BREAKING$56M Series C closed - April 2026/ First Phase 2 sarcoma patient dosed with STC-15/ STC-15: first RNA-modifying enzyme inhibitor in humans/ 150+ RNA modifications. ~300 enzymes. One frontier./ AlidaBio collaboration signed - January 2026/ BREAKING$56M Series C closed - April 2026/ First Phase 2 sarcoma patient dosed with STC-15/ STC-15: first RNA-modifying enzyme inhibitor in humans/ 150+ RNA modifications. ~300 enzymes. One frontier./ AlidaBio collaboration signed - January 2026/
Company File / RNA Epigenetics

STORM Therapeutics

A Cambridge biotech drugging the molecular edits cancer uses to survive. The first to put an RNA-modifying enzyme inhibitor into a human being.

CAMBRIDGE, UNITED KINGDOM  |  FOUNDED 2015  |  CLINICAL-STAGE

STORM Therapeutics scientific imagery
EXHIBIT A: The molecular weather system STORM is learning to forecast - RNA, mid-edit, before anyone thought to aim a drug at it.
Dateline: Cambridge, Now

A 14-person lab is leading a field that didn't exist.

In a building off the Cambridge Biomedical Campus, a small team checks a number that almost nobody else in the world can check: how a single patient's RNA changed after swallowing a pill. The pill is STC-15. The patient is in a Phase 2 sarcoma trial. And the entire premise - that you can drug the enzymes that edit RNA - was, until recently, a question for academic papers, not pharmacies.

STORM Therapeutics is what happens when a footnote in biology grows up. RNA, the molecule we were taught simply carries instructions from DNA to protein, turns out to be heavily annotated - chemically tagged, methylated, edited in flight. Cancer reads those annotations. STORM writes drugs that erase them.

"STORM is a pioneer in the field of RNA epigenetics, developing small-molecule inhibitors of RNA-modifying enzymes for the treatment of cancer." - STORM Therapeutics, company description
The Problem They Saw

Everyone studied the message. Almost nobody studied the edits.

For decades, drug hunters chased DNA and proteins. RNA sat in the middle, treated as a courier - dutiful, temporary, beneath suspicion. The inconvenient truth was that RNA gets modified more than 150 different ways, by roughly 300 enzymes, and that those modifications quietly decide which genes get translated and when. Cancer, it turns out, is an excellent forger.

The opportunity was enormous and, conveniently for a biology textbook, almost entirely ignored. A target space of hundreds of enzymes, untouched by any approved drug. The catch: to drug an RNA-modifying enzyme, you first have to prove the modification matters, then prove you can measure it, then prove you can change it without breaking everything else. Three impossible-sounding steps. STORM took them as a to-do list.

150+
Known RNA modifications
~300
RNA-modifying enzymes
1
In-human inhibitor (theirs)
2015
Spun out of Cambridge

Fig. 1 - The math of a frontier: a vast target space, and exactly one company that had gotten a drug from it into a patient.

"There are more than 150 RNA modifications and roughly 300 RNA-modifying enzymes - a largely untouched landscape of therapeutic targets." - The thesis, in one sentence
The Founders' Bet

Two professors decided the footnote was the headline.

STORM was spun out of the University of Cambridge in 2015 by Professor Tony Kouzarides and Professor Eric Miska, two scientists who had spent careers on the regulatory machinery sitting on top of the genome. Kouzarides had helped build the modern understanding of how chromatin is chemically marked; he would later be knighted for services to healthcare innovation. The bet was simple to state and very hard to fund: RNA modifications are a drug target, and we are early.

Being early is romantic in retrospect and terrifying in real time. There was no playbook, no competitor to copy, no validated target to fast-follow. So STORM did the unglamorous thing - it built the tools first. An RNA mass-spectrometry and analytics platform to actually read the modifications, then a discovery engine to design molecules against the enzymes that write them.

"The foundational work in RNA epigenetics underpins everything that followed - the platform, the pipeline, the first patient." - On the Cambridge origin story

Sir Tony Kouzarides

SCIENTIFIC FOUNDER

Cambridge professor, chromatin and epigenetics pioneer, knighted for services to healthcare innovation.

Eric Miska

SCIENTIFIC CO-FOUNDER

Cambridge professor whose RNA biology research helped seed the company's platform.

Jerry McMahon

CHIEF EXECUTIVE

Leads STORM through the clinical-stage chapter: Phase 2, partnerships and the Series C.

The Product

STC-15: a pill that tells cancer to stop forging.

STC-15 is an oral, first-in-class small-molecule inhibitor of METTL3 - the enzyme responsible for adding the m6A methyl mark to messenger RNA. That mark is one of the levers cancer stem cells pull to keep dividing. Switch METTL3 off, and the forged instructions stop getting written. It sounds tidy. Getting it from a Nature paper to a patient's bloodstream took the better part of a decade.

The science arrived with receipts. STORM published data in Nature showing its METTL3 inhibitor worked against acute myeloid leukemia, then data in Cancer Discovery showing METTL3 inhibition could rouse the immune system against tumors. In 2022 the program cleared regulators to begin first-in-human dosing - the first time any RNA-modifying enzyme inhibitor entered a clinical trial. Beyond METTL3, STORM has advanced first-in-class inhibitors of the tRNA enzyme METTL1.

"STC-15 is the first RNA-modifying enzyme inhibitor to enter human clinical development." - The line that makes this company unusual

STC-15

Oral METTL3 inhibitor. First-in-human, first-in-class. Now in Phase 2 for selected sarcomas after durable Phase 1 tumor regression.

METTL1 program

First-in-class inhibitors of a tRNA methyltransferase, presented at the ESMO Targeted Anticancer Therapies Congress.

The Platform

RNA mass spectrometry plus target biology - the instrument that turns "RNA is modified" into "here is a molecule that changes it."

Midpoint / The Record

From spin-out to Phase 2, in milestones.

2015
Spun out of the University of Cambridge by Tony Kouzarides and Eric Miska to commercialize RNA epigenetics.
2019
Closes a $30M Series B led by existing investors including M Ventures and Pfizer Ventures.
2021
Publishes in Nature: first-in-class METTL3 inhibitor effective against AML.
2022
STC-15 cleared to begin Phase 1 - the first RNA-modifying enzyme inhibitor dosed in humans.
2023
Publishes in Cancer Discovery: METTL3 inhibition induces anti-tumour immunity.
Jan 2026
Strategic collaboration with AlidaBio to measure m6A changes in STC-15 patient samples.
Apr 2026
$56M Series C closed; first patient dosed in Phase 2 sarcoma study of STC-15.

Fig. 2 - A decade compressed. Note the gap between "interesting paper" and "patient dosed." That gap is the whole job.

The Proof

When skeptics asked for evidence, STORM brought data, capital, and partners.

In April 2026 STORM raised a $56 million Series C - funded entirely by existing backers including M Ventures, Pfizer Ventures, Taiho Ventures, IP Group, UTokyo IPC and Fast Track Initiative. There is a particular kind of validation in returning investors writing the whole check: people who have already seen the data deciding to see more of it. The money is pointed squarely at the Phase 2 sarcoma study, designed to support a potential accelerated approval path.

The proof is not only financial. In Phase 1, STC-15 showed durable tumor regression across multiple sarcoma subtypes. And in January 2026 STORM signed a collaboration with AlidaBio to use next-generation sequencing platforms to measure exactly how m6A marks shift in treated patients - turning "we think it works" into "here is the molecular fingerprint."

Funding raised by round

USD, approximate, per public announcements
Series B '19
$30M
Series C '26
$56M
Total raised
~$127M

Fig. 3 - Capital follows conviction. The Series C came from the same investors who funded the last one.

"Backed entirely by existing investors - the rarest kind of vote of confidence in biotech." - On the $56M Series C
The Mission

Make RNA modification a routine place to find a drug.

STORM's stated aim is to harness RNA epigenetics into a new class of medicines - first in oncology, with an eye toward inflammation, viral infection and CNS disease. The ambition is bigger than any single molecule. If STC-15 works, it does not just treat sarcoma; it proves a category. It tells every other drug hunter that the 150-plus modifications and 300-odd enzymes are fair game.

That is the quiet leverage of being first. Wilde would have appreciated the irony: the most radical thing a company can do is make a wild idea look ordinary. STORM wants RNA-modifying enzymes to become as unremarkable a drug target as a kinase. Unremarkable, here, is the goal.

"The most radical outcome isn't one drug. It's an entire target class that no longer needs defending." - The long game
Why It Matters Tomorrow

Back to that small room in Cambridge.

Return to where we started: a 14-person team reading how one patient's RNA changed overnight. A decade ago that sentence would have been science fiction - there was no drug to give, no enzyme cleared as a target, no platform sensitive enough to catch the shift. STORM built each of those, in order, and then handed the result to a person with cancer.

The Phase 2 readout will decide a great deal. But the harder thing - proving that RNA epigenetics is somewhere you can actually find medicine - has already happened. The room is no longer asking whether the idea is real. It is asking how far it goes. That is a very different room than the one Kouzarides and Miska walked into in 2015.

STORM Therapeutics didn't just enter a field. It made the field credible enough to crowd into.

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