In vivo data confirm activation of prodrug payload inside tumor cells following systemic administration of BiTAC-ADC molecules leading to potent anti-tumor activity
ZURICH, SWITZERLAND - October 13, 2026 -- VERAXA Biotech AG (NASDAQ: VRXA; "VERAXA"), an emerging leader in designing novel cancer therapies, today presented first in vivo proof-of-concept data and additional in vitro data validating its novel BiTAC-ADC technology platform at the 17th World ADC Congress in San Diego, CA, USA. The in vivo data demonstrate that a systemically applied, single dose of the two-component BiTAC-ADC selectively triggered a tumor-specific response resulting in a significant reduction in tumor volume, while continuing to show differentiated safety features and the potential to overcome systemic toxicity, the primary limitation of current ADCs.
The in vivo data presented at the World ADC Congress showed that treatment with BiTAC-ADCs resulted in strong tumor regression in a xenograft breast cancer model even at a single dose of 3 mg/kg. As intended, BiTAC-ADCs utilizing one non-targeted component, thereby only delivering one component to the tumor, showed no significant effect. A control ADC, engineered by VERAXA using the same conjugation and linker-payload technology and with the same drug-antibody ratio (DAR) as its BiTAC-ADC counterpart, performed similarly. In the BiTAC-ADC treatment arm, no decrease in body weight could be observed.
"These novel datasets on the BiTAC-ADC platform underline the rapid progress our team has made in demonstrating the potentially transformative safety benefits of BiTAC-ADCs compared to conventional ADCs," said Christoph Erkel, Ph.D., Chief Scientific Officer at VERAXA. "While BiTAC-TCEs remain our priority, the rapid validation of our BiTAC-ADC concept bodes well for establishing a second pillar in our R&D and partnering strategy towards safer drugs for solid tumor patients."
"Demonstrating that BiTAC-ADCs can reach the tumor site following intravenous administration, induce a specific effect only upon arrival of both BiTAC components, and shrink the tumor in a living organism is a significant platform milestone and validates its underlying concept," added Paul Sauter, Ph.D., Senior Director and Department Head ADC Tech & Chemistry at VERAXA.
The poster presented at the World ADC congress also expanded on previously published in vitro studies and shows that BiTAC-ADCs can discriminate between cancer and healthy cells, require both BiTAC-ADC constructs to be co-targeted to the tumor site and do not release active toxins in the periphery. The BiTAC-ADC concept was also successfully evaluated across a wide range of cancer cell lines and against several validated ADC targets. Taken together, the data sets underline the potential for this novel therapeutic concept with comparable efficacy to a conventional ADC, but a mechanistically highly differentiated safety profile.
The BiTAC therapeutic strategy is designed to unlock a new level of precision in cancer treatment via dual-targeting using two complementary precursors and enabling a tumor-restricted activation of the desired therapeutic effect. Applied to the development of antibody drug conjugates (ADCs), the technology delivers a systemically inactive prodrug and a cell-impermeable proactivator through two separate antibodies, each addressing a defined tumor-associated antigen. While the single BiTAC-ADC precursors are therefore not toxic by design, the selective internalization of both components into the same cancer cell leads to dose-dependent cytotoxicity.
The data poster presented will be made available on the Company's website.
About VERAXA Biotech AG (NASDAQ: VRXA)
At VERAXA, we are building a premier engine for the discovery and development of next-generation antibody-based therapeutics, including bispecific T cell engagers, bispecific ADCs and other innovative formats. Powered by a suite of transformative technologies and guided by rigorous quality-by-design principles, we are rapidly advancing our pipeline of ADCs and proprietary BiTAC formats into clinical development and beyond. VERAXA was founded on scientific breakthroughs made at the European Molecular Biology Laboratory (EMBL), a world-renowned institution known for pioneering life science research and cutting-edge technology.
For regular updates about VERAXA Biotech, visit https://investors.veraxa.com/ or follow us on LinkedIn, X (formerly known as Twitter) and Bluesky.
BiTAC is a registered trademark of VERAXA Biotech GmbH.
Forward-looking Statements
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Forward-looking statements contained in this press release should be evaluated together with the many uncertainties that affect the Company's business, particularly those identified or referenced herein and in the risk factors section of the Company's most recent Annual Report on Form 20-F and any subsequent reports on Form 6-K. These documents are available from the Securities and Exchange Commission, the Company website or from Company Investor Relations.
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Contact VERAXA Biotech AG - Corporate Christoph Antz, Ph.D. Chief Executive Officer, Co-Founder investors@veraxa.com For Media and Investors - U.S. Brandon Weiner ICR Healthcare VERAXA@icrhealthcare.com For Media and Investors - EU Mario Brkulj media@veraxa.com
