REGENXBIO Inc.

today's call with a recap of our recent business highlights, as well as an update on our corporate goals. Dr. Steve Ficola, our Chief Medical Officer, will then provide an update on our clinical program, and Vince Vecista, our Chief Financial Officer, will provide an overview of financial results for the fourth quarter ended December 31st, 2022. At the end of the call, we will open up the line for questions. At Regenexx Bio, our mission is to improve lives through the curative potential of gene therapy, and we are focused on developing therapies for diseases that have significant unmet needs. We continue to be a leader in gene therapy with thousands of patients who have been dosed with AAV therapeutics derived from our NAV technology platform. Today, we recognize that we're at the intersection of Rare Disease Day and the final day of February that was part of Low Vision Awareness Month. I'm encouraged by the momentum in AAV gene therapy. With recent approvals, upcoming regulatory decisions, encouraging clinical trial outcomes, and positive signals and actions from leaders at the FDA about the importance of accelerating gene therapy development, I believe the opportunity for gene therapy, and particularly AAV therapeutics, has never been stronger. Additionally, with our expected near-term approval goals and continued efforts from research through clinical development and commercial-ready manufacturing, I'm proud of Regenexx Bio's leadership in this field. We've continued to make great progress in the fourth quarter and throughout the course of the year, advancing our internal pipeline as we execute our five by 25 strategy to advance five AAV therapeutics from our internal pipeline and licensed programs into pivotal stage or commercial products by 2025. To summarize some of our program and operational highlights, We've made significant progress across our global eye care collaboration with AbbVie. Enrollment is ongoing in Atmosphere and Ascent, the two pivotal trials for RGX314 for the treatment of wet AMD using subretinal delivery. The pivotal trials are expected to support a BLA filing in 2024. Regenexx Bio's NavXpress platform process has been incorporated into these pivotal trials and is expected to be produced at our Manufacturing Innovation Center for future commercialization of RGX314. Related to that, earlier this month, we presented initial data from a Phase II bridging study of RGX314 using subretinal delivery, where we evaluated wet AMD patients receiving RGX314 manufactured by our NavXpress platform process at the same dose levels being used in the two pivotal trials. The clinical profile of these pivotal doses of RGX314 using the commercial scale process is encouraging and provides validation for our plans for future commercialization. Now, we've also progressed RGX314 this year using supracroidal delivery for both wet AMD and diabetic retinopathy, with positive interim data updates in the last quarter of 2022 supporting the emerging clinical profile and the potential of this in-office approach for a one-time gene therapy. The AVE and altitude trials are ongoing. We expect to complete recent enrollment of recently announced new cohorts in these trials in the first half of 2023 and report additional interim data, including initial data from these cohorts in the second half of 2023. Quickly moving over to our rare disease pipeline, we announced earlier this year that the Affinity Duchenne trial of RGX202 is active in recruiting patients. Duchenne is a key piece of our 5x25 strategy and represents a large patient population with significant unmet need. Our Duchenne program features a highly differentiated product candidate, including an optimized novel microdystrophin and a unique AAV8 capsid, which has the potential to improve muscle strength, motor function, and increase access to gene therapy for boys with Duchenne. We are also starting our trial using our proprietary commercial scale CGMP NavXpress manufacturing process that has demonstrated increased purity and yield and that we believe will support efficient advancement from the clinic to commercial readiness. Today, we announced that we expect to report initial data from the Affinity Duchenne trial in the second half of this year. As I mentioned, our NavXpress platform process and the commercial scale manufacturing innovation center represent key differentiators for Regenexx file that we're using across our entire clinical trial pipeline to support accelerating the development of AAV therapeutics. Our pivotal program for RGX121 for the treatment of MPS2, or Hunter Syndrome, also is expected to incorporate our NavXpress drug product manufactured at our Manufacturing Innovation Center to support future commercialization. And today we announced that the campsite trial, the pivotal trial, is expected to complete enrollment in the first half of 2023 to support a BLA filing in 2024 using the accelerated approval pathway. We had multiple presentations last week at the 2023 World Symposium, where we certainly provided positive updates from trials associated with RGX121, as well as RGX111 in severe MPS1 or Hurler syndrome, and treatments that we're developing for CLN2, a form of Batten disease, all of which Steve will review in greater detail momentarily. We expect to share additional updates on Batten, Hurler, and the Hunter program plans and clinical progress throughout 2023. With that, I'm going to turn the call over to Steve so he can review in more detail our clinical progress.

Thank you, Ken. I'll begin with an update on RGX314, which is being developed in collaboration with AbbVie to treat wet AMD and diabetic retinopathy. RGF314 uses the NAVAVA vector to deliver a gene encoding a therapeutic antibody fragment to inhibit vascular endothelial growth factor, or VEGF. Wet AMD is the leading cause of vision loss in people over 60, affecting more than 2 million patients in the US, Europe, and Japan. The current standard of care for wet AMD patients are anti-VEGF treatments, which require patients to receive frequent injections in the eye. Real-world evidence shows that patients with wet AMD are severely undertreated due to the unsustainable treatment burden of these frequent injections. As a result, the majority of wet AMD patients experience significant vision loss over time. Last quarter, we presented positive data from the Phase I-IIa long-term follow-up study of RGS314 for the treatment of wet AMD using subretinal delivery at the AAO annual meeting that was held in October. We expect this trial, along with our two ongoing pivotal trials, Atmosphere and Ascent, to support our planned BLA submission in 2024. As Ken mentioned, we also presented data from the Phase II pharmacodynamic bridging study of RGX314 for the treatment of wet AMD using subretinal delivery at the Angiogenesis Conference earlier this month. The data demonstrated that RGX314 produced by the NavXpress platform process exhibited a similar clinical profile to the initial adherence cell culture process used in the Phase 1-2A trial, validating the NavXpress platform process to support the production of RGX314 for future commercialization. RGX314 has been well-tolerated in this ongoing trial. Patients in the two high-dose cohorts also demonstrated stable-to-improve BCVA and CRT and meaningful reductions in anti-VEGF burden, with the majority of subjects injection-free. The Phase II pharmacodynamic study is designed to evaluate the same dose levels being used in the two pivotal trials. We also continue to advance two additional RGX314 programs for the treatment of wet AMD and diabetic retinopathy using in-office suprachoroidal delivery. Last quarter, we announced new data from the Phase II ABA trial, a randomized dose escalation study evaluating RGX314 in subjects with wet AMD. We also announced the expansion of this trial to further explore the third dose level in a sixth cohort with a short course of prophylactic ocular steroids following RGX314 administration to potentially prevent the observed incidence of mild to moderate IOI. Patients are being enrolled in cohort six regardless of NAP status. Moving to RGX314 for the treatment of diabetic retinopathy. DR is a complication of diabetes and is the leading cause of blindness in adults between the ages of 24 to 75 and affects an estimated 27 million patients worldwide. DR is a slowly progressing disease that can lead to vision-threatening complications, including diabetic macular edema and neovascularization, that can lead to blindness. Like in wet AMD, patients with DR are treated with anti-VEGF therapy, which has proven to reduce the risk of developing vision-threatening complications. However, due to the unsustainable treatment burden of frequent anti-VEGF injections, many patients with this condition either elect to forego treatment or put off receiving any treatment until symptoms become unavoidable. We believe a one-time gene therapy like RGS314 could potentially overcome this hurdle and provide an important therapy for DR patients to significantly alter their disease progression. In November, we announced new data from Altitude, our randomized controlled dose escalation phase 2 trial, evaluating suprachoroidal delivery of RGF314 in patients with DR at the Retina Society annual meeting. We also announced that we expanded that trial to include a higher third dose level with patients stratified by DRSS levels across cohorts and all receiving a short course of prophylactic ocular steroids following RGX314 administration to potentially prevent the observed incidence of mild IOI. Shifting to our rare disease portfolio, RGX202 is our potential one-time gene therapy for the treatment of Duchenne, being developed as a highly differentiated product designed to deliver a transgene for a novel microdystrophin that includes the functional elements of the CT terminal or CT domain found in naturally occurring dystrophin. In preclinical studies, the presence of the CT domain has been shown to recruit several key proteins to the muscle cell membrane, leading to improved muscle resistance to contraction-induced muscle damage in dystrophic mice models. Additional design features, including codon optimization and reduced CPG content, have the potential to improve gene expression, increase translational efficiency, and reduce immunogenicity. RGS202 is designed to support the delivery and targeted gene expression throughout skeletal and heart muscle using our NAB-AAB8 vector and a well-characterized muscle-specific promoter. In January, we announced that our Phase I-II Affinity to Duchenne trial is active and recruiting and will assess the safety and tolerability of RGS202 as well as microdystrophin protein expression levels, muscle strength and functional measures, and muscle MRI in patients with Duchenne. We are on track to dose our first patient in this trial using commercial-scale CGMP material from our NavXpress platform process in the first half of this year. We are also recruiting patients in the Affinity Beyond trial, an observational screening study with the primary objective to evaluate the presence of AAV8 antibodies in patients with Duchenne to potentially help identify participants for the Affinity Duchenne trial and other possible future trials of RGX202. We also continue to progress our two programs for mucopolysaccharidoses, RGX-121 for MPS II and RGX-111 for MPS I, last week represented positive data from both programs at the 2023 World Symposium. Additional positive interim data from the Phase 1-2-3 campsite trial of RGX-121 for MPS II showed patients in Cohort 3 using the pivotal program dose continue to demonstrate the largest reduction in CSF GAGs and these patients continue to approach normal levels at week 48. As a reminder, heparin sulfate, or HS, and D2S6, a component of HS, closely correlated with severe MPS II, are GAGs that are key biomarkers of I2S enzyme activity and are being measured in the CSF at baseline and after administration of RGX121. CSF GAGs have the potential to be considered a surrogate endpoint that is reasonably likely to predict clinical benefit in MPS II disease under the accelerated approval pathway, as buildup of GAGs in the CSF of MPS II patients correlates with clinical manifestations, including neurodevelopmental deficits. Additionally, patients demonstrated continued improvement in neurodevelopmental and daily activity skill acquisition up to three years after RGX121 administration. As of January 3rd, 2023, RGX121 was reported to be well-tolerated across all cohorts with no drug-related SAEs. At World, we also shared additional positive interim data from the Phase 1-2 trial of RGX111 for the treatment of severe MPS1. As of January 17, 2023, RGX111 was reported to be well-tolerated with no drug-related serious adverse events. Patients demonstrated positive IgA biomarker activity in the CNS and encouraging continued neurodevelopmental skill acquisition as measured by age and developmentally appropriate validated instruments for neurodevelopmental testing. Following these two programs, we are also developing two programs to help treat the manifestations of CLN2, RGX181 to treat the neurodegenerative manifestations and RGX381 to treat the ocular manifestations. As we recently announced, we expect to initiate the Phase 1-2 clinical trial of RGX381 in the UK in the first half of this year. And late last year, a patient was dosed under a single-patient investigator-initiated study of RGS181 in Brazil. To conclude, we have made significant progress with data updates and trial progression across all of the programs in our pipeline as we continue working toward our goal of 5 by 25. As Ken mentioned, today is Rare Disease Day and February is Low Vision Awareness Month, And I'd like to take this opportunity to acknowledge the patients, caregivers, investigators, and physician partners who participate in our work. Without them, our progress in advancing our programs with the goal of delivering the curative potential of gene therapy simply would not be possible. And with that, I would like to turn the call over to Vit to review our financial guidance. Vit?

Thank you, Steve. Regenexx Bio ended the quarter and year on December 31, 2022, with cash, cash equivalents, and marketable securities totaling $565 million, compared to $849 million as of December 31, 2021. The decrease was primarily driven by cash used to fund operating activities and capital expenditures in 2022. R&D expenses were $242 million for the year ended December 31, 2022, compared to $181 million in 2021. The increase was primarily attributable to personal costs and expenses associated with clinical trials and manufacturing-related activities for our lead product candidates, and was partially offset by Regenexx 314 development costs reimbursable by AbbVie under our iCare collaboration. In accordance with the collaboration agreement, Regenexx Bio was responsible for the funding of certain ongoing clinical trials for Regenexx 314 through the end of 2022, while other RGX 314 development costs were shared with AbbVie. Beginning in 2023, ABBYY will be responsible for funding the majority of all RGX 314 development expenses. We expect a balance in cash, cash equivalents, and marketable securities of $565 million as of December 31st, 2022 to fund our operations into 2025. This cash runway guidance is based on the company's current operational plans and excludes the impact of any payments that may be received from ADVI on the achievement of development or commercial milestones under our RGX314 collaboration. With that, I will turn the call back to Ken to provide final thoughts.