Genomic Medicine · South San Francisco, CA
Moonwalk Biosciences
A biotech that wants to fix sick cells the way you'd patch software - by flipping switches, not rewriting the code underneath.
A biotech that wants to fix sick cells the way you'd patch software - by flipping switches, not rewriting the code underneath.
Inside an office park off the 101, a small team is staring at a problem most of biology politely ignores: a cell can carry perfectly healthy DNA and still behave badly. The instructions are fine. The cell is just reading them wrong. Moonwalk Biosciences thinks that's the more interesting bug - and the more fixable one.
The company is preclinical, which is biotech for "no product yet, plenty of conviction." It launched publicly in January 2024 with $57 million and a deliberately narrow thesis: most disease is a problem of gene regulation, not gene sequence. Fix the regulation - the chemical marks and switches sitting on top of the genome - and you can coax a cell back toward health without ever taking scissors to its DNA.
"Epigenome engineering is the next frontier of genetic medicines, allowing us to create safer treatments without damaging the underlying DNA sequence."
Alex Aravanis - Co-Founder & CEOThe first generation of genetic medicine made a thrilling, terrifying promise: we can rewrite your DNA. CRISPR could find a faulty letter and change it. Wonderful - until you remember DNA is the one document in your body you can't easily get a fresh copy of. A wrong cut doesn't have an undo button.
There's a second, quieter problem. Most common diseases - the metabolic ones, the messy multi-gene ones - aren't caused by a single typo. They're caused by dozens of genes being dialed slightly too high or too low. You can't fix that with one precise cut. You'd need to adjust the volume on many knobs at once, gently, and ideally without leaving a scar.
"Most disease isn't a spelling error in the genome. It's the cell reading a correct sentence with the wrong emphasis."
The Moonwalk thesis, paraphrasedThis is where the epigenome comes in - the layer of chemical tags, chiefly methylation, that tells each cell which genes to express and how loudly. It's the cell's settings menu. And unlike DNA, settings are meant to be changed.
Alex Aravanis spent roughly a decade at Illumina, eventually as Chief Technology Officer, building the machines and diagnostics that made reading DNA cheap and routine. Reading, he had down. The bet he wanted to make next was about writing.
So he called Feng Zhang - one of the inventors of CRISPR gene editing at the Broad Institute, the kind of scientist whose papers get cited in headlines. The two had known each other for twenty-odd years, since overlapping at Stanford as a postdoc and a grad student. Zhang's lab had been developing tools to edit the epigenome rather than the genome: same molecular GPS, no scissors. Together with co-founders Arash Jamshidi and Justin Valley, they built a company around the idea.
"Moonwalk's epigenetic engineering platform represents an exciting new era in genetic medicine, by targeting the root cause of disease."
Rick Gerson - Chairman, Alpha Wave GlobalAravanis and Zhang cross paths as a postdoc and a grad student. No company yet - just the start of a long professional friendship.
Aravanis helps make DNA sequencing cheap and routine, rising to CTO. Reading the genome becomes a solved problem. Writing it is the next one.
Aravanis, Zhang, Jamshidi and Valley incorporate around a "read-and-write" epigenetics platform and quietly raise seed capital.
The company emerges publicly with backing from ARCH, GV, Khosla, Alpha Wave, Future Ventures and YK Bioventures.
Team expands across South San Francisco and San Diego - biology, platform and translational science hires stack up.
The stated goal: file an investigational new drug application for a lead therapeutic within a few years of launch.
Moonwalk's platform has two halves, and the order matters. You don't get to rewrite a cell until you understand what it's currently saying.
Whole-genome, single-cell epigenome mapping captures methylation across roughly 28 million sites in both healthy and diseased cells. AI then predicts which marks actually matter.
CRISPR-based, non-DNA-cutting tools built on Feng Zhang's epigenome editing work. They adjust methylation states and can tune multiple genes in one step.
A modality-agnostic, preclinical pipeline aimed at reprogramming cells back toward a healthy state - with interest signaled in cardiometabolic and adipose biology.
"Control multiple genes accurately and durably, in a single step, without altering the DNA sequence."
How the editing platform is describedBars illustrate Moonwalk's design intent for epigenetic editing - the appeal is breadth and reversibility without permanent cuts. Directional, not a benchmark.
Preclinical companies can't show you cures. They show you who believed them early. Moonwalk's $57 million round wasn't a single check from a single optimist - it was a syndicate of funds that have written some of biotech's better-known cheques.
"We look forward to what new innovations Moonwalk can advance in epigenetic engineering."
Robert Nelsen - Managing Director, ARCH Venture PartnersThe other proof point is provenance. The "write" tools trace back to Feng Zhang's lab at the Broad Institute - not a generic CRISPR claim, but a specific lineage in epigenome editing. In a field crowded with promising slide decks, knowing exactly whose bench your technology came off of counts for something.
The mission is stated plainly: develop precision epigenetic medicines that reprogram cells to a healthy state by editing the epigenome instead of the DNA. The ambition tucked inside that sentence is the word "curative" - the hope that targeting the root regulatory cause, rather than managing symptoms, produces durable fixes.
It's a big claim, and Moonwalk knows skeptics are the default audience in biotech. That's why the platform leads with reading. You map what's broken in the cell's settings before you touch anything - the opposite of the move-fast posture the name might suggest.
Whole categories of disease - metabolic, age-related, the stubbornly multi-gene kind - have resisted single-target drugs precisely because there is no single target. A tool that can gently retune many genes at once, reversibly, without cutting DNA, would be a genuinely different instrument in the cabinet.
Back in that office park off the 101, the team is still arguing with cells. But the argument has changed shape. They're no longer asking how to rewrite a cell's DNA. They're asking how to change its mind - and they've raised $57 million from people who'd like to find out if cells will listen.
"The genome is the hardware. Moonwalk is trying to write the software."
The one-line version