Gemtuzumab Ozogamicin

ADCs are a major new market; Company demonstrates ability to discern antibody toxicity from payload toxicity and show differential linker chemistry toxicity SAN DIEGO, March 24, 2026 (GLOBE NEWSWIRE) -- VivoSim Labs, Inc. (Nasdaq: VIVS) (the “Company” or “VivoSim”), a provider of next-generation New Approach Methodologies (NAMs) for preclinical safety, today announced at the Society of Toxicology (“SOT”) meeting in San Diego, CA, that its NAMkind™ liver and NAMkind™ Intestine models have been validated for predicting toxicity and side effect profiles of antibody drug conjugates (ADCs). When considering the hundreds of ADCs in development across the globe, the potential for off-target toxicity due to their common use in oncology to deliver cytotoxic payloads, and a lack of current available scientific solutions to separate anticancer activity from unwanted cytotoxicity, the Company believes that the use of NAMkind™ models becomes a powerful tool to use in conjunction with existing methods to select and improve the best ADC candidates for drug development. Testing of approved ADC therapies in NAMkind™ models shows close correlation with clinical results VivoSim NAMkind™ liver model was shown to clearly see the toxicity of liver toxic ADCs such as gemtuzumab ozogomicin and clearly showed drugs with low liver toxicity such as enfortumab vedotin as lacking liver toxicity. Issues of linker cleavage and target engagement can be studied, as differential toxicity between drugs like trastuzumab emtansine and trastuzumab deruxtecan were demonstrated with strong comparability to clinical outcomes. NAMkind™ intestine models were also validated with ADCs and have the ability to detect differential effects such as antibody activity on epithelium, payload impact on epithelium, and overall ADC impact on epithelium. Permeability endpoints are sensitive to the exact chemical compound, be it ADC, antibody alone, or payload. “These ADC toxicity results show a close correlation to clinical safety outcomes,” said Amar Sethi, Chief Scientific Officer at VivoSim. “We consider these models validated for ADC use and think that our partners may be able to screen out toxicities during lead candidate optimization or earlier stages, which may result in greater success in the clinic at eliminating cancers using drugs with limited side effect pro ” he continued. “With clearly demonstrated success in detecting differential toxicity in ADCs, our NAMkind models are now well-established at the cutting edge of the field,” said Keith Murphy, VivoSim’s Executive Chairman. “We continue to trailblaze into new modalities and empower our partners in new ways.” NAMKind™ liver and small intestine toxicology services are now available in the US, Europe, and via local distributor engagement across Korea and China, with VivoSim continuing to scale capacity to support expanding global demand and urgent, real-world development needs. About VivoSim Labs VivoSim Labs, Inc. (“VivoSim” and the “Company”), is a pharmaceutical and biotechnology services company that is focused on providing testing of drugs and drug candidates in three-dimensional (“3D”) human tissue models of liver and intestine. The Company offers partners liver and intestinal toxicology insights using its new approach methodologies (“NAM”) models. The Company anticipates accelerated adoption of human tissue models following the U.S. Food and Drug Administration (“FDA”) announcement on April 10, 2025 to refine animal testing requirements in favor of these non-animal NAM methods. VivoSim Labs operates from San Diego, CA. Visit Forward-Looking Statements Any statements contained in this press release that do not describe historical facts constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. Any forward-looking statements contained herein are based on current expectations but are subject to a number of risks and uncertainties. Forward-looking statements include statements regarding NAMKind™, including the use of NAMkind™ models in conjunction with existing methods to select and improve the best ADC candidates for drug development and the Company’s models being well-established at the cutting edge of the field; VivoSim’s partners’ ability to screen out toxicities during lead candidate optimization or earlier stages, which may result in greater success in the clinic at eliminating cancers using drugs with limited side effect pro VivoSim’s ability to trailblaze into new modalities and empower their partners in new ways; and the Company’s scaling capacity to support expanding global demand and development needs. Such forward-looking statements are not guarantees of performance and actual actions or events could differ materially from those contained in such statements. These risks and uncertainties and other factors are identified and described in more detail in the Company’s filings with the SEC, including its Annual Report on Form 10-K filed with the SEC on June 5, 2025, as such risk factors are updated in its most recently filed Quarterly Report on Form 10-Q filed with the SEC on February 11, 2026. You should not place undue reliance on these forward-looking statements, which speak only as of the date that they were made. These cautionary statements should be considered with any written or oral forward-looking statements that the Company may issue in the future. Except as required by applicable law, including the securities laws of the United States, the Company does not intend to update any of the forward-looking statements to conform these statements to reflect actual results, later events, or circumstances or to reflect the occurrence of unanticipated events. Contact(s): Investor Relations info@vivosim.ai VivoSim Labs, Inc.

None\n Beyond the ADC Hype: Innovation is accelerating through bispecifics and dual payload strategiesAntibody drug conjugates (ADCs) mark a new era in targeted cancer therapy, delivering potent cytotoxic chemotherapy via monoclonal antibodies directly into the tumor cells — an era with potentially new standard-of-care therapies without systemic chemotherapy and its associated side-effects for cancer patients.Since approval of the first ADC Mylotarg® in 2000, 15 ADCs have been approved and 3 obtained Breakthrough Therapy Designation in 2025 alone. Now, the ADC market is poised for significant expansion, expected at $31B by 2030, reflecting a shift towards even more effective therapeutic options.Medical community enthusiasm and confidence in the success of next-gen ADCs is high enough that top pharmaceutical companies are expanding their ADC pipelines either via M&A or licensing deals, such as AbbVie’s acquisition of Immunogen in 2024 or Merck Sharp & Dohme’s licensing agreement with Daiichi Sankyo in 2023.The need for improvement persists—and with it, the imperative to innovateCurrently approved ADCs are associated with severe toxicities, including adverse events affecting the lungs, eyes and skin. Treatment resistance and tumor heterogeneity can also compromise the efficacy of those therapies. It has been shown that several mechanisms of resistance exist, from target downregulation, target mutation, to changes in internalization rates. Payload resistance is an additional growing issue that clinicians must face, as today approximately 45% of clinical-stage ADCs have a Topo1 payload class.Optimization opportunities are truly multifaceted with improvements possible for the target, linker, conjugation method, payload MOA and carrier. Emerging approaches such as bispecific antibodies and dual-payload ADCs are opening new avenues to address heterogeneity and resistance.Indeed, for these targeted therapies to achieve optimal efficacy, they must bind to cancer cells with optimal specificity and affinity. However, tumors are typically heterogeneous — meaning not all cells express the target receptor at the same level, and some may lack it entirely or become resistant by losing expression following specific treatment. This variability affects how well targeted molecules work in a certain population.“If you target two receptors, you diminish the selection effectof cells that can escape the ADC killing” said Leo Marx, Debiopharm’s Head of ADC Research and Technologies. “This is one aspect where bispecific antibodies could make a difference - the second binding site can compensate if one receptor is not expressed, helping eradicate more tumor cells while sparing healthy tissue.”Dual payload ADCs also address the resistance challenge. “What we’ve seen in our research is that 10 to 50% of cancer cells do not respond to a given cytotoxin, and there is no biomarker to select which patients would respond to one type of toxin or the other,” said Marx. “By combining them, we can increase the percentage of cancer cells that respond to ADCs and overcome resistance.”Dual payload ADCs must be designed with even more emphasis on sparing healthy cells, as they may also express the target antigen at some level. “The goal is to avoid an additive effect on the toxicity profile,” said Marx. Optimizing drug delivery via linker chemistry and conjugation strategies is also a way to mitigate on- and off-target toxicity. All these developments hold the promise to ultimately increase ADC efficacy and therapeutic index.Driving Innovation to Deliver More for Patients“Targeted therapy options are limited for patients battling tumor types such as colorectal, pancreatic and certain rare cancers, underscoring a critical need for new treatment strategies”, said Sophie Brachet, Head of Early Commercial and Access for Debiopharm. “There are therefore unexplored opportunities to improve patient outcomes in new indications, and in tumor types where ADCs are already established, they are moving earlier in the treatment paradigm and increasingly used in combination regimens. However, sequencing ADCs is becoming a growing challenge, as many ADCs share the same payload — Topo1 inhibitors — raising concerns about cross-resistance.”Oncologists are indeed introducing ADCs earlier lines of treatments in selected indications. Enfortumab vedotin (EV), approved in 2023 to treat advanced urothelial carcinoma, has become a new standard of care in first-line treatment in combination with pembrolizumab. Previously, advanced bladder cancer was typically treated with platinum-based chemotherapy, with serious side effects and limited long-term benefits.Advancing next-gen ADCs at DebiopharmThe most advanced program, Debio 1562M, a 1st-in-class CD37-targeted ADC, is being evaluated in a first-in-human trial (NCT06969430), to treat acute myeloid leukemia and myelodysplastic syndrome.“Debio 1562M is our front running clinical-stage program, among a broad and well-balanced ADC pipeline. We aim to drive innovation with first-in-class ADCs and differentiated best-in-class ADCs—leveraging novel bispecific designs and dual cytotoxic payload strategies.” commented Brachet.The pipeline encompasses HER3-based bispecific ADCs, including the promising HER3-HER2 pair, with alternative payloads to the Topo1 class or dual payloads. The Swiss-based team is also uncovering novel targets, identifying new antigens on cancer cells, especially those on hard-to-treat solid tumors.The Swiss, oncology focused biotech has developed a proprietary technology, on which all their ADC programs are built. The MultiLINKTM Technology Suite encompasses a range of linkers and conjugation technologies which uniquely allow building of dual payload ADCs at elevated DAR without impacting aggregation and exposure. In preclinical models, the MLINK Duo ADCs demonstrated excellent activity and enabled the resistance observed in models treated only with single-payload ADCs to be overcome. Research is also on-going on synergistic and non-cytotoxic novel payload classes.“MultiLINKTM linker technology is engineered with hydrophilic components to offset the toxicity caused by lipophilic payloads,” added Marx. “We’ve shown that even with dual payload constructs — for example, eight molecules of one drug combined with eight molecules of another on a single antibody — we maintain excellent PK and low clearance in preclinical models.”“Our ultimate ambition is for these next-gen ADCs to further enhance patient outcomes, particularly overall survival. We strive to fulfill the promise of precision chemotherapy and achieve the goal of replacing traditional chemotherapy as the standard treatment for select  cancers.” said Brachet.Debiopharm focuses on R&D and then partners with major pharmaceutical companies to bring medicines to the market and make them accessible to as many patients as possible throughout the world. Contact us to discuss your next project.