesenchymal stem cells in medicine and research expanded tremendously with the advent of improved Lentiviral-vectors capable of inserting stable copies of genes of interest and expressing proteins or biologically active RNA species ad libitum, performing delicate gene editing or active gene silencing or serving as advanced drug delivery systems utilized in ex vivo cell therapy. The combination of these two fields has created a number of new areas of research in the landscape of modern medicine which are now extensively studied and discussed here. These areas include tissue engineering, tissue repair, wound healing and tissue implants, anticancer therapies, angiogenesis, myocardial infarction and repair as well as understanding and treating acute lung damage and injury. In addition, genetically modified, tagged MSCs are being intensively deployed in research and therapeutic attempts of the various ailments of the central nervous system including Parkinson’s disease, Alzheimer’s disease, various phases of acute ischemia and trauma. The emergence of new and important data for type II diabetes research is being followed with treatment suggestions and studies of senescence to find novel applications for genetically engineered MSCs. We find in ­general that genetically modified MSCs are at the cusp of breaking through from basic research into the next phase of clinical trials.

Meeting abstracts Genetically engineered T cells have broadened the opportunity for use of T cell immunotherapy in cancer patients. The possibility of improving T cell efficacy via introduction of additional genes potentially gives them an advantage over TIL. Studies in adoptive T cell transfer

3043 Background: Studies in adoptive T-cell transfer have suggested that persistence of the transduced T-cells is central to the viability of this therapeutic option. The objectives of this phase I...

This review is intended to exemplify the roles and responsibilities of the two agencies under the Department of Health and Human Services, the National Institutes of Health and the Food and Drug Administration, that have oversight for human gene transfer clinical protocols, as seen through our experience of bringing a first-in-its-class lentiviral vector to clinical trials. In response to the changing circumstances in gene therapy research between 1999 and 2002, the concerns of these agencies regarding gene therapy have been evolving. This review provides an overview of the major safety concerns regarding insertional oncogenesis, the generation of a replication- competent lentivirus (RCL), and vector mobilization thought to be related to lentiviral vectors, which had to be addressed during the regulatory review process before initiating the clinical trial. Specific monitoring assays to address these concerns were established to test for RCL generation, vector mobilization, persistence of vector-modified cells, and abnormal clonal expansion of modified cells. We hope to provide a basic understanding and appreciation of the regulatory process and major safety concerns, toward providing useful insight to those presently embarking on the development of clinical application of lentiviral vectors.

Top of pageAbstract Emerging drug resistance raises concerns about HAART as a long-term therapy. We have developed an HIV-1-based lentiviral vector expressing a 937-base antisense gene against the HIV envelope for autologous T cell therapy for HIV/AIDS. The vector introduces no new sequences to an HIV-infected individual. In preclinical studies, HIV replication was inhibited over 95%, and up to 4 logs, in primary CD4 T lymphocytes isolated from HIV-infected patients. For evaluation of safety and tolerability of this therapy, a Phase I open-label non-randomized clinical trial has been carried out. Five patients who have failed at least two HAART regimens due to intolerance or resistance, and have CD4 counts above 150 cells/mm3 and a viral load greater than 5000 copies/ml, have been serially enrolled for a 6-month study with 21 day, 3, 6, 9, and 12-month monitoring points. Each patient was given a single i.v. dose of |[sim]| 1 |[times]| 1010 genetically-modified autologous T cells, and then monitored for viral load, CD4 count, replication competent lentivirus (RCL), outgrowth of vector-modified cells, immunological parameters, and adverse events. Serious adverse events (SAE) were defined in part by a sustained 30% increase in viral load, or sustained 0.5 log decrease in CD4 count within 3 weeks post dose. All five patients have been dosed, and have completed the critical 3-week safety timepoint. No SAEs related to the product have occurred, and all RCL tests have been negative, including a biological RCL assay performed on apheresed patient PBMCs at 6 months. Patients 1-3 have reached their 1 year follow-up and all three have demonstrated clinically significant (>0.5 log) reductions in their viral loads at 1 year at 0.78 log, 1.61 log, and 0.57 log, respectively. Furthermore, patients 2 and 3 have had a 20% and 30% increase in CD4 counts, respectively, while patient 1 has maintained a steady CD4 count. Patient 4 will reach his 9-month follow up in March, and Patient 5 has just completed his 3-month follow up. Circulating vector-modified cells was detected in patient 2 at one year, to month 9 in patients 1 and 3, and they remain detectable in patients 4 and 5. To date, 211 total integration sites from the transduced clinical products of all 5 patients have been analyzed; initial results indicate that VRX496 preferentially integrates into transcription units and disfavors integration into alphoid repeats, a pattern that is comparable to and indistinguishable from wild type HIV. These data support the safety and feasibility of lentiviral vector therapy in the setting of ex vivo cellular therapy.

Meeting abstracts Previous studies in adoptive T-cell transfer have suggested that persistence of the transduced T-cells is central to making this therapy a viable option. Understanding the behavior of tumor-reactive T-cells in cancer patients and measuring persistence are two objectives in a phase

TPS1616 Background: The administration of radiation therapy (RT) and concomitant and adjuvant temozolomide (TMZ) for the treatment of newly-diagnosed glioblastoma (GBM) is associated with modestly prolonged survival. However, the benefit of concurrent therapy is restricted to a subgroup of patients whose tumor exhibits methylation of the promoter for methylguanine-DNA-methyltransferase (MGMT). Promoter methylation silences the expression of DNA alkyltransferase (AGT), the product of the MGMT gene which functions to repair alkylated DNA. Unfortunately, the majority of GBMs have non-methylated MGMT promoters and do not appear to benefit from adding TMZ to radiotherapy. Two potential strategies for targeting MGMT-induced chemoprotection in gliomas include depletion of tumor MGMT, and dose escalation of TMZ accomplished by minimizing TMZ-induced bone marrow toxicity. In this study, we propose to combine the irreversible MGMT inhibitor O6-benzylguanine (BG) with infusion of autologous hematopoetic stem cells (HSCs) transduced with lentiviral P140K-MGMT, an MGMT mutant which is highly resistant to inactivation by BG, with the intent to reduce or prevent the myelosuppressive effects of TMZ. The primary objective is to assess the safety and feasibility of combining these two strategies in patients with newly-diagnosed GBM. Methods: This is a three cohort, Phase I study for patients with newly resected supratentorial GBM. There will be at least four evaluable patients per cohort. Cohort 1 will receive standard RT and concomitant TMZ prior to infusion of autologous lentiviral P140K-MGMT transduced HSCs, followed by adjuvant TMZ. Cohort 2 will receive an induction dose of TMZ+BG followed by infusion of autologous LV-P140K-MGMT HSCs prior to concomitant RT +TMZ and adjuvant TMZ. Cohort 3 will include intra-patient dose escalation of TMZ in patients who exhibit detectable levels of P140K-MGMT marked cells in vivo, using the design (i.e. cohort 1 or 2) proven to be safest and most effective. The study is open and has accrued the first patient.

Abstract 4177 Temozolomide (TMZ) is a standard of care treatment for patients with glioma post surgical resection, but induces dose limiting myelosuppresion. Gene transfer of O6-benzylguanine (BG) resistant mutant O6-methylguanine-DNA-methyltransferase (MGMT P140K) into hematopoietic stem cells (HSCs) protects hematopoiesis from alkylating agents and allows efficient in vivo selection of transduced HSCs in mice, dogs and primates. We designed a clinical trial to improve HSC tolerance of TMZ in patients with glioma [clinicaltrials.gov]. This trial uses a lentiviral backbone for gene delivery, and infuses cells during the active phase of treatment to maximize the potential for stem cell protection and selection. The viral construct was synthesized by Lentigen, with an EF1-alpha promoter driving MGMTP140K (LV-P140K MGMT). Clinical grade vector was subject to safety and toxicity analysis at the request of both NCI and FDA. Transduction conditions were optimized towards a high rate of gene transfer and expression with ≤2 copies per cell to minimize adverse insertions. This study presents the validation of the vector by assessing the engraftment, drug resistance and copy number after gene transfer into human CD34+ cells followed by in vivo selection using a nonobese diabetic (NOD)/severe combined immunodeficient (SCID) gammaC (NSG) mice. We are currently analyzing the insertion sites of the clinical grade LV-P140K MGMT in human cord blood progenitors as a safety monitoring tool for LV-HSC gene therapy. Engraftment of LV-P140K MGMT (LG631) transduced CD34+ cells in irradiated NSG mice, and the analysis of engrafted human CD45+ cells in peripheral blood, spleen and bone marrow showed consistent but slightly decreased (10%) engraftment of transduced cells compared to the freshly isolated non transduced cells and was multilineage. There was no toxicity to the mice or human HSC as a result of transduction with lentiviral vector. The NSG recipients of the LG631 transduced CD34+ cells received two rounds of 3-consecutive day treatments of 30 mg/kg of BG and 60 mg/kg of TMZ, and three weeks after the second round of treatment, expression of MGMT was examined by PCR in the CFUs from the BM of the recipient mice. Combined treatment with BG and TMZ showed efficient selection of human cells and human CFU expressing MGMT (100% after treatment vs 44+/−4.1% without treatment). Copy number and characterization of insertion sites of the clinical grade LV-P140K MGMT in human CD34 cells serve as a critical safety monitoring tool for LV-HSC gene therapy. Insertion site analysis showed a polyclonal pattern and selection did not result in oligoclonality. The insertion database will continue to be made publically available as the data is generated prior to and during clinical trial application. We have fully characterized the preclinical safety and efficacy of a clinical grade lentiviral vector for clinical trial application in patients with glioma. Disclosures: No relevant conflicts of interest to declare.

Lentiviral vectors (LV) offer improved therapeutic benefit of gene therapy applications as a result of their ability to stably transduce a wide range of cycling and non-cycling cells. The first Phase I clinical trial using a lentiviral vector, VRX496, was initiated in January of 2003. The vector evaluated is an HIV-1 based lentiviral vector, fully gutted but retaining the 5′ and 3′ long terminal repeats, the packaging sequence, cPPT/CTS, splice donor and splice acceptor, and rev response element (RRE). VRX496 contains a splice-independent 937-base antisense sequence targeting the envelope gene in the HIV genome, and a small 186-base tag derived from the GFP gene to serve as a molecular marker for vector in HIV infected patient cells. Five (5) HIV-infected patients with CD4 counts between 200 and 500, and viral loads above 5000 copies/ml, no history of opportunistic infections, who have failed two regiments of highly active antiretroviral therapy (HAART), were serially enrolled in the trial. After leukopheresis, patient’s CD4 T lymphocytes were isolated by negative selection of CD8+ cells, and then cultured for three days in the presence of immobilized CD3/28 beads, and VRX496. Thereafter, the vector and beads were removed, cells were expanded to the dose of 1 x 1010, and then given intravenously over 15 minutes. At the time of this abstract, 4 patients have been dosed and have passed the initial 21-day safety assessment; a fifth patient is scheduled for dosing. No serious adverse events have occurred. All patients have steady CD4 counts, and viral loads have decreased below baseline in all patients, notably from 218,000 pre dose to 36,000 1 year post dosing in the first patient, and from 22,000 pre dose to 1,625 at 9 months post dosing in the second patient; patients 3 and 4 are at 3 months and 21 days post-infusion, respectively. Importantly, persistence of vector-modified CD4 cells are detected in the peripheral blood out to 9 months post dosing. This trial establishes for the first time the safety of lentiviral vectors for clinical gene therapy application.

Despite the significant advancement in HIV/AIDS treatment with highly active antiretroviral therapy (HAART), HIV/AIDS remains incurable. Limitations of HAART include expense, disabling complications, and a stringent requirement for compliance. In the United States, where HAART has become the standard of care, approximately 20% of newly transmitted virus is already resistant to at least one antiretroviral drug. In anticipation of expanded HAART in Africa, there is concern regarding rapid emergence of drug resistant strains of HIV that brings into question HAART as a long-term solution. We have developed an alternative therapy for HIV/AIDS therapy using an HIV-1-based lentiviral vector expressing a 937-base antisense gene against the HIV envelope, VRX496, for autologous T cell therapy. T cells are transduced with vector in the presence of co-stimulatory CD3/CD28 beads, and subsequently expanded in culture. Preclinical studies demonstrated the feasibility of this approach in normal CD4+ T cells and inCD4+ T cells isolated from 20 early and late stage patients, as defined by viral loads. An efficient gene transfer procedure was established, which demonstrated stable transfer rates of 94% +/- 5%. Antisense inhibited HIV in cultures by >93% over mock transduced controls, regardless of patient status or the tropism of the infecting virus. A Phase I open label non-randomized clinical trial was then initiated to investigate the safety and tolerability of autologous T cells modified with VRX496. In this study, 5 HAART resistant patients having CD4 T cells counts between 200-500 cells/mm3 are serially enrolled in the study that includes 3-week, and 3 and 6-month monitoring points. Each patient is given approximately 1 1010 modified autologous CD4 T cells in a single dose. Patients are monitored for viral load, CD4 count, emergence of any replication competent lentivirus (RCL), immunological parameters, and clinical indications. Adverse events are defined in part by a sustained 0.5 log increase in viral load, or sustained 0.5 log decrease in CD4 count within 3 weeks post dose. To date, 3 subjects have been infused, and the first and second subjects have completed the 6 and 3-month monitoring points, respectively. No adverse events have been noted, and all RCL assays have been negative. CD4 counts remained steady and engraftment of VRX496-modified cells was observed for at least 6 months in the first patient and 3 months in the second patient. At dosing, subject 1 had an average viral load of 188,500 and subject 2 had an average viral load of 40,428. After three and six months post dosing, subjects 1 and 2 respectively, had viral loads below baseline. This interim analysis supports the promise of lentiviral vectors for late stage HIV infection, and that VRX496 could become a viable treatment modality for individuals infected with HIV/AIDS.

Background CD19 redirected chimeric antigen receptor (CAR) T-cell therapy has proven efficacy in relapsed or chemotherapy-refractory (r/r) aggressive B-cell non-Hodgkin lymphoma (B-NHL). However, targeting a single B-cell antigen leads to selective pressure with potential antigen-escape and subsequent relapse. A tandem CAR targeting CD20 and CD19 (pLTG1497) has been developed to overcome this limitation. Preclinical evaluation showed improved anti-lymphoma activity. Thus, we initiated a first-in-human, phase I clinical study of autologous pLTG1497-transduced CAR T-cells (MB-CART2019.1) in r/r B-NHL patients. Aims In this phase I prospective multi-center trial (NCT03870945) we aimed to evaluate the maximum tolerated dose (MTD) of MB-CART2019.1 in adult patients with CD20 and CD19 positive r/r B-NHL as determined by dose limiting toxicities (DLTs). Methods This was a 6+3 trial design with two predefined dose levels (DL1 1x106 and DL2 2.5x106 CAR T-cells/kg body weight, respectively). Secondary endpoints included adverse events (AEs) and best overall response rate (ORR). Pharmacodynamic assessments included maximum concentration (Cmax) of CAR T-cells, time to peak expansion (tmax), AUC (d0 to d28), and persistence. MB-CART2019.1 was produced by lentiviral transduction of autologous fresh leukapheresis in the closed automated CliniMACS Prodigy® System (Miltenyi Biotec, Bergisch Gladbach, Germany). Re-infusion (Day 0) of fresh MB-CART2019.1 was scheduled 14 days after leukapheresis. Fludarabine/cyclophosphamide lymphodepleting chemotherapy was administered from day -5 to -3. Results A total of 12 patients, 6 per dose level have been enrolled and treated between February and December 2019, 5 female and 7 male patients. Median age was 72 y (range 20, 78 y), with 10 patients >65 y and 8 >70 y. Histologies included aggressive B-NHL (11) and mantle cell lymphoma (1). Five (5) patients had refractory disease at study entry and IPI was ≥3 in 7 patients. Median time from leukapheresis to re-infusion was 14 d (range 13, 14 d). No DLT and no cytokine release syndrome (CRS) or neurotoxicity grade ≥3 were observed. One patient in dose level 1 experienced a grade 5 AE, which was due to disease progression. CRS grade 1 occurred in 3/6 patients on DL1 and DL2 each, and CRS grade 2 in 2 patients on DL2. Tocilizumab was given in 1 patient. Neurotoxicity grade 1 occurred in 1 patient on DL2. The above described CRS and neurotoxicity resolved completely. Mean Cmax of MB-CART2019.1 was 348.3 cells/µl (range 3.9, 830.4 cells/µl) on DL1 and 692 cells/µl (range 5.3, 3147.8 cells/µl) on DL2. Mean tmax was 15.8 d (range 9, 21 d) on DL1 and 11.5 d (range 9, 14 d) on DL2. Mean AUC was 3155 d*cells/µl (DL1) and 4339 d*cells/µl (DL2). Persistence of MB-CART2019.1 was observed in 12/12 patients until data cut-off. Altogether 9/12 patients (ORR 75%) responded to MB-CART2019.1 with 5/12 CRs. In DL1 3/6 patients responded (ORR 50%) and in DL2 6/6 patients (ORR 100%). The 3 patients without response to MB-CART2019.1 had a mean AUC0-28 of 870 d*cells/µl, whereas mean AUC0-28 in 9 responders was 4843 d*cells/µl reflecting the correlation between the pharmacodynamic parameters and the clinical response. Responses are ongoing in 5/9 patients, with a maximum duration of response of 330 days at data cut-off. Summary/Conclusions In this first-in-human dose finding study of MB-CART2019.1 no DLT and no severe (grade ≥3) CRS or neurotoxicity were observed. Feasibility and safety were very good in this cohort of elderly r/r B-NHL patients. The sustained expansion of tandem CAR T-cells was accompanied by efficacy: all patients (6/6) treated on DL2 responded and all 5 patients with CR (5/5) are in ongoing remission by the time of this report. Based on the promising risk-to-benefit ratio observed in our study, evaluation of MB-CART2019.1 at a dose of 2.5x106/kg body weight in clinical phase II and phase III trials for patients with relapsed aggressive B-NHL is underway. Disclosures Borchmann: Miltenyi Biotec B.V. & Co. KG: Honoraria. Balke-Want:Miltenyi Biotec B.V. & Co. KG: Honoraria. Ayuk:Celgene: Consultancy, Honoraria; Kite/Gilead: Honoraria; Therakos/Mallinckrodt: Honoraria, Research Funding; Neovii: Research Funding; Novartis: Honoraria. Holtkamp:Miltenyi Biomedicine GmbH: Current Employment. Preussner:Miltenyi Biomedicine GmbH: Ended employment in the past 24 months. Zadoyan:Miltenyi Biomedicine GmbH: Current Employment. Hanssens:Miltenyi Biomedicine GmbH: Current Employment. Kaiser:Miltenyi Biotec B.V. & Co. KG: Current Employment. Jurk:Miltenyi Biotec B.V. & Co. KG: Current Employment. Bürger:Miltenyi Biotec B.V. & Co. KG: Current Employment. Schneider:Lentigen Technology Inc., A Miltenyi Company: Current Employment, Patents & Royalties. Dropulic:Lentigen Technology Inc., A Miltenyi Company: Current Employment. Overstijns:Miltenyi Biomedicine GmbH: Current Employment, Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotec B.V. & Co. KG: Current Employment, Membership on an entity's Board of Directors or advisory committees. Scheid:Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria; Takeda: Honoraria, Research Funding. Holtick:Miltenyi Biotec B.V. & Co. KG: Honoraria. Miltenyi:Miltenyi Biomedicine GmbH: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Lentigen Technology Inc., A Miltenyi Company: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Miltenyi Biotec B.V. & Co. KG: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.