scholarly journals Posoleucel (ALVR105), an Off-the-Shelf, Multivirus-Specific T-Cell Therapy, for the Prevention of Viral Infections Post-HCT: Results from an Open-Label Cohort of a Phase 2 Trial

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1760-1760
Author(s):  
Sanjeet S Dadwal ◽  
Michael Shuster ◽  
Gary Douglas Myers ◽  
Keith Boundy ◽  
Marshelle Warren ◽  
...  

Abstract Background: Patients who undergo allogeneic hematopoietic cell transplantation (allo-HCT) are at high risk of reactivation or de novo infection with double-stranded (ds) DNA viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), adenovirus (AdV), BK virus (BKV), and JC virus (JCV). After allo-HCT, up to 90% patients develop detectable viremia by PCR. EMR data collected between 2018 and April 1, 2021, from over 1400 high-risk allo-HCT patients at 21 US centers suggest that 40-50% develop clinically significant viral infection or disease associated with ≥1 of these dsDNA viruses within 200 days of transplant. Multiple studies demonstrate increased morbidity and mortality associated with viremia, with or without end-organ disease. Prophylactic and preemptive therapies have substantial side effects and can lead to the development of resistance, especially in CMV. HCT donor-derived virus-specific T-cells have shown promise in preventing single virus infections in prior clinical trials but were infeasible for wide-scale use. There is an urgent unmet medical need for preventive strategies targeting multiple viruses in patients undergoing high-risk allo-HCT. Methods: We are conducting a clinical trial (NCT04693637) to evaluate the safety and efficacy of posoleucel (ALVR105, Viralym-M) for preventing clinically significant viral infections due to CMV, EBV, HHV-6, AdV, BKV, and JCV in high-risk allo-HCT recipients. Posoleucel is an ex-vivo expanded, partially HLA-matched, off-the-shelf, multivirus-specific T cell investigational product generated from healthy, third-party donors targeting CMV, EBV, HHV-6, AdV, BKV, and JCV. In the open-label portion of the study, patients receive up to seven infusions of 4×10 7 cells of posoleucel administered once every 14 days. High-risk patients are those who received a graft from a sibling or unrelated donor with ≥1 HLA mismatch; from a haploidentical donor; from umbilical cord blood or with T-cell-depletion; as well as patients with lymphocytes <180/mm 3 or CD4 T cells <50/mm 3 at enrollment. Patients must be engrafted and within 15-49 days of allo-HCT. Those with grade ≥3 GVHD as well as those requiring steroids (>0.5 mg/kg/day prednisone equivalent) at enrollment are ineligible. Patients are tested weekly for viremia using quantitative PCR assays and are monitored every other week for adverse events. The primary endpoint is the number of clinically significant viral infections or episodes of end-organ disease due to CMV, EBV, HHV6, AdV, BKV, or JCV by week 14. Results: Data are available for 12 of 25 planned participants thus far (Table 1). No patient developed a clinically significant infection within 14 weeks, the primary study endpoint. Over the entire study duration, defined as the primary 14-week treatment period plus the additional 12-week follow-up, 11 (92%) patients have remained free of any clinically significant viral infections, the key secondary endpoint. One patient, a 49-year-old female haploidentical transplant recipient, developed clinically significant AdV viremia after receiving over a month of high-dose methylprednisolone exceeding 0.5 mg/kg/day for recurrent aGVHD. This patient was administered IV cidofovir in week 15 of the study. During the primary study efficacy period one participant received 2 doses of valganciclovir following transient CMV viremia deemed not to be clinically significant by the principal investigator. Posoleucel has been well tolerated to date, with no drug-related serious adverse events, new-onset acute GVHD, or cytokine release syndrome. Safety and efficacy data from the entire open-label cohort will be presented. Conclusions: Preliminary results in this open-label cohort show that in high-risk allo-HCT patients receiving off-the-shelf posoleucel, clinically significant viral infections or disease from the 6 targeted dsDNA viruses were uncommon. No clinically significant infections were observed among participants treated in accordance with the protocol. These results, combined with the favorable safety and tolerability profile of posoleucel, support its continued evaluation in high-risk allo-HCT recipients for the prevention of CMV, EBV, HHV6, AdV, BK virus, or JC virus infection and disease. Figure 1 Figure 1. Disclosures Dadwal: Shire/Takeda: Research Funding; Astellas: Speakers Bureau; Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AlloVir: Research Funding; Aseptiscope: Consultancy; Janssen: Other: Investigator; Karius: Other: Investigator. Shuster: Bristol Myers Squibb: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Genentech: Consultancy, Speakers Bureau; Intellisphere: Consultancy, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company; Rafael: Research Funding; Celgene: Consultancy, Current equity holder in publicly-traded company; Incyte: Research Funding; Beigene: Consultancy; Seattle Genetics: Consultancy, Speakers Bureau; Actinium: Research Funding; GSK: Research Funding; Pharmcyclics: Consultancy, Research Funding, Speakers Bureau; Epizyme: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; AlloVir: Research Funding; Janssen: Consultancy, Speakers Bureau; Astellas: Consultancy, Research Funding, Speakers Bureau; MorphSys: Consultancy, Research Funding, Speakers Bureau; Takeda: Consultancy, Research Funding, Speakers Bureau. Myers: Novartis: Consultancy, Speakers Bureau; AlloVir: Research Funding; Eliana: Consultancy, Membership on an entity's Board of Directors or advisory committees. Boundy: AlloVir: Current Employment, Current equity holder in publicly-traded company. Warren: AlloVir: Consultancy. Stoner: AlloVir: Current Employment, Current equity holder in publicly-traded company. Hill: Octapharma: Consultancy; OptumHealth: Consultancy; CRISPR therapeutics: Consultancy; CLS Behring: Consultancy; Allogene therapeutics: Consultancy; Gilead: Consultancy, Research Funding; Allovir: Consultancy, Research Funding; Amplyx: Consultancy; Takeda: Consultancy, Research Funding; Karius: Research Funding.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2759-2759
Author(s):  
Francis J. Giles ◽  
Gianantonio Rosti ◽  
Gert Ossenkoppele ◽  
Michel Tulliez ◽  
Jesper Stentoft ◽  
...  

Abstract Abstract 2759 BACKGROUND Nilotinib, a highly potent, selective inhibitor of BCR-ABL, is now approved for frontline treatment of Philadelphia chromosome positive (Ph+) CP CML. ENEST1st (Evaluating Nilotinib Efficacy and Safety trial as first line treatment) is a phase IIIb, open-label study of nilotinib in adult patients with newly diagnosed CP CML (ClinicalTrials.gov NCT01061177). The primary study aim is to establish the rate of molecular remission with a sensitivity of 4 log (MR4) rate through EUTOS (European Treatment and Outcomes Study) laboratories to improve the sensitivity and standardisation of RT-PCR for low level BCR-ABL detection and further refine the working definition of deep molecular response. The attainment of sustained MR4 will identify a patient population potentially eligible to join studies of tyrosine kinase inhibitor discontinuation in CP CML. METHODS 806 patients (pts) with newly diagnosed BCR-ABL+ CML-CP, diagnosed within 6 months, were to be treated with nilotinib 300 mg BID for a study period of 24 months. The primary study endpoint is MR4 rate at 18 months, initially defined as undetectable BCR-ABL transcripts by quantitative RT- PCR in a peripheral blood sample of at least 10 ml with a minimum sensitivity of 1:10,000. Molecular monitoring was performed by 13 EUTOS laboratories with conversion factors to the International Scale to facilitate standardised measurement. Key secondary endpoints include: rate of progressions to accelerated phase (AP) or blast crisis (BC) in year 1 and 2; rate of events in patients achieving MR4 at 1 year; rate of MMR (<0.1% IS) at and by 12/24 months; rate of CCyR at and by 12/24 months; rate of CHR at and by 12/24 months; the rate of early events, EFS, OS; and nilotinib safety/tolerability. Two interim analyses were planned: when the first 200 pts had reached 6 months, (1st IA), and when a subsequent 400 pts had also reached 6 months of study treatment and the first 200 pts had 18 months follow up. Additionally, 11 translational and correlative science sub studies were performed. RESULTS The 1st IA results are as follows: Baseline demographics: 208 pts were recruited in 102 sites in 15 countries. Median age was 53 years, median time from diagnosis 1.1 months (range 0.07–5.39). 39.0% pts were female, 91.8% had typical b2a2 or b3a2 BCR-ABL transcripts, 71.2% had been previously treated. 37.6% with standard dose imatinib (maximum of 12 weeks) and 55.1% with hydroxyurea. 34.0%, 37.2% and 17.8% pts were classified as Sokal low, intermediate and high risk. 80.4% and 9.3% pts were classified as EUTOS score low and high risk. The median dose intensity was 600 mg/day. 29.8% pts experienced a dose interruption of a median cumulative duration of 14 days. Rate of MMR by 3 and 6 months was 22.5% and 50.3%. MMR by 3 and 6 months was 43.9% and 61.1% for EUTOS low risk and 17.6% and 41.2% for EUTOS high risk pts. Quality control of molecular responses beyond MMR is ongoing. Adverse events (AE) were mostly grade 1 and 2, mainly rash (22.4%), pruritus (17.1%), alopecia (11.7%), fatigue (11.7%), headache and nausea (10.2%) which were usually manageable with appropriate dose interruptions/reduction. Grade 3–4 hematological AE rates were low, with thrombocytopenia and neutropenia reported in 5.3 and 3.5% pts respectively. The incidence of treatment –related Grade 3–4 non-hematological AEs was low, with lipase increase and hyperbilirubinaemia reported in 2.4% and 1.5% pts respectively. 8.8% patients reported study drug related SAEs. 7.8% and 0.5% of pts showed a prolongation of QTcF above 450ms and 500ms respectively. At 6 months, 88.8% pts remain on study, 14 pts (6.8%) have discontinued due to AE (3 discontinued due to hyperbilirubinemia), 1 due to abnormal laboratory value, 5 withdrew consent, 1 died due to a metastatic neoplasm, and 2 discontinued due to protocol violations. No pt has progressed during the first 6 months of study. Methodological improvements in RT-PCR have allowed refinement of the working definition of MR4 as either (i) detectable disease ≤0.01% BCR-ABLIS or (ii) undetectable disease in cDNA with ≥10,000 ABL transcripts. CONCLUSIONS Results of the ENEST1st first IA with over 100 pt years of nilotinib treatment demonstrate nilotinib's efficacy and safety to be similar to that reported in other front line trials. Through methodological improvements of RT-PCR, a network of EUTOS laboratories are now able to define and measure MR4 in a standardised and validated manner. Disclosures: Giles: Novartis: Consultancy, Honoraria, Research Funding. Rosti:Novartis: Consultancy; Bristol Myers Squibb: Consultancy; Novartis: Research Funding; Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Ossenkoppele:Novartis Pharmaceutical: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria. Tulliez:Novartis: Investigator in Novartis Study. Stentoft:Novartis: Investigator in Novartis Study. Giagounidis:Novartis: Investigator in Novartis Study. Nobile:Novartis: Investigator in Novartis Study. le Coutre:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria. Gattermann:Novartis: Honoraria, Research Funding. Griskevicius:Novartis: Investigator in Novartis Study. Cross:Novartis: Research Funding. Hill:Novartis: Employment. Schuld:Novartis: Employment. Pellegrino:Novartis: Employment. Magazzù:Novartis: Employment. Hochhaus:Novartis Pharmaceutical: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding; Ariad: Consultancy, Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 19-21
Author(s):  
Gina L. Mazza ◽  
Carolyn Mead-Harvey ◽  
John Mascarenhas ◽  
Abdulraheem Yacoub ◽  
Ronald Hoffman ◽  
...  

Introduction Essential thrombocythemia (ET) and polycythemia vera (PV) patients suffer from various symptoms that worsen quality of life (QOL), yet serial data on symptom changes resulting from therapy are sparse in the literature. Patient questionnaires from 2 large multicenter trials (MPN-RC 111, 112) were used to assess change in symptom burden and QOL over 12 months and impact of baseline symptom burden on subsequent change in ET / PV patients on hydroxyurea (HU) or pegylated interferon alfa-2a (PEG). Methods Trials MPN-RC 111 was a single-arm, open-label, phase II trial evaluating response to PEG in high-risk ET / PV patients with HU resistance/intolerance or splanchnic vein thrombosis (SVT; NCT01259817). MPN-RC 112 was a randomized, open-label, phase III trial comparing response to PEG versus HU in cytoreductive therapy naïve high-risk ET / PV patients diagnosed &lt; 5 years ago (NCT01258856). Measures Patients reported disease-related symptoms via the validated Myeloproliferative Neoplasms Symptom Assessment Form (MPN-SAF), QOL via the European Organisation for the Research and Treatment of Cancer Core QOL Questionnaire (EORTC QLQ-C30), and (if applicable) PEG-related symptoms (flu-like symptoms, injection site irritation, blurry vision, vision change, flushing) at baseline, 3, 6, 9, and 12 months. Analysis Mixed models assessed mean changes from baseline in the MPN-SAF Total Symptom Score (TSS), MPN-SAF items, QOL, and PEG-related symptoms in MPN-RC 111, 112 PEG, and 112 HU patients. Mixed models also assessed the impact of baseline symptom burden (high [TSS ≥ 20] versus low) on subsequent change in PEG (MPN-RC 111 and 112) and HU patients. Results Patients Of the 135 enrolled MPN-RC 111 patients, 20 with SVT and 1 with no questionnaires were excluded. Of the remaining 114, 64 (56%) / 50 (44%) had ET / PV. Patients were 51% / 48% female. Median age was 65 / 64 years, and median time since diagnosis was 38 / 55 months. 31% / 22% had prior thrombosis, and 19% / 56% had splenomegaly. Of the 168 enrolled MPN-RC 112 patients (82 PEG, 86 HU), 2 with no questionnaires were excluded. Of the remaining 166, 79 (48%) / 87 (52%) had ET / PV. Patients were 50% / 33% female. Median age was 60 / 62 years, and median time since diagnosis was 3 / 3 months. 25% / 29% had prior thrombosis, and 11% / 37% had splenomegaly. Symptoms Questionnaire completion rates ranged from 90 - 99%, 87 - 100%, and 75 - 96% for on-treatment MPN-RC 111, 112 PEG, and 112 HU patients. At baseline, TSS (0 [absent] - 100 [worst imaginable]) and QOL (0 [very poor] - 100 [excellent]) means (SDs) were 19.5 (18.4) and 71.6 (20.1) for MPN-RC 111, 17.0 (13.6) and 67.9 (24.3) for MPN-RC 112 PEG, and 14.6 (11.4) and 73.8 (18.8) for MPN-RC 112 HU patients. On average, MPN-RC 111 patients had significant improvement of TSS, fatigue, abdominal pain, abdominal discomfort, dizziness, numbness, night sweats, and fever; MPN-RC 112 PEG patients had significant worsening of fever; and MPN-RC 112 HU patients had significant worsening of inactivity (no mean changes indicating improvement were observed). PEG patients had significant worsening of PEG-related symptoms. The greatest improvements occurred in the 46 (40%), 27 (33%), and 23 (28%) MPN-RC 111, 112 PEG, and 112 HU patients with high baseline symptom burden. On average, PEG patients with high baseline symptom burden had significant improvement of TSS, fatigue, early satiety, abdominal pain, abdominal discomfort, inactivity, headache, concentration, dizziness, numbness, insomnia, cough, night sweats, itching, bone pain, fever, weight loss, and QOL, while those with low baseline symptom burden had significant worsening of TSS, early satiety, headache, itching, and bone pain. On average, HU patients with high baseline symptom burden had significant improvement of TSS, early satiety, abdominal discomfort, headache, dizziness, numbness, insomnia, itching, and weight loss, while those with low baseline symptom burden had significant worsening of TSS, early satiety, abdominal discomfort, inactivity, concentration, and sexual desire/function (Figures 1 and 2). Conclusions Although no statistical comparisons were made across trials, overall improvements were seen in MPN-RC 111 but not 112. Patients with high baseline symptom burden experienced the greatest improvements in symptom burden and QOL during treatment with PEG or HU, which may explain the improvements seen in the more advanced patients in MPN-RC 111 compared to 112. Disclosures Mascarenhas: Celgene, Prelude, Galecto, Promedior, Geron, Constellation, and Incyte: Consultancy; Incyte, Kartos, Roche, Promedior, Merck, Merus, Arog, CTI Biopharma, Janssen, and PharmaEssentia: Other: Research funding (institution). Yacoub:Dynavax: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Cara Therapeutics: Current equity holder in publicly-traded company; Hylapharm: Current equity holder in private company; Incyte: Speakers Bureau; Agios: Honoraria, Speakers Bureau; Novartis: Speakers Bureau; Roche: Other: Support of parent study and funding of editorial support. Hoffman:Protagonist: Consultancy; Forbius: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Dompe: Research Funding. Silver:PharmaEssentia: Speakers Bureau. Mesa:Bristol Myers Squibb: Research Funding; Incyte: Research Funding; AbbVie: Research Funding; Samus Therapeutics: Research Funding; Genentech: Research Funding; CTI BioPharma: Research Funding; Promedior: Research Funding; Sierra Oncology: Consultancy; LaJolla Pharmaceutical Company: Consultancy; Novartis: Consultancy.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2828-2828
Author(s):  
Hannah Kinoshita ◽  
Kenneth R. Cooke ◽  
Melanie Grant ◽  
Maja Stanojevic ◽  
Conrad Russell Young Cruz ◽  
...  

Abstract Background: Patients with hematologic malignancies relapsing after allogeneic blood or marrow transplantation (BMT) have limited response to conventional salvage therapies with an expected 1-year overall survival (OS) of &lt;20%. Current strategies to treat relapsed hematopoietic cancer after BMT, such as chemotherapy and donor lymphocyte infusions (DLI) to enhance the immunologic graft-versus-leukemia (GVL) effect, have low efficacy and are associated with graft-versus-host disease (GVHD). An alternative strategy to boost the GVL effect is to infuse donor-derived T-cells targeting tumor-associated antigen (TAA) peptides as circulating TAA-specific T-cells are associated with maintenance of remission post-BMT. In this phase-I study, we evaluated the safety and clinical outcomes following administration of a novel T-cell therapeutic targeting three TAAs, WT1, PRAME and survivin in patients with acute leukemia who relapsed or were at high-risk of relapse after allogeneic BMT. Methods: Lymphocytes obtained from the BMT donor were manufactured to target TAAs; WT1, PRAME and survivin, which are over-expressed and immunogenic in most hematologic malignancies. Patients received TAA-T infusions at doses of 0.5-4x10 7/m 2. Patients were evaluated for acute infusion-related toxicity, cytokine release syndrome (CRS), neurotoxicity, GVHD and monitored for clinical response post-infusion. T-cell receptor sequencing was conducted on the TAA-T product and the recipients' peripheral blood prior to and post-infusion to monitor persistence and expansion of the product. Results: Twenty-three BMT recipients with relapsed/refractory (n=11) and/or high-risk (n=12) acute myeloid leukemia (n=20) and acute lymphoblastic leukemia (n=3) were infused post-transplant. No patient developed CRS or neurotoxicity, and only one patient developed grade III GVHD. Of the patients who relapsed post-BMT and received bridging therapy, the majority (n=9/11) achieved complete hematologic remission before receiving TAA-T. Relapsed patients exhibited a 1-year OS of 36% and 1-year leukemia-free survival of 27.3% post-TAA-T (Figure 1A and B). The poorest prognosis patients (relapsed less than 6 months after transplant) exhibited a 1-year OS of 42.8% post-relapse (n=7) (Figure 1C). Median survival was not reached for high-risk patients who received pre-emptive TAA-T post-transplant (n=12) with eight of the nine (88.9%) evaluable patients at 1-year post-infusion remaining alive (Figure 1B). Of those, five (62.5%) were alive and in continued remission at the time of submission. Evaluation of unique T-cell receptor clonotypes (present in the product but not the recipient prior to infusion) demonstrated expansion and persistence in patients up to 1-year post-infusion (Figure 1D). Conclusions: Although as a Phase-I study, concomitant anti-leukemic therapy was allowed, TAA-T cell therapy was shown to be safe and well-tolerated with sustained remissions observed in high-risk and relapsed patients. Moreover, adoptively transferred TAA-T expanded in vivo as detected by T-cell receptor V-beta (TCRVb) sequencing persisted up to at least 1-year post-infusion (Figure 1D). (ClinicalTrials.gov numbers, NCT002203902) Figure 1 Figure 1. Disclosures Cruz: Mana Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Catamaran Bio: Consultancy, Patents & Royalties, Research Funding. Hanley: Mana Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellevolve: Consultancy; Maxcyte: Membership on an entity's Board of Directors or advisory committees. Bollard: SOBI: Honoraria, Membership on an entity's Board of Directors or advisory committees; Cabaletta Bio: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Catamaran Bio: Membership on an entity's Board of Directors or advisory committees; Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees; ROCHE: Consultancy, Honoraria; Repertoire Immune Medicines: Current equity holder in publicly-traded company; Neximmune: Current equity holder in publicly-traded company; Mana Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 33-35 ◽  
Author(s):  
Marina Kremyanskaya ◽  
Yelena Ginzburg ◽  
Andrew T. Kuykendall ◽  
Abdulraheem Yacoub ◽  
Jay Yang ◽  
...  

Background. Polycythemia vera (PV) patients are treated with periodic therapeutic phlebotomy (TP) in order to maintain hematocrit levels &lt;45% in an effort to reduce the incidence of thrombotic events [Marchioli NEJM 2013]. Since, they are seen periodically, PV patients likely spend significant time with hematocrit levels &gt;45%, thereby potentially increasing their risk of thrombosis. Symptomatic iron deficiency represents a challenge in PV as it is commonly present at diagnosis [Ginzburg Leukemia 2018] and worsens after repeated and/or frequent TP, and often symptomatic from their iron deficiency. We hypothesized that both iron deficiency and expanded erythropoiesis in PV lead to suppression of hepcidin, the body's main negative regulator of iron metabolism, and that hepcidin suppression enhances iron absorption and availability for enhanced erythropoiesis in TP-requiring PV patients. We previously demonstrated that PTG-300, a hepcidin-mimetic, caused dose-related anemia in preclinical studies. In a phase 2 trial in β-thalassemia, PTG-300 leads to a sustained (3-7 days) decrease in serum iron and transferrin saturation (TSAT) but did not demonstrate off-target effects. The current study aims to compare the iron status and phlebotomy requirements in high TP-requiring PV patients before and during treatment with PTG-300 (Figure 1). Methods. PTG-300-04 is a 3-part Phase 2 trial consisting of (1) a 28-week dose-finding; (2) a 12-week blinded randomized withdrawal (1:1) PTG-300 vs placebo; and (3) a 52-week open label extension (Figure 1). Eligibility criteria include PV diagnosis (by 2016 WHO criteria) and ≥3 phlebotomies with or without concurrent cytoreductive therapy to maintain hematocrit ≤45% in the 24 weeks prior to enrollment. PTG-300 doses of 10, 20, 40, 60 and 80 mg administered subcutaneously weekly were adjusted to maintain hematocrit &lt;45%. Results. Thirteen subjects were enrolled to date: 7/13 with low risk, mean age 57.4 years (range 31-74). Six receiving TP alone, 6 concurrent hydroxyurea, 1 on concurrent interferon; TP in the 24 weeks prior to enrollment = 3-9; median time between TP = 42 days. After instruction, each of the patients self-administered the drug at home. Eight subjects have been treated for ≥3 months with PTG-300 (Figure 2a). Three subjects have been randomized. During the open label dose finding portion of the study, all subjects were phlebotomy-free with the exception of one subject. Three subjects completed part 1 (28 weeks) with no TP as compared to 3-5 TP required in a similar period prior to study initiation. During the 28-week dose-finding period, the hematocrit was continuously controlled below 45% in all but two subjects' (Figure 2b). Two subjects had hematocrits transiently &gt;45% but remained below 45% after phlebotomy in one and dose increase in both. Furthermore, erythrocyte numbers decreased (Figure 2c) and MCV increased in all but two subjects. These findings suggest a redistribution of iron within erythropoiesis. Lastly, prior to treatment, mean iron-related parameters were consistent with systemic iron deficiency while serum ferritin increased progressively toward normal range. Most frequent adverse events were injection site reaction (ISR) reported by three patients. Most of the reactions were grade 1-2 and were transient in nature and no patient discontinued the drug. Conclusions. The current results indicate that PTG-300 is an effective agent for the treatment of PV, reversing iron deficiency and eliminating the need for TP in PV patients. Elimination of TP requirements for 7 months in TP-dependent PV patients is significant and unexpected. The effect of PTG-300 on PV-related symptoms is also being evaluated. Continued patient enrollment will enable more definitive conclusions regarding the efficacy and safety of hepcidin mimetic PTG-300 in PV patients with high TP requirements. PTG-300 looks very promising in eliminating the therapeutic phlebotomies in both low and high-risk patients. Disclosures Kremyanskaya: Incyte Corporation: Research Funding; Bristol Myers Squibb: Research Funding; Protagonist Therapeutics: Consultancy, Research Funding; Constellation Pharmaceuticals: Research Funding; Astex Pharmaceuticals: Research Funding. Kuykendall:Blueprint Medicines: Research Funding; BMS: Research Funding; Novartis: Research Funding; Incyte: Research Funding. Yacoub:Roche: Other: Support of parent study and funding of editorial support; Novartis: Speakers Bureau; Incyte: Speakers Bureau; Hylapharm: Current equity holder in private company; Cara Therapeutics: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Agios: Honoraria, Speakers Bureau; Dynavax: Current equity holder in publicly-traded company. Yang:AROG: Research Funding; AstraZeneca: Research Funding; Jannsen: Research Funding; Protagonist: Research Funding. Gupta:Protagonist: Current Employment. Valone:Protagonist: Current Employment. Khanna:Protagonist: Current Employment, Current equity holder in publicly-traded company. Verstovsek:PharmaEssentia: Research Funding; Blueprint Medicines Corp: Research Funding; Gilead: Research Funding; NS Pharma: Research Funding; Roche: Research Funding; Celgene: Consultancy, Research Funding; Genentech: Research Funding; AstraZeneca: Research Funding; Promedior: Research Funding; Novartis: Consultancy, Research Funding; Sierra Oncology: Consultancy, Research Funding; Incyte Corporation: Consultancy, Research Funding; CTI Biopharma Corp: Research Funding; Protagonist Therapeutics: Research Funding; ItalPharma: Research Funding. Hoffman:Forbius: Consultancy; Dompe: Research Funding; Protagonist: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-17
Author(s):  
M. Lia Palomba ◽  
Monika P. Jun ◽  
Jacob Garcia ◽  
James Lymp ◽  
November McGarvey ◽  
...  

Background: Chimeric antigen receptor (CAR) T cell therapy is generally limited to inpatient settings; yet, exploration of outpatient infusion and monitoring is ongoing. Information on health care resource utilization (HCRU) and costs associated with CAR T cell therapy administration is limited and may differ by postinfusion monitoring site. Liso-cel is an investigational, CD19-directed, defined composition, 4-1BB CAR T cell product administered at equal target doses of CD8+ and CD4+ CAR+ T cells. An interim analysis from the OUTREACH study (NCT03744676) observed lower HCRU with outpatient vs inpatient administration (Bachier et al. J Clin Oncol 2020;38:8037). The patient journey after CAR T cell therapy administration may differ for patients with outpatient vs inpatient monitoring and may result in varying costs of care. This study estimated the cost of postinfusion monitoring by site of care for patients with R/R LBCL who received third-line or later treatment with liso-cel in the TRANSCEND NHL 001 (TRANSCEND; NCT02631044) and OUTREACH clinical trials. Methods: This retrospective study analyzed HCRU reported in clinical trial databases from TRANSCEND and OUTREACH. A 2-step microcosting method was used to identify key HCRU and to estimate postinfusion costs: (1) HCRU was analyzed from the index date (day of liso-cel infusion) through the 6-month follow-up; and (2) costs were applied to each HCRU. HCRU included standard inpatient and intensive care unit (ICU) length of stay (LOS), diagnostics (laboratory work and imaging), procedures (dialysis and intubation), and medications (supportive care, prophylactic treatment, and adverse event management). Unit costs were obtained from the health care system (provider) perspective and adjusted to 2020 US dollars. Cost per standard inpatient day ($2,542) was estimated from Healthcare Cost and Utilization Project databases, and cost per ICU day ($7,556) was sourced from Dasta et al (Crit Care Med. 2005;33:1266-77). All medication costs were obtained from REDBOOK (IBM Micromedex) using wholesale acquisition costs. Diagnostic and procedure costs were obtained from the Centers for Medicare & Medicaid Services laboratory fee schedule, physician fee schedule, or outpatient prospective payment system. A payment-to-cost ratio was applied to Medicare payment rates to estimate unit costs. Costs were adjusted to reflect the site of care where the HCRU occurred. A cost ratio was applied to adjust costs from the physician's office/community oncology clinic to the hospital outpatient department (Winfield, Muhlestein, Leavitt Partners; 2017) and from outpatient to inpatient (Meisenberg et al. Bone Marrow Transplant. 1998;21:927-32). Costs were aggregated by HCRU category, specifically medications, diagnostics, procedures, and facility costs. An average total cost by post-liso-cel infusion month was calculated for patients with ongoing status in that month (patients censored due to data cutoff were not included). Analyses were stratified by site of postinfusion monitoring (inpatients vs outpatients). Results: A total of 303 patients with R/R LBCL across the 2 trials received liso-cel and postinfusion monitoring (inpatients, n = 256; outpatients, n = 47). HCRU and LOS, including standard inpatient and ICU days, are shown in the Table. Inpatients had higher rates of inpatient stays (&lt;100% vs 62%) and tocilizumab use (for CRS and/or NE; 20% vs 9%) than outpatients, respectively. Rates of ICU admission, corticosteroid use, vasopressor use, dialysis, and intubation were similar between groups. Median and average LOS in standard inpatient and ICU settings were higher among inpatients. Median (range) total LOS for inpatients and outpatients was 15 (0-88) and 4 (0-77) days, respectively. The estimated mean postinfusion cost of care was $89,535 for inpatients and $36,702 for outpatients. Over 6 months, most costs were incurred in the first month after infusion ($50,369 [56%] for inpatients and $19,837 [54%] for outpatients). Costs were largely driven by facility costs, namely standard inpatient and ICU stays (Figure). Conclusions: Lower overall HCRU was observed with outpatient liso-cel postinfusion monitoring, primarily due to hospitalizations, which resulted in a mean 6-month cost savings of $52,833 (59%) compared with inpatient monitoring. These results are based on national average costs and may not be generalizable to specific institutions. Disclosures Palomba: Regeneron: Research Funding; Juno Therapeutics, a Bristol-Meyers Squibb Company: Honoraria, Research Funding; Genentech: Research Funding; Merck: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Pharmacyclics: Honoraria. Jun:Bristol-Myers Squibb Company: Current Employment, Current equity holder in publicly-traded company. Garcia:Bristol-Myers Squibb Company: Current equity holder in publicly-traded company; Juno Therapeutics, a Bristol-Myers Squibb Company: Current Employment. Lymp:Bristol-Myers Squibb Company: Current equity holder in publicly-traded company; Juno Therapeutics, a Bristol-Myers Squibb Company: Current Employment. McGarvey:Pfizer, Inc.: Ended employment in the past 24 months; BluePath Solutions: Current Employment. Gitlin:BMS: Research Funding. Pelletier:BMS: Current Employment, Current equity holder in publicly-traded company. Nguyen:BluePath Solutions: Current Employment.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3113-3113 ◽  
Author(s):  
Nico Gagelmann ◽  
Francis Ayuketang Ayuk ◽  
Djordje Atanackovic ◽  
Nicolaus Kroeger

Background Cellular immunotherapies represent an enormously promising strategy for relapsed/refractory multiple myeloma (RRMM). Chimeric antigen receptor (CAR) T cells targeting B cell maturation antigen (BCMA) have shown impressive results in early-phase clinical studies. Here, we summarize the current body of evidence on the role of anti-BCMA CAR T cell therapy for RRMM. Methods We performed a systematic literature review to identify all publicly available prospective studies. We searched Medline, Cochrane trials registry, and www.clinicaltrials.gov. To include the most recent evidence, meeting abstracts from international hematology congresses were added. A conventional meta-analysis was conducted using meta and metafor packages in R statistical software. Pooled event rates and 95% confidence intervals (CIs) were calculated using the inverse variance method within a random-effects framework. Main efficacy outcomes were overall response, complete response (CR), and minimal residual disease (MRD). Furthermore, relapse rates, progression-free survival, and overall survival were evaluated. In terms of safety, outcomes were cytokine release syndrome (CRS), neurotoxicity, and hematologic toxic effects. Results Fifteen studies comprising a total of 285 patients with heavily pretreated RRMM were included in quantitative analyses. Patients received a median of seven prior treatment lines (such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, stem cell transplantation) which included autologous stem cell transplantation in 90% of patients. The median age of patients was 59 years and median follow-up duration ranged from 1.1 to 11.3 months. Most studies used 4-1BB (or CD137), a member of the TNF receptor superfamily, as an activation-induced T-cell costimulatory molecule. Most studies used fludarabine and cyclophosphamide for lymphodepletion while one study used busulfan and cyclophosphamide and one study used cyclophosphamide only. Most studies used the former Lee criteria for CRS grading. Anti-BCMA CAR T cells resulted in a pooled overall response of 82% (95% CI, 74-88%). The pooled proportion of CR in all evaluable patients was 36% (95% CI, 24-50%). Within responders, the pooled proportion of MRD negativity was 77% (95% CI, 67-85%). Higher dose levels of infused CAR+ cells were associated with higher overall response rates resulting in a pooled proportion of 88% (95% CI, 78-94%). In addition, peak CAR T cell expansion appeared to be associated with responses.The presence of high-risk cytogenetics appeared to be associated with lower overall response rates resulting in a pooled proportion of 68% (95% CI, 47-83%). The presence of extramedullary disease at time of infusion did not influence outcome and was associated with similar response rates compared with RRMM patients who did not have extramedullary disease, resulting in a pooled proportion of 78% (95% CI, 47-93%). The pooled relapse rate of all responders was 45% (95% CI, 27-64%) and the median progression-free survival was 10 months. In terms of overall survival, pooled survival rates were 84% (95% CI, 60-95%) at last follow-up (median, 11 months). In terms of safety, the pooled proportion of CRS of any grade was 69% (95% CI, 51-83%). Notably, the pooled proportions of CRS grades 3-4 and neurotoxicity were 15% (95% CI, 10-23%) and 18% (95% CI, 10-31%). Peak CAR T cell expansion appeared to be more likely in the setting of more severe CRS in three studies. Most hematologic toxic effects of grade 3 or higher were neutropenia (85%), thrombocytopenia (70%), and leukopenia (60%). Conclusion Anti-BCMA CAR T cells showed high response rates, even in high-risk features such as high-risk cytogenetics and extramedullary disease at time of CAR T cell infusion. Toxicity was manageable across all early-phase studies. However, almost half of the patients who achieved a response eventually relapsed. Larger studies with longer follow-up evaluating the association of response and survival are needed. Disclosures Ayuk: Novartis: Honoraria, Other: Advisory Board, Research Funding. Kroeger:Medac: Honoraria; Sanofi-Aventis: Honoraria; Neovii: Honoraria, Research Funding; Riemser: Research Funding; JAZZ: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; DKMS: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1464-1464 ◽  
Author(s):  
Allison Barz Leahy ◽  
Kaitlin J. Stanley ◽  
Regina M. Myers ◽  
Amanda M. DiNofia ◽  
Lisa Wray ◽  
...  

Background: CTL019 is a therapy derived from autologous T cells expressing a CD19-specific chimeric antigen receptor (CAR) that was approved by the FDA in August 2017 (tisagenlecleucel). Complete and durable remissions have been seen in the setting of pediatric and young adult patients with relapsed and refractory B cell acute lymphoblastic leukemia (ALL) (Maude NEJM 2018). Initial case reports suggested that there may be differential outcomes mediated by cytogenetic characteristics of the leukemia at CAR T cell infusion. Here, we report results from a single institution experience of 112 patients. Methods: Patients with relapsed/refractory ALL were identified as having received CTL019 either in the context of a clinical trial (NCT02906371) or commercial product (tisagenlecleucel) at Children's Hospital of Philadelphia from October 2016 to April 2019. Patients who received prior CAR T therapy were excluded. Demographic, cytogenetic, and outcome data were manually abstracted from the medical record or clinical trial datasets. High risk lesions were defined as MLL(KMT2A) rearrangements, Philadelphia-chromosome (Ph+), Ph-like, hypodiploidy, and TCF3/HLF fusion. Favorable cytogenetics were defined as the presence of hyperdiploidy or ETV6/RUNX1fusion and intermediate were defined as iAMP21, IKZF1deletion, or TCF3/PBX1. Patients were classified according to their highest risk cytogenetic characteristic and stratified by cytogenetic risk category present at CAR T cell infusion. Relapse-free survival (RFS) and overall survival (OS) was described for cohorts with more than 10 patients. Results: One hundred and twelve patients were included in the analysis, with a median age of 11 years (range 1-29) at infusion, of which 32% had had a previous allogeneic hematopoietic stem cell transplant (alloHSCT). Disease burden at the time of CTL019 infusion was heterogenous, with 61% having detectable disease in the bone marrow and 21% having more than 25% blasts by flow cytometry. Thirty-six patients (32%) had leukemias with high-risk genetic lesions at infusion, including 12 with MLL rearrangements and 18 with Ph+ or Ph-like lesions (Table 2). Thirty-one patients (28%) had hyperdiploidy or ETV6/RUNX1; 3 additional were in conjunction with high-risk cytogenetics (t(17;19) and 2 with Ph+), and 3 in the setting of intermediate-risk cytogenetics (iAmp21, TCF3/PBX1, IKZF1deletion). Figure 1 demonstrates RFS for those patients in remission at day 28 following infusion, stratified by cytogenetic risk category. Complete remission (CR) rate in the high-risk cytogenetics group was 94%. RFS at 12 months was 69% (0.50-0.82), 69% (0.40-0.86), and 67% (0.48-0.80) for non-informative, favorable, and high-risk cytogenetic groups, respectively. Figure 2 shows OS of patients infused with CTL019, again stratified by cytogenetic categories of interest, with a maximum follow-up time of 30 months. OS at 12 months was 84% (0.68-0.93) and 76% (0.56-0.88) for the non-informative and high-risk cytogenetic groups, respectively. There were no deaths in that time period for the favorable risk category. There was no statistically significant difference in RFS or OS for patients with high-risk cytogenetics. The intermediate-risk cytogenetics group (n&lt;10) was excluded from these analyses. Conclusion: Durable remissions can be achieved with CTL019 across several high-risk cytogenetic subtypes of B-ALL. Stratifying outcomes by cytogenetic risk category in this unadjusted analysis does not show a statistically significant difference in either RFS nor OS. Further investigation is needed to parse out the contribution of individual cytogenetic lesions as well as the effects of other relapse and survival risk factors at play. Figure Disclosures Rheingold: Novartis: Consultancy; Pfizer: Research Funding. Callahan:Novartis: Consultancy. Hunger:Bristol Myers Squibb: Consultancy; Amgen: Consultancy, Equity Ownership; Jazz: Honoraria; Novartis: Consultancy. Grupp:Novartis: Consultancy, Research Funding; Roche: Consultancy; GSK: Consultancy; Cure Genetics: Consultancy; Humanigen: Consultancy; CBMG: Consultancy; Novartis: Research Funding; Kite: Research Funding; Servier: Research Funding; Jazz: Other: study steering committees or scientific advisory boards; Adaptimmune: Other: study steering committees or scientific advisory boards. Maude:Kite: Consultancy; Novartis: Consultancy.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 22-23
Author(s):  
Tanya Siddiqi ◽  
Ulrich Jaeger ◽  
Olga Moshkovich ◽  
Jennifer Devlen ◽  
Matthew Miera ◽  
...  

Background: Chimeric antigen receptor (CAR) T cell therapy is a novel treatment modality for patients with R/R LBCL. Limited information exists regarding patients' views of CAR T cell therapy. Our research aimed to better understand patients' needs by capturing their expectations/concerns, current well-being, and treatment experiences during the beginning stages of CAR T cell therapy in the clinical trial setting. Methods: Patients with R/R LBCL from 2 ongoing trials of the investigational, CD19-directed CAR T cell therapy liso-cel (TRANSCEND WORLD [NCT03484702] or PLATFORM [NCT03310619]) were invited to participate in an optional interview component. Semistructured interviews were conducted to gain insight about patients' experience with CAR T cell therapy in the clinical trials. Interviews of ≤1 hour (in-person or over the phone) were conducted in parallel with screening procedures (interview 1), after leukapheresis (interview 2), and up to 3 days after liso-cel infusion (interview 3). Interviews were audio recorded and transcribed. MAXQDA (VERBI GmbH, Berlin, Germany) qualitative analysis software was used to manage and thematically organize interview transcript data to identify key concepts related to each research objective. Previously reported results of interview 1 showed a high perception of unmet needs, lack of alternative options, and expectations for positive outcomes. The analysis presented here primarily focused on interviews 2 and 3. Denominators shown in the Results vary by question as some patients skipped questions. Results: A total of 75 interviews were analyzed, including 35, 24, and 16 patients at interviews 1, 2, and 3, respectively, across sites in the US (n = 14), Europe (n = 26), and Japan (n = 2). Among 42 patients who completed ≥1 interview, the mean age was 62 years and 69% were male. Treatment Experience: Of 24 patients who completed interview 2, 22 (92%) reported positive experiences during leukapheresis and 16 (67%) reported the procedure was as expected. Patients thought the most difficult part of leukapheresis was the length of the procedure (n = 8/21 [38%]). Of 15 patients who provided feedback on lymphodepleting chemotherapy, a majority reported that it was as expected (n = 8 [53%]) or easier than expected (n = 3 [20%]); when asked about the most difficult part, many patients (n = 7/17 [41%]) discussed side effects (eg, nausea, fatigue, and lack of appetite). Of patients who described liso-cel infusion as different than expected, differences included easier (n = 12/13 [92%]) or quicker (n = 3/12 [25%]) than expected, and 5/12 (42%) reported few/no side effects within 3 days post-infusion. Over half of patients (n = 8/14 [57%]) reported that the infusion, as a whole, was not difficult. Changes over Time: At interviews 1, 2, and 3, respectively, 47% (n = 14/30), 47% (n = 9/19), and 69% (n = 9/13) of patients reported hoping for successful treatment. Similarly, patients generally had fewer concerns later in the process, with 21 (64%) and 11 (33%) of 33 patients reporting side-effect and treatment efficacy concerns, respectively, during interview 1 vs 5 (33%) and 3 (20%) of 15 patients, respectively, during interview 3. At time of enrollment, most patients (n = 21/34 [62%]) were able to function normally or with minimal impact from their lymphoma, although most reported some symptoms like fatigue, pain, or stomach problems. At interview 1, 14 (40%) of 35 patients were employed; most patients reported no changes in their work life at interviews 2 (n = 19/20 [95%]) and 3 (n = 11/12 [92%]). From enrollment to immediately post-infusion, the physical health of most patients remained stable (n = 4/16 [25%]) or deteriorated (n = 9/16 [56%]). However, most patients (n = 14/15 [93%]) reported feeling positive at interview 3. Conclusions: This study provided the unique opportunity to gather feedback directly from patients participating in clinical trials of liso-cel therapy, specifically during the initial treatment stages. The overall impression of the treatment was positive, with most patients reporting that study procedures were easier than expected. The results of this qualitative research provide useful insight into the motivations, expectations, and experiences of patients with R/R LBCL receiving liso-cel therapy, which can inform the design of health care support systems and future clinical trials to better meet patients' needs. Disclosures Siddiqi: AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding; Juno: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Oncternal: Research Funding; TG Therapeutics: Research Funding; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau. Jaeger:F. Hoffmann-La Roche: Honoraria, Research Funding; AbbVie: Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Karyopharm: Honoraria; CDR Life AG: Consultancy, Research Funding; Miltenyi: Consultancy, Honoraria. Moshkovich:Icon Plc: Current Employment. Devlen:Icon Plc: Current Employment, Current equity holder in publicly-traded company. Miera:Icon Plc: Current Employment. Williams:Icon Plc: Current Employment. Hasskarl:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Liu:Bristol-Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Braverman:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Salles:MorphoSys: Consultancy, Honoraria, Other; Kite: Consultancy, Honoraria, Other; Debiopharm: Consultancy; Novartis: Consultancy, Honoraria, Other; Janssen: Consultancy, Honoraria, Other: Participation in educational events; Gilead: Consultancy, Honoraria, Other: Participation in educational events; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Other; Epizyme: Consultancy; Takeda: Consultancy, Honoraria, Other; Bristol Myers Squibb: Consultancy, Other; Karyopharm: Consultancy; Amgen: Honoraria, Other: Participation in educational events; Celgene: Consultancy, Honoraria, Other: Participation in educational events; Abbvie: Consultancy, Honoraria, Other: Participation in educational events; Autolus: Consultancy; Genmab: Consultancy.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-30
Author(s):  
Sjoukje van der Stegen ◽  
Pieter Lindenbergh ◽  
Roseanna Petrovic ◽  
Benjamin Whitlock ◽  
Raedun Clarke ◽  
...  

Chimeric Antigen Receptor (CAR) T cells are a new treatment paradigm for relapsed/refractory hematopoietic malignancies. However, their autologous nature imposes manufacturing constraints that can delay CAR T cell availability and increase their cost. We previously established proof of principle that αβ T cell-derived induced pluripotent stem cells (TiPSCs) can provide a self-renewing source for in vitro CAR T cell production (Themeli, Nat Biotechnol, 2013). The use of cloned TiPSC further enhances the feasibility of verifying genome integrity of the genetically engineered stem cells and should in principle yield highly homogenous cell products. Using αβ T cell-derived TiPSCs transduced with a well-defined CD19-specific CAR (1928z; Park, NEJM, 2018), we previously demonstrated that TiPSCs can be differentiated into CAR T cells. These T cells retained their endogenous T cell receptor (TCR) and also displayed characteristics of innate lymphoid cells. We have now examined how the timing of CAR expression as well as the CAR signaling strength influence T cell lineage commitment, enabling better control towards αβ T cell lineage commitment. αβ T cell lineage development depends in part on a precisely orchestrated interactions between NOTCH and (pre)TCR signaling, the timing and strength of which are crucial for αβ lineage commitment. Because TiPSCs harbor rearranged TCRα and TCRβ genes, mature TCR expression occurs earlier than if it required VDJ recombination, skewing differentiation towards acquiring innate features including CD4-CD8- double-negative or CD8αα single-positive phenotypes. We show that providing strong NOTCH stimulation counteracts the effects of early antigen receptor expression, facilitating CD4+CD8αβ+ double positive (DP) formation. We hypothesized that CAR signaling in the absence of ligand binding (tonic signaling) may mimic a TCR signal, the strength and timing of which could re-direct lineage commitment. We therefore investigated CARs providing different levels of signaling strength and the impact of delaying the onset of CAR expression. Tonic CAR signaling was measured in peripheral blood T cells expressing 1928z or 1928z-1XX, a construct in which the second and third ITAM in the CD3ζ domain have been mutated to be non-functional (Feucht, Nat Med, 2019), following either retroviral transduction (SFG vector) orTRAC-targeted cDNA integration, placing CAR expression under the transcriptional control of the TCRα promoter (Eyquem, Nature, 2017). CAR signaling in the absence of antigen exposure, measured by phosphorylation of ITAM3, ERK1/2 and ZAP70, was reduced by bothTRAC-targeting and reduction of functional ITAMs, with additive effects when combined inTRAC-1928z-1XX. Three of these engineering strategies (virally expressed 1928z,TRAC-1928z andTRAC-1928z-1XX) were evaluated in the context of TiPSC-derived T cell differentiation. Virally expressed 1928z (resulting in constitutive CAR expression throughout differentiation) resulted in the predominant generation of innate-like CD8αα T cells, associated with the absence of early T cell lineage markers such as CD5, CD2 and CD1a. Delayed expression of 1928z throughTRACtargeting resulted in increased CD5, CD2 and CD1a, but did not yield any more CD4+CD8αβ+ DP cells. In TiPSC expressingTRAClocus-encoded 1928z-1XX, a greater DP population emerged, from which CD8αβ single-positive T cells could be induced. Phenotypic analyses of clonal TRAC-1928z-1XX TiPSC lines further establish the interplay between CAR and NOTCH1 in determining αβ lineage commitment. Together these data show that early TCR and CAR expression skew T cell lineage commitment towards an innate-like T cell fate, which can be overcome by controlling the strength and timing of NOTCH, TCR and CAR signaling. These studies pave the way for the predetermined generation of a variety of CAR T cell types endowed with different functional attributes. Disclosures Whitlock: Fate Therapeutics Inc.:Current Employment, Current equity holder in publicly-traded company.Clarke:Fate Therapeutics Inc.:Current Employment, Current equity holder in publicly-traded company.Valamehr:Fate Therapeutics, Inc:Current Employment, Current equity holder in publicly-traded company.Riviere:Juno Therapeutics:Other: Ownership interest, Research Funding;Takeda:Research Funding;Fate Therapeutics Inc.:Consultancy, Other: Ownership interest , Research Funding;FloDesign Sonics:Consultancy, Other: Ownership interest;Atara:Research Funding.Sadelain:Atara:Patents & Royalties, Research Funding;Fate Therapeutics:Patents & Royalties, Research Funding;Mnemo:Patents & Royalties;Takeda:Patents & Royalties, Research Funding;Minerva:Other: Biotechnologies , Patents & Royalties.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Michela Cioni ◽  
Christian Mittelholzer ◽  
Marion Wernli ◽  
Hans H. Hirsch

Background. Among human polyomaviruses, only BK virus (BKV) and JC virus (JCV) encode an agnoprotein upstream of VP1 on the viral late transcript. BKV agnoprotein is abundantly expressed late in the viral life cycle, but specific cellular and humoral immune responses are low or absent. We hypothesized that agnoprotein might contribute to BKV immune evasion by downregulating HLA expression, similar to Herpes simplex virus-1 ICP47. Methods UTA-6 or primary human renal proximal tubular epithelial cells (RPTEC) were co-transfected with plasmids constitutively expressing agnoprotein, or ICP47, and enhanced green-fluorescent protein (EGFP). EGFP-gated cells were analyzed for HLA-ABC and HLA-DR expression by flow cytometry. HLA-ABC and HLA-DR expression was also analyzed on UTA-6 bearing tetracycline-regulated agnoprotein or ICP47. Effects of agnoprotein on viral peptide-dependent T-cell killing were investigated using51Cr release.Results. ICP47 downregulated HLA-ABC without affecting HLA-DR, whereas agnoprotein did not affect HLA-ABC or HLA-DR expression. Interferon-γtreatment increased HLA-ABC in a dose-dependent manner, which was antagonized by ICP47, but not by agnoprotein. In UTA-6 cells, agnoprotein expression did neither impair HLA-ABC or -DR expression nor peptide-specific killing impaired by HLA-matched T-cells.Conclusion. Unlike the HSV-1 ICP47, BKV agnoprotein does not contribute to viral immune evasion by down-regulating HLA-ABC, or interfere with HLA-DR expression or peptide-dependent T-cell cytotoxicity.


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