Gemtuzumab Ozogamicin

Bristol Myers Squibb has axed the degrader-antibody conjugate (DAC) it bought from Orum Therapeutics for $100 million, walking away from the asset after seeing phase 1 data. Orum, which disclosed (PDF) the news in a financial filing, sold the DAC to BMS in 2023. The therapy, dubbed ORM-6151, delivers a GSPT1 degrader to cells expressing CD33. Degrading the housekeeping protein GSPT1 can lead to cell death. Because acute myeloid leukemia and myelodysplastic syndrome cells often express CD33, ORM-6151 could theoretically selectively eliminate the blood cancers. BMS began testing that idea in 2024, starting a phase 1 clinical trial of ORM-6151 as a monotherapy and in double and triple combination with azacitidine and venetoclax. The study was due to wrap up in February 2027, according to the federal trials register. But Orum disclosed that BMS has now stopped developing the DAC after reviewing clinical data. The termination of work on ORM-6151, which BMS called BMS-986497, deprived Orum of the chance to earn (PDF) up to $80 million in milestones tied to clinical development. The program is one of many projects that BMS has jettisoned since Christopher Boerner, Ph.D., took over as CEO in 2023. BMS struck the Orum deal days into Boerner’s time as CEO, suggesting that the agreement was largely forged by the previous regime. Early in Boerner’s reign, the Big Pharma axed multiple internal and partnered projects advanced by the old leadership. BMS’ termination of ORM-6151 is another blow to the DAC field. AbbVie beat BMS to the clinic by starting a phase 1 trial in 2023 of ABBV-787, a CD33-directed DAC with a BET degrader payload. But AbbVie terminated the study last year, citing strategic considerations. The focus on CD33 DACs echoes the early years of antibody-drug conjugate (ADC) development. In 2000, Wyeth, now part of Pfizer, won (PDF) accelerated FDA approval for its CD33-directed ADC, Mylotarg. Orum based the antibody in ORM-6151 on the targeting molecule in Mylotarg, gemtuzumab, limiting its changes to modifications intended to support manufacturing and improve safety.

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.