Phase 2 Study Evaluating Autologous CD30.CAR-T Cells in Adult and Pediatric Patients With Relapsed/Refractory HL
548 Phase 2 study of FLX475 in combination with ipilimumab in advanced melanoma
BackgroundRegulatory T cells (Treg) can dampen antitumor immune responses in the tumor microenvironment (TME) and have been shown to correlate with poor clinical outcome. Translational studies have demonstrated an accumulation of Treg in tumors after treatment with immunotherapies including CAR-T cells and anti-CTLA-4, which could potentially reflect a mechanism of adaptive immune resistance.1–2 CCR4, the receptor for the chemokines CCL17 and CCL22, is the predominant chemokine receptor on human Treg and is responsible for the migration and accumulation of Treg in the TME. Preclinical studies with orally available CCR4 antagonists have demonstrated potent inhibition of Treg migration into tumors, an increase in the intratumoral Teff/Treg ratio, and antitumor efficacy as a single agent and in combination with checkpoint inhibitors, including anti-CTLA-4.3 In a first-in-human trial conducted in healthy volunteers, the oral CCR4 antagonist FLX475 was demonstrated to be well tolerated with outstanding pharmacokinetic and pharmacodynamic properties.4 An ongoing Phase 1/2 clinical trial of FLX475 is examining the safety and preliminary antitumor activity of FLX475 as monotherapy and in combination with pembrolizumab in subjects with several types of advanced cancer.5 Given the preclinical data demonstrating a significant enhancement of the antitumor activity of anti-CTLA-4 when combined with FLX475, a Phase 2 study investigating the combination of FLX475 and ipilimumab is now being conducted in subjects with advanced melanoma.MethodsThis clinical trial is a Phase 2, multicenter, open-label, single-arm study to determine the antitumor activity of FLX475 in combination with ipilimumab in subjects with advanced melanoma previously treated with an anti-PD-1 or anti-PD-L1 agent. The primary objectives of the study are to evaluate objective response rate, and the safety and tolerability of this combination. The study will first examine the safety of the combination of the 100 mg PO QD recommended Phase 2 dose of FLX475 and the approved 3 mg/kg IV Q3W dose of ipilimumab as part of a safety run-in phase, prior to examining the degree of antitumor activity in approximately 20 subjects. Evidence of an overall response rate (ORR) notably greater than the expected ORR of ipilimumab monotherapy alone in such subjects, which has been shown to be approximately 14%,6 would provide preliminary clinical evidence in support of the clinical hypothesis that CCR4 blockade by FLX475 can significantly enhance the antitumor activity of an anti-CTLA-4 checkpoint inhibitor.Trial RegistrationClinicalTrials.gov Identifier: NCT04894994ReferencesO’Rourke D, Nasrallah M, Desai A, Melenhorst J, Mansfield K, Morrissette J, Martinez-Lage M, Brem S, Maloney E, Shen A, Isaacs R, Mohan S, Plesa G, Lacey S, Navenot J, Zheng Z, Levine B, Okada H, June C, Brogdon J, Maus M. A single dose of peripherally infused EGFRvIII-directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma. Sci Transl Med 2017;9:eaaa0984. doi: 10.1126/scitranslmed.aaa0984.Sharma A, Subudhi S, Blando J, Vence L, Wargo J, Allison JP, Ribas A, Sharma P. Anti-CTLA-4 immunotherapy does not deplete FOXP3+ regulatory T cells (Tregs) in human cancers-Response. Clin Cancer Res 2019;25:1233–1238.Marshall L, Marubayashi S, Jorapur A, Jacobson S, Zibinsky M, Robles O, Hu D, Jackson J, Pookot D, Sanchez J, Brovarney M, Wadsworth A, Chian D, Wustrow D, Kassner P, Cutler G, Wong B, Brockstedt D, Talay O. Tumors establish resistance to immunotherapy by regulating Treg recruitment via CCR4. J Immunother Cancer 2020;8:e000764.van Marle S, van Hoogdalem E, Johnson D, Okal A, Kassner P, Wustrow D, Ho W, Smith S. Pharmacokinetics, pharmacodynamics, and safety of FLX475, an orally-available, potent, and selective small-molecule antagonist of CCR4, in healthy volunteers. J Immunother Cancer 2018; 6(Suppl 1):P484(SITC 2018).Powderly J, Chmielowski B, Brahmer J, Piha-Paul S, Bowyer S, LoRusso P, Catenacci D, Wu C, Barve M, Chisamore M, Nasrah N, Johnson D, Ho W. Phase I/II dose-escalation and expansion study of FLX475 alone and in combination with pembrolizumab in advanced cancer. Journal of Clinical Oncology 2020;38(15_suppl): TPS3163 (ASCO 2020).Long G, Mortier L, Schachter J, Middleton M, Neyns B, Sznol M, Zhou H, Ebbinghaus S, Ibrahim N, Arance A, Ribas A, Blank C and Robert C. Society for Melanoma Research 2016 Congress. Pigment Cell & Melanoma Research 2017;30:76–156.Ethics ApprovalThis study has been approved by the Institutional Review Board at each investigational site.
Abstract Chimeric Antigen Receptor (CAR) therapy targeting CD19 achieves complete remission (CR) rates of 70%-90% in relapsed/refractory B-ALL. Relapse due to loss of the CD19 targeted epitope presents a therapeutic challenge as evidenced by the largest global pediatric CD19-CAR experience which showed 15 of 16 relapses to be explained by CD19 downregulation (Maude et al, NEJM 2018). Alternatively targeting CD22 using CD22-CAR therapy has demonstrated a CR rate of approximately 70% in both CD19+ and CD19- B-ALL, however relapse due to CD22 downregulation limits the curative potential of singularly-targeting CD22 (Fry et al, Nat Med. 2018). We hypothesized that simultaneous targeting of CD19 and CD22 via a bispecific CAR-T cell would be a safe and tolerable treatment strategy in relapsed/refractory B-cell ALL and address immune evasion. Here, we report the first clinical experience in pediatric patients using bispecific CD19-CD22 CAR T cells. We describe a single institution phase I dose escalation study in pediatric patients with relapsed or refractory B cell ALL. We utilized lentiviral transduction of a bivalent CAR construct incorporating the fmc63 CD19 and m971 CD22 single chain variable fragments (scFvs) used in clinically tested CAR constructs and a 41BB costimulatory endodomain (Fry et al, Nat Med. 2018). Our primary objectives are feasibility of production of this bivalent CAR and safety at 3 dose escalation levels (1x106, 3x106 and 1x107 CAR T cells/kg). Clinical response assessment is evaluated as a secondary aim. All patients described received lymphodepletion with fludarabine (25mg/m2 x 3 days) and cyclophosphamide (900mg/m2 x 1) followed by fresh or cryopreserved CAR T cell infusion after a 7-9 day production time. Patients were prospectively monitored at predefined intervals for disease response and correlative assessments. Four pediatric patients with precursor-B ALL, age 2-17, have been enrolled and treated with CD19/CD22 bispecific CAR T cells at dose level 1 (1x106) [Table 1]. Three patients entered CAR therapy with low disease burden detected by minimal residual disease (MRD) alone and 1 patient initiated therapy with 12% bone marrow blasts. All patients were CNS1 at time of treatment. The toxicity profile mirrored that of the singular CD19 and CD22 CAR experience with 3 patients experiencing reversible CRS (2 Grade I, 1 Grade II), onset day 3-8, and 2 patients experiencing grade I neurotoxicity, onset day 3-9. In our cohort, we experienced lower grade toxicities than previously reported, likely due to a mean lower disease burden. Only 1 patient with CRS met criteria for tocilizumab and this patient was the singular study patient treated with higher burden disease. Neurotoxicity was managed with supportive care and fully reversible. Peripheral blood flow cytometry analysis detects circulating CAR by day 6 in all patients and demonstrates peak CAR expansion between day 6-10. Peak CAR T expansion reached levels of 10-25% of total T cells with inter-patient variability in CD4 and CD8 predominance, favoring CD8 expansion in 3 of 4 patients. Clinical symptoms and inflammatory markers expectedly correlate with peak CAR expansion. Four of 4 patients achieved complete remission (CR) at day 28 post-CD19/CD22 bispecific CAR therapy. Three of 4 patients demonstrated MRD- remissions by flow cytometry and of these, next generation sequencing (NGS) was negative where available (N=2). Multi-parametric CyTOF studies permitting CAR T cell phenotyping in conjunction with single cell TCR tracking, proteomics, epigenomics and cytokine profiling are ongoing and will be used to further characterize persisting CAR T cells and define inter-product and inter-patient variability. In this phase I study, we demonstrate safety and tolerability of this bispecific CD19/CD22 CAR at a dose of 1x106 CAR T cells/kg in pediatric patients with relapsed/refractory B cell ALL. The CD19/22-bispecific CAR mediated antileukemic activity in 100% of patients studied thus far. Long-term follow up and further accrual will be required to inform the effect of bispecific CAR targeting on surface antigen remodeling. Disclosures Muffly: Adaptive Biotechnologies: Research Funding; Shire Pharmaceuticals: Research Funding. Miklos:Genentech: Research Funding; Kite - Gilead: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Pharmacyclics - Abbot: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.
P-BCMA-101 is a novel chimeric antigen receptor (CAR)-T cell product targeting B Cell Maturation Antigen (BCMA). P-BCMA-101 is produced using the piggyBac® (PB) DNA Modification System instead of the viral vector that is used with most CAR-T cells, requiring only plasmid DNA and mRNA. This makes it less costly and produces cells with a high percentage of the favorable T stem cell memory phenotype (TSCM). The higher cargo capacity of PB permits the incorporation of multiple genes in addition to CAR(s), including a safety switch allowing for rapid CAR-T cell elimination with a small molecule drug infusion in patients if desired, and a selection gene allowing for enrichment of CAR+ cells. Rather than using a traditional antibody-based binder, P-BCMA-101 has a Centyrin™ fused to a CD3ζ/4-1BB signaling domain. Centyrins are fully human proteins with high specificity and a large range of binding affinities, but are smaller, more stable and potentially less immunogenic than traditional scFv. Cumulatively, these features are predicted to result in a greater therapeutic index. A Phase 1, 3+3 dose escalation from 0.75 to 15 x 106 P-BCMA-101 CAR-T cells/kg (RP2D 6-15 x 106 cells/kg) was conducted in patients with r/r MM (Blood 2018 132:1012) demonstrating excellent efficacy and safety of P-BCMA-101, including notably low rates and grades of CRS and neurotoxicity (maximum Grade 2 without necessitating ICU admission, safety switch activation or other aggressive measures). These results supported FDA RMAT designation and initiation of a pivotal Phase 2 study. A Phase 2 pivotal portion of this study has recently been designed and initiated (PRIME; NCT03288493) in r/r MM patients who have received at least 3 prior lines of therapy. Their therapy must have contained a proteasome inhibitor, an IMiD, and CD38 targeted therapy with at least 2 of the prior lines in the form of triplet combinations. They must also have undergone ≥2 cycles of each line unless PD was the best response, refractory to the most recent line of therapy, and undergone autologous stem cell transplant or not be a candidate. Patients are required to be >=18 years old, have measurable disease by International Myeloma Working Group criteria (IMWG; Kumar 2016), adequate vital organ function and lack significant autoimmune, CNS and infectious diseases. No pre-specified level of BCMA expression is required, as this has not been demonstrated to correlate with clinical outcomes for P-BCMA-101 and other BCMA-targeted CAR-T products. Interestingly, unlike most CAR-T products patients may receive P-BCMA-101 after prior CAR-T cells or BCMA targeted agents, and may be multiply infused with P-BCMA-101. Patients are apheresed to harvest T cells, P-BCMA-101 is then manufactured and administered to patients as a single intravenous (IV) dose (6-15 x 106 P-BCMA-101 CAR-T cells/kg) after a standard 3-day cyclophosphamide (300 mg/m2/day) / fludarabine (30 mg/m2/day) conditioning regimen. One hundred patients are planned to be treated with P-BCMA-101. Uniquely, given the safety profile demonstrated during Phase 1, no hospital admission is required and patients may be administered P-BCMA-101 in an outpatient setting. The primary endpoints are safety and response rate by IMWG criteria. With a 100-subject sample, the Phase 2 part of the trial will have 90% power to detect a 15-percentage point improvement over a 30% response rate (based on that of the recently approved anti-CD38 antibody daratumumab), using an exact test for a binomial proportion with a 1-sided 0.05 significance level. Multiple biomarkers are being assessed including BCMA and cytokine levels, CAR-T cell kinetics, immunogenicity, T cell receptor diversity, CAR-T cell and patient gene expression (e.g. Nanostring) and others. Overall, the PRIME study is the first pivotal study of the unique P-BCMA-101 CAR-T product, and utilizes a number of novel design features. Studies are being initiated in combination with approved therapeutics and earlier lines of therapy with the intent of conducting Phase 3 trials. Funding by Poseida Therapeutics and the California Institute for Regenerative Medicine (CIRM). Disclosures Costello: Takeda: Honoraria, Research Funding; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Gregory:Poseida: Research Funding; Celgene: Speakers Bureau; Takeda: Speakers Bureau; Amgen: Speakers Bureau. Ali:Celgene: Research Funding; Poseida: Research Funding. Berdeja:Amgen Inc, BioClinica, Celgene Corporation, CRISPR Therapeutics, Bristol-Myers Squibb Company, Janssen Biotech Inc, Karyopharm Therapeutics, Kite Pharma Inc, Prothena, Servier, Takeda Oncology: Consultancy; AbbVie Inc, Amgen Inc, Acetylon Pharmaceuticals Inc, Bluebird Bio, Bristol-Myers Squibb Company, Celgene Corporation, Constellation Pharma, Curis Inc, Genentech, Glenmark Pharmaceuticals, Janssen Biotech Inc, Kesios Therapeutics, Lilly, Novartis, Poseida: Research Funding; Poseida: Research Funding. Patel:Oncopeptides, Nektar, Precision Biosciences, BMS: Consultancy; Takeda, Celgene, Janssen: Consultancy, Research Funding; Poseida Therapeutics, Cellectis, Abbvie: Research Funding. Shah:University of California, San Francisco: Employment; Genentech, Seattle Genetics, Oncopeptides, Karoypharm, Surface Oncology, Precision biosciences GSK, Nektar, Amgen, Indapta Therapeutics, Sanofi: Membership on an entity's Board of Directors or advisory committees; Indapta Therapeutics: Equity Ownership; Celgene, Janssen, Bluebird Bio, Sutro Biopharma: Research Funding; Poseida: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nkarta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees; Teneobio: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ostertag:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Martin:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Ghoddusi:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Shedlock:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Spear:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Orlowski:Poseida Therapeutics, Inc.: Research Funding. Cohen:Poseida Therapeutics, Inc.: Research Funding.
Background: Relapsed/refractory (R/R) large B cell lymphoma (LBCL) is associated with poor outcomes to standard salvage therapy (Crump M, et al. Blood. 2017). In SCHOLAR-1, a large multicenter, patient-level, retrospective study, patients with R/R diffuse LBCL had a 26% objective response rate (ORR) to the next line of therapy, a 7% complete response (CR) rate, and a median overall survival of 6.3 months (Crump M, et al. Blood 2017). Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for patients with R/R LBCL with ≥ 2 prior systemic therapies. With a median follow-up of 27.1 months in ZUMA-1, the ORR with axi-cel was 83% (58% CR rate) in patients with refractory LBCL (Locke FL, et al. Lancet Oncol. 2019). Activation of the costimulatory receptor 4-1BB (CD137) on CAR T cells may enhance axi-cel antitumor activity by enhancing T cell proliferation, function, and survival. Utomilumab (uto), an investigational monoclonal antibody agonist of the 4-1BB pathway, enhanced T cell function and survival in preclinical studies (Fisher TS, et al. Cancer Immunol Immunother. 2012) and had favorable single-agent safety in patients (Segal NH, et al. Clin Cancer Res. 2018). Possible mechanisms of resistance to axi-cel are thought to be suboptimal CAR T cell expansion an exclusionary tumor microenvironment and CD19 target antigen loss (Neelapu SS, et al. Blood 2017, Rossi JM, et al J Immunother Cancer. 2018). Combination strategies that increase proliferation, expansion, and persistence of CAR T cells or prevent activation-induced cell death of CAR T cells may improve clinical outcomes observed with axi-cel. ZUMA-11 is a Phase 1/2 study investigating the efficacy and safety of axi-cel + uto in patients with refractory LBCL. Methods: The primary objectives of this study are to determine the safety, recommended Phase 2 dosing and timing (Phase 1), and efficacy (Phase 2) of axi-cel + uto in adult patients with refractory LBCL. Patients with progressive or stable disease as the best response to second-line chemotherapy or relapse ≤ 12 months after autologous stem cell transplantation, a prior anti-CD20 antibody and anthracycline-containing regimen, and Eastern Cooperative Oncology Group performance status 0-1 are eligible. Patients with histologically proven primary mediastinal B cell lymphoma, history of Richter's transformation or chronic lymphocytic lymphoma, prior CAR T cell therapy, or central nervous system involvement of lymphoma are ineligible. In Phase 1, ≈24 patients in ≤ 3 cohorts will receive a single dose of axi-cel and escalating doses of uto (10, 30, or 100 mg) using a 3 + 3 design in up to 4 of 6 cohorts. The recommended uto dose will be based on dose-limiting toxicities and other factors. Patients will be leukapheresed and may receive optional, nonchemotherapy bridging therapy per investigator decision. After conditioning chemotherapy, patients will receive a single infusion of axi-cel (target dose, 2 × 106 CAR T cells/kg) on Day 0 followed by uto on Day 1 and every 4 weeks for 6 months or until progressive disease. Patients will be treated one at a time during Phase 1, and patients treated with axi-cel will be staggered by ≥ 2 weeks. Day 21 uto administration will be explored if toxicity is unacceptable with Day 1 administration. The primary endpoints are incidence of dose-limiting toxicities in Phase 1 and CR rate in Phase 2. Secondary endpoints include ORR, duration of response, progression-free survival, overall survival, safety, and levels of CAR T cells and cytokines in blood. This study uses a single-arm design to estimate the true CR rate; with a sample size of 27 patients, of which ≤ 3 patients will have been treated in the Phase 1 portion, the maximum half-width of the 95% confidence interval about response will be ≥ 21%. ZUMA-11 is open and accruing patients. Disclosures Reshef: Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; Celgene: Research Funding; Incyte: Consultancy, Research Funding; Shire: Research Funding; BMS: Consultancy; Atara: Consultancy, Research Funding; Magenta: Consultancy; Pfizer: Consultancy; Pharmacyclics: Consultancy, Research Funding. Miklos:Pharmacyclics: Consultancy, Patents & Royalties, Research Funding; Precision Bioscience: Consultancy; Adaptive Biotechnologies: Consultancy, Research Funding; Miltenyi: Consultancy, Research Funding; Becton Dickinson: Consultancy; Janssen: Consultancy; AlloGene: Consultancy; Novartis: Consultancy; Kite, A Gilead Company: Consultancy, Research Funding; Celgene-Juno: Consultancy. Timmerman:Spectrum Pharmaceuticals: Research Funding; Kite, A Gilead Company: Consultancy, Honoraria, Other: travel support, Research Funding; ImmunGene: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Other: travel support, Research Funding. Jacobson:Novartis: Consultancy, Honoraria, Other: travel support; Bayer: Consultancy, Other: travel support; Precision Biosciences: Consultancy, Other: travel support; Humanigen: Consultancy, Other: travel support; Celgene: Consultancy, Other: travel support; Pfizer: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: travel support. Bennani:Kite, A Gilead Company: Consultancy, Research Funding. Rossi:Kite, A Gilead Company: Employment. Sherman:Kite, A Gilead Company: Employment. Sun:Kite, A Gilead Company: Employment. Palluconi:Kite, A Gilead Company: Employment. Kim:Kite, A Gilead Company: Employment. Jain:Kite/Gilead: Consultancy.
Abstract T cells can be genetically modified to target tumor antigens through the expression of a chimeric antigen receptor (CAR). CAR T cells targeting the CD19 antigen is a novel therapeutic approach for patients with relapsed B cell acute lymphoblastic leukemia (B-ALL). We have previously demonstrated that CAR T cells have a significant clinical benefit in adult patients with relapsed B-ALL. The primary objective of this study (NCT01860937) is to extend the use and test the safety of CD19 specific CAR T cells in children with relapsed CD19+ B-ALL. To date, 11 pediatric patients with very high risk (VHR) or relapsed B-ALL have been enrolled on protocol with a median age of 13 years (range 2-23 years) at time of T cell collection. We have treated 4 pediatric patients with relapsed B-ALL (ages 13, 14, 19, and 22 years) using patient derived T cells expressing a CD19 specific CAR (19-28z). Complete response (complete remission or complete remission with incomplete count recovery) occurred in 2/4 (50%) patients. Severe cytokine release syndrome (sCRS) defined by fever for ≥3 consecutive days, elevated serum cytokine levels, and one clinical sign of toxicity (hypotension, hypoxia, neurologic disorder including altered mental status, obtundation, and/or seizure) occurred in both patients who responded to CAR T cells. Morphologic disease (≥5% bone marrow blasts) at time of treatment was present in three patients including both patients with sCRS. Systemic immunosuppressants (corticosteroids or anti-IL6 receptor antibody tocilizumab) abrogated clinical symptoms of sCRS. Elevated serum cytokines of IFN-g (>20 fold), fractalkine (>20 fold), Flt-3L (>55 fold), IL-5 (>15 fold), IL-6 (>100 fold), and IL-10 (>15 fold) were demonstrated in patients with sCRS. Monitoring of bone marrow demonstrated peak 19-28z CAR T-cell detection within 1-2 weeks following infusion with gradual contracture over 2-3 months. These early results demonstrate the feasibility and significant clinical impact of this approach in patients with relapsed B-ALL. To more rapidly generate statistically relevant data, demonstrate the “exportability” of this technology between academic institutions, and offer this therapeutic option to a broader number of pediatric patients with chemo-refractory B-ALL our trial will expand into a phase I multicenter clinical trial with a collaborating institution. Subsequent cohorts of patients will receive 19-28z CAR T cells and will be evaluated for toxicity, persistence of CAR T cells, and for anti-leukemic efficacy. Disclosures Off Label Use: CAR T cells for relapsed B-ALL. Riviere:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other. Boulad:Genzyme Sanofi: Trials partially funded by Genzyme Sanofi Other. Sadelain:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other. Brentjens:Juno Therapeutics: Consultancy, Scientific co-founder and Stock holder Other.
Abstract OBJECTIVE Immunotherapy for hematologic malignancies with CD19-directed CAR T cells is complicated by neurotoxicity in approximately 40% of patients. We have previously reported evidence of glial injury in pediatric patients with CAR T neurotoxicity by elevated CSF levels of GFAP and S100b. We now hypothesize that NFL is also a useful biomarker of neuronal injury related to abnormal blood-brain-barrier and glial function. METHODS We used the Mesoscale Discovery platform to measure CSF and serum NFL levels in a consecutive cohort of 43 pediatric patients with B cell ALL who received CD19-directed CAR T cells. In addition, we will present expansion cohort measurements of NFL and GFAP (N=95). RESULTS CSF NFL levels prior to CAR T cell infusion positively correlated with the risk of subsequently developing severe neurotoxicity (no neurotoxicity, median 275pg/mL, mild 378pg/mL, severe 951pg/mL, P=0.0182 for severe vs none, P=0.0458 for severe vs mild). During neurotoxicity, mean CSF NFL levels increased to 1179pg/mL (mild neurotoxicity, P=0.0338) and 1345 pg/mL (severe neurotoxicity, P=0.0148), respectively. In serum, pretreatment NFL levels were highly abnormal in many patients (median 368pg/mL, range 10–56,321pg/mL; healthy control median 4pg/mL, range 1–7.5pg/mL). However, there was no correlation with neurotoxicity, history of CNS radiation, peripheral neuropathy, stem cell transplant, or number of prior chemotherapies. Day 7 serum NFL levels did not change significantly (median 439pg/mL, range 5–17,439pg/mL, P=0.3254). CONCLUSION We conclude that CSF NFL is promising biomarker of CAR T neurotoxicity risk and severity. The abnormal baseline serum NFL concentrations remain unexplained and require further study.
Abstract Background T-ALL/LBL represent a class of devastating hematologic cancers with high rates of relapse and mortality in both children and adults. Despite intensive multi-agent chemotherapy regimens, fewer than 50% of adults and 85% of children with T-ALL survive beyond five years. For those who relapse after initial therapy, salvage regimens induce remissions in only ~20-30% of cases, and survival is dismal. T-ALL/LBL is a genetically diverse group, but with universal overexpression of CD7, making this a suitable target for immunotherapy. Despite the success of CAR-T cells in B-cell malignancies, CAR-T cell development in T-cell malignancies has proven challenging due to fratricide and high risk of contamination of the genetically modified CAR-T product with the patient's malignant T cells. WU-CART-007 is a CD7-directed, genetically modified, allogeneic, 'off the shelf', fratricide-resistant chimeric antigen receptor (CAR) T-cell product for the treatment of CD7+ve hematologic malignancies. Methods This multicenter, open-label, dose-escalation, Phase 1/2 study (NCT#04984356) of WU-CART-007 in patients ≥ 12 years old, with relapsed or refractory T-ALL/LBL is designed to characterize the safety, tolerability, dose-limiting toxicities (DLTs), and maximum tolerated dose (MTD)/maximum administered dose (MAD; if no MTD defined) (Phase 1), and to investigate the preliminary anti-tumor activity, as measured by objective response rate (ORR) and duration of response (DOR) (Phase 2). Phase 1 is comprised of a dose escalation segment and will proceed according to a standard 3+3 design testing up to 4 dose levels from 1 to 9 x 10 8 cells. Adolescent patients, ages 12-17, will be eligible for enrollment in Phase 1 Dose Escalation beginning at Dose level 3 and 4, and during Phase 2 Cohort Expansion. Upon reaching the MTD and/or RP2D, the Phase 2 portion comprised of the cohort expansion segment will be launched. A Simon's optimal two-stage design will be implemented to enroll patients (an interim analysis for futility in the first stage and the final analysis in the second stage) for Phase 2 dose expansion cohort to confirm safety and explore preliminary efficacy. All patients will receive a single infusion of WU-CART-007 cells on day 1 following a lymphodepleting conditioning therapy consisting of fludarabine and cyclophosphamide on days -5 to -3. Patients will be hospitalized for a minimum of 7 days following WU-CART-007 administration. Response will be assessed on Cycle 1 Day 28 (± 1 days), and at Months 3, 6, 12, and 24, by bone marrow aspirate and biopsy and PET/CT if indicated. Response will be defined as per modified NCCN Guidelines Version 2.2020. Disclosures Ghobadi: Atara: Consultancy; Amgen: Consultancy, Research Funding; Wugen: Consultancy; Celgene: Consultancy; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding. Locke: Janssen: Consultancy, Other: Scientific Advisory Role; Kite, a Gilead Company: Consultancy, Other: Scientific Advisory Role, Research Funding; Iovance Biotherapeutics: Consultancy, Other: Scientific Advisory Role; Legend Biotech: Consultancy, Other; Novartis: Consultancy, Other, Research Funding; Takeda: Consultancy, Other; Wugen: Consultancy, Other; Cowen: Consultancy; Umoja: Consultancy, Other; Bluebird Bio: Consultancy, Other: Scientific Advisory Role; Calibr: Consultancy, Other: Scientific Advisory Role; BMS/Celgene: Consultancy, Other: Scientific Advisory Role; GammaDelta Therapeutics: Consultancy, Other: Scientific Advisory Role; Cellular Biomedicine Group: Consultancy, Other: Scientific Advisory Role; Amgen: Consultancy, Other: Scientific Advisory Role; Allogene Therapeutics: Consultancy, Other: Scientific Advisory Role, Research Funding; EcoR1: Consultancy; Emerging Therapy Solutions: Consultancy; Gerson Lehrman Group: Consultancy; Moffitt Cancer Center: Patents & Royalties: field of cellular immunotherapy. Maude: Wugen: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding. Davidson-Moncada: Wugen: Current Employment. Cooper: Wugen: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Patents & Royalties; NeoImmune Tech: Patents & Royalties; RiverVest: Consultancy.
Abstract 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.