CF Foundation Commits $11 Million to Accelerate 4DMT’s AAV Gene Therapy for Cystic Fibrosis Lung Disease

EMERYVILLE, Calif. – October 13, 2025 – 4D Molecular Therapeutics (4DMT) today announced that the Cystic Fibrosis Foundation (CF Foundation) will provide up to $11 million in additional funding and strategic support to accelerate the development of 4D-710, an investigational AAV gene therapy for Cystic Fibrosis (CF) lung disease.

The new commitment, which includes an initial $7.5 million tranche, brings the CF Foundation’s total funding for 4DMT’s CF programs to nearly $32 million to date.

Strategic Support for Late-Stage Development
The funding coincides with the creation of a Joint Steering Committee (JSC) featuring senior clinical development and regulatory experts from the CF Foundation. This committee will enhance strategic planning and coordination as 4D-710 advances toward a pivotal Phase 2 trial and Phase 3 readiness.

“This funding and strategic support are critical as 4D-710 advances through Phase 2, with the goal of delivering a durable, redosable, and variant-agnostic genetic medicine with the potential to become a foundational treatment for individuals with CF with remaining unmet pulmonary needs,” said David Kirn, M.D., Co-founder and CEO of 4DMT.

AAV Technology Designed for Durable, Redosable Lung Delivery
4D-710 is designed to address the underlying cause of CF—mutations in the CFTR gene—regardless of the specific variant. It utilizes 4DMT’s proprietary next-generation A101 AAV vector, which was specifically invented for efficient aerosol delivery and transduction throughout the lung airways. The vector’s design is intended to enable repeat dosing to maintain clinical benefit over time.

4D-710 is the first known genetic medicine to demonstrate successful delivery and expression of the CFTR transgene throughout the airways of CF patients after aerosol delivery.

The new funding will support:

Phase 1 Redosing Cohort: Selected participants from Phase 1 will receive a second dose (2.5E14 vg), at least one year after the initial dose.

Phase 2 Cohort: Enrollment has begun, using the 2.5E14 vg dose, which is anticipated to be the pivotal and commercial dose.

Interim Phase 1 Data Expected by Year-End 2025
4DMT is expected to share interim Phase 1 data from the AEROW clinical trial by year-end 2025. The update will focus on functional respiratory endpoints from lower-dose cohorts (n=9) with follow-up between 3 and 18 months.

The data will highlight:

Functional Durability: Transgene expression and durability results, including analysis of paired lung biopsies collected up to three years post-dosing.

Novel Endpoints: Results from multiple-breath washout (MBW) measuring Lung Clearance Index (LCI2.5), a sensitive measure of small airway function, and High-Resolution Computed Tomography (HRCT) to assess changes in airway structure like mucus plugging.

4D-710 has received the Rare Pediatric Disease Designation and Orphan Drug Designation from the FDA.