Jerry McMahon

In September 2022, a company in Cambridge, England named a new President and CEO who had spent most of his career on the other side of an ocean and most of it on cancer. STORM Therapeutics does one unfashionable, difficult thing: it makes small molecules that block RNA modifying enzymes. Jerry McMahon runs it, and the reason he is worth reading about sits in a single capsule called STC-15 - an oral METTL3 inhibitor that became the first RNA modification enzyme inhibitor ever taken into human trials.

Most biology drug hunters chase DNA and proteins. RNA, the messenger in between, was long treated as a courier you did not bother arresting. STORM's premise is that the chemical marks placed on RNA - the enzymes that write, erase and read them - are a control layer worth attacking. METTL3 is the marquee example: an enzyme that methylates RNA and, in cancer, helps tumors keep their bad habits. Knock it out with a pill and, at least in STORM's hands, tumors start behaving like something the immune system can see.

The strange, specific fact: STC-15 made tumors shrink at every dose STORM tested. Not the top dose. Every dose.

That is the sentence McMahon inherited a company to prove out. He did not invent RNA epigenetics - that traces to founding science out of Cambridge - but he is the operator charged with turning an elegant idea into a medicine, a financing story, and eventually a business that can stand on its own.

McMahon's résumé reads like a map of how a scientist becomes a chief executive without ever quite leaving the science. He earned both his BS in biology and his PhD in biochemistry and genetics from Rensselaer Polytechnic Institute - the same school, twice. He then held academic appointments at the Yale Comprehensive Cancer Center, Tufts University School of Medicine, and MIT, which is an unusual trio to collect on the way to running companies.

As President at SUGEN - later folded into Pharmacia and then Pfizer - he was instrumental in developing sunitinib, the kidney-cancer drug the world knows as Sutent. That is a rare line to have on a CV: a marketed drug you helped push through. He went on to senior oncology leadership at MedImmune, AstraZeneca's biologics arm, then took the top job at Kolltan Pharmaceuticals, which was acquired by Celldex.

His best-known operator chapter is Harpoon Therapeutics. From 2016, he built the Bay Area immuno-oncology company from an early-stage story through a Nasdaq IPO, follow-on financings and development collaborations. Building a company to the point where public markets will fund it is a specific and unforgiving skill. He did it, then went looking for the next hard problem.

RNA epigenetics is not a quick win. It asks investors and patients to believe in a mechanism they cannot picture and a target class with no marketed precedent. McMahon's whole career is the argument for why he is the person to sell that patience - he has repeatedly turned early science into things that get funded and, occasionally, approved.

In 2025 STORM moved STC-15 out of solo testing and into combination, dosing the first patient in a Phase 1b/2 study pairing it with the PD-1 inhibitor LOQTORZI (toripalimab) across lung, head-and-neck, melanoma and endometrial cancers, and bringing on a new chief medical officer. The logic is the immuno-oncology bet McMahon has made before: a drug that makes tumors more visible should play well with one that unleashes the immune system.

He inherited a thesis. His job is to make it inevitable.