CHOP

--Researchers found exposing cells to a small molecule drug improved their fitness during hematopoietic stem cell transplants, which could broaden access and improve outcomes for ex vivo gene therapy– PHILADELPHIA, Sept. 27, 2023 /PRNewswire/ -- A readily available, inexpensive small molecule drug can improve the fitness of hematopoietic stem and progenitor cells (HSPCs) that are modified outside of the body, potentially improving the success of procedures like ex vivo gene therapy, according to a new study by researchers at Children's Hospital of Philadelphia (CHOP). The study, published in the journal Blood, showed that targeting components in the cells called extracellular vesicles (EVs) relieves the stress on cells when outside of the body, improving their performance when they are transplanted back inside. "We initially embarked on this project to better understand the role of these vesicles, assuming – wrongly, as it turns out – that blocking their function would have detrimental effects on the cells," said first author Stephanie Hurwitz, MD, PhD, a research fellow in the Kurre Lab at CHOP and Hematopathologist at the University of Pennsylvania. "We discovered the opposite is true: blocking the formation of these vesicles over a relatively short period of time actually improved the cells' fitness, initiating an adaptive stress response that protects them from the stress of being outside of the body. Ultimately, this serendipitous finding could enhance the quality of transplant products used in treatments like ex vivo gene therapy, improving patient outcomes." Hematopoietic stem cell transplantation (HSCT) involves the transfer of HSPCs from a donor to patients with both benign and malignant diseases. In some cases, as in ex vivo gene therapy, the patient acts as their own donor: the patient's HSPCs are removed, modified outside of the body using gene addition or gene editing, and then transplanted back in. When enough cells are available for modification, this strategy has proven to be a powerful platform for treating genetic blood disorders, including sickle cell disease and beta thalassemia. However, maintaining the fitness of these cells outside of the body poses a challenge, and any loss of fitness introduces the risk that the cells will not properly restore the blood and immune cell system in patients. For this reason, researchers have sought to better understand HSPC programming and signaling so that every attempt could be made to maintain cell health ahead of transplant. One process that we now learn contributes to cell equilibrium is the secretion of EVs, which are important for delivering messages from cell to cell and maintaining proper cell function. However, technical challenges have previously prevented researchers from fully understanding the role these EVs might play in HSPC fitness outside of the body. To explore the role of EVs, the researchers exposed both mouse and human HSPCs to GW4869, a readily available small molecule drug that blocks neutral sphingomyelinase-2 (nSMase2), an enzyme involved in EV formation. The researchers found that an exposure of 24 hours led to sustained improvements in cell fitness and transplantation efficiency after ex vivo culture, with improved rates of blood cell function in mouse models. Additionally, the researchers found that blocking nSMase2 in human CD34+ cells leveled disparities in how well the cells of varying HLA types performed after transplantation into mice. This is of particular interest given important role of HLA in long-term transplantation outcomes. Drilling down on the mechanisms behind these phenomena, the researchers determined that blocking nSMase2 activates an integrated stress response, effectively putting the cells into a state of quiescence, where they are protected from external stressors. This occurs due, in part, from GW4869 disrupting sphingolipid metabolism, which impairs the release of nSMase2-dependent EVs. "While numerous advances have been made over past decades to improve safety and efficiency of HSPC transplantation and ex vivo gene therapy, constraints in cell quantity and graft success continue to limit outcomes," said senior author Peter Kurre, MD, Director of the Pediatric Comprehensive Bone Marrow Failure Center at CHOP. "This important study, which links EV trafficking and the integrated stress response as a regulatory dyad guarding HSPC integrity and long-term fitness, has important implications for potentially broadening patient eligibility to ex vivo gene therapies. Researchers should continue to explore the potential of this small molecule drug in improving ex vivo HSPC culture and transplantation." This research was supported by NIH grants R01-HL164633, 4-R38-HL143613-04 , T32 HL-07439, and P30ES013508. The analyses were made possible through collaboration with the CHOP Flow Cytometry core laboratory, CHOP Department of Veterinary Resources, University of Pennsylvania Stem Cell and Xenograft Core, University of Pennsylvania Hematopoietic Stem Cell Laboratory, CHOP-PENN Proteomics Core Facility, and CHOP Center for Applied Genomics core laboratory. Hurwitz et al. "Neutral sphingomyelinase blockade enhances hematopoietic stem cell fitness through an integrated stress response," Blood, online Sept. 12, 2023, DOI: 10.1182/blood.2023022147 About Children's Hospital of Philadelphia: A non-profit, charitable organization, Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals, and pioneering major research initiatives, the 595-bed hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country. The institution has a well-established history of providing advanced pediatric care close to home through its CHOP Care Network, which includes more than 50 primary care practices, specialty care and surgical centers, urgent care centers, and community hospital alliances throughout Pennsylvania and New Jersey, as well as an inpatient hospital with a dedicated pediatric emergency department in King of Prussia. In addition, its unique family-centered care and public service programs have brought Children's Hospital of Philadelphia recognition as a leading advocate for children and adolescents. For more information, visit . Contact: Jennifer Lee Children's Hospital of Philadelphia (267) 426-6084 [email protected] SOURCE Children's Hospital of Philadelphia

Orum’s new program in immuno-oncology achieves simultaneous blockade of PD-1/PD-L1 pathway and delivery of a Cbl-b inhibitor using anti-PD-1-Cbl-bi conjugates and demonstrates enhanced T cell activation in vitro compared to anti-PD-1 alone, even in the presence of immunosuppressive factors ORM-6151 shows superior tolerability and robust single-dose efficacy, both in vitro and in vivo compared to CC-90009 or Mylotarg™, suggesting the potential for an improved therapeutic option in AML that appropriately balances efficacy with safety and tolerability of a clinically validated GSPT1 degradation mechanism Orum has identified pharmacodynamic biomarkers as predictors of efficacy to support clinical development of ORM-5029 in HER2-expressing solid tumors BOSTON & DAEJEON, South Korea--(BUSINESS WIRE)-- Orum Therapeutics, a clinical-stage private biotechnology company pioneering cell-specific targeted protein degradation (TPD² ™) and targeted protein stabilization (TPS² ™), today announced new preclinical data for three of Orum’s therapeutic programs: ORM-5029, which is a proprietary GSPT1 degrader conjugated to HER2-targeting antibody pertuzumab; ORM-6151, which delivers GSPT1 degrader to CD33+ tumors; and its new immuno-oncology program for a Cbl-b inhibitor (Cbl-bi) conjugated to anti-PD-1 antibody pembrolizumab. The data were presented in three posters at the 2023 American Association for Cancer Research (AACR) Annual Meeting. “We are pleased to present new data supporting clinical development of two programs from our TPD² GSPT1 Degrader Platform, which was developed to improve the therapeutic window and realize the full potential of GSPT1 degraders through precision delivery to cancer cells via antibody drug conjugates,” said Peter Park, Ph.D., Chief Scientific Officer of Orum Therapeutics. “We are also excited to unveil at AACR our new TPS² platform, which has the potential to achieve the full promise of Cbl-b inhibitors through T cell-specific delivery. With this novel approach, we show that we can limit unwanted systemic exposure, including the risk of toxicity associated with c-Cbl inhibition, prolong the activation of exhausted PD-1+ T cells, and provide resistance to negative environmental cues such as TGF-β or regulatory T cells. We believe our approach of harnessing the power of protein degraders and stabilizers with the precision of antibody targeting will improve the treatment of cancer for more patients.” Details of the data presented are as follows: Title: A novel antibody-enabled Dual-precision Targeted Protein Stabilization (TPS²) that augments anti-tumor immune response by targeting Cbl-b inhibitor to exhausted T cells while blocking checkpoint molecule, PD-1 Presenter: Joanne Lim, Ph.D. Abstract Number: 4436 Summary: Cbl-b inhibition results in stabilization of intracellular proteins downstream of the T cell activation pathways. Using a murine model well-established to be refractory to anti-PD-1 antibody treatment, we demonstrated that anti-PD-1-Cbl-b inhibitor approach increased effector T cell markers in the tumor and delayed tumor growth. Presented Data: The delivery of Cbl-b inhibitor (Cbl-bi) conjugated to anti-PD-1 antibody enhances the saturating, maximum activation of anti-PD-1 antibody by 300% in PD-1/PD-L1 blockade assay. Anti-PD-1-Cbl-bi conjugates enhance T cell responses of mixed lymphocyte reaction in a dose-dependent manner and overcome suppressive effects of TGF-β and Treg cells compared to antibody alone in vitro. Anti-PD-1-Cbl-bi conjugates enhance ex vivo activation of tumor-associated T cells from human cancer patients compared to antibody alone or when treated with antibody and unconjugated Cbl-bi. Anti-PD-1-Cbl-bi conjugates delay the growth of melanoma tumors in hPD-1 transgenic mice, with corresponding increase in intratumoral transcript levels of CD3e, granzyme B, and perforin in the tumor. Title: ORM-6151: A first-in-class CD33-antibody enabled GSPT1 degrader for AML Presenter: James Palacino, Ph.D. Abstract Number: 2700 Summary: ORM-6151 shows robust single-dose efficacy, both in vitro and in vivo with superiority or comparability to standard of care (SOC) agents. In addition, in vitro testing demonstrated superior tolerability to healthy bone marrow progenitor cells, suggesting better tolerability. Responses in representative TP53 wild-type and mutant AML models demonstrated comparable activity, indicating the potential for responses in a large percentage of AML patients with poor treatment options. Presented Data: ORM-6151 shows robust in vitro activity in p53 wild-type and mutant cell models. In ex-vivo AML blasts, ORM-6151 demonstrates efficacy superior to CC-90009, a small-molecule GSPT1 degrader, or Mylotarg, an FDA-approved treatment for AML. Compared to CC-90009 or Mylotarg, ORM-6151 exhibits minimal cytotoxic activity to healthy hematopoietic progenitor cells in vitro. A single treatment of ORM-6151 at 3 mg/kg regresses MV4-11 tumors in vivo mouse model with 9/9 complete response (CR), and a single dose of 1 mg/kg produced equivalent antitumor effect as SOC doublet given at optimal repeated dose. Title: Development of RNAscope multiplex-based assay for exploratory pharmacodynamic biomarkers assessment in breast cancer patients from Phase I clinical trial of ORM-5029, a potent GSPT1 degrader Presenter: Shikha Saini, Ph.D. Abstract Number: 2118 Summary: To fulfill the need to develop pharmacodynamic biomarkers as predictors of efficacy to support clinical development of ORM-5029, Orum identified a novel GSPT1 antibody for detection of depletion following treatment with ORM-5029. GSPT1 depletion and subsequent activation of the integrated stress response are both seen following in vitro or in vivo treatment with ORM-5029. Degree of pharmacodynamic (PD) change correlates with depth and duration of in vivo response. Orum is currently developing a multiplexed (IF/ISH/ISH) assay to track PD responses in patients, with an aim to better predict responses and efficacious doses. Presented Data: Orum identified the depletion of GSPT1 as a target-proximal pharmacodynamic biomarker in ORM-5029 treated in vitro and in vivo samples. Loss of GSPT1 drives activation of integrated stress response and upregulation of ATF3 and DDIT3 mRNA and these responses are also seen following treatment with ORM-5029, in both in vitro BT-474 cells and in vivo HCC1568 mouse model. PD responses correlate with degree and duration of response in an in vivo model treated with ORM-5029. The posters are available to download through the links below: PD-1-Cbl-bi TPS² preclinical poster: ORM-6151 preclinical poster: ORM-5029 predictive biomarker poster: About Orum’s TPS² Approach Orum’s Dual-precision Targeted Protein Stabilization (TPS²) approach combines novel payloads with the precise cell delivery mechanism of antibodies to increase the levels of intracellular target proteins in a cell-type-specific manner for oncology and immuno-oncology. The first program applying the TPS² approach is a Cbl-b inhibitor (Cbl-bi) conjugated to anti-PD-1 antibody. By delivering Cbl-bi specifically to exhausted T cells, the conjugate is designed to restore effector T cell function, where PD-1 checkpoint blockade alone is insufficient, while also enabling T cells to overcome the immunosuppressive mechanisms in a tumor microenvironment. About Orum’s GSPT1 Platform Using the TPD² Approach Orum’s GSPT1 platform uses the company’s unique Dual-precision Targeted Protein Degradation (TPD²) approach to build novel targeted protein degraders combined with the precise tumor cell delivery mechanisms of antibodies to generate innovative, first-in-class, cell-specific TPDs for the treatment of cancer. Orum has developed new molecular glue degrader payloads to specifically degrade an intracellular target protein within cancer cells via the E3 ubiquitin ligase pathway. Conjugated to antibodies, the payloads are designed to be delivered specifically to cancer cells and degrade the intracellular target protein GSPT1 and cause tumor cell death. About Orum Therapeutics Orum Therapeutics is a private, clinical-stage biotech pioneering the development of tumor-directed targeted protein degraders (TPD²) and stabilizers (TPS²) with the precision of antibody targeting to improve cancer treatment for more patients. The first therapeutic candidates from the TPD² GSPT1 platform, ORM-5029 and ORM-6151, are in clinical development for the treatment of solid tumors and hematologic cancers, respectively. The first program applying the TPS² approach is a Cbl-b inhibitor conjugated to anti-PD-1 antibody. Orum is located in Boston, US, and Daejeon, South Korea. For more info, visit . Forward-Looking Statements This press release contains forward-looking statements that are based on the current expectations and beliefs of Orum Therapeutics, Inc. (“Orum”). Statements in this release regarding matters that are not historical facts, including, but not limited to, statements relating to the potential for clinical efficacy, potency, and tolerability of Orum’s products; the potential for conducting and successfully completing clinical trials, translation of preclinical and non-human data to the clinical and human contexts, obtaining favorable trial results, conducting later-phase trials, obtaining regulatory approval of product candidates for sale, successfully commercializing product candidates, and improving the cancer treatment for more patients; the types of cancer that might be treated by Orum products; the successful prediction of patient responses and efficacious doses; and the preferability of Orum products to others available are forward-looking statements. These forward-looking statements are based on management’s expectations and assumptions as of the date of this release and are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such statements. These risks and uncertainties include, without limitation, the uncertain and continually changing impacts and expected duration of the COVID-19 pandemic; the uncertainty of success in research and development activities; risks related to clinical trials, including potential delays, safety issues, or negative results; competition from alternative therapies; the risk that Orum may not be able to maintain and enforce its intellectual property; the risk that product candidates may not be successfully commercialized or adopted; the availability of financing; and risks related to the recruitment and retention of key employees, fluctuating markets and economic conditions, health care reform, prices, and reimbursement rates. The forward-looking statements in this presentation speak only as of the date of this release, and Orum undertakes no obligation to update or revise any of the statements. Orum cautions investors not to place considerable reliance on the forward-looking statements contained in this release.

--Study shows viral proteins utilize phase separation to coordinate complex process of replicating viral genomes and then encapsulating that DNA in a viral particle-- PHILADELPHIA, April 5, 2023 /PRNewswire/ -- In a twist on the question, "Which came first, the chicken or the egg?", scientists have long faced a similar question about how human adenovirus replicates: "Which comes first, assembly of the viral particle, or packaging of the viral genome?" Now, in a new study published today in Nature, researchers at Children's Hospital of Philadelphia (CHOP) have answered that question, showing that viral proteins use a process called phase separation to coordinate production of viral progeny. Continue Reading "This study answers a fundamentally important question: how a viral nucleic acid gets inside a particle so that viral offspring can be delivered to cells," said Matthew Charman, PhD, a research associate in the Weitzman Lab at Children's Hospital of Philadelphia. "These findings have broad implications, from potential therapeutic interventions to improved gene therapy delivery, in addition to expanding our understanding of basic cell biology." "These findings have broad implications, from potential therapeutic interventions to improved gene therapy delivery." Tweet this Viruses hijack host cellular processes to replicate and produce infectious offspring that are key for viral spread and transmission. To do so, they must both replicate their viral genomes and package those genomes into viral particles, so that the infectious cycle can continue. However, little is known about how genome replication, particle assembly, and genome packaging are coordinated in the crowded nuclear environment. "If we think of viral replication as an old-fashioned milk assembly line, we know how the milk bottles are formed and that they come out filled, but prior to this study, the process of filling them was somewhat of a black box," said senior author Matthew D. Weitzman, PhD, a professor in CHOP's Department of Pathology and Laboratory Medicine. "Our findings suggest that the viral particle forms around the viral genome. Extending the analogy, many have assumed that the bottle must be made before being filled, but it turns out the bottle is actually formed around the milk. Led by Dr. Charman, we have shown that a biophysical process known as phase separation allows this process to occur in an orderly, coordinated fashion." Emerging evidence suggests that membraneless compartments form inside virus-infected cells by phase separation. These membraneless compartments, known as biomolecular condensates (BMCs), can regulate biological processes by concentrating or sequestering biomolecules in an enriched dense phase, while limiting their concentration in the light phase. Although BMCs have been linked to several viral processes, there was insufficient evidence that phase separation contributes functionally to the assembly of infectious viral offspring in infected cells. To investigate the potential role of BMCs in this process, the researchers studied adenovirus, a nuclear-replicating DNA virus. Because the adenovirus proteins involved in genome replication are distinct from those involved in particle assembly and genome packaging, the researchers reasoned focusing on this virus would allow them to dissect and more easily identify the role of phase separation in specific viral processes. Through a variety of techniques, including homopropargylglycine (HPG) labeling and fluorophore click chemistry, the researchers demonstrated that the adenovirus 52 kDa protein – a dedicated assembly/packaging protein – makes its own membraneless structures through phase separation and plays a critical role in the coordinated assembly of new infectious particles. They showed that not only does the 52 kDa protein organize viral capsid proteins into nuclear BMCs, but also that this organization is essential for the assembly of complete, packaged particles containing viral genomes. Additionally, the researchers performed experiments with a mutant adenovirus lacking the 52 kDa protein and showed that incomplete capsids formed in the absence of viral BMCs. Thus, the researchers were able to show that by altering the formation of these membraneless structures within the cell, the "assembly line" producing viral offspring no longer functioned properly. "Now knowing these steps, the question becomes: could we reengineer viruses based on this biological process to, for example, become better delivery vehicles for innovations like gene therapy?" Dr. Charman said. "Understanding how viruses are made opens up a world where we could not only potentially target those viruses more effectively in the future but also create gene therapy tools that lack the limitations of current delivery approaches." This research was supported by NIAID grants R01-AI145266 and R01-AI121321. Charman et al. "A viral biomolecular condensate coordinates assembly of progeny particles," Nature, April 5, 2023, DOI: 10.1038/s41586-023-05887-y About Children's Hospital of Philadelphia: A non-profit, charitable organization, Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals, and pioneering major research initiatives, the 595-bed hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country. The institution has a well-established history of providing advanced pediatric care close to home through its CHOP Care Network, which includes more than 50 primary care practices, specialty care and surgical centers, urgent care centers, and community hospital alliances throughout Pennsylvania and New Jersey, as well as an inpatient hospital with a dedicated pediatric emergency department in King of Prussia. In addition, its unique family-centered care and public service programs have brought Children's Hospital of Philadelphia recognition as a leading advocate for children and adolescents. For more information, visit . Contact: Dana Bate Children's Hospital of Philadelphia (267) 426-6055 [email protected] SOURCE Children's Hospital of Philadelphia