The deal gives Novartis a new class of antibody drug conjugate toxins: N myristoyltransferase inhibitors, which attack tumors through a different intracellular target than existing ADC payloads.
Novartis agreed on July 6 to acquire UK-based Myricx Bio for $1.1 billion upfront and up to $400 million in milestones, a $1.5 billion bet on a new class of cancer-killing chemistry rather than a single new molecule, according to Novartis's release and a synchronized Myricx statement. The roughly $400 million in milestone payments on top of the cash component signals a platform premium for a privately held company with no late-stage clinical assets in hand.
The asset Novartis is buying is chemistry rather than a single molecule. Myricx's platform is built around NMTi payloads, short for N-myristoyltransferase inhibitors, a class of small molecules that disrupt a specific protein-modification step tumor cells rely on. Established ADC toxins fall into two camps: microtubule disruptors, including the auristatins and maytansines used in approved ADCs like Enhertu and Adcetris, and DNA-damaging agents such as calicheamicin, duocarmycin, and topoisomerase inhibitors. NMT inhibitors act on neither target. Instead, they block the enzyme that attaches a myristoyl lipid group to proteins, a step Myricx describes as essential for cancer-cell survival but largely dispensable in healthy tissue, per the Myricx release on BioSpace.
That mechanistic gap is what makes this a payload-platform deal rather than a single-asset buyout. An ADC is, in practice, three components: an antibody that binds a tumor antigen, a linker that holds the payload in transit, and the cytotoxic payload that kills the cell once the conjugate is internalized. For two decades, the field's strategy has been to find better antibodies against new targets such as HER2, HER3, TROP2, and CLDN18.2, and to ship them with the same handful of warheads. NMTi payloads let a developer reuse well-characterized antibodies while changing the killing mechanism, a faster and cheaper path to differentiated activity, including in tumors that have stopped responding to standard ADC toxins.
The Myricx deal extends a string of ADC-focused acquisitions, building on earlier investments in the modality as the company tries to reassert its oncology franchise. Buying payload chemistry rather than a single molecule lets Novartis develop an internal ADC pipeline, pairing the new warhead with its own antibodies and linkers, without depending on a biotech partner's clinical timeline. The Novartis press release frames the deal as "expanding options for cancer patients" across "multiple solid-tumor indications," language that signals a broad platform bet, not a single-indication asset.
Myricx remains privately held, and the public disclosures describe a preclinical-to-early-stage platform. The company has not, in either the Novartis or Myricx statements, named a lead candidate, disclosed a target antigen, or announced an IND timeline. Claims that the platform can overcome resistance or spare healthy tissue are, for now, company-stated. Independent validation in peer-reviewed work or clinical-trial registries will determine whether NMTi chemistry is a real new warhead class or another well-funded hypothesis.
The market test is whether Novartis can move an NMTi-armed conjugate into the clinic and demonstrate activity in tumors that have already failed conventional ADC treatment. Watch for an IND filing on a Myricx-derived candidate, and for whether the company uses the new payload to revive or build out internal ADC programs already in its pipeline. The deal closed the Myricx question; the chemistry now has to answer for itself.