South San Francisco-based Encoded Therapeutics has closed a USD 275 million Series F financing round to advance its lead gene therapy candidate through pivotal development in Dravet syndrome and expand its neurology pipeline.
The round was co-led by GV alongside an unnamed healthcare fund, with participation from ARCH Venture Partners, Braidwell LP, Farallon Capital Management, Illumina Ventures, Invus, Janus Henderson Investors, Matrix Capital Management, Nolan Capital, RTW Investments, SoftBank Vision Fund 2, and Venrock. Several of these investors have backed the company across prior rounds, including a USD 135 million Series D in 2020 that also supported the first clinical trials of its lead asset. Proceeds from the Series F will fund pivotal and expansion studies of ETX101 in Dravet syndrome, commercial-scale buildout of internal GMP manufacturing, and advancement of ETX301 toward a 2027 investigational new drug (IND) submission.
ETX101 is an adeno-associated virus (AAV)-based gene therapy designed to upregulate SCN1A expression selectively in GABAergic inhibitory interneurons — the cell type where haploinsufficiency drives Dravet syndrome pathology. Because the SCN1A gene exceeds AAV packaging capacity, Encoded's approach relies on engineered human genomic regulatory elements to activate the endogenous gene rather than replace it, while simultaneously reducing off-target expression in tissues such as dorsal root ganglia. Interim Phase I/II data from the POLARIS program, presented at the European Epilepsy Congress, showed substantial and sustained reductions in seizure frequency alongside neurodevelopmental signals, the company said. A pivotal study in infants and young children with SCN1A+ Dravet syndrome, and an expansion study in patients up to 18 years of age, are under way.
ETX301, the pipeline's second asset, applies a related nociceptive neuron-selective promoter — NociPro — derived from the same human genomic regulatory element engineering platform, and is intended as a one-time gene therapy for post-amputation neuroma pain, with initial evaluation planned in lower-limb amputees.