Merck KGaA-Backed Cyllene Raises €33m for Gene Therapy

Paris-based biotech Cyllene Therapeutics has raised €33m ($37.75m) in Series C financing to advance its pipeline of herpes virus-based gene therapies, with lead candidate EG110A targeting severe neurogenic bladder conditions. Announced on 7 July 2026, the round was co-led by Merck KGaA’s venture arm and GordonMD Global Investments, with participation from Bpifrance Investissement. The company has also rebranded from EG 427, adopting the Cyllene name from the birthplace of the Greek god Hermes.

Cyllene’s HERMES platform uses non-replicating herpes simplex virus type 1 (HSV-1) as a gene therapy vector, leveraging the virus’s natural affinity for neuronal tissue. Lead candidate EG110A is being developed for neurogenic detrusor overactivity, designed to express a botulinum toxin fragment specifically in bladder sensory neurons while preserving motor neuron and muscle cell function. Phase Ib/IIa data (NCT06596291) showed EG110A reduced urinary incontinence episodes by over 88%. The company plans a Phase IIb/III study in 2027 and is at IND-enabling stage for overactive bladder and interstitial cystitis.

CEO Philippe Chambon described the round as a defining moment as EG110A moves toward later-stage development. The financing lands in a gene therapy funding environment that has been through several years of oscillation, with the modality peaking in 2021 before reimbursement and scaling challenges triggered a lull that saw Pfizer and Takeda exit and Galapagos (now Lakefront Biotherapeutics) refocus on immunology and oncology. Investor appetite has picked up sharply in 2026, with Eli Lilly’s $1.12bn acquisition of Seamless Therapeutics in January and Scribe Therapeutics preparing an IPO.

The commercial signal is a double one. On the pipeline side, EG110A’s early efficacy in a large, underserved bladder disorder market makes Cyllene a credible late-stage biotech candidate. On the sector side, Merck KGaA’s continued push into gene therapy alongside Eli Lilly, Scribe and MeiraGTx signals that the 2022-2024 gene therapy funding freeze has genuinely thawed, particularly for platform-based developers.

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