Lentiviral globin gene therapy with reduced-intensity conditioning in adults with β-thalassemia: a phase 1 trial

2022 ◽  
Author(s):  
Farid Boulad ◽  
Aurelio Maggio ◽  
Xiuyan Wang ◽  
Paolo Moi ◽  
Santina Acuto ◽  
...  
Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3970-3970
Author(s):  
Michael Grimley ◽  
Monika Asnani ◽  
Archana Shrestha ◽  
Sydney Felker ◽  
Carolyn Lutzko ◽  
...  

Abstract Introduction: Sickle cell disease (SCD) is a genetic red blood cell (RBC) disorder that causes chronic hemolytic anemia, progressive organ damage, and life-threatening acute complications such as painful vaso-occlusive crises. Allogeneic hematopoietic stem cell transplant (allo-HSCT) with myeloablative conditioning remains the only curative therapy for SCD but has several limitations including low donor availability and conditioning-related toxicity. Genetic modification of autologous hematopoietic system cells (HSCs) with reduced-intensity conditioning (RIC) using a high-potency drug product may address these limitations. ARU-1801 is a gene therapy that uses a modified γ-globin lentiviral vector to produce HbF G16D within autologous CD34+ HSCs. Preclinical studies in SCD mice have shown the G16D mutation enables γ-globin G16D to bind α-globin with higher affinity; lentiviral transfer of γ-globin G16D resulted in 1.5-2x more HbF per vector copy number (VCN) compared to analogous wild-type γ-globin vector. Early studies also suggested HbF G16D may be more potent for anti-sickling than HbF, lowering reticulocyte counts in SCD mice to a greater extent at similar protein levels. We hypothesize ARU-1801 with RIC could lessen toxicities and resource utilization relative to myeloablative approaches, allowing expanded access to gene therapy for a broader group of SCD patients. Updated data from patients in the ongoing Phase 1/2 study (NCT02186418) including laboratory and clinical markers of efficacy are presented here. Methods: Adults (18-45 years old) with severe SCD (defined by recurrent vaso-occlusive events [VOE] and acute chest syndrome) were screened for eligibility. Prior to ARU-1801 drug product (DP) infusion, all patients received a single IV dose of RIC melphalan (140 mg/m 2). Endpoints included measures of safety, engraftment, VCN, hemoglobin sub-fractions, and SCD-related outcomes. Patients were weaned off transfusions 3-6 months after DP infusion. Levels of anti-sickling globins (including HbF G16D) are presented as proportions of non-transfused total hemoglobin. Results: As of 28 July 2021, four patients (mean, 26 [19-35] years old) have been treated with ARU-1801 gene therapy for SCD with three patients followed for ≥12 months post-transplant. Transient neutropenia and thrombocytopenia were the predominant adverse events, lasting a median seven days each. There have been no other serious adverse events related to chemotherapy or ARU-1801 to date. At 36 months post-transplant, Patient 1 has shown stable HbF expression (27%) and 64% F-cells. Patient 2 has maintained 14% HbF and 37% F-cells at 36 months despite lower engraftment of ARU-1801 due to renal hyperfiltration (eGFR = 200 mL/min/1.73 m 2) at time of conditioning, which resulted in lower melphalan exposure. Both patients saw marked improvements in SCD manifestations, including 93% and 85% fewer annualized VOEs, respectively, in the two years after receiving ARU-1801 gene therapy compared to two years prior. Patient 3 received ARU-1801 manufactured with several process modifications (including improvements of HSC collection timing and lentiviral production) and has maintained 36% HbF at month 15 with pancellular distribution (96% F-cells). To date, Patient 3 has had no VOEs since ARU-1801 administration, representing 100% reduction from baseline. Conclusion: Amelioration of SCD phenotype and engraftment of ARU-1801 gene-modified HSCs is possible with a single RIC dose of melphalan, as demonstrated in three patients. The first patient shows 27% HbF expression at three years, and 93% reduction in VOEs. The second patient had lower HSC engraftment due to below-target melphalan exposure (likely caused by renal hyperfiltration), with 14% HbF and 5% HbA2 at three years. Nonetheless, an 85% reduction in VOEs in Patient 2 demonstrates significant clinical benefit. Dose-adjusted melphalan has the potential to improve engraftment in SCD patients with renal hyperfiltration. Following manufacturing process improvements, the third patient has shown the highest HbF (36%) at one year, the highest F-cells (96%), and no VOEs since receiving ARU-1801. ARU-1801, with RIC melphalan conditioning, is a promising alternative to myeloablative transplants for achieving durable responses with a favorable safety profile in patients with severe SCD. Longer follow-up and additional patients will be presented. Figure 1 Figure 1. Disclosures Asnani: Avicanna Ltd.: Research Funding; Aruvant Sciences: Research Funding. Lutzko: Aruvant Sciences: Patents & Royalties: preclinical vector development. Quinn: Forma Therapeutics: Consultancy; Emmaus Medical: Research Funding; Novo Nordisk: Consultancy; Aruvant: Research Funding. Lo: Aruvant Sciences: Current Employment. Little: Aruvant Sciences: Current Employment. Dong: Aruvant Sciences: Current Employment. Malik: Aruvant Sciences: Consultancy; Forma Therapeutics: Consultancy; Aruvant Sciences: Patents & Royalties; CSL Behring: Patents & Royalties. OffLabel Disclosure: Plerixafor was used for stem cell mobilization. Melphalan was used as chemotherapy conditioning prior to autologous transplant with ARU-1801


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-21
Author(s):  
Michael Grimley ◽  
Monika Asnani ◽  
Archana Shrestha ◽  
Sydney Felker ◽  
Carolyn Lutzko ◽  
...  

Introduction: ARU-1801 is a gene therapy consisting of autologous CD34+ hematopoietic stem cells and progenitors (HSCPs) transduced with a lentiviral vector (LV) encoding a modified γ-globinG16D gene. Preclinical studies in SCD mice have shown that g-globinG16D binds α-globin with higher affinity; hence, the g-globinG16D LV produces 1.5-2x more HbF/vector copy number (VCN) than a g-globin LV. Preliminary studies also show greater reduction in reticulocytes in SCD mice expressing HbFG16D compared to those expressing the same level of HbF, suggesting that HbFG16D may have a more potent anti-sickling effect than HbF. We hypothesized a high potency anti-sickling globin would allow ARU-1801 to be effective with reduced intensity conditioning (RIC). RIC would result in lower toxicities and resource utilization compared to myeloablative approaches, allowing access of gene therapy to a broader group of SCD patients. We previously reported early data from patient 1 (P1) and 2 (P2) in the ongoing Phase 1/2 study (NCT02186418), who were treated with drug product (DP) from the initial ARU-1801 manufacturing process (Process I). We now present the long-term data on these patients and early data from P3, the first patient treated with our new manufacturing process (Process II). Methods: Adults with severe SCD, as defined by recurrent vaso-occlusive events (VOE) and acute chest syndrome deemed eligible were enrolled. Manufacturing process improvements in Process II included optimized timing of HSCP collection after plerixafor mobilization, LV production and improved HSCP transduction. Prior to DP infusion, all patients received a single dose of IV melphalan (140 mg/m2 BSA) and were weaned off transfusions 3-6 months after DP infusion. Patients were monitored for safety, engraftment, VCN, anti-sickling Hb (ASG) expression, and hematological and clinical manifestations of SCD. Levels of ASG (including HbFG16D) are presented as fractions of endogenous Hb. Results: As of 28 July 2020, data from 3 patients treated with ARU-1801 are available. P1 (34yr old) has HbSβ0- and P2 (24yr old) has HbSβ+ thalassemia (2-3% HbA). Both have 30 months (mo) post-transplant (PT) follow up. P3 (19yr old) has HbSS genotype with 6 mo PT follow up. ARU-1801 demonstrated a favorable safety profile with no treatment-related adverse events to date. Time to neutrophil engraftment (ANC ≥500) was 9, 7, and 7 days PT, and time to platelet recovery (Plt >50,000) was 12, 7, and 6 days PT, in P1, P2, and P3, respectively. Figure 1 shows HSPC dose, conditioning exposure and gene transfer; Figure 2 shows ASG over time. Using Process I, P1 has shown stable expression of 20% HbFG16D, 31% ASG and 31%à64% F-cells over 2.5 years, despite a low DP VCN of 0.2 and low HSPC dose of 1.4 x106 cell/kg. P2 received a higher cell dose of 7.1 x106 cell/kg with a DP VCN of 0.47 but had below target melphalan exposure, likely due to rapid clearance from hyperfiltration (GFR= 200 mL/min/1.73m2). Despite lower engraftment and HbFG16D level, P2 maintains stable total ASG of 22% at 30 mo due to a compensatory increase in HbF. Using Process II, P3 received DP of 6.8 x106 cells/kg with a VCN of 1.0, and demonstrated an engrafted VCN of 0.74, 71% F-cells and 91% F-reticulocytes at 6 mo. As P3 is being weaned off transfusions, HbFG16D is progressively rising, showing the selective advantage to HbFG16D-containing RBCs. P1 and P2 have maintained improvements in VOEs, no VOE in P3 so far (data will be presented). Conclusion: We show that engraftment of ARU-1801 and amelioration of disease is possible with RIC using IV melphalan, with persistent stable ASG expression and meaningful improvement in VOEs in P1 and P2. P1 shows stable HbFG16D and high ASG despite low, albeit stable VCN. P2 had lower HSCP engraftment, which we hypothesize was due to below target melphalan exposure. Nevertheless, significant clinical benefit was observed in P2 due to stable ASG of 22% at mo 30. It is likely that the presence of this amount of HbFG16D has provided enough ASG to prevent sickling/ineffective erythropoiesis, resulting in the preferential survival of HbF+HbFG16D-expressing RBC. Process II DP in P3 resulted in 2-4X higher engraftment of transduced HSCPs at 6 mo. Additional process enhancements are under development for future treated patients. ARU-1801, administered with RIC, holds significant promise for achieving durable responses with a favorable safety profile in patients with severe SCD. Disclosures Asnani: Aruvant Sciences: Research Funding; Avicanna Ltd.: Research Funding. Lutzko:Aruvant Sciences: Patents & Royalties: pre-clinical vector development. Lo:Aruvant Sciences: Current Employment. Little:Aruvant Sciences: Current Employment. McIntosh:Aruvant: Current Employment, Current equity holder in private company. Malik:Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents & Royalties. OffLabel Disclosure: Plerixafor - stem cell mobiliziation Melphalan - chemotherapy conditioning pre autologous transplant with ARU-1801


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1176-1176 ◽  
Author(s):  
Julie Kanter ◽  
Mark C. Walters ◽  
Matthew M. Hsieh ◽  
Lakshmanan Krishnamurti ◽  
Janet Kwiatkowski ◽  
...  

Abstract β-globin gene transfer into hematopoietic stem cells (HSCs) has the potential to reduce or eliminate the symptoms and long-term complications of severe sickle cell disease (SCD). LentiGlobin Drug Product (DP) is a gene therapy product containing autologous CD34+ cells transduced with the BB305 lentiviral vector. BB305 encodes a human β-globin gene containing a single point mutation (AT87Q) designed to confer anti-sickling properties similar to those observed in fetal hemoglobin (γ-globin). In two ongoing studies, subjects with transfusion-dependent β-thalassemia (Studies HGB-204 and HGB-205) or SCD (Study HGB-205) receiving LentiGlobin DP have demonstrated sustained expression of 3-9 g/dL therapeutic hemoglobin (HbAT87Q) and have shown marked improvements in clinical symptoms 1 year post-treatment. Study HGB-206 is a multi-center, Phase 1/2 safety and efficacy study of LentiGlobin DP in adults with severe SCD. We previously (ASH 2015) presented results from 2 subjects, who had 3 and 6 months of follow-up after LentiGlobin treatment. We now present data from 7 treated subjects, 4 of whom have ≥6 months of follow-up data. Subjects (≥18 years of age) with severe SCD (history of recurrent vaso-occlusive crisis [VOC], acute chest syndrome, stroke, or tricuspid regurgitant jet velocity of >2.5 m/s) were screened for eligibility. Following bone marrow harvest (BMH), CD34+ cells were transduced with the BB305 vector. Subjects underwent myeloablative conditioning with busulfan prior to infusion of the transduced cells. Safety assessments include adverse events (AEs), integration site analysis (ISA) and surveillance for replication competent lentivirus (RCL). After infusion, subjects are monitored for hematologic engraftment, vector copy number (VCN), HbAT87Q expression, and other laboratory and clinical parameters. As of July 2016, 7 subjects with severe SCD (median age: 26 years, range 18-42 years) have received LentiGlobin DP in this study. All subjects successfully underwent BMH, with a median of 2 harvests required (range 1-4). Fifteen Grade 3 AEs in 5 subjects were attributed to BMH: pain (n=10), anemia (n=3) and VOC (n=2); all resolved with standard measures. Table 1 summarizes cell harvest, DP characteristics, and lab results. The median LentiGlobin DP cell dose was 2.1x10e6 CD34+ cells/kg (range 1.6-5.1) and DP VCN was 0.6 (0.3-1.3) copies/diploid genome. Median post-infusion follow-up as of July 2016 is 7.1 months (3.7-12.7 months). All subjects successfully engrafted after receiving LentiGlobin DP, with a median time to neutrophil engraftment of 22 days (17-29 days). The toxicity profile observed from start of conditioning to latest follow-up was consistent with myeloablative conditioning with single-agent busulfan. To date, there have been no DP-related ≥Grade 3 AEs or serious AEs, and no evidence of clonal dominance or RCL. The BB305 vector remains detectable at low levels in the peripheral blood of all subjects infused, with median VCN 0.08 (0.05-0.13, n=7) at last measurement. All subjects express HbAT87Q, with a median of 0.4g/dL (0.1-1.0 g/dL, n=7) at 3 months; most subjects demonstrated modest increases over time, and the 2 subjects with the longest follow-up expressed 0.31 and 1.2 g/dL HbAT87Q at 9 months. All 4 subjects with ≥6 months of follow-up experienced multiple VOCs in the 2 years prior to study entry (2-27.5 VOCs annually). Since LentiGlobin DP infusion, 3 of these 4 subjects have had fewer VOCs, although this trend may be confounded by the short follow-up, the effects of transplant conditioning, and/or post-transplant RBC transfusions. The decrease in VCN between DP and peripheral cells contrasts with previous reports of successful LentiGlobin gene therapy in ongoing studies HGB-204 and HGB-205. The relatively low in vivo VCN in this study appears to result in the lower HbAT87Q expression seen to date. We are exploring multiple hypotheses as to the etiology of the VCN drop between DP and peripheral blood, including the adverse impact of sickle marrow pathology on HSCs, the adequacy of myeloablation, and the magnitude of the transduced cell dose. We will provide an update on study data and ongoing efforts to increase in vivo VCN in patients with SCD, such as increasing the transduced cell dose through alternate HSC procurement methods or enhancing the DP VCN through manufacturing improvements. Disclosures Kanter: Novartis: Consultancy. Walters:Bayer HealthCare: Honoraria; AllCells, Inc./LeukoLab: Other: Medical Director ; ViaCord Processing Laboratory: Other: Medical Director ; Leerink Partners, LLC: Consultancy; Kiadis Pharma: Honoraria; bluebirdBio, Inc: Honoraria. Kwiatkowski:Ionis pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Shire Pharmaceuticals: Consultancy; Sideris Pharmaceuticals: Consultancy; Apopharma: Research Funding; Luitpold Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. von Kalle:bluebird bio: Consultancy; GeneWerk: Equity Ownership. Kuypers:Children's Hospital Oakland Research Institute: Employment; bluebird bio: Consultancy. Leboulch:bluebird bio: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding. Joseney-Antoine:bluebird bio: Employment, Equity Ownership. Asmal:bluebird bio: Employment, Equity Ownership. Thompson:bluebird bio: Consultancy, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Amgen: Research Funding; Baxalta (now part of Shire): Research Funding; ApoPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mast: Research Funding; Eli Lily: Research Funding.


2019 ◽  
Vol 85 (5) ◽  
pp. 704-714 ◽  
Author(s):  
Chadwick W. Christine ◽  
Krystof S. Bankiewicz ◽  
Amber D. Van Laar ◽  
R. Mark Richardson ◽  
Bernard Ravina ◽  
...  

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 990-990 ◽  
Author(s):  
Julie Kanter ◽  
John F. Tisdale ◽  
Markus Y. Mapara ◽  
Janet L. Kwiatkowski ◽  
Lakshmanan Krishnamurti ◽  
...  

Background β-globin gene transfer into hematopoietic stem cells (HSCs) could reduce or eliminate sickle cell disease (SCD)-related manifestations. LentiGlobin for SCD gene therapy contains autologous CD34+ cells transduced with the BB305 lentiviral vector (LVV), encoding a human β-globin gene with the anti-sickling T87Q mutation (βA-T87Q). The safety and efficacy of LentiGlobin for SCD is being evaluated in the ongoing Phase 1/2 HGB-206 Study (NCT02140554). The initial 7 patients (Group A) were treated with LentiGlobin made from bone marrow harvested HSCs. The protocol was modified to improve HbAT87Q production by including pre-harvest red blood cell (RBC) transfusions, increasing the total busulfan exposure, and using a refined LentiGlobin manufacturing process (Group B, n=2). An additional modification was made for Group C patients where HSC collection by plerixafor mobilization followed by apheresis was instituted. Data from these Group C patients are discussed here. Results from patients in Groups A and B are reported separately. Methods Patients (≥ 18 years) with severe SCD (including those with recurrent vaso-occlusive crisis [VOC] and acute chest syndrome [ACS]) were screened for eligibility. Patients received 240 µg/kg of plerixafor 4-6 hours prior to HSC collection via apheresis. CD34+ cells were transduced with BB305 LVV. Patients underwent myeloablative busulfan conditioning and subsequent LentiGlobin drug product (DP) infusion. Patients were monitored for adverse events (AEs), engraftment, vector copy number (VCN), total hemoglobin (Hb) and HbAT87Q expression, hemolysis markers, and SCD clinical manifestations. Data are presented as median (min-max). Results: As of 7 March 2019, 19 Group C patients, aged 26 (18-36) years, had initiated mobilization/apheresis and 13 patients were treated with LentiGlobin for SCD gene therapy. Median DP VCN, % transduced cells, and CD34+ cell dose in the 13 treated patients were: 3.8 (2.8-5.6) copies/diploid genome (c/dg), 80 (71-88) %, and 4.5 (3.0-8.0) x 106 CD34+ cells/kg, respectively. The median follow-up was 9.0 (1.0-15.2) months. Twelve patients achieved neutrophil and platelet engraftments at a median of 19 (15-24) days and 28 (19-136) days, respectively. As of the data cut-off, engraftment was not yet evaluable in 1 patient at 1-month post-infusion. All patients stopped red blood cell (RBC) transfusions within about 3 months post-LentiGlobin gene therapy. Median total hemoglobin (Hb) and Hb fractions in patients at various time points are shown in Figure 1. Median HbS levels were at or below 50% in all patients with at least 6 months follow-up. The median total Hb at last visit in 8 patients with at least 6 months of follow-up, was 11.5 (10.2-15.0) g/dL, with a corresponding HbAT87Q median contribution of 5.3 (4.5-8.8) g/dL and a median HbS 5.7 (4.8-8.0) g/dL. Of these 8 patients, 6 had a history of VOCs or ACS. The median annualized VOC+ACS rate in these patients was 5.3 (3-14) pre-treatment and decreased to 0 (0-2) post-treatment. One Grade 2 VOC was observed 3.5 months post-treatment. No ACS or serious VOCs were observed in Group C patients' post- treatment. Lactate dehydrogenase, reticulocyte count, and total bilirubin at last visit post-LentiGlobin infusion were 225.0 (130.0-337.0) U/L, 150.0 (42.1-283.0) 109/L, 22.2 (3.42-39.3) µmol/L, respectively, trending towards normalization. The most common non-hematologic Grade ≥ 3 AEs were febrile neutropenia (n=10) and stomatitis (n=7) post-DP infusion. Serious AEs were reported in 6 patients post-LentiGlobin treatment, most common being nausea and vomiting. To date, there have been no DP-related AEs or graft failure, vector-mediated replication competent lentivirus detected, or clonal dominance reported. Longer follow-up and additional patient data will be presented. Summary The safety profile of LentiGlobin gene therapy for SCD remains consistent with single-agent busulfan conditioning and underlying disease. Patients in HGB-206 Group C experienced high-level, sustained expression of gene-therapy derived hemoglobin, with median HbS levels reduced to ~50% and median total Hb levels of 11.5 g/dL at 6 months. The cessation of clinical complications (no ACS or serious VOCs) and decreased hemolysis suggest a strong therapeutic effect after LentiGlobin gene therapy in patients with SCD. Disclosures Kanter: Peerview: Honoraria; NHLBI: Membership on an entity's Board of Directors or advisory committees; Rockpointe: Honoraria; SCDAA: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria; Imara: Consultancy; Jeffries: Consultancy; Modus: Consultancy; Guidepoint Global: Consultancy; GLG: Consultancy; Cowen: Consultancy; bluebird bio, Inc: Consultancy; Medscape: Honoraria; Sangamo: Consultancy. Kwiatkowski:Terumo: Research Funding; Novartis: Research Funding; Apopharma: Research Funding; Imara: Consultancy; Celgene: Consultancy; bluebird bio, Inc.: Consultancy, Research Funding; Agios: Consultancy. Schmidt:German Cancer Research Center, Heidelberg, Germany: Employment; GeneWerk GmbH, Heidelberg, Gemrany: Equity Ownership. Miller:bluebird bio, Inc.: Employment, Equity Ownership. Pierciey:bluebird bio, Inc.: Employment, Equity Ownership. Huang:bluebird bio, Inc.: Employment, Equity Ownership. Ribeil:bluebird bio, Inc.: Employment, Equity Ownership. Thompson:Baxalta: Research Funding; Novartis: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; bluebird bio, Inc.: Consultancy, Research Funding. Walters:AllCells, Inc: Consultancy; TruCode: Consultancy; Editas Medicine: Consultancy.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2354-2354
Author(s):  
Ajay Perumbeti ◽  
Tomoyasu Higashimoto ◽  
Fabrizia Urbinati ◽  
Kristy Lauderback ◽  
Anastacia Loberg ◽  
...  

Abstract While genetic delivery of recombinant anti-sickling β-globin genes have been shown to correct murine sickle cell anemia (SCA), correction of SCA by delivery of a natural hemoglobin, fetal hemoglobin (HbF), the proportion of genetically modified hematopoietic stem cells (HSC), or amount of HbF necessary to correct the disease is unknown. We designed a lentivirus vector carrying γ-globin exons with β-globin regulatory elements and non-coding sequences, GbG. First, GbG or mock transduced Berkeley sickle HSC were transplanted using a myeloablative (lethal irradiation) transplant model, to acheive full donor chimerism. GbG mice showed high HbF expression (HbF 41 ± 5% measured by HPLC) that was sustained in primary (6 mo) and secondary (7.5 mo) transplant recipients, and resulted in effective correction of hematological and functional RBC parameters, and reduction of inflammation that results from sickle cell disease. We found significantly reduced irreversibly sickled cells (2.3 ± 0.7% in GbG versus 10.2 ± 0.3% in mock mice; p<0.001), minimal sickling of RBC when exposed to graded hypoxia using tonometry, improved RBC deformability (performed by ektacytometry), and a four-fold increase in RBC half-life (by in vivo biotin labeling) in the GbG group of mice. There was correction of anemia, and reduction in hemolysis (measured by LDH levels), reticulocytes, and leukocytosis (Table 1). This was accompanied by a dramatic improvement in chronic organ damage that is seen in untransplanted Berkeley/mock group of mice: there was a significant reduction in spleen weights and normalization of splenic follicular architecture, correction in bone marrow myeloid:erythroid ratios, and a notable absence of kidney infarction and atrophy, and liver infarction and extramedullary hematopoiesis that was observed in mock mice. Untransplanted Berkeley and mock mice showed shortened survival consistent with a severe SCA phenotype. Genetic correction with GbG improved survival to 100% compared to a 20% survival in the mock transplanted. Notably, in our proof-of principle studies, comparable functional sickle RBC correction was also seen in the Townes knock-in sickle mice (Wu et al, Blood 2006) transduced with GbG. Myeloablative conditioning in this setting allowed non-competitive repopulation of donor genetically modified HSC, resulting in high HbF and correction of disease. However, myeloablation in SCA is associated with peri-transplant mortality and long-term effects, and may not be necessary for achieving correction of phenotype. To address this, we used a unique reduced-intensity conditioning transplant model. We transplanted GbG-modified Berkeley HSC into sub-lethally irradiated Berkeley mice. In this model, when HbF was <10%, there was a small and variable improvement in hematological and functional sickle RBC parameters. However, when HbF was γ10%, there was consistent long-term correction in RBC sickling, deformability, RBC survival, and improvement in hematological parameters for 10–11 months (Table 1). Impressively, when HbF was γ10%, there was a significant reduction in splenomegaly, absence of liver and kidney pathology, and a dramatically improved overall survival of the mice, comparable to that seen in the myeloablative model. Comparison of the proportion of F-cells (HbF containing RBC) and HbF/F-cell to the assays showing correction of SCA revealed that >30% HbF/F-cell and >60% F-cells consistently corrected SCA. The mean HSC transduction (assessed by secondary HbF+ CFU-S at 6 months post transplant) was 50% and 30% in the myeloablative and reduced intensity transplant models, respectively, with 1–3 GbG copies/ cell. Furthermore, three GbG mice showed correction of SCA with 20% HSC transduction, a clinically achievable goal. Taken together, this study is the first demonstration of correction of SCA with gene therapy using γ-globin, and defines critical determinants for effective gene therapy of this disease. Mouse Model Hb (g/dl) RBC 106/ul) Reticulocyte (%) WBC (K/ul) *p<0.05; ** p<0.001 Mock Myeloablative 7.6±0.7 5.8±0.4 40.0±3.0 29.7±1.4 GbG Myeloablative 10±0.8* 9.4±0.8** 15.8±3.2** 10.6±3.1** GbG, HbF ≥ 10% Reduced intensity 9.3±0.6* 8.1±0.5** 21.2±1.9** 13.4±1.1**


Blood ◽  
2009 ◽  
Vol 114 (6) ◽  
pp. 1174-1185 ◽  
Author(s):  
Ajay Perumbeti ◽  
Tomoyasu Higashimoto ◽  
Fabrizia Urbinati ◽  
Robert Franco ◽  
Herbert J. Meiselman ◽  
...  

Abstract We show that lentiviral delivery of human γ-globin gene under β-globin regulatory control elements in hematopoietic stem cells (HSCs) results in sufficient postnatal fetal hemoglobin (HbF) expression to correct sickle cell anemia (SCA) in the Berkeley “humanized” sickle mouse. Upon de-escalating the amount of transduced HSCs in transplant recipients, using reduced-intensity conditioning and varying gene transfer efficiency and vector copy number, we assessed critical parameters needed for correction. A systematic quantification of functional and hematologic red blood cell (RBC) indices, organ pathology, and life span was used to determine the minimal amount of HbF, F cells, HbF/F-cell, and gene-modified HSCs required for correcting the sickle phenotype. We show that long-term amelioration of disease occurred (1) when HbF exceeded 10%, F cells constituted two-thirds of the circulating RBCs, and HbF/F cell was one-third of the total hemoglobin in sickle RBCs; and (2) when approximately 20% gene-modified HSCs repopulated the marrow. Moreover, we show a novel model using reduced-intensity conditioning to determine genetically corrected HSC threshold that corrects a hematopoietic disease. These studies provide a strong preclinical model for what it would take to genetically correct SCA and are a foundation for the use of this vector in a human clinical trial.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii33-ii33
Author(s):  
E Antonio Chiocca ◽  
Rimas Lukas ◽  
Clark Chen ◽  
Ganesh Rao ◽  
Christina Amidei ◽  
...  

Abstract A published clinical trial of veledimex (V)-regulatable interleukin-12 (IL-12) gene therapy (“Controlled IL-12”) under the control of a transcriptional switch (RheoSwitch Therapeutic Systemâ, RTSâ) as monotherapy in recurrent glioblastoma (rGBM) showed sustained infiltration of activated T cells within the tumor months after treatment (Sci Transl Med. 2019;11(505)). These T cells demonstrated up-regulation of immune checkpoint signaling, providing a rationale for combination therapy with the PD-1 inhibitor, nivolumab (nivo). We report interim findings following completion of enrollment (with follow-up ongoing) for a multi-institutional, open label, dose-escalation phase 1 trial (NCT03636477) evaluating safety and tolerability of loco-regional Controlled IL-12 in combination with nivo in adults with rGBM. Replication-incompetent adenovirus coding for RTS-IL-12 (Ad) was administered during surgery by free-hand injection into the tumor and periphery (2 x 1011 viral particles, Day 0) accompanied by V (10 or 20 mg) PO QD x 15 (Days 0 to 14) in combination with nivo (1 or 3 mg/kg) IV on Days -7, 15, then Q2W. Twenty-one subjects were treated (Cohort 1: V 10 mg, nivo 1 mg/kg, n=3; Cohort 2: V 10 mg, nivo 3 mg/kg, n=3; and Cohort 3: V 20 mg, nivo 3 mg/kg, n=3 & 12 in expansion). Safety data were comparable to Ad+V monotherapy. Adverse reactions (ARs) during follow-on nivo dosing were consistent with nivo labeling. ARs were manageable and generally reversible with no synergistic toxicities. Updated overall survival findings will be presented. Baseline and post-treatment histochemical staining and multiplex immunofluorescence analyses for a subgroup of subjects will be discussed. The safety of this combination immunotherapy has been established, leading to a currently accruing phase 2 clinical trial of loco-regional Controlled IL-12 gene therapy in combination with the PD-1 inhibitor cemiplimab-rwlc (NCT 04006119).


Sign in / Sign up

Export Citation Format

Share Document