He builds medicines with an off-switch - biologics that stay dark until they touch their target. Then he does it again, in a field he's never worked in.
Most drugs are blunt. They flood the bloodstream and hope the dose finds the tumor before it finds everything else. John Mulligan spends his days trying to give a molecule a sense of place - a way to know it has arrived before it bothers to work.
That is the whole idea behind Bonum Therapeutics, the Seattle company he founded and runs. Bonum's molecules carry an antibody that acts as a sensor. Bind the right marker, and the therapeutic component wakes up. Miss it, and the drug stays quiet. Cytokines like IL-12 and IFN-alpha - powerful, toxic, notoriously hard to aim - become things that switch on at the target and nowhere else.
The science is not theoretical. Roche bought his last company, Good Therapeutics, in 2022 for $250 million upfront, specifically for one program built this way. Bonum is the bet that the same trick works everywhere else.
If it worked out, it's perhaps because of an excess level of perseverance.
The trouble with cytokines is that they work too well, everywhere. Bonum's answer is to wire activation to recognition: the therapy only turns on once its antibody sensor has confirmed the right address. Here is the logic, stripped down.
Mulligan calls these conditionally active therapeutics. The pitch is brutally simple - more punch where you want it, far less collateral where you don't - which is why the pipeline reaches past oncology into autoimmunity, metabolic disease, and pain.
There is a pattern, and Mulligan is happy to admit it. When he raised money to build Blue Heron Biotech, a gene-synthesis company, nobody asked whether he had ever synthesized a gene commercially. The honest answer was no. He built it anyway, grew it from concept to a commercial entity, and sold it.
He did it again with Glycostasis, engineering insulin that responds to blood glucose - bought by Eli Lilly. Again with Good Therapeutics and its PD-1-regulated IL-2 program - bought by Roche. Before any of it, at Darwin Molecular, he pioneered a genomic approach to target discovery that surfaced an osteoporosis drug target.
The throughline isn't a particular molecule. It's a tolerance for being a beginner. "I find it super interesting to learn something completely new," he says. "It's a challenge as a business but a real education."
When Roche acquired Good Therapeutics, the deal kept the lead program and spun the rest of the platform - and the entire team - into Bonum. The $93 million Series A that followed was led by existing backers, with Roche Venture Funds in and Vivo Capital joining. He raised it, by his own account, while "floating through the biotech downturn."
Antibody-regulated biologics with precision activation across oncology, autoimmunity, metabolic disease, and pain. Backed by a $93M Series A.
Bio-therapeutic proteins that regulate their own activity. Its PD-1-regulated IL-2 program fetched $250M upfront plus milestones.
A human protein engineered to regulate insulin release in response to blood-glucose levels. Smart insulin, made real.
Gene-synthesis pioneer grown from a concept to a commercial entity - the company he built while learning the business in public.
As Director of Genomics, pioneered a genomic target-discovery method that identified an osteoporosis drug target.
Continues to serve on the board, lending the pattern-recognition of a four-time founder to another team's odds.
Oncology is the lead, but the conditional-activation idea is deliberately disease-agnostic. A rough read on where the technology is being aimed:
Directional emphasis based on public statements, not disclosed allocation.