ReCode Therapeutics Launches Phase 2 Combination Trial of Inhaled CFTR mRNA Therapy

MENLO PARK, Calif. – November 17, 2025 — ReCode Therapeutics, a clinical-stage genetic medicines company specializing in tissue-specific delivery, today announced that the U.S. Food and Drug Administration (FDA) has cleared the initiation of Part 3 of its ongoing Phase 2 clinical trial. The study evaluates RCT-2100, an investigational inhaled CFTR mRNA therapy, in combination with ivacaftor in people with cystic fibrosis (CF).

CFTR mRNA Therapy in Combination with Ivacaftor

Part 3 of the multi-part, open-label Phase 2 trial is currently enrolling participants at clinical sites across the United States, with plans to expand enrollment to the United Kingdom and the European Union in the first quarter of 2026.

The primary endpoints of Part 3 will assess the safety and tolerability of inhaled CFTR mRNA therapy (RCT-2100) when co-administered with ivacaftor over a six-week treatment period in up to 12 individuals with CF. Secondary endpoints include assessments of lung function and quality of life.

“Advancing the study of the combination of RCT2100 with ivacaftor represents an important milestone for the program and for patients,” said Shehnaaz Suliman, M.D., CEO of ReCode Therapeutics. “This study will provide further insight into the potential additive benefits of RCT2100 when combined with ivacaftor on clinically meaningful measures such as lung function and patient-reported outcomes.”

Inhaled mRNA Designed to Address Root Cause

RCT2100 is formulated using ReCode’s proprietary Selective Organ Targeting (SORT) lipid nanoparticle (LNP) platform. This platform is designed to deliver the therapeutic CFTR mRNA directly to target cells in the lungs via oral inhalation through a nebulizer.

The goal of this mRNA approach is to instruct lung cells to produce a functional version of the CFTR protein, which is missing or dysfunctional in individuals with CF due to genetic mutations. By delivering this therapeutic CFTR mRNA, the treatment aims to address the root cause of the disease.

While advancements in CFTR modulator treatments have improved care, approximately 10% of the CF community have mutations that prevent them from benefiting from existing therapeutics. The development of a functional CFTR mRNA treatment could offer a solution for this underserved patient population. Previous parts of the study (Part 1 and Part 2) investigated single and multiple ascending doses of the inhaled mRNA therapy in healthy volunteers and CF participants, respectively.