Cyllene Therapeutics Raises €33m Series C to Advance HSV-1 Gene Therapy for Neurogenic Bladder Conditions
Key Insights
Cyllene Therapeutics (search) (formerly EG 427) secured €33m ($37.75m) in Series C financing co-led by Merck KGaA's M Ventures and GordonMD Global Investments (search).
Lead candidate EG110A, delivered via a non-replicating HSV-1 (search) vector, reduced urinary incontinence episodes by over 88% in a Phase Ib/IIa trial for neurogenic detrusor overactivity (search).
The company plans to initiate a Phase IIb/III study in 2027 and expand into overactive bladder (search) and additional neurological indications.
Paris-based biotech Cyllene Therapeutics (search) has raised €33 million ($37.75 million) in a Series C financing round to advance its pipeline of precision genetic medicines, anchored by lead candidate EG110A for severe neurogenic bladder conditions. The company, previously known as EG 427, also announced a rebranding alongside the funding close.
The round was co-led by Merck KGaA's venture arm M Ventures and equity firm GordonMD Global Investments (search), with participation from existing backers including Andera Partners, Bpifrance Investissement (search) through its InnoBio 3 fund, and Lamond Ventures.
A Novel HSV-1 (search) Vector Platform
Cyllene's HERMES platform employs non-replicating herpes simplex virus type 1 (HSV-1 (search)) as a gene therapy vector. While wild-type HSV-1 is the virus responsible for herpes, the company has engineered it to deliver therapeutic DNA safely and efficiently. The approach is designed to achieve focal transduction and selective expression of transgenes in targeted subsets of neurons.
EG110A, the most advanced candidate, has been designed to express a botulinum toxin fragment in bladder sensory neurons while preserving motor neuron and muscle cell function. Specifically, the therapy targets type C sensory neurons involved in bladder overactivity, aiming to preserve normal bladder voiding function.
Compelling Early Clinical Data
In a Phase Ib/IIa trial (NCT06596291), EG110A demonstrated a reduction in the incidence of urinary incontinence episodes by over 88%. The company reported that these reductions were substantial and sustained nine months after treatment.
The current trial builds on a €27 million Series B round raised in 2025, which funded Phase Ib/IIa testing at four US study sites. At that time, Cyllene described the study as the first human trial using a non-replicating HSV-1 (search) vector to target sensory neuron-based disease.
Development Path Forward
Cyllene is planning a Phase IIb/III study for EG110A in 2027, which will assess dosing, safety, efficacy, and durability. In parallel, the company will monitor very long-term efficacy in a separate observational study for up to five years.
Beyond neurogenic detrusor overactivity (search), EG110A is at the investigational new drug (IND)-enabling stage for overactive bladder (search) and interstitial cystitis (search). The company also intends to expand into additional neurological indications. Cyllene's broader pipeline includes further products in development for undisclosed neuromuscular, sensory, and neurodegenerative diseases.
Executive Commentary
"This financing marks a defining moment as we advance EG110A toward later-stage development and broaden our HERMES pipeline," said CEO Philippe Chambon. "Early data support our belief that localised DNA medicines can deliver durable efficacy with a strong safety profile in chronic neurological diseases."
Chambon added: "Early clinical data generated to date with EG110A support our belief that localized, targeted DNA medicines can deliver durable efficacy with a strong safety profile in chronic neurological diseases. This financing will help us move further towards delivering this approach to more patients."
Gene Therapy Investment Landscape
The financing comes amid a fluctuating investment environment for gene therapy. Venture capital investment in the modality peaked in 2021, with reimbursement and scaling challenges contributing to a subsequent downturn. Several major pharmaceutical companies, including Pfizer and Takeda, have ended their gene therapy programs, while Galapagos—now Lakefront Biotherapeutics—has pivoted to immunology and oncology. Cyllene's successful raise signals continued investor appetite for differentiated gene therapy platforms targeting well-defined neurological conditions.