Sandy Macrae
Analyst · Aspen Mori of Bank of America. Your line is now open
Thank you, Aron, and good morning to everyone on the call. This is such an important moment for Sangamo as we share clinical data and business updates across several programs demonstrating that we have three important assets in or progressing towards late stage development. Our gene therapy portfolio is advancing with accumulating safety and efficacy data in our Fabry and Hemophilia A programs. Additionally, we are delighted with the preliminary proof-of-concept data demonstrated the clinical potential of our genome engineering, zinc finger technology in sickle cell disease. This morning, we announced preliminary clinical data from our Phase 1/2 STAAR study, evaluating isaralgagene civaparvovec or ST-920, our Fabry disease gene therapy product candidate. Data from this important study were evaluated from the four patients in the first two cohorts. Those levels point 5e13 and 1e13 vg/kg as of the cutoff date September 17 of this year. These encouraging results showed that for the first four patients ST-920 was generally well tolerated. There were no treatment related adverse events higher than Grade 1, and no treatment related serious adverse events. No patient experienced liver enzyme elevations, or required steroid treatment. All four patients exhibited above normal alpha-Gal A activity, which were maintained for up to one year for the first patient treated and through 14 weeks for the most recently treated patients. Levels ranged from two to 15 fold above normal levels at last measurement as of the cutoff date. Interestingly, the first three patients dose reported improvements in ability to sweat a primary and common Fabry disease symptom that limits exercise tolerance for the patient. ERT withdrawal is now complete for one patient and is planned for the other patient on ERT based on the stability of their alpha-Gal A activity following treatment. Based on these data, we've initiated Phase 3 filing. The fifth patient in the study, who is the first patient in the third dose cohort at [indiscernible] was recently dosed. The sixth patient is currently in screening also of the third dose cohort. And we expect to provide updated results throughout 2022 and present these data at a medical meeting. This morning, we also announced that preliminary proof-of-concept results from the Phase 1/2 PRECIZN study of SAR445136, an investigation zinc finger nucleus gene edited cell therapy in patients with sickle cell disease will be presented at ASH. This program is partnered with our friends at Sanofi. The data in the abstract showed that as of June 25, 2021 cutoff date none of the four patients treated require blood transfusions post engraftment through 65 weeks of follow-up for the longest treated patient. The four treated patients all experienced increases in total hemoglobin, fetal hemoglobin and percent F cells. No adverse events or serious adverse events related to treatment were reported as the cutoff date. Further data will provided in a poster presentation at ASH on December the 12th. Sangamo and Sanofi are continued to advance the sickle cell disease program. The companies recently obtained manufacturing requirements guidance from the FDA in preparation for potential further clinical studies. Separately, we and Sanofi made the business decision to cease development for the beta thalassemia indication and allowing us to focus resources on the sickle cell disease program. Moving now onto our Hemophilia A program partnered with Pfizer, we announced this morning, the updated follow-up results from the Phase 1/2 Alta study of giroctocogene fitelparvovec will be presented at ASH. For the four patients in the highest dose cohort who have been followed for at least 104 weeks as of May 19, 2021 cutoff. Mean Factor VIII activity was 30.9% at week 104 as measured by chromogenic assay. In this cohort, the annualized bleeding rate was zero for the first year after treatment and 0.9 throughout total duration of follow-up. As demonstrated in the study, the gene therapy was generally well tolerated in patients with severe hemophilia A. Further data will provide in a poster presentation at ASH on December the 12th 2021. We and Pfizer also announced that some of the patients treated today in the Phase 3 AFFINE trial experienced FVIII levels greater than 150% following treatment. To date, none of these patients have experienced thrombotic events and some have been treated with direct oral anticoagulants to reduce thrombotic risk. Out of an abundance of caution, Pfizer voluntary paused screening, and dosing of patients in the trial in order to implement a protocol amendment, which will provide guidelines for clinical management of elevated FVIII levels. On November the 3rd, Pfizer was informed that the FDA has put this trial on clinical hold. Pfizer and Sangamo are committed to resuming patient dosing as soon as possible. We continue to believe that this gene therapy will represent an important treatment option for patients with hemophilia A. The next step is to share the proposed protocol amendment with health authorities and respond to the clinical hold after which the companies will be able to provide updated timing for the trial. Turning now to our kidney transplant program. We have now enrolled the first patient in our Phase 1/2 STEADFAST study evaluating TX200, our wholly owned autologous CAR Treg cell therapy candidate. We believe that this is the first inhuman CAR Treg study, and that this field is growing with much excitement as a promising approach for challenging autoimmune conditions. In this study, similar to other genetically engineered cell therapy approaches, patients will undergo leukapheresis procedure from which their Treg cells will be isolated, engineered, and then cryopreserved. The HLA-A2 negative patient will subsequently undergo kidney transplant and following a recovery period will receive their personalized TX200 therapy. We expect to dose the first two patients in this study by the middle of 2022, following their kidney transplants. We continue to open sites and screen patients. We believe this proof-of-concept study may represent an important treatment for patients undergoing renal transplant and will help us understand CAR Treg biology in humans, as well as advanced process development knowledge. We hope that this study establishes the foundation for a portfolio of wholly owned CAR Treg therapies for autoimmune indications. Finally, I'm delighted to share that Mark McClung has been appointed as Sangamo’s the Chief Operating Officer effective November 1. Mark's expanded role as COO is an important organizational step for Sangamo, which will support the multiple advancing wholly owned and partnered programs. We look forward to Mark's continued leadership as we continue to build the capabilities to bring genomic medicines to patients and to the marketplace. Everyone at Sangamo thrilled with this clinical momentum. And we look forward to presenting updated Fabry results through 2022, as well as working with our collaboration partners and investigators to present the ASH data in December. And with that, I'll turn the call over to Prathyusha for a financial update. Prathyusha?