Early Results from a Phase 1/2 Study of Aru-1801 Gene Therapy for Sickle Cell Disease (SCD): Manufacturing Process Enhancements Improve Efficacy of a Modified Gamma Globin Lentivirus Vector and Reduced Intensity Conditioning Transplant

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

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Safety and Efficacy of Aru-1801 in Patients with Sickle Cell Disease: Early Results from the Phase 1/2 Momentum Study of a Modified Gamma Globin Gene Therapy and Reduced Intensity Conditioning

Blood ◽

10.1182/blood-2021-147469 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3970-3970

Author(s):

Michael Grimley ◽

Monika Asnani ◽

Archana Shrestha ◽

Sydney Felker ◽

Carolyn Lutzko ◽

...

Keyword(s):

Gene Therapy ◽

Stem Cell ◽

Research Funding ◽

Drug Product ◽

Phase 1 ◽

Cell Disease ◽

Reduced Intensity Conditioning ◽

Renal Hyperfiltration ◽

F Cells ◽

Reduced Intensity

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

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Interim Results from a Phase 1/2 Clinical Study of Lentiglobin Gene Therapy for Severe Sickle Cell Disease

Blood ◽

10.1182/blood.v128.22.1176.1176 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1176-1176 ◽

Cited By ~ 19

Author(s):

Julie Kanter ◽

Mark C. Walters ◽

Matthew M. Hsieh ◽

Lakshmanan Krishnamurti ◽

Janet Kwiatkowski ◽

...

Keyword(s):

Gene Therapy ◽

Board Of Directors ◽

Research Funding ◽

Phase 1 ◽

Globin Gene ◽

Advisory Committees ◽

Cell Dose ◽

Cd34 Cells ◽

Equity Ownership

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.

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

Nature Medicine ◽

10.1038/s41591-021-01554-9 ◽

2022 ◽

Author(s):

Farid Boulad ◽

Aurelio Maggio ◽

Xiuyan Wang ◽

Paolo Moi ◽

Santina Acuto ◽

...

Keyword(s):

Gene Therapy ◽

Phase 1 ◽

Globin Gene ◽

Reduced Intensity Conditioning ◽

Phase 1 Trial ◽

Reduced Intensity

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Multicenter Investigation Of Unrelated Donor Hematopoietic Cell Transplantation (HCT) For Thalassemia Major After a Reduced Intensity Conditioning Regimen (URTH Trial)

Blood ◽

10.1182/blood.v122.21.543.543 ◽

2013 ◽

Vol 122 (21) ◽

pp. 543-543 ◽

Cited By ~ 8

Author(s):

Shalini Shenoy ◽

Lisa. Murray ◽

Mark C. Walters ◽

Sonali Chaudhury ◽

Sandeep Soni ◽

...

Keyword(s):

Median Time ◽

Graft Rejection ◽

Research Funding ◽

Hla Antigens ◽

Pulmonary Hemorrhage ◽

Thalassemia Major ◽

Unrelated Donor ◽

Reduced Intensity Conditioning ◽

Reduced Intensity

Abstract Background HCT cures thalassemia major (TM). In the absence of a family donor, marrow or less frequently umbilical cord blood (UCB) from unrelated donors (URD) has been used. Due to risks of graft rejection, myeloablative preparative regimens are primarily utilized. URD marrow and UCB HCT have 65-90% and 21-74% event free survival (EFS) and rejection rates of 9-17% and 17-57% respectively. The URTH trial was developed in collaboration with the Thalassemia Clinical Research Network (TCRN), National Heart, Lung and Blood Institute (NHLBI), Pediatric Blood and Marrow Transplant Consortium (PBMTC) and New England Research Institutes (NERI) to explore URD HCT for TM as a strategy to expand availability of HCT. It employed reduced intensity conditioning (RIC) as a means to decrease early and late toxicities. The study tested our hypothesis that an immunosuppressive RIC regimen was sufficient for engraftment in children with TM (age > 1 year to < 17 years) after URD HCT. The primary objective was to determine EFS at 1 year after URD marrow or UCB HCT. Methods Patients with transfusion dependent beta thalassemia and a suitable URD (matched at 8/8 HLA-alleles in marrow donors or 5 to 6/6 HLA antigens in UCB donors) were conditioned with hydroxyurea (30mg/kg x 30 days) (day -50 to -21), alemtuzumab (48 mg) (-22 to -19), fludarabine (150 mg/m2) (-8 to -4), thiotepa (8mg/kg) (-4), and melphalan (140mg/m2) (-3). Patients received tacrolimus or cyclosporine with methotrexate and methylprednisone (marrow) or mycophenolate mofetil (UCB) after HCT to prevent graft-versus-host disease (GVHD). Suitable UCB units were defined as having a pre-thaw total nucleated cell content >4.0x10E7/Kg recipient weight. Patients were eligible irrespective of Pesaro classification but the presence of liver fibrosis by histology was an exclusion criterion. Results Twenty-three patients from 11 US centers (11M: 12F) with a median age of 10 years (2–17 years) received unrelated donor allografts: marrow (14) or UCB matched at 6/6 (1) or 5/6 HLA antigens (8). The median follow up time was 12 months (range 120 days-2 years). The median time to neutrophil engraftment was 13 days (range 10-25) and 34 days (range 12-46) after marrow and UCB HCT respectively. The median time to platelet engraftment after marrow and UCB HCT was 24 days (range 18-34) and 54.5 days (range 32-234) respectively. Primary graft rejection occurred in 1 patient (4% of all patients) following UCB HCT and was accompanied by autologous hematopoietic recovery 35 days after HCT. All others had >90% donor chimerism and achieved transfusion independence. There were no late graft rejections. The overall and EFS probabilities were 82% and 78% respectively at the most recent encounter. One patient developed mild VOD which resolved uneventfully. Of 15 patients who had CMV reactivation, 13 responded to pre-emptive therapy and had no progression to CMV disease. The probabilities of grade II-IV and grade III-IV acute GVHD were 30% and 9% respectively. Limited chronic GVHD was noted in 35% of the cohort; 9% developed extensive cGVHD. Four patients died on days 25, 86, 106 and 366. The causes of death included 1) pulmonary hemorrhage associated with CMV, adenovirus, and Pneumocystis jiroveci infections, 2) diffuse alveolar pulmonary hemorrhage, 3) cGVHD with pneumonia associated with CMV and adenovirus infections, and 4) cGVHD with pulmonary failure associated with CMV and EBV infections and presumed central nervous system post-transplantation lymphoproliferative disease. Conclusion HCT after RIC for thalassemia is feasible and sufficient for engraftment after URD marrow and UCB transplantation with survival exceeding 80%. The principal transplant- related complications we observed were early opportunistic viral reactivations; otherwise the preparative regimen was tolerated well with very little early toxicity. Fatal and late viral infections were noted only in the setting of severe GVHD. Patients should be monitored carefully and treated promptly for infectious complications after HCT until there is adequate immune reconstitution. The risk of severe GVHD was low despite unrelated and mismatched (UCB) donor sources. Longer follow up will determine if this regimen can reduce late toxicities. An extension of this trial is ongoing and currently recruiting patients to evaluate additional HCT related and quality of life measures. Disclosures: Neufeld: Shire: Consultancy. Kwiatkowski:Resonance Health: Research Funding; Shire: Consultancy. Thompson:Novartis: Consultancy, Research Funding; ApoPharma: Consultancy, Honoraria; Glaxo Smith Kline: Research Funding; Eli Lilly: Research Funding; Amgen: Research Funding; bluebird bio: Research Funding.

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Resolution of Sickle Cell Disease Manifestations in Patients Treated with Lentiglobin Gene Therapy: Updated Results from the Phase 1/2 Hgb-206 Group C Study

Blood ◽

10.1182/blood-2019-128894 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 990-990 ◽

Cited By ~ 5

Author(s):

Julie Kanter ◽

John F. Tisdale ◽

Markus Y. Mapara ◽

Janet L. Kwiatkowski ◽

Lakshmanan Krishnamurti ◽

...

Keyword(s):

Gene Therapy ◽

Research Funding ◽

Phase 1 ◽

Globin Gene ◽

Post Treatment ◽

Employment Equity ◽

Advisory Committees ◽

Cd34 Cells ◽

Equity Ownership

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.

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Updated Follow-up of the Alta Study, a Phase 1/2 Study of Giroctocogene Fitelparvovec (SB-525) Gene Therapy in Adults with Severe Hemophilia a

Blood ◽

10.1182/blood-2020-137648 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 12-12

Author(s):

Andrew D. Leavitt ◽

Barbara A. Konkle ◽

Kimo Stine ◽

Nathan Visweshwar ◽

Thomas J. Harrington ◽

...

Keyword(s):

Gene Therapy ◽

Stock Options ◽

Research Funding ◽

Hemophilia A ◽

Phase 1 ◽

Severe Hemophilia ◽

Bleeding Events ◽

Dose Cohort ◽

Fviii Activity

Introduction: Hemophilia A is a rare bleeding disorder caused by pathogenic variants in the F8 gene, resulting in insufficient factor VIII (FVIII) activity. Adeno-associated virus (AAV)-mediated gene transfer enables the delivery of a modified functional F8 gene to hepatocytes that subsequently synthesize FVIII at levels that may prevent bleeding events in the absence of exogenous FVIII. Updated results and follow-up from the Alta study, an ongoing gene therapy study in patients with severe hemophilia A, are presented. Methods: The Alta study is a phase 1/2 dose-ranging, single-dose study of giroctocogene fitelparvovec (also known as SB-525 and PF-07055480), a recombinant AAV serotype 6 (rAAV6) vector encoding a modified F8 gene. Adults aged ≥18 years with severe hemophilia A were eligible for inclusion. Giroctocogene fitelparvovec was infused into patients in 4 cohorts of 2 patients each across 4 ascending doses (9e11, 2e12, 1e13, and 3e13 vg/kg). The 3e13 vg/kg dose cohort was expanded with 3 additional patients. Key end points included safety, circulating FVIII activity, use of FVIII replacement therapy, and frequency of bleeding events. Presented data are from the ongoing Alta study (NCT#03061201; data cutoff date, 26 May 2020; database not locked; data reflect those at time of data cutoff, have not undergone standard quality checks, and may be subject to change). Results: Eleven male patients participated in the study (mean [SD] age, 30.3 [7.8] years; white, 81.8%). As of the cutoff date, patients have been followed for 35 to 144 weeks; one patient in the 1e13 vg/kg cohort discontinued from the study. Overall, the most commonly reported adverse events (AEs; n) included increased alanine aminotransferase (ALT; 8 [72.7%]), increased aspartate aminotransferase (AST; 5 [45.5%]), upper respiratory tract infection (4 [36.4%]), and pyrexia (4 [36.4%]). Treatment-related serious AEs were reported in 1 patient (in the 3e13 vg/kg cohort) who experienced hypotension and fever ≈6 hours after giroctocogene fitelparvovec infusion; the events fully resolved with treatment and did not delay post-infusion discharge. In the 3 lower-dose cohorts, no ALT elevation requiring more than 7 days of corticosteroid treatment was observed. Of the 5 patients in the 3e13 vg/kg cohort, 4 had elevations in ALT that were managed with a tapering course of corticosteroids (ranging from 10-134 days) without loss of clinically relevant FVIII activity through 40 weeks, as evidenced by a lack of bleeding events before and after treatment with corticosteroids. Increases in FVIII activity from baseline were generally dose-dependent. Patients in the 3e13 vg/kg cohort achieved a mean normal-range of FVIII activity within 5 weeks post-infusion, with mean FVIII activity maintained through week 40, which is the last time point with data for all 5 patients in this cohort (Table). Following the initial prophylactic period of up to ≈3 weeks after giroctocogene fitelparvovec administration, no bleeding events occurred in any patient treated in the 3e13 vg/kg cohort. Use of FVIII replacement therapy ≥3 weeks after giroctocogene fitelparvovec administration was reported in 5/6 patients in the lower-dose cohorts (range: 9-115 infusions); none of the patients in the 3e13 vg/kg cohort required FVIII replacement beyond initial use of prophylactic factor for up to ≈3 weeks (prophylactic coverage stopped 3 weeks and 2 days after giroctocogene fitelparvovec administration in 1 patient in the 3e13 vg/kg cohort). Conclusions: To date, a single infusion of giroctocogene fitelparvovec gene therapy in patients with severe hemophilia A resulted in dose-dependent and sustained increases in FVIII levels without administration of exogenous FVIII, bleeding episodes or sustained adverse events in the highest-dose cohort (3e13 vg/kg). Additionally, patients treated in the highest-dose cohort achieved a mean FVIII activity in the normal range within 5 weeks, which was maintained through week 40. Data on all patients with more than 1 year of follow-up will also be presented. The study is ongoing, and these interim results support further development of giroctocogene fitelparvovec for the treatment of patients with severe hemophilia A. Disclosures Leavitt: BioMarin: Membership on an entity's Board of Directors or advisory committees. Konkle:Sanofi: Consultancy, Research Funding; Takeda: Research Funding; Uniquire: Research Funding; CSL Behring: Consultancy; BioMarin: Consultancy; Baxalta: Research Funding; Spark: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Sigilon: Consultancy, Research Funding; Roche: Consultancy. Stine:Biomarin: Consultancy; Applied Stem Cell Therapeutics: Consultancy. Visweshwar:Biogen Idec: Membership on an entity's Board of Directors or advisory committees. Giermasz:uniQure: Consultancy, Research Funding; Sangamo Therapeutics: Research Funding; Bioverativ/Sanofi: Consultancy, Research Funding, Speakers Bureau; BioMarin: Consultancy, Research Funding, Speakers Bureau; Genentech/Roche: Consultancy, Research Funding, Speakers Bureau. Arkin:Pfizer: Current Employment, Current equity holder in publicly-traded company, Other: own stock/options in the company. Fang:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Plonski:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Smith:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Tseng:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Di Russo:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Cockroft:Sangamo Therapeutics: Current Employment, Other: Shareholder of Sangamo Therapeutics. Rupon:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Rouy:Sangamo Therapeutics: Current Employment, Other: Shareholder of Sangamo Therapeutics.

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Reduced Intensity Conditioned Bone Marrow Transplant with Post-Transplant Cyclophosphamide and Donor-Derived Mesenchymal Stromal Cell Infusions for Recessive Dystrophic Epidermolysis Bullosa

Blood ◽

10.1182/blood-2018-99-113035 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2165-2165 ◽

Cited By ~ 1

Author(s):

Christen L. Ebens ◽

John A McGrath ◽

Katsuto Tamai ◽

Hovnanian Alain ◽

John E. Wagner ◽

...

Keyword(s):

Disease Activity ◽

Research Funding ◽

Reduced Intensity Conditioning ◽

Dystrophic Epidermolysis Bullosa ◽

Type Vii Collagen ◽

Medical Photography ◽

Recessive Dystrophic Epidermolysis Bullosa ◽

Skin Biopsies ◽

Reduced Intensity

Abstract Introduction: Recessive dystrophic epidermolysis bullosa (RDEB) is a severe, life-limiting systemic genodermatosis, characterized by COL7A1 mutation(s) yielding inadequate type VII collagen to maintain the integrity of the cutaneous basement and mucosal membranes. The mainstay of therapy for RDEB is supportive care to minimize the daily morbidity of blistering/scarring, pain/pruritis, systemic inflammation, and high metabolic demand. Leveraging the pluripotency of bone marrow cells, investigations of BMT as a systemic therapy for RDEB showed promise in pre-clinical murine (Tolar J, et al., Blood 2009, 113(5): 1167-74) as well as early phase human clinical trials utilizing fully myeloablative conditioning (Wagner J, et al., NEJM 2010, 363(7): 629-39). However, regimen-rated toxicity limited dampened enthusiasm for the clinical approach. Methods: In an effort to modulate disease activity with decreased toxicity, we investigated the safety of and preliminary responses to BMT with a reduced-intensity conditioning regimen (rabbit anti-thymocyte globulin 2.5 mg/kg with a methylprednisolone taper, cyclophosphamide 28 mg/kg, fludarabine 150 mg/m2, and low dose total body irradiation 300-400 cGy). Graft-versus-host disease (GvHD) prophylaxis included post-transplant cyclophosphamide (PTCy, 50 mg/kg recipient weight/dose on days +3 and 4) and mycophenylate mofetil from day +5 to 35. All except HLA-matched related donor recipients received tacrolimus from day +5 until tapered at day +100. Immunomodulatory donor-derived mesenchymal stromal cells (MSCs, 2 x 106 cells/kg recipient weight/dose) were infused at 60, 100 and 180 days post-BMT. Skin biopsies, medical photography, and dynamic assessments of RDEB disease activity by providers and parents were completed at baseline, day +100, +180 and 1 year post-BMT. Results: Ten RDEB patients were transplanted at a median age of 9.9 years (range 1.8 to 22.1), with a median follow-up of 16 months (1 year evaluations available for only 4 of 10). Donors were haploidentical related (n=6), HLA-matched related (n=3), and HLA-matched unrelated (n=1). BMT complications included graft failure in 3 patients (2 elected to pursue a 2nd PTCy BMT), veno-occlusive disease in 2, posterior reversible encephalopathy in 1, and chronic GvHD in 1, the latter deceased. Infectious complications in the first 100 days were limited to 3 viremia, 7 bacteremia, and 0 fungemia episodes. No serious adverse events were observed with MSC infusions. In the 9 ultimately engrafted patients, median donor chimerism at day +180 was 100% in both myeloid and lymphoid fractions of peripheral blood and 27% in skin. Skin biopsies at day +180 show stable (n=7) to improved (n=2) type VII collagen protein expression by immunofluorescence (IF) and gain of anchoring fibril components by transmission electron microscopy in 4 of 9 patients. Early clinical response included a trend toward reduced body surface area of blisters/erosions from a median of 45.5% at baseline to 27.5% at day +100 (p=0.05), with parental measures indicating stable quality of life. Select medical photography and skin biopsy results are shown for Patient 1 [IF: 40x merged dapi (blue) and C7 collagen antibody (red); immunoelectron microscopy with C7 collagen-directed immunostain (black)]. Conclusions: BMT using reduced-intensity conditioning, PTCy and donor-derived MSC infusion for RDEB was largely well tolerated with low rates of GvHD and death from regimen-related toxicity in 1 of 10 patients undergoing 12 total BMTs. Early follow-up suggests this treatment modulates RDEB disease activity but requires longer follow-up for evaluation of efficacy. Importantly, the PTCy BMT platform provides a means of attaining immunotolerance for future donor-derived cellular grafts. Figure Figure. Disclosures Wagner: Magenta Therapeutics: Consultancy, Research Funding; Novartis: Research Funding.

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Matching-Adjusted Indirect Treatment Comparison (MAIC) of Acalabrutinib Alone or in Combination with Obinutuzumab Versus Ibrutinib or Venetoclax Plus Obinutuzumab in Patients with Treatment-Naïve Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood-2021-146976 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2633-2633

Author(s):

Matthew S. Davids ◽

Ugochinyere Emeribe ◽

Priyanka Gaitonde ◽

Ling Cai

Keyword(s):

Skin Cancer ◽

Safety Profile ◽

Research Funding ◽

Lymphocytic Leukemia ◽

Non Melanoma Skin Cancer ◽

Treatment Naïve ◽

Grade 3 ◽

Favorable Safety ◽

Melanoma Skin

Abstract Introduction: Acalabrutinib (A) and ibrutinib (I) are both highly effective Bruton tyrosine kinase inhibitors (BTKi) approved for the treatment of chronic lymphocytic leukemia (CLL) and given as continuous treatments until disease progression or unacceptable toxicity. Venetoclax is a BH3 mimetic compound and B-cell lymphoma-2 inhibitor prescribed in combination with obinutuzumab (V+O) for a fixed (12-cycle) duration in treatment-naïve CLL patients. Although the ELEVATE-RR study demonstrated an improved safety profile of A compared with I in a head-to-head clinical trial, this study did not include treatment-naïve CLL patients (Byrd et al. J Clin Oncol. 2021). This MAIC builds upon the published analysis by Davids et al (Leuk Lymphoma. 2021) in treatment-naïve patients with CLL (which demonstrated a favorable safety profile for A-based therapy compared with other targeted therapies without compromising efficacy) by including longer follow-up data for A and the comparators. Methods: Individual patient data for A ± obinutuzumab (A+O) from ELEVATE-TN (47 months median follow-up) (Sharman et al. ASCO 2021) were weighted to match the aggregate baseline characteristics of the I monotherapy arm from the ALLIANCE trial (Woyach et al. NEJM. 2018) (I + rituximab was not included as this treatment is not approved for CLL) and the V+O arm from the CLL-14 trial (Al-Sawaf et al. Lancet Oncol 2020). These baseline characteristics, TP53 mutation, serum β 2 microglobulin, ECOG, IGHV status, del(11q), CrCl, Rai stage or CLL-IPI, are potential prognostic variables (PV). Pseudo-individual patient data were generated from the digitized Kaplan-Meier curves published in the aforementioned comparator trials. An unanchored MAIC was conducted to adjust for these PVs between trials. The PVs selected were based on literature, clinical judgement, and demonstrated statistically significant association with progression-free survival (PFS) in univariate and multivariate regression analysis (Ahn et al. J Clin Oncol. 2020; Eichorst and Hallek. Hematol Am Soc Hematol Educ Prog. 2016). After matching, a weighted Cox proportional hazard model was used to analyze PFS and overall survival (OS) while a weighted logistic regression model was used for comparative safety analysis (grade ≥3 adverse events [AEs]). Two-sided p<0.05 was considered statistically significant. Results: This MAIC included 47-month data from ELEVATE-TN, 38-month data from ALLIANCE, and 40-month data from CLL-14 as opposed to 28-month data from ELEVATE-TN, 29-month data from RESONATE-2, and 29-month data from CLL-14 included in the previously published analysis. In the A vs I comparison, the PFS (hazard ratio [HR] 0.83 [95% CI 0.50, 1.37]) and OS (HR 0.69 [95% CI 0.37, 1.29]) numerically favored A but the difference was not significant. The A vs V+O comparison did not show significant differences in PFS (HR 0.96 [95% CI 0.56, 1.65] and OS (HR 0.99 [95% CI 0.51, 1.91]). For A+O vs I, significant differences in PFS (HR 0.48 [95% CI 0.27, 0.88]) and OS (HR 0.41 [95% CI 0.18, 0.91]) were observed. Similarly, for A+O vs V+O, significant differences were observed for PFS (HR 0.38 [95% CI 0.20, 0.73]) and OS (HR 0.43 [95% CI 0.19, 0.99]). Significant differences in rate of grade ≥3 AEs in favor of A and A+O were observed vs I for atrial fibrillation, hypertension, decreased neutrophil count, and decreased platelet count. Compared with V+O, patients treated with A had significantly lower rates of febrile neutropenia, leukopenia, neutropenia, thrombocytopenia, non-melanoma skin cancer, and secondary primary malignancies, excluding non-melanoma skin cancer. For A+O vs V+O, significantly lower rates of infusion-related reaction, neutropenia, and non-melanoma skin cancer were observed among patients treated with A+O. Conclusions: Based on these MAIC results, A and A+O are associated with a favorable safety profile vs both I and V+O while, with longer follow-up, these MAIC results demonstrate that A+O is associated with a significant efficacy benefit vs both I and V+O. A limitation of this MAIC is not including all potential PVs as a trade-off to conserve the effective sample size. Our findings are consistent with the results of ELEVATE-RR comparing A with I in the relapsed population and also provide insight into comparisons of A-based therapy with V+O as we await more definitive prospective data on this question from a phase 3 trial. Figure 1 Figure 1. Disclosures Davids: Genentech: Consultancy, Research Funding; Ascentage Pharma: Consultancy, Research Funding; Surface Oncology: Research Funding; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; BeiGene: Consultancy; Celgene: Consultancy; Eli Lilly and Company: Consultancy; BMS: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Janssen: Consultancy; Novartis: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Research Funding; MEI Pharma: Consultancy; Merck: Consultancy; Research to Practice: Consultancy; Takeda: Consultancy. Emeribe: AstraZeneca: Current Employment, Current holder of stock options in a privately-held company. Gaitonde: AstraZeneca: Current Employment, Current holder of stock options in a privately-held company, Research Funding. Cai: AstraZeneca: Current Employment, Current equity holder in publicly-traded company; Google: Current equity holder in publicly-traded company; Celgene Corporation: Ended employment in the past 24 months.

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Gene Therapy for Fanconi Anemia, Complementation Group a: Updated Results from Ongoing Global Clinical Studies of RP-L102

Blood ◽

10.1182/blood-2020-137106 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 14-14

Author(s):

Agnieszka Czechowicz ◽

Rajni Agarwal ◽

Julián Sevilla ◽

Paula Río ◽

Susana Navarro ◽

...

Keyword(s):

Gene Therapy ◽

Bone Marrow ◽

Fanconi Anemia ◽

Research Funding ◽

Phase 1 ◽

Phase 2 ◽

Medicinal Products ◽

Publicly Traded ◽

Hematopoietic Stem

Background: Fanconi anemia (FA) is a rare inherited disorder of defective cellular deoxyribonucleic acid (DNA) repair, associated with developmental abnormalities and characterized by progressive bone marrow failure (BMF) and a predisposition to hematologic malignancies and solid tumors. Approximately 60-70% of all cases result from mutations in the Fanconi Anemia Complementation Group A (FANCA) gene (FA-A). 80% of FA patients develop BMF within the first decade of life. Although allogeneic hematopoietic stem cell transplant (allo-HSCT) is a potentially curative treatment for BMF, its utilization and efficacy are limited by availability of suitable human leukocyte antigen (HLA)-matched donors, risk of graft-versus-host disease (GVHD) and transplant-related toxicities. Ex-vivo lentiviral mediated gene therapy of autologous FA-A CD34+ enriched hematopoietic stem and progenitor cells (HSPCs) has been shown to confer a survival advantage to gene-modified HSPCs in preclinical studies and, most recently, in the investigator initiated Phase 1/2 FANCOLEN-I clinical trial conducted in Madrid, Spain. Based on the highly favorable safety profile and promising preliminary efficacy data, global studies using "Process B" optimization including transduction enhancers, commercial-grade vector, and modified cell processing are underway. Herein, we report updated results from the US Phase 1 clinical trial and preliminary data from the global Phase 2 study in US and EU. Design and Methods: Subjects with a confirmed FANCA gene mutation aged 1 year or older, with no HLA-matched sibling donor and at least 30 CD34+ cells/µL in bone marrow (BM) were eligible for enrollment. Peripheral blood (PB) mononuclear cells were collected via leucocytapheresis on two consecutive days after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. CD34+ HSPCs were enriched, transduced with a lentiviral vector (PGK-FANCA-WPRE) and infused fresh (not cryopreserved) without any antecedent conditioning. Patients are being followed for 3 years post-infusion for safety assessments (replication competent lentivirus (RCL), insertion site analysis (ISA)) and to ascertain evidence of efficacy (increasing PB vector copy number (VCN) and BM mitomycin-C (MMC) resistance), along with stabilization/correction of cytopenias. Results: As of August 2020, 2 subjects (aged 5 and 6 years) have received RP-L102 infusion on the Phase 1 study with over 12 months of follow up. Preliminary evidence of gene marking in PB post-RP-L102 infusion at various timepoints has been observed in both subjects. Increased bone marrow (BM) mitomycin-C (MMC) resistance post treatment has also been identified in at least 1 subject. Subject L102-001-1001 has had blood count stabilization over the 12 months following gene therapy administration. Subject L102-001-1002's course has been complicated by influenza B infection with concomitant decreases in blood counts requiring red blood cell transfusions. Transfusion requirements have decreased following resolution of infection. Since November 2019, 5 additional subjects have been enrolled onto the global Phase 2 study and received investigational infusion. Updated preliminary safety and efficacy data including PB VCN, blood counts and BM MMC resistance will be available at the time of presentation for subjects with over 12 months of follow up; drug product (DP) information (VCN and CD34+ cell dose) will be available for all treated subjects. Conclusions: DP has been successfully manufactured in the Phase I (N=2) and Phase 2 (N=5) to meet the required specificationsSafety profile of RP-L102 continues to be highly favorable.Evidence of engraftment has been seen in at least 1 subject with follow up of at least 12 months as indicated by PB genetic markings and increasing BM CFC MMC resistance; 12+ months of follow-up may be required to observe the proliferative advantage of transduced HSPCs. Disclosures Czechowicz: Rocket Pharmaceuticals, Inc.: Research Funding. Sevilla:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company. Río:Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: PR has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Navarro:Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: SN has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Beard:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Wagner:BlueRock: Research Funding; Magenta Therapeutics: Consultancy, Research Funding; Gadeta: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company. Schwartz:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from this company., Patents & Royalties, Research Funding.

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Correction of Sickle Cell Anemia with γ-Globin Gene Delivered by Lentivirus Vector in the Setting of Myeloablative or Reduced Intensity Conditioning, and Establishing Critical Determinants for Successful Gene Therapy for Sickle Cell Disease.

Blood ◽

10.1182/blood.v112.11.2354.2354 ◽

2008 ◽

Vol 112 (11) ◽

pp. 2354-2354

Author(s):

Ajay Perumbeti ◽

Tomoyasu Higashimoto ◽

Fabrizia Urbinati ◽

Kristy Lauderback ◽

Anastacia Loberg ◽

...

Keyword(s):

Gene Therapy ◽

Sickle Cell Disease ◽

Sickle Cell ◽

Cell Disease ◽

Lentivirus Vector ◽

Reduced Intensity Conditioning ◽

F Cells ◽

Transplant Model ◽

Reduced Intensity

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**

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