Magnet Biomedicine launches to pursue molecular glues beyond protein degradation

Another molecular glue company has entered the growing field, and with big names behind it. Today, Cambridge, Massachusetts-based Magnet Biomedicine emerged from stealth to pursue the monovalent small molecules that draw two proteins close together. The start-up’s founders include chemical biologists Stuart Schreiber, Benjamin Cravatt, and David Spiegel, as well as geneticists Richa Saxena and 2017 Nobel Laureate Michael Rosbash. ARCH Venture Partners and Newpath Partners co-led a $50 million series A financing round.

Molecular glues are typically used to induce protein degradation, binding together a target protein and an E3 ligase, which marks the target protein for destruction. While Magnet may pursue degraders, it aims to look beyond that classical use case for glues, according to Magnet CEO Brian Safina.

Safina says the firm is interested in tissue-specific inhibition. The glue would bind to a protein specific to the target tissue, which Magnet calls a presenter protein, and to the protein it’s intended to inhibit. “If the binding and the mechanism of action is dependent upon that presenter protein . . . you’re now restricting the biological mechanism to that tissue,” he says.

More than just serving as a localization tool, the presenter protein could also be involved in the disease in some way. In these instances, the glue would also inhibit the presenter protein’s function, according to Safina.

Several of Magnet’s founders are entrepreneurial veterans in the small molecule space. Schreiber and Cravatt were two of the scientific cofounders of Belharra Therapeutics, which launched earlier this year to pursue noncovalent small-molecule drugs for any protein. They are also among the founders of Kojin Therapeutics, which launched in 2021 to target cells that are susceptible to ferroptosis.