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Tessera Therapeutics showcases new preclinical data demonstrating progress of In Vivo programs for sickle cell disease and T Cell Therapies at the 67th American Society of Hematology Annual Meeting. December 08, 2025 08:00 ET | Source: Tessera Therapeutics * Presented new data in non-human primates (NHP) for sickle cell disease (SCD), where RNA Gene Writer achieved approximately 40% and 60% of long-term hematopoietic stem cells (LT-HSCs) with at least one edited allele after 1 or 2 doses, respectively, exceeding the anticipated curative threshold * Evidence in NHP that T cell directed lipid nanoparticles (LNP) produced functional chimeric antigen receptor (CAR)-T cells in vivo, with significant B cell clearance observed in blood and lymph nodes SOMERVILLE, Mass., Dec. 08, 2025 (GLOBE NEWSWIRE) - Tessera Therapeutics, the biotechnology company pioneering a new approach in genetic medicine known as Gene Writing(TM), is presenting updates across its in vivo genetic medicine programs for SCD and T cell therapies, including its proprietary delivery platform that enables extra-hepatic LNP delivery to hematopoietic stem cells (HSCs) and T cells. These data were shared across three poster presentations at the American Society of Hematology (ASH) Annual Meeting taking place in Orlando, Florida, December 6 - 9, 2025. "These latest data highlight meaningful progress towards a potentially curative, non-viral approach for treating sickle cell disease (SCD), with our Gene Writers achieving in vivo editing levels in long-term stem cells that exceed the established efficacy thresholds for transformative clinical benefit, without the use of stem cell mobilization, toxic myeloablative pre-conditioning, or transplantation," said Michael Severino, M.D., CEO of Tessera Therapeutics. "We are also encouraged by our T cell engineering results, which demonstrate the ability to generate functional CAR-T cells in NHPs in vivo. Together, these findings underscore the broad potential of our Gene Writing and delivery platforms to pioneer a new generation of in vivo therapies for patients." In Vivo SCD Data SCD is the most common lethal monogenic disease globally, arising from a mutation in the hemoglobin beta-globin (HBB) gene that results in hemoglobin S, which can cause red blood cell sickling, acute and chronic pain, and widespread organ damage. * Based on single cell analysis of LT-HSCs collected from NHPs treated with an optimized Gene Writer formulated in LNP, approximately 40% and 60% of cells after 1 or 2 doses, respectively, had at least one edited HBB gene. This data improves upon earlier data presented at the American Society of Gene and Cell Therapy 28th Annual Meeting, where 35-50% of cells had mono or bi-allelic HBB editing after 2 doses of Gene Writer administered. * This level of % edited cells exceeds the observed efficacy threshold of 20-30% edited HSCs associated with significant clinical benefit, including resolution of vaso-occlusive crises (VOCs) and improved anemia[1] [-] [4] . * Edited LT-HSCs continue to demonstrate durability in NHP, including out to 15 months with beta-2 microglobulin (B2M) surrogate editing and out to approximately 14 months with HBB editing. These cells showed intact HSC function, with editing seen in multiple hematopoietic lineages with continued follow-up. * RNA Gene Writers achieved efficient levels of in vivo HBB editing with a single intravenous administration, including ~35% correction to wild type in humanized mice engrafted with mobilized peripheral blood cells across SCD donors, and >50% editing across multiple healthy donors. * HSC targeted LNPs demonstrated favorable pharmacokinetics in NHP, including higher early plasma concentrations and slower initial clearance compared to liver LNP, resulting in improved systemic persistence after intravenous dosing. Advances Towards In Vivo T-Cell Therapies Tessera is applying its Gene Writing and proprietary LNP delivery platforms to develop in vivo cell therapies for potential oncology and autoimmune disease applications. * For the first time, demonstrated proof-of-concept in NHP that T cell directed LNP with CD20 targeted CAR cargo successfully delivered to T cells in vivo, which enabled robust and rapid CAR-T cell expansion and B cell clearance was observed in peripheral blood and immunohistochemistry (IHC) further confirmed significant B cell clearance in lymph nodes. * Proof-of-concept in a naïve humanized mouse model, with a single intravenous infusion of RNA Gene Writer delivered in a proprietary LNP, successfully generated functional CAR-T cells in vivo targeting CD20, resulting in the elimination of circulating human B cells. * Further, we highlighted the ability to multiplex different edits in a single step, including two different CARs, CD19 and CD20, with these dual edited CAR-T cells demonstrating superior cancer cell killing in vitro. About Tessera Therapeutics Tessera Therapeutics is pioneering a new approach to genome engineering through the development of its Gene Writing(TM) and delivery platforms, with the aim to unlock broad new therapeutic frontiers. Our Gene Writing platform is designed to write therapeutic messages into the genome by efficiently changing single or multiple DNA base pairs, precisely correcting insertions and deletions, or adding exon-length sequences and whole genes. Our proprietary lipid nanoparticle delivery platform is designed to enable the in vivo delivery of RNA to targeted cell types. We believe our Gene Writing and delivery platforms will enable transformative genetic medicines to not only cure diseases that arise from errors in a single gene, but also modify inherited risk factors for common diseases and create engineered cells to treat cancer and potentially autoimmune and other diseases. Tessera Therapeutics was founded in 2018 by Flagship Pioneering, a life sciences innovation enterprise that conceives, creates, resources, and develops first-in-category bioplatform companies to transform human health and sustainability. For more information about Tessera, please visit www.tesseratherapeutics.com.

Regeneron inks gene editing deal with startup Tessera. Summary Regeneron Pharmaceuticals has announced a partnership with Tessera Therapeutics to develop a gene editing treatment for alpha-1 antitrypsin deficiency (AATD), a rare liver and lung disease. The deal involves a $150 million upfront payment from Regeneron to collaborate on the program and split development costs and profits, with potential milestone payments of $125 million. Tessera will lead the first-in-human trial, with Regeneron taking over for future development and commercialization. Access impact The partnership between Regeneron and Tessera has significant implications for pricing and reimbursement of the potential gene editing treatment for AATD. If successful, this treatment could become a top target among drugmakers for the rare disease, potentially leading to competition and potentially lower prices. Additionally, the one-time treatment approach may also impact reimbursement decisions, as it may be seen as a more cost-effective option compared to ongoing treatment options for AATD. Top-3 domain lens Clinical Effectiveness: The article mentions that the gene editing treatment being developed by Tessera, TSRA-196, is designed to precisely correct the underlying genetic mutation in AATD and durably restore production of the AAT protein through a one-time treatment. This could have a significant impact on the clinical effectiveness of the treatment, potentially providing a more durable and effective solution for AATD patients. Budget Impact & Resources: If approved, the one-time gene editing treatment for AATD could potentially have a significant impact on healthcare budgets. While the upfront cost may be higher, the long-term cost of ongoing treatment for AATD could be reduced, potentially making it a more cost-effective option for payers. Evidence Quality & Robustness: The article mentions that Tessera has presented preclinical data for their gene editing treatment and is expecting to begin human testing by the end of 2025. This suggests that there is still a level of uncertainty and lack of robust evidence for the treatment, which could impact its evaluation by payers and HTA agencies. Hashtags #MarketAccessRiskAssessment #Pricing #Reimbursement #MarketAccess #MARArating #Regeneron #Tessera #AATD Source source: https://www.biopharmadive.com/news/regeneron-gene-editing-deal-tessera-AATD/806650/

Regeneron and Tessera join forces to forge in vivo AATD gene therapy. If approved, TSRA-196 could become the first curative therapy to reach patients with AATD. Regeneron Pharmaceuticals has teamed up with Tessera Therapeutics to develop and commercialise Tessera's rare disease in vivo gene writing programme, TSRA-196. Regeneron will now hand over $150m in equity investment and upfront cash payments in exchange for half of the global development and commercialisation rights to TSRA-196, which is being developed as a one-time treatment for the rare genetic disorder, alpha-1 antitrypsin deficiency (AATD). Tessera could also be eligible to receive $125m in milestone payments, so the total deal value may reach $275m. Under the agreement, Regeneron and Tessera will share the development costs for TSRA-196 equally, while subsequent profits associated with the therapy will be split 50:50 if the drug were to reach the market. TSRA-196 has already shown potential in preclinical studies, with durable SERPINA1 locus editing observed through the drug's administration in both mice and non-human primates following a single dose. SERPINA1 is the gene encoding the alpha-1 antitrypsin (AAT) protein, so its defectiveness or inactivity is directly responsible for AATD's disease pathology. AATD is commonly characterised by degeneration of the respiratory and hepatic systems. US tariffs are shifting - will you react or anticipate? Don't let policy changes catch you off guard. Stay proactive with real-time data and expert analysis. Tessera hypothesises that replacing inactive SERPINA1 with a functioning version of the gene could halt the development of AATD. To test this theory, the company will conduct the initial first-in-human study on the gene therapy. If the first-in-human study shows potential, Regeneron will take the reins on the subsequent global development and commercialisation efforts for TRSA-196. Tessera is therefore in the process of completing an investigational new drug (IND) and clinical trial application (CTA) for TSRA-196, which are both set to be submitted to the US Food and Drug Administration (FDA) by the end of 2025. If TSRA-196 is proven effective and safe for use in patients with AATD, it could become the first-ever disease-modifying treatment for the disease. According to a paper published in the Journal of Internal Medicine, the illness currently impacts between zero and 30 in 100,000 individuals worldwide. AATD landscape broadens. While there are no approved curative treatments for AATD, there are currently five different augmentation therapies available to patients with the disease. While these therapies can protect a patient from further AATD-driven respiratory damage, they do not address the root cause of the condition, which is the body's inability to produce the protein. Tessera and Regeneron hope to change this dynamic with TSRA-196, though they will not be the only company looking to achieve this goal. Beam Therapeutics is betting on its RNA candidate, BEAM-302. Thus far, the candidate has shown promise, with a Phase I/II trial in AATD finding that one dose of the therapy triggered durable increases in the production of the corrected form of AAT while diminishing the prevalence of aberrant AAT by up to 78%. Meanwhile, CRISPR Therapeutics is also looking to take its gene therapy, CTX460, to clinical trials in mid-2026. Analysts at GlobalData valued the AATD market at $1.2bn across the two major markets (2MM: the US and Germany) in 2023. The indication's worth is also forecast to grow significantly, with analysts predicting the market will reach a value of $3.48bn by 2031 - exhibiting a compound annual growth rate (CAGR) of 11.2% over this time period. GlobalData is the parent company of Pharmaceutical Technology. 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