Epicrispr Closes $90M Series C to Push the First Epigenetic Therapy for FSHD Into Pivotal Trials

Gene therapy usually conjures an image of cutting bad DNA out and writing better DNA in. But when the disease isn’t caused by a broken gene so much as by a gene that should be switched off and isn’t, there’s no reason to touch the DNA at all. You just flip the switch back. That’s epigenetic editing — leaving the sequence intact and changing only whether it gets read — and its first real clinical data is arriving in a muscle disease.

Epicrispr Biotechnologies, which develops programmable epigenetic medicines, announced on August 11 that it closed a $90 million Series C. The round was oversubscribed.

A gene that refuses to stay off

The target is facioscapulohumeral muscular dystrophy (FSHD), an inherited muscle disease that weakens the face, shoulders and upper arms, as the name says. The culprit is DUX4, a gene that does a brief job in early embryonic development and is supposed to stay silenced for life afterward. In FSHD patients, that lock doesn’t hold. DUX4 switches back on in adult muscle, and muscle cells start dying. No approved disease-modifying treatment exists.

Epicrispr’s tool is its Gene Expression Modulation System (GEMS), which selectively activates or silences a target gene without permanently altering the underlying DNA sequence — unlike conventional CRISPR, it leaves no cut behind. The company was founded by Stanford bioengineer Stanley Qi, who developed CRISPRi — repressing expression without cutting — and is a co-inventor on the University of California’s CRISPR patent. He brought with him an exclusive license to the smallest known Cas protein, which matters because only something that small fits inside a single AAV vector for delivery to target organs in the body.

CEO Amber Salzman comes from a different direction. She holds a PhD in mathematics from Bryn Mawr and ran drug development operations at GSK, overseeing global trials with more than 30,000 enrolled patients, 1,600 staff and a $1.25 billion budget. She then led Cardiokine through its sale to Cornerstone Therapeutics, co-founded Annapurna and served as CEO of Adverum Biotechnologies, and led Ohana Biosciences before joining Epicrispr. Her route into gene therapy was personal: in December 2000, her son and two nephews were diagnosed with adrenoleukodystrophy (ALD). She and her sisters founded the Stop ALD Foundation, drove the first human proof-of-concept for ALD gene therapy, and helped get ALD added to newborn screening panels.

The signal, from three patients

Lead candidate EPI-321 is the first clinical-stage epigenetic therapy for FSHD. A single intravenous dose is carried to muscle tissue in one AAV vector, where it suppresses pathological DUX4 expression. One administration, not a course.

Interim Phase 1/2 data released on June 26 is what this round is buying into. Across the first three evaluable patients, whole-body lean muscle volume measured by MRI rose by roughly 370 mL on average — about 0.8 pounds — with individual gains between 0.5 and 1.3 pounds and some muscles up 15%. The company also reported circulating biomarker changes consistent with DUX4 suppression, favorable strength and functional outcomes, and a manageable safety profile. In a disease that only ever takes muscle away, this is the first clinical evidence of muscle coming back. Enrollment and dose escalation in the trial, running at US and New Zealand sites, are complete, with further data due later this year.

Three patients are still three patients. This is an early, uncontrolled signal in a handful of people — and scaling it into a pivotal trial is exactly what the money is for.

“This financing marks a pivotal milestone for Epicrispr as we advance EPI-321 and the next generation of programmable epigenetic medicines,” said Salzman. “The strength of this investor syndicate reflects the progress we’ve made in translating our platform into the clinic. This financing positions us to advance EPI-321 into pivotal studies, expand our pipeline and continue building a new class of epigenetic therapies for patients.”

Crossover money arrives

Octagon Capital and Janus Henderson Investors co-led the round, with participation from Fidelity Management & Research Company, Cormorant Asset Management, Duquesne Family Office, Sanofi Ventures, funds managed by abrdn, Angelini Ventures, Readout Capital and existing investors. Octagon’s Anran Li joins the board.

“Epicrispr has established itself as a leader in the field of programmable epigenetic medicine,” Li said. “The team has demonstrated exceptional execution by translating a differentiated platform into encouraging early clinical data for EPI-321 in a remarkably short period of time. We believe Epicrispr’s proprietary technology, strong leadership team and expanding clinical pipeline position the Company to define an entirely new therapeutic modality.”

The shape of the syndicate has changed. The $55 million Series A in July 2022 was led by Horizons Ventures and the $68 million Series B in March 2025 by Ally Bridge Group — conventional venture rounds. The Series B also drew SOLVE FSHD, the venture philanthropy vehicle founded by Lululemon founder Chip Wilson, who has FSHD himself. This round is stacked with crossover and hedge funds that buy public healthcare equities, which is what a pre-IPO cap table tends to look like. Total funding now stands at $213 million.

Why everyone crowds an 80,000-patient market

Something here doesn’t add up at first glance. FSHD is not a big market. Prevalence runs somewhere between 1 in 8,000 and 1 in 20,000, with roughly 80,000 patients in the US. Analyst estimates put the market at about $210 million in 2024, growing to perhaps $482 million by 2034 — nowhere near blockbuster territory. Even the $12 billion Novartis paid for Avidity wasn’t for FSHD alone; it bought a platform spanning myotonic dystrophy (DM1) and Duchenne as well. And yet large pharma and platform startups keep lining up for this narrow field.

Three reasons. First, DUX4 is an unusually clean target. Most diseases involve several genes or none anyone can pin down; FSHD reduces to “one gene that should be off is on.” There is no better stage on which to prove a technology that modulates gene expression in a chosen direction.

Second, winning here opens what comes next. Epicrispr’s GEMS and Tune’s TEMPO are platforms, not single drugs. Clinical data in one indication licenses the same machinery for others — which is why Tune picked chronic hepatitis B, a far larger market, as its opener. For these companies FSHD is less a market than a gate.

Third, rare-disease economics work. Small patient counts are offset by per-patient pricing in the hundreds of thousands of dollars, plus orphan drug tax credits, market exclusivity and accelerated approval pathways. Trials are smaller, so development costs less. That is how 80,000 patients becomes a viable business.

So this isn’t a fight over dividing a large market. It’s a group of companies bringing different answer sheets to a small, unusually legible problem — which is also why Novartis reaching approval first wouldn’t end the game.

The competition: Novartis is already ahead

Epicrispr is not the frontrunner in FSHD. That would be Novartis and delpacibart braxlosiran (del-brax), an antibody-oligonucleotide conjugate originally developed by Avidity Biosciences that uses the antibody as a courier to deliver a payload degrading DUX4 mRNA. Novartis agreed to acquire Avidity for roughly $12 billion in all cash last October and closed the deal on February 27. In June, del-brax met its primary and key secondary endpoints in the biomarker cohort of the Phase 1/2 FORTITUDE trial. An accelerated-approval filing is planned for the second half of this year, with a Phase 3 enrolling. If it holds, it becomes the first therapy addressing the genetic cause of FSHD.

The approaches differ, though. Del-brax degrades mRNA on a repeat-dosing schedule; EPI-321 aims to hold the switch down with a single dose. How long the effect lasts — and whether patients face injections for life — is where the two diverge, and it’s why Epicrispr keeps returning to the word durable.

Fulcrum Therapeutics went at FSHD earlier with losmapimod, an oral drug blocking enzymes that regulate DUX4 activity, but it failed in Phase 3 and development was halted. Arrowhead Pharmaceuticals also has a DUX4 program and signed a collaboration with Sarepta Therapeutics in November 2024.

Judged as a technology rather than a disease, epigenetic editing is a different field again. The best-capitalized player is Tune Therapeutics, which raised over $175 million in Series B in January 2025 from NEA, Regeneron Ventures and others, leading with chronic hepatitis B and delivering via lipid nanoparticles. nChroma Bio, formed from Chroma Medicine and Nvelop, targets liver disease with epigenetic silencing, and Sangamo Therapeutics attacks the same problem with zinc finger proteins. None of them has yet shown a disease-modifying signal in actual patients. Epicrispr has — which goes some way toward explaining an oversubscribed round.