Sangamo Announces Gene Therapy and Ex Vivo Gene-Edited Cell Therapy Data Presentations at the American Society of Hematology Annual Meeting
Abstract #2060: “Updated Follow-up of the Alta Study, a Phase 1/2, Open Label, Adaptive, Dose-Ranging Study to Assess the Safety and Tolerability of SB-525 Gene Therapy in Adult Patients with Severe Hemophilia A”
Barbara Konkle, M.D., Bloodworks Northwest, Professor of Medicine at University of Washington December 7th, 2019, 5:30-7:30pm Eastern Time
The SB-525 poster will show updated Alta study data including durability of Factor VIII (FVIII) levels, bleeding rate, factor usage, and safety, for all five patients in the high dose cohort of 3e13 vg/kg, with approximately 4 months to 11 months of follow-up after treatment with SB-525.
As of the abstract submission date, four patients in the 3e13 vg/kg cohort achieved FVIII levels within the normal range with no bleeding events reported up to 24 weeks post-administration. These patients did not require FVIII replacement therapy following the initial prophylactic period of up to approximately 3 weeks post-SB-525 administration. The fifth patient in the 3e13 vg/kg cohort had only recently undergone treatment with SB-525 at the time of the abstract submission. As previously reported, one patient had treatment-related serious adverse events (SAEs) of hypotension and fever, which occurred approximately 6 hours after completion of the vector infusion and resolved with treatment within 24 hours, with no loss of FVIII expression. SB-525 is being developed as part of a global collaboration between Sangamo and Pfizer.
“The rapid kinetics of Factor VIII expression, durability of response, and the relatively low intra-cohort variability in the context of a complete cessation of bleeding events and elimination of exogenous Factor VIII usage continues to suggest SB-525 is a differentiated hemophilia A gene therapy,” said
Ex Vivo Gene-Edited Cell Therapy
Abstract #3544: “Preliminary Results of a Phase 1/2 Clinical Study of Zinc Finger Nuclease-Mediated Editing of BCL11A in Autologous Hematopoietic Stem Cells for Transfusion-Dependent Beta Thalassemia”
Angela Smith, MD, Associate Professor in the Division of Pediatric Blood and Marrow Transplantationat the University of Minnesota December 9th, 2019, 6:00-8:00pm Eastern Time
Abstract #974: “Zinc Finger Nuclease-Mediated Disruption of the BCL11A Erythroid Enhancer Results in Enriched Biallelic Editing, Increased Fetal Hemoglobin, and Reduced Sickling in Erythroid Cells Derived from Sickle Cell Disease Patients”
Samuel Lessard, Ph.D., Scientist, Sanofi
The ST-400 beta thalassemia poster will show preliminary results from the first three patients enrolled in the Phase 1/2
As of the abstract submission date, Patient 1 and Patient 2 had experienced prompt hematopoietic reconstitution. Patient 1 had increasing fetal hemoglobin (HbF) fraction that contributed to a stable total hemoglobin. After being free from packed red blood cell (PRBC) transfusions for 6 weeks, the patient subsequently required intermittent transfusions. Patient 2 had rising HbF levels observed through 90 days post-infusion. For both patients, as of the most recent follow-up reported in the abstract, on-target insertions and deletions (indels) were present in circulating white blood cells. Patient 3 had just completed ST-400 manufacturing at the time of abstract submission. As previously disclosed, Patient 1 experienced an SAE of hypersensitivity during ST-400 infusion considered by the investigator to be related to the product cryoprotectant, DSMO, and which resolved by the end of the infusion. No other SAEs related to ST-400 have been reported and all other AEs have been consistent with myeloablation. No clonal hematopoiesis has been observed. Longer follow-up will be required to assess the clinical significance of these early results. ST-400 is being developed as part of a global collaboration between Sangamo and
“The first three patients enrolled in the
Sanofi’s in vitro sickle cell disease poster details a similar approach to ST-400, using mobilized HSPCs from normal donors and SCD patients and utilizing the same zinc finger nuclease for gene editing, delivered as transient non-viral RNA, and designed to disrupt the erythroid specific enhancer of the BCL11A gene, which represses the expression of the gamma globin genes, thereby switching off HbF synthesis. Results from ex vivo studies demonstrated enriched biallelic editing, increased HbF, and reduced sickling in erythroid cells derived from non-treated sickle cell disease patients.
About the Alta study
The Phase 1/2 Alta study is an open-label, dose-ranging clinical trial designed to assess the safety and tolerability of SB-525 gene therapy in patients with severe hemophilia A. SB-525 was administered to 11 patients in 4 cohorts of 2 patients each across 4 ascending doses (9e11 vg/kg, 2e12 vg/kg, 1e13vg/kg and 3e13vg/kg) with expansion of the highest dose cohort by 3 additional patients.
The Phase 1/2
This press release contains forward-looking statements regarding Sangamo's current expectations. These forward-looking statements include, without limitation, statements regarding the Company's ability to develop and commercialize product candidates to address genetic diseases with the Company's proprietary technologies, as well as the timing of commencement of clinical programs and the anticipated benefits therefrom. These statements are not guarantees of future performance and are subject to certain risks, uncertainties and assumptions that are difficult to predict. Factors that could cause actual results to differ include, but are not limited to, the outcomes of clinical trials, the uncertain regulatory approval process, uncertainties related to the execution of clinical trials, Sangamo's reliance on partners and other third-parties to meet their clinical and manufacturing obligations, and the ability to maintain strategic partnerships. Further, there can be no assurance that the necessary regulatory approvals will be obtained or that Sangamo and its partners will be able to develop commercially viable product candidates. Actual results may differ from those projected in forward-looking statements due to risks and uncertainties that exist in Sangamo's operations and business environments. These risks and uncertainties are described more fully in Sangamo's Annual Report on Form 10-K for the year ended
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