Novartis Bets $1.5 Billion on a Novel ADC Payload, Acquiring Myricx to Address the Drug-Resistance Gap

Competition in antibody-drug conjugates (ADCs) is expanding from the search for tumor targets to a more fundamental question: once the antibody enters a cancer cell, what kind of cytotoxic weapon should it release? Novartis has agreed to acquire UK-based Myricx Bio for up to $1.5 billion, betting on a novel payload platform that remains at the preclinical stage but has a mechanism of action distinct from mainstream ADCs.

Under the terms announced by the two companies, Novartis will pay $1.1 billion upfront, with up to an additional $400 million in milestone payments. The acquisition includes two lead ADCs targeting B7-H3 and HER2, respectively, as well as the broader N-myristoyltransferase inhibitor (NMTi) payload technology. The transaction remains subject to regulatory review and other customary closing conditions and is expected to be completed in the second half of 2026.

In an ADC, the antibody can be viewed as a navigation system that delivers a highly toxic drug payload more selectively to cancer cells expressing a specific antigen. Common payloads currently either disrupt microtubules or inhibit topoisomerase I (TOPO-1); Myricx instead targets N-myristoyltransferase. This class of enzymes adds lipid tags to various proteins, affecting their localization and function. Inhibiting them may simultaneously disrupt multiple pathways that cancer cells rely on for survival.

Myricx and Novartis said preclinical studies have shown activity in multiple solid-tumor models, including models resistant to TOPO-1 payloads. If this distinction holds true in humans, NMTi payloads may be able to bypass some resistance mechanisms associated with existing ADCs and provide additional options for patients who have already received related treatments. However, the information currently available publicly is insufficient to determine the effective dose, therapeutic window, or whether tolerability can truly be improved compared with existing ADCs.

This also makes the size of the deal particularly striking: Novartis is committing an $1.1 billion upfront payment at a stage when no human efficacy data are yet available, acquiring not only two drug candidates but also a technology foundation for the continued design of ADCs against different targets. Myricx was spun out of Imperial College London and the Francis Crick Institute and completed a $114 million Series A financing in 2024, co-led by Novo Holdings and Abingworth.

The next key question is not merely whether the candidates can enter clinical trials, but whether NMT inhibition can leave sufficient room between cancer-cell killing and toxicity to normal tissues. Preclinical drug-resistant models provide a reasonable starting point for development but cannot predict human responses. Until data on dosing, safety, and preliminary tumor responses are released, the deal is better viewed as Novartis purchasing a high-priced option on next-generation ADC payloads than as a validated therapeutic breakthrough.