SpliceBio Raises $135 Million Series B to Advance First Dual AAV Gene Therapy for Stargardt Disease
Key Insights
SpliceBio (search) secured $135 million in Series B funding co-led by EQT Life Sciences (search) and Sanofi Ventures (search) to advance SB-007, the first dual AAV gene therapy cleared by FDA for Stargardt disease (search) treatment.
The company's proprietary Protein Splicing platform addresses a fundamental limitation of AAV vectors (search) by enabling delivery of large genes that exceed the 4.7 kilobase packaging capacity through engineered inteins (search).
SB-007 has received Orphan Drug Designation from both FDA and European Commission, with the first patient dosed in the Phase 1/2 ASTRA study in March 2025.
SpliceBio (search), a clinical-stage genetic medicines company, has closed a $135 million Series B financing round to advance its lead gene therapy program SB-007 for Stargardt disease (search), marking a significant milestone in addressing one of gene therapy's most pressing technical challenges. The round was co-led by EQT Life Sciences (search) and Sanofi Ventures (search), with participation from Roche Venture Fund and all existing investors.
Breakthrough Technology Addresses Critical Gene Therapy Limitation
SpliceBio (search)'s proprietary Protein Splicing platform tackles a fundamental limitation that has prevented many genetic disorders from being treated with gene therapy. Traditional AAV vectors (search) can only deliver genes up to 4.7 kilobases in size, leaving numerous genetic conditions caused by larger genes without treatment options.
The company's innovative approach leverages engineered proteins called inteins (search), originally developed at Princeton University, to split large genes into two or more transgenes delivered via dual AAV vectors (search). Once inside the cell, the DNA is transcribed into messenger RNA and translated into protein, with SpliceBio (search)'s engineered inteins designed to assemble the full-length protein needed for therapeutic effect.
"SpliceBio (search) is redefining and expanding the scope of diseases that can be tackled with gene therapies by addressing a fundamental limitation of AAV vectors (search)," the company stated, emphasizing how many genetic disorders remain untreatable because the necessary gene exceeds AAV packaging capacity.
SB-007 Achieves Historic FDA Clearance
The company's lead program, SB-007, represents a groundbreaking achievement as the first dual AAV gene therapy to receive FDA IND clearance for Stargardt disease (search) treatment. This investigational therapy is designed to restore expression of the native full-length ABCA4 (search) protein in the retina, targeting the root cause of this genetic eye disease that causes blindness in children and adults.
SB-007 has been granted Orphan Drug Designation from both the FDA and European Commission. The Phase 1/2 ASTRA study commenced with the first patient dosed in March 2025, alongside the ongoing POLARIS natural history study of the disease.
Miquel Vila-Perelló, CEO and co-founder of SpliceBio (search), highlighted the rapid progression from preclinical proof-of-concept to first patient dosing in just three years following FDA clearance. "This progress was rapid and demonstrated a good example of disciplined execution," he noted, crediting the team's proven ability to execute with quality within expected timelines and budgets.
Strategic Investor Backing Validates Platform Potential
The Series B round attracted significant strategic investment from major pharmaceutical companies, reflecting confidence in both the technology and market opportunity. Daniela Begolo, Managing Director at EQT Life Sciences (search), commented: "We are proud to support SpliceBio (search), a pioneer among the next-generation of genetic medicine companies. Its Protein Splicing platform is designed to offer a novel solution to deliver large genes with AAV, one of the field's most pressing challenges."
Laia Crespo, Partner at Sanofi Ventures (search), emphasized the platform's differentiation: "With compelling data for its lead program, SB-007, and a highly differentiated platform, we are excited to support SpliceBio (search) as it tackles a fundamental challenge for genetic medicines. By enabling the delivery of large and complex genes through its novel AAV vector Protein Splicing technology, SpliceBio has the potential to make a significant impact on the field of gene therapy."
Carole Nuechterlein, Head of Roche Venture Fund, highlighted the clinical momentum: "We are impressed by the team's strong execution, the momentum behind SB-007 in Stargardt disease (search), and the platform's potential to unlock a new class of genetic medicines."
Addressing High Unmet Medical Need
Stargardt disease (search) represents a significant unmet medical need as an inherited retinal disorder caused by mutations in the ABCA4 (search) gene, leading to progressive vision loss and blindness with no currently approved treatments available. This therapeutic gap has driven substantial investment into advanced therapy options for patients.
Vila-Perelló identified three key factors that attracted investors: the team's proven execution capabilities, a differentiated first-in-class therapy with compelling preclinical data and clear regulatory pathway, and a unique proprietary platform demonstrating transformative potential across multiple therapeutic areas.
Platform Expansion Beyond Ophthalmology
SpliceBio (search)'s pipeline extends beyond its lead ophthalmology program to include additional gene therapy programs across neurology and other therapeutic areas. The company's platform technology, based on over 20 years of pioneering intein and protein engineering research from Princeton University's Muir Lab, positions it to address genetic disorders previously considered untreatable due to gene size limitations.
The financing will support clinical development of SB-007 while expanding the pipeline of genetic medicines leveraging the Protein Splicing platform. With the Series B completed, Vila-Perelló emphasized the company's focus on execution and delivering on program milestones rather than additional fundraising in the near term.