UBE3A

GTX-102 is the first Angelman syndrome therapeutic candidate to receive PRIME designation Phase 1/2 study fully enrolled; expansion data expected in first half of 2024 NOVATO, Calif., Feb. 05, 2024 (GLOBE NEWSWIRE) -- Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) today announced that the European Medicines Agency (EMA) has granted Priority Medicine (PRIME) designation to GTX-102 for the treatment of Angelman syndrome (AS). GTX-102 is an investigational antisense oligonucleotide delivered via intrathecal administration and is designed to target and inhibit expression of UBE3A antisense transcript (UBE3A-AS). The EMA granted this designation in response to compelling early clinical data from the extension cohorts in the Phase 1/2 study of GTX-102 demonstrating clinically meaningful improvements in several neurodevelopmental domains including cognition, receptive communication and gross motor skills in individuals with Angelman syndrome. "By granting PRIME designation, the EMA is recognizing the potential for GTX-102 to address the critical need for new treatments for children and families impacted by Angelman syndrome in the EU,” said Eric Crombez, M.D., chief medical officer at Ultragenyx. “Our team is working with urgency on the development of GTX-102 for Angelman syndrome and looks forward to working closely with regulators in the U.S. and EU to bring this innovative treatment to patients.” PRIME designation is granted by the EMA to provide early and proactive support to developers of promising medicines that may offer a major therapeutic advantage over existing treatments or benefit to patients without treatment options. These medicines are considered priority medicines by the EMA, whose aim is to optimize development plans and speed up evaluations so these medicines that address significant unmet medical needs can reach patients faster. About the Phase 1/2 study The Phase 1/2, open-label, multiple-dose, dose-escalating study is evaluating the safety and tolerability of GTX-102 administered by intrathecal (IT) injection to pediatric patients with Angelman syndrome with a genetically confirmed diagnosis of full maternal UBE3A gene deletion. The study is also assessing clinical response as measured by a panel of efficacy assessments for the functional domains impacted in Angelman syndrome. Patients in the earlier extension cohorts (Cohorts 4-7) of the study have moved into long-term maintenance dosing, and the study has completed enrollment for the new expansion cohorts to verify the GTX-102 dose range and treatment regimen that will be used in the Phase 3 program. About Angelman Syndrome Angelman syndrome is a rare, neurogenetic disorder caused by loss-of-function of the maternally inherited allele of the UBE3A gene. The maternal-specific inheritance pattern of Angelman syndrome is due to genomic imprinting of UBE3A in neurons of the central nervous system (CNS), a naturally occurring phenomenon in which the maternal UBE3A allele is expressed and the paternal UBE3A is not. Silencing of the paternal UBE3A allele is regulated by the UBE3A antisense transcript (UBE3A-AS), the intended target of GTX-102. In almost all cases of Angelman syndrome, the maternal UBE3A allele is either missing or mutated, resulting in limited to no protein expression. This condition is generally not inherited but instead occurs spontaneously. It is estimated to affect one in 12,000 to one in 20,000 people globally. Individuals with Angelman syndrome have developmental delay, balance issues, motor impairment and debilitating seizures. Some individuals with Angelman syndrome are unable to walk and most do not speak. Anxiety and disturbed sleep can be serious challenges in individuals with Angelman syndrome. Although individuals with Angelman syndrome have a normal lifespan, they require continuous care and are unable to live independently. Angelman syndrome is not a degenerative disorder, but the loss of the UBE3A protein expression in neurons results in abnormal communications between neurons. Angelman syndrome is often misdiagnosed as autism or cerebral palsy. There are no currently approved therapies for Angelman syndrome; however, several symptoms of this disorder can be reversed in adult animal models of Angelman syndrome suggesting that improvement of symptoms can potentially be achieved at any age. About GTX-102 GTX-102 is an investigational antisense oligonucleotide delivered via intrathecal administration and designed to target and inhibit expression of UBE3A-AS. Nonclinical studies have shown that GTX-102 reduces levels of UBE3A-AS and reactivates expression of the paternal UBE3A allele in neurons of the CNS. Reactivation of paternal UBE3A expression in animal models of Angelman syndrome has been associated with improvements in some of the neurological symptoms associated with the condition. GTX-102 has been granted Orphan Drug Designation, Rare Pediatric Disease Designation, and Fast Track Designation from the FDA, and Orphan Designation and PRIME designation from the EMA. About Ultragenyx Pharmaceutical Inc. Ultragenyx is a biopharmaceutical company committed to bringing novel products to patients for the treatment of serious rare and ultrarare genetic diseases. The company has built a diverse portfolio of approved therapies and product candidates aimed at addressing diseases with high unmet medical need and clear biology for treatment, for which there are typically no approved therapies treating the underlying disease. The company is led by a management team experienced in the development and commercialization of rare disease therapeutics. Ultragenyx’s strategy is predicated upon time- and cost-efficient drug development, with the goal of delivering safe and effective therapies to patients with the utmost urgency. For more information on Ultragenyx, please visit the company's website at: . Ultragenyx Forward-Looking Statements and Use of Digital Media Except for the historical information contained herein, the matters set forth in this press release, including statements related to Ultragenyx's expectations and projections regarding its future operating results and financial performance, future clinical and regulatory developments for GTX-102, the clinical benefit, tolerability and safety of GTX-102, timing for enrollment, dosing and data for GTX-102 and the company’s other investigational therapies and regulatory meetings are forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements involve substantial risks and uncertainties that could cause our clinical development programs, collaboration with third parties, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainty of clinical drug development and unpredictability and lengthy process for obtaining regulatory approvals, the ability of the company to successfully develop GTX-102, the company’s ability to achieve its projected development goals in its expected timeframes, risk that access to PRIME for our product candidates, if granted, may not lead to faster development or regulatory review or approval process, and does not increase the likelihood that our product candidates will receive marketing approval; risks related to adverse side effects, risks related to reliance on third-party partners to conduct certain activities on the company’s behalf, the potential for any license or collaboration agreement, smaller than anticipated market opportunities for the company’s products and product candidates, manufacturing risks, competition from other therapies or products and other matters that could affect sufficiency of existing cash, cash equivalents and short-term investments to fund operations, the Company’s future operating results and financial performance, the timing of clinical trial activities and reporting results from same, and the availability or commercial potential of Ultragenyx’s products and product candidates. Ultragenyx undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of Ultragenyx in general, see Ultragenyx's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on November 3, 2023, and its subsequent periodic reports filed with the SEC. In addition to its SEC filings, press releases and public conference calls, Ultragenyx uses its investor relations website and social media outlets to publish important information about the company, including information that may be deemed material to investors, and to comply with its disclosure obligations under Regulation FD. Financial and other information about Ultragenyx is routinely posted and is accessible on Ultragenyx’s Investor Relations website ( ) and LinkedIn website ( ). Contacts Ultragenyx Pharmaceutical Inc. Investors Joshua Higa +1-415-475-6370 ir@ultragenyx.com Media Carolyn Wang +1-415-225-5050 media@ultragenyx.com

KANAZAWA, Japan, Jan. 10, 2024 /PRNewswire/ -- Researchers at Nano Life Science Institute (WPI-NanoLSI), Kanazawa University report in Nano Letters how the flexibility of a protein hinge plays a crucial role in the transfer of proteins in key cell processes. Ubiquitination – the addition of the protein ubiquitin - is a key stage in many cell processes, such as protein degradation, DNA repairs, and signal transduction. Using high-speed atomic force microscopy (HS-AFM) and molecular modelling, researchers led by Hiroki Konno and Holger Flechsig at WPI-NanoLSI, Kanazawa University have identified how the mobility of a ubiquitination related enzyme hinge allows ubiquitination to take place. Previous studies have identified a number of enzymes that facilitate ubiquitination, including an enzyme that activates ubiquitin (E1), an enzyme that conjugates it (E2), and an enzyme that catalyzes ubiquitin protein joining (i.e. a ligase, E3) to target protein (Fig. 1). The HECT-type E3 ligase is characterized by a HECT domain that comprises an N lobe with the E2-binding site and a C lobe with a catalytic Cys residue, a flexible hinge connects the two lobes, leading to the hypothesis that ubiquitination is facilitated by the rearrangement of the protein around this hinge. Konno and their collaborators deployed their high-speed atomic force microscope to hunt for evidence that this was the case. The researchers noted that when the HECT domain was crystallized with a type of E2 enzyme, it formed an L shape such that the distance between the catalytic Cys residue of the HECT domain and the catalytic Cys of the E2 enzyme was 41 Å – too far for the transfer of ubiquitin. However, in its catalytic conformation the HECT domain has a different shape where the distance between the two catalytic Cys residues is much closer – just 8 Å – so this is thought to be a 'catalytic conformation'. Analysis of HS-AFM images of a wild-type HECT domain of E6AP revealed two conformations – one of which looked spherical and the other oval (Fig. 2). Using AFM simulations they attributed the oval shapes to the L conformation and spherical shapes are either the catalytic conformation or the so called inverted T conformation, which had been observed in the another type of HECT domain where the distance between the Cys residues is 16 Å (Fig. 2). To overcome the spatio-temporal resolution limitations of imaging, the experiments were complemented by molecular modelling to visualize HECT domain conformational motions at the atomistic level. Simulation AFM was used to generate a corresponding pseudo AFM movie, which clearly showed the change from spherical to the oval shaped topography (Fig. 2). "Although experimental limitations do not allow us to resolve the intermediate conformations," explain the researchers in their report of the work. "The performed modeling provides evidence that the transitions between spherical and oval HECT domain shapes observed under HS-AFM correspond to functional conformational motions under which the C-lobe rotates relative to the N-lobe, thereby allowing the change between catalytic and L-shape HECT conformations." Further experiments with mutant HECT domains with less flexibility in the hinge revealed no flipping between conformations – the mutant HECT domains were locked in the catalytic conformation. They also found that while these mutant HECT domains could form two ubiquitin proteins joined together more efficiently than the wild type. E6AP, the HECT-type E3 in this study, interacts with E6 protein derived from human papillomavirus (HPV) and ubiquitinates p53, a tumor suppressor protein. It is also known that ubiquitination of p53 by E6AP and E6 is a major cause of cervical cancer. However, the mechanism of p53 ubiquitination by the interaction of E6AP and E6 proteins remains unclear. In the future, we will elucidate the structural dynamics of E6AP/E6, and the E6AP/E6/p53 complex with HS-AFM, and clarify how E6 increases the activity of p53 ubiquitination by E6AP. Figure 1 link: Fig 1 caption: Ubiquitination and degradation of protein by the ubiquitin-proteasome system. © 2023 Takeda, et al., Published by American Chemical Society Fig. 2 link: Fig 2 caption: High-speed AFM observation and simulation of the structural dynamics of the HECT domain of E6AP. (A) HS-AFM image of the HECT domain. Spherical (white dotted line) and oval (blue dotted line) conformational states were observed. (B) Simulated transition process of the structural state of the HECT domain and its pseudo AFM image. (C) Ubiquitin (Ub) is transferred from E2 to E3 (HECT domain). After the addition of ubiquitin-containing E2 (E2-Ub), E2-Ub (white arrow) binds to the HECT domain, and after E2 dissociates, a small particle (blue arrow) that appears to be ubiquitin is added to the HECT domain. © 2023 Takeda, et al., Published by American Chemical Society Glossary Ubiquitin The protein takes its name from the term 'ubiquitous' because it is found in almost all tissues. It can be added as a single protein or further proteins added into a chain. This 'ubiquitination' is an essential step in many cell processes. High-speed atomic force microscopy This imaging technique uses a nanosized tip at the end of a cantilever that is scanned over a sample. It can be used to determine the topography of a sample surface from the change in the strength of forces between the tip and the sample with distance, and the resulting deflection of the cantilever. It was first developed in the 1980s but a number of modifications have augmented the functionality of the technique since. It is better suited to imaging biological samples than the scanning tunnelling microscope developed that had been developed because it does not require a conducting sample. In the 2000s Toshio Ando at Kanazawa University was able to improve the scanning speed to such an extent that moving images could be captured. This allowed people to use the technique to visualize molecular processes for the first time. Reference Kazusa Takeda†, Holger Flechsig†, Ikumi Muro†, Romain Amyot, Fuminori Kobayashi, Noriyuki Kodera, Toshio Ando and Hiroki Konno, Structural Dynamics of E6AP E3 Ligase HECT Domain and Involvement of a Flexible Hinge Loop in the Ubiquitin Chain Synthesis Mechanism, Nano Letters, 2023, 23, 24, 11940–11948. †These authors contributed equally to this work DOI：10.1021/acs.nanolett.3c04150 Contact Hiroe Yoneda Senior Specialist in Project Planning and Outreach NanoLSI Administration OfficeNano Life Science Institute (WPI-NanoLSI) Kanazawa University Kakuma-machi, Kanazawa 920-1192, Japan Email: [email protected] Tel: +81 (76) 234-4555 About Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Understanding nanoscale mechanisms of life phenomena by exploring 'uncharted nano-realms'. Cells are the basic units of almost all life forms. We are developing nanoprobe technologies that allow direct imaging, analysis, and manipulation of the behavior and dynamics of important macromolecules in living organisms, such as proteins and nucleic acids, at the surface and interior of cells. We aim at acquiring a fundamental understanding of the various life phenomena at the nanoscale. About the World Premier International Research Center Initiative (WPI)