He spent a decade running early immunotherapy trials in academic labs, then a decade selling billion-dollar cancer brands. Marengo is where the bench and the boardroom finally argue it out.
Most cancer drugs try to add something the body lacks - a new weapon, a borrowed gun. Marengo Therapeutics, the Cambridge biotech Zhen Su has run since July 2021, makes a quieter bet. The T cells that should be killing a tumor are usually already there. They are just pointed at the wrong thing, or asleep, or outnumbered. Marengo's STAR platform - Selective T cell Activation Repertoire - is built to wake the right subset and send it where it is needed.
The harder problem is the tumors that hide. Immunologists call them "cold": low on the immune traffic that makes a tumor visible, and stubbornly resistant to the checkpoint drugs that defined the last decade of oncology. Su talks about them the way a fire chief talks about a smoldering attic. The danger is real, the smoke is invisible, and the whole job is getting the right crew to the right room. The company's later Tri-STAR platform exists precisely to drag those cold tumors into the open.
It is an unfashionable kind of ambition - not a brand-new mechanism, but better aim. And it is exactly the sort of problem someone who has lived on both sides of the drug-development wall would pick.
"The ultimate precision IO goal of delivering the right T cells to the right tumor."Zhen Su, on the Tri-STAR platform
In 2001, on the faculty at Duke University Medical School, Su was running some of the earliest mRNA-based and cell-based immunotherapy clinical studies - work that sat at the fringe of oncology long before mRNA became a word people said at dinner parties. He stayed in academic medicine through 2009, directing the Cell and Gene Therapy program at the University of Florida.
Then he switched costumes. GlaxoSmithKline across oncology, respiratory and urology. Sanofi Oncology, where he worked on Taxotere and Jevtana. As Chief Medical Officer of EMD Serono, he had a hand in eight major regulatory approvals across oncology and neurology, including Bavencio, Tepmetko, Erbitux and Mavenclad. Getting one drug to approval is a career. Eight is a pattern.
The capstone of the corporate years came at Merck KGaA, where as Senior Vice President and Global Head of the Oncology Business Franchise he led a turnaround to double-digit organic growth and more than a billion dollars in annual revenue. He could have stayed. Instead he took an $80M check from Apple Tree Partners and started building.
"This collaboration is an important validation of our STAR platform beyond our lead candidate."Zhen Su, on the Ipsen partnership
Most biotechs spend years proving a platform before a big partner bites. Marengo landed Ipsen twice. The first strategic partnership, announced in 2022 and valued at up to $2.8B, validated the STAR platform beyond Marengo's own lead asset. The second, around the Tri-STAR platform, came after the collaboration had already delivered its first development candidate - a rare thing to be able to say out loud.
By AACR 2026 the company was reporting initial Phase 2 results for its lead candidate, invikafusp alfa, in combination with Trodelvy, and advancing a second partnered STAR program into Phase 1. The lead asset that Su inherited as a platform promise is now a clinical-stage reality. That is the whole arc of the job: turn biology into something a regulator, and eventually a patient, can hold.
Su is the Founding Chair of the Biotech Committee of the Society for Immunotherapy of Cancer - the field's central forum - and he sits on the boards of Karyopharm Therapeutics, CytomX Therapeutics, and Galvanize Therapeutics. He turns up on conference stages and on BiotechTV, talking through the state of immuno-oncology with peers like Kristen Hege ahead of SITC. None of it is the day job. All of it keeps him in the room where the field's direction gets argued.
The aspiration he keeps returning to is narrow and, for that reason, credible: not curing cancer in a press release, but getting the right T cells to the right tumor - including the cold ones everyone else has written off. A physician who became a professor who became a pharma executive who became a CEO has, by now, played every role in oncology except patient. He is not done.