On November 4, 2025 Defence Therapeutics Inc. ("Defence" or the "Company"), a leading biotechnology company specialized in drug delivery technologies, reported at the World ADC Conference in San Diego, USA, highly encouraging results from its latest preclinical in vivo study evaluating Accum-Kadcyla, a novel version of Genentech/Roche’s marketed ADC Kadcyla (ado-trastuzumab emtansine), in mouse models of HER2-positive breast cancer.

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Study Results: 20-Fold Increased Potency at Equivalent Dose

In the comparative in vivo study, Accum-Kadcyla demonstrated a ~20-fold higher anti-tumor efficacy than Kadcyla alone when administered at the same dose (0.5 mg/kg). Tumor growth was significantly halted in the Accum-Kadcyla-treated group, resulting in a durable and near-complete response in most mice while Kadcyla at the same dose (0.5 mg/kg) had no effect on tumor growth. Importantly, 100% of the animals survived throughout the duration of the study with no signs of toxicity, underscoring the excellent tolerability of the treatment.

Implications for Patients and the Industry

These results confirm that Defence’s Accum platform can dramatically enhance the intracellular delivery and potency of ADCs by overcoming endosomal entrapment—a known bottleneck in ADC performance. By increasing the therapeutic payload’s reach inside cancer cells, Accum enables a more efficient drug release and tumor killing, even at lower doses.

This finding is particularly meaningful for patients: the ability to achieve the same or better efficacy at reduced doses translates into a potential reduction in toxicity and side effects, addressing one of the main limitations of current ADC therapies. Practically, it could potentially bring this current second line of treatment to a first line of treatment for the benefit of the patients.

Dr. Maxime Parisotto, Chief Scientific Officer of Defence Therapeutics, commented:

"These results further validate the power of Accum as a transformative technology for ADCs. By amplifying the potency of a clinically proven ADC like Kadcyla by 20 times at the same dose, we demonstrate that Accum can unlock a new generation of safer and more effective targeted therapies for cancer patients."

Next Steps and Commercial Outlook

Following these promising results, Defence Therapeutics plans to expand its Accum-ADC program to additional HER2-positive and HER2-low tumor models and to advance discussions with potential pharmaceutical partners.

(Press release, Defence Therapeutics, NOV 4, 2025, View Source;utm_medium=rss&utm_campaign=defence-therapeutics-demonstrates-strong-preclinical-in-vivo-efficacy-results-evaluating-accum-kadcyla-in-breast-cancer-models [SID1234659633])