The epigenetic editing pioneer that reached the clinic with a no-cut hepatitis B silencer
HQ: Boston, Massachusetts, USA (201 Brookline Avenue; now operates as nChroma Bio) | Founded: 2021 | Employees: ~70 est. post-merger (Revelio Labs, March 2026); LinkedIn lists the 51–200 band; Chroma alone reached ~80 in early 2023 (Boston Business Journal) | Stage: Clinical Stage (Private) | Website: https://chromamedicine.com (redirects to nchromabio.com)
Chroma Medicine is a Boston genomic medicine company built on the premise that the epigenome — not the genome sequence — is the right place to intervene. Formed ~2020 and launched November 17, 2021 with $125M in combined seed and Series A financing, it develops programmable epigenetic editors that durably turn genes off (or on) by depositing DNA methylation and remodeling chromatin without cutting DNA — avoiding the DNA breaks of nuclease editing and the permanent sequence changes of base and prime editing.
The company was co-founded by six leading scientists: Luke Gilbert (UCSF/Arc), Keith Joung (Harvard/MGH), David Liu (Broad Institute), Angelo Lombardo (San Raffaele), Luigi Naldini (SR-Tiget) and Jonathan Weissman (Whitehead/MIT). CEO Catherine Stehman-Breen (ex-Regeneron, Exelixis) and President/CSO Vic Myer (ex-Editas) led it; Chroma acquired Lombardo's Milan-based Epsilen Bio at launch. The launch package paired an Atlas/Newpath-led seed with a Cormorant-led Series A; a $135M Series B followed on March 1, 2023, led by GV with ARCH, DCVC Bio, Mubadala Capital and Sixth Street joining.
On December 11, 2024, Chroma merged with Nvelop Therapeutics — the in vivo delivery company co-founded by Liu and Joung — to form nChroma Bio, with a concurrent oversubscribed $75M round led by Cormorant, ARCH, Atlas and Newpath; combined capital totals roughly $435M. Jeff Walsh (ex-Nvelop, bluebird bio) became CEO. As nChroma, lead candidate CRMA-1001 — an LNP-delivered epigenetic silencer methylating both cccDNA and integrated HBV DNA without cutting — entered Phase 1/2 in January 2026 (NCT07200193) after Hong Kong clearance, with further authorizations in New Zealand and the UK. The pipeline adds candidate-enabled PCSK9 and research-stage CNS programs.
Chroma Medicine was the most science-dense bet in epigenetic editing: six academic co-founders from the labs behind CRISPRoff, base editing and prime editing — David Liu, Keith Joung, Luke Gilbert, Jonathan Weissman, Angelo Lombardo and Luigi Naldini — around a thesis: regulating genes through the epigenome, without cutting DNA, could be safer than nucleases. Launched in November 2021 with $125M (Atlas/Newpath seed; Cormorant-led Series A), it built modular editors that durably silence, activate and multiplex genes via DNA methylation — no DNA breaks, no permanent sequence changes.
The decisive move: a December 11, 2024 merger with Nvelop Therapeutics, the Liu/Joung virus-like particle (eVLP) delivery company, forming nChroma Bio with a concurrent oversubscribed $75M round led by Cormorant, ARCH, Atlas and Newpath — solving Chroma's biggest open problem, delivery. The combined entity, led by CEO Jeff Walsh (ex-Nvelop, bluebird bio), has one clinical asset: CRMA-1001, an LNP-delivered silencer that methylates both cccDNA and integrated HBV DNA without cutting — a potential functional cure for chronic hepatitis B (>250M patients, company figure). First-in-human Phase 1/2 dosing began January 28, 2026 (NCT07200193), with sites in Hong Kong, New Zealand, UK; Nature Biomedical Engineering data (September 2026) showed up to 3.7-log10 sustained HBV biomarker reductions, up to 90% of mice with undetectable HBsAg and HBV DNA at six months, and no detectable off-target changes in human cells.
Caveats are substantial: no epigenetic editing medicine has been approved; durability of methylation in humans over years is unproven; and nuclease peers have stumbled — Intellia's 2025 FDA holds and Lilly's discounted buyouts of Verve and Orna show how hard the clinical bar is. Chroma/nChroma enters that gauntlet with ~$435M raised, a leaner ~70-person team, a no-cut mechanism validated across species, and the first clinical test of epigenetic silencing in virology's largest disease.
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