Splice Bio is a technology company.
Splice Bio has raised $197.0M across 2 funding rounds.
Splice Bio has raised $197.0M in total across 2 funding rounds.
Splice Bio has raised $197.0M in total across 2 funding rounds.
Splice Bio's investors include Asabys Partners, EQT Life Sciences, Forbion, Ed Mathers, New Enterprise Associates, Novartis Venture Fund, Roche Venture Fund, Sanofi Ventures, Ysios Capital.
# Splice Bio: Pioneering Protein Splicing for Next-Generation Gene Therapies
Splice Bio is a clinical-stage genetic medicines company developing gene therapies using a proprietary Protein Splicing platform to treat diseases caused by mutations in large genes.[3] The company addresses a fundamental limitation in current gene therapy: adeno-associated viruses (AAVs), the most widely used delivery vectors, have insufficient cargo capacity to carry many corrective genes.[4] Splice Bio's solution uses engineered split inteins—specially designed proteins that catalyze protein trans-splicing—to deliver large genes in two separate AAV pieces that reassemble into functional full-length proteins inside cells.[2]
The company serves patients with genetic diseases currently considered untreatable by conventional gene therapy approaches. Its lead program, SB-007, targets Stargardt disease, the most common inherited retinal disorder caused by mutations in the ABCA4 gene, which at 6.8 kb exceeds AAV packaging limits.[2] Beyond ophthalmology, Splice Bio is developing programs in neurology and other undisclosed therapeutic areas, demonstrating the broad applicability of its platform.[4]
Splice Bio traces its roots to more than 20 years of pioneering intein and protein engineering research conducted in the Muir Lab at Princeton University.[3] The company was launched in 2014 under the name ProteoDesign, initially focused on immuno-oncology conjugates before pivoting to gene therapy.[8] This strategic refocus proved transformative: the team recognized that their protein splicing technology could solve a critical bottleneck constraining the entire gene therapy field.
Co-founder and CEO Miquel Vila-Perelló, who conducted the foundational protein design research at Princeton, led this evolution.[4] Vila-Perelló holds a PhD in Chemistry from the University of Barcelona and has authored over 23 peer-reviewed publications and multiple granted patents.[3] The company rebranded to Splice Bio and relocated to Barcelona, Spain, establishing itself as a clinical-stage biotech with operations spanning the US and Europe.[8] A pivotal moment came when the company dosed its first Stargardt patient, validating the platform's clinical feasibility and attracting institutional backing.[8]
Inteins are auto-processing protein domains that catalyze protein splicing—a multi-step biochemical reaction involving cleavage and formation of peptide bonds.[5] Splice Bio's engineered versions enable highly efficient protein trans-splicing in vivo, allowing two separate AAV-delivered gene fragments to reconstitute into full-length therapeutic proteins.[2]
The platform directly addresses the most fundamental constraint in gene therapy: AAV vectors' small packaging capacity prevents delivery of genes larger than ~4.7 kb.[4] By splitting large genes and reassembling them post-delivery, Splice Bio enables treatment of diseases previously inaccessible to AAV-based approaches.[2]
Beyond engineered split inteins, the company has developed additional proprietary technologies in-house that collectively form its Protein Splicing platform, creating defensible intellectual property.[2][5]
Splice Bio's lead program (SB-007) is in Phase 1/2 clinical testing for Stargardt disease, demonstrating clinical-stage maturity.[4] The company has also secured a collaboration with Spark Therapeutics for an undisclosed inherited retinal disease, with potential milestone payments up to $216 million plus royalties, validating the platform's commercial potential.[6]
In June 2025, Splice Bio closed a $135 million Series B round co-led by EQT Life Sciences and Sanofi Ventures, with participation from Roche Venture Fund and existing investors including New Enterprise Associates, UCB Ventures, and Novartis Venture Fund.[3] This capital influx supports advancement of its lead program and pipeline expansion.
Splice Bio operates at the intersection of two powerful trends: the maturation of gene therapy as a clinical modality and the growing recognition that AAV limitations require innovative solutions. The company is riding a wave of investment in genetic medicines—the global gene therapy market is expanding rapidly as regulatory pathways mature and manufacturing scales.[4]
The timing is particularly favorable because multiple therapeutic areas remain underserved by conventional gene therapy due to cargo size constraints. Inherited retinal diseases like Stargardt represent a large addressable market with high unmet medical need, but Splice Bio's platform extends far beyond ophthalmology into neurology and other genetic disorders.[3][4]
Notably, Splice Bio is not alone in pursuing this approach—competitors like AAVantgarde are developing similar strategies—but the company's deep scientific foundation, clinical progress, and strategic partnerships position it as a leader in this emerging modality.[4] By solving a problem that constrains an entire industry, Splice Bio influences how the broader gene therapy ecosystem approaches large-gene diseases, potentially opening new therapeutic possibilities for thousands of patients.
Splice Bio stands at an inflection point. The company has transitioned from proof-of-concept to clinical validation with SB-007's Phase 1/2 trial, and the $135 million Series B provides runway to generate efficacy and safety data—the critical value drivers for gene therapy companies.[8] Success in Stargardt disease would validate the platform's clinical utility and likely accelerate development of additional programs in ophthalmology and neurology.
The Spark Therapeutics collaboration signals that large pharmaceutical players recognize the platform's potential, suggesting a pathway to commercialization through partnerships or eventual acquisition. As Splice Bio executes on clinical readouts and expands its pipeline, it will likely influence how the broader biotech industry approaches the challenge of delivering large therapeutic genes—a problem affecting hundreds of potential indications. The company's success could reshape the competitive landscape of gene therapy by making previously untreatable genetic diseases addressable, ultimately expanding the total addressable market for genetic medicines.
Splice Bio has raised $197.0M across 2 funding rounds. Most recently, it raised $140.0M Series B in June 2025.
| Date | Round | Lead Investors | Other Investors |
|---|---|---|---|
| Jun 1, 2025 | $140.0M Series B | Asabys Partners, EQT Life Sciences, Forbion, Ed Mathers, New Enterprise Associates, Novartis Venture Fund, Roche Venture Fund, Sanofi Ventures, Ysios Capital | |
| Feb 1, 2022 | $57.0M Series A | Asabys Partners, EQT Life Sciences, Forbion, Ed Mathers, New Enterprise Associates, Novartis Venture Fund, Roche Venture Fund, Sanofi Ventures, Ysios Capital |