Flagship fledging fetches $50M to fire drugs at specific organs, fix on-target, off-tissue toxicity

Flagship Pioneering is back with a new biotech designed to tackle a key drug development challenge: on-target, off-tissue toxicity. By creating drugs that only act at the diseased tissue, regardless of whether a target is expressed elsewhere, the biotech aims to provide powerful punches without the side effects. 

Today, drug developers largely rely on differences in the levels of target expression to achieve a balance between safety and efficacy. Ideally, a receptor will only be found in the target tissue, limiting safety issues to off-target toxicity. But in reality some promising targets are found at high levels in healthy tissues, meaning safety concerns can torpedo the program. 

The situation has resulted in a pool of targets that have validated roles in disease pathways but are found at too high levels in healthy tissues to be viable therapeutic opportunities. Biotech builder Flagship has spent the past two years trying to find a solution for that problem.

Now, the VC fund is ready to lift the lid on its work, albeit only by a fraction, and introduce Ampersand Biomedicines to the wider world. The biotech starts life with $50 million from Flagship and a platform for making molecules that target the site of disease without affecting healthy cells and tissues. 

As is typical for early-stage biotechs, full details of exactly how Ampersand will pull off that trick are yet to emerge. The approach relies on the multiomics characterization of human biology, spanning healthy and diseased states. Using the data, Ampersand aims to identify localizers that ensure the drug only acts on particular organs or cells. 

The biotech says the platform is applicable to a range of modalities—including proteins, small molecules, lipid nanoparticles and nucleic acids—and therapeutic areas. Ampersand is yet to share details of its first areas of focus.

Flagship has put together the initial leadership team for the startup, with its partner Avak Kahvejian, Ph.D., taking the founding CEO role and Raffi Afeyan, Ph.D., heading up innovation and strategy.