Analysis
Souffle Therapeutics, a Watertown, Massachusetts-based RNA therapeutics company, closed an oversubscribed $135 million Series B led by Juvia Group, according to a release carried by FinancialContent. New institutional investors TCG Crossover Management, BB Biotech, Fidelity Management & Research, Balyasny Asset Management and an unnamed sovereign wealth fund joined existing backers Amgen Ventures, ARCH Venture Partners, Bessemer Venture Partners, Breyer Capital, The Invus Group, Janus Henderson, Leaps by Bayer, Polaris Partners, Safar Partners, TAS Partners, Temasek and Vida Ventures.
- Funding history:
- Series A (Oct. 2025): $200 million
- Series B (Oct. 2026, this round): $135 million, oversubscribed
- Disclosed total: more than $330 million
What does Souffle's platform actually target?
Souffle's REMEDY platform (Receptor Mediated Delivery) is built to deliver oligonucleotide therapies to specific cell types outside the liver, which has been the default destination for most RNA drugs to date. The company identifies internalizing receptors on target tissue and builds binders, including monoclonal antibodies, to carry therapies there directly. Its three funded programs target facioscapulohumeral muscular dystrophy (FSHD), for which the company says there is no approved disease-modifying therapy; heart failure with reduced ejection fraction, aimed at the phospholamban gene in heart muscle cells; and an undisclosed target in muscle and metabolic disorders. CEO Amir Nashat said the company is "honored and grateful" for the backing "as we advance our first program into the clinic" -- language that confirms the lead program has not yet entered clinical testing.
The tissue-targeting problem Souffle is chasing is the same one Avidity Biosciences, a publicly traded company, built its pipeline around with antibody-oligonucleotide conjugates, including programs in muscle disease. Alnylam Pharmaceuticals remains the most clinically advanced and commercially successful company in RNA interference more broadly, giving Souffle two well-capitalized points of comparison before its own science reaches human trials.
Juvia Group co-founder Stefan Vitorovic said "patients have waited long enough for real precision from targeted therapies," and TCGX managing partner Chen Yu said the firm was "compelled by Souffle's lead programs that are already making meaningful progress in FSHD and heart failure." The company has described more than $3.5 billion in combined fundraising and pharma partnerships, though that figure includes milestone-based deal value rather than equity raised. With three programs still preclinical or just entering the clinic, the next milestone to watch is Souffle's first human proof-of-concept data, not the size of the round that funds the wait for it.
