ReCode Therapeutics’ inhaled mRNA therapy RCT1100 showed early biologic activity in primary ciliary dyskinesia, improving mucociliary clearance and validating its SORT LNP platform. Findings presented at ATS 2026 highlight safety, biomarker potential, and support continued development toward disease‑modifying trials.
Written By: Mahathi Palivela, PharmD
Reviewed By: Pharmacally Editorial Team
ReCode Therapeutics presented new clinical data from its inhaled mRNA candidate RCT1100 at the 2026 American Thoracic Society (ATS) International Conference, marking the first reported evidence of biologic activity from a genetic medicine in patients with primary ciliary dyskinesia (PCD).
Results from the multinational Phase 1b RCT1100-103 study (NCT06633757) showed that 57% of treated patients achieved meaningful improvement in mucociliary clearance (MCC) at 12 weeks compared with baseline. Bronchoscopy confirmed restoration of target protein expression and ciliary activity in the airway, with protein restoration correlating with MCC improvement.
Mechanistic and Platform Validation
The findings provide early clinical validation for inhaled mRNA delivery in the human lung and support ReCode’s proprietary SORT lipid nanoparticle (LNP) platform, which enables targeted delivery of genetic medicines to airway tissue.
RCT1100 delivers mRNA directly to airway cells through inhalation to restore production of functional proteins involved in ciliary movement. The program represents one of the first attempts to use inhaled mRNA therapeutics to correct underlying genetic dysfunction in respiratory disease.
Disease Context and Unmet Need
PCD is a rare inherited disorder caused by dysfunctional motile cilia, resulting in impaired mucus clearance, chronic respiratory infections, bronchiectasis, and progressive lung damage. More than 50 genes have been linked to the disease, and no approved disease-modifying therapies currently exist.
Safety Profile Across Early-Phase Studies
The therapy was well tolerated in RCT1100-103, with no serious adverse events reported. ReCode also presented supporting safety data from the earlier Phase 1a RCT1100-101 single-dose study and the Phase 1b RCT1100-102 multiple-dose study. Across dose levels up to 5 mg administered three times weekly, investigators observed no Grade 3 or higher treatment-emergent adverse events, underscoring consistent tolerability across cohorts.
Biomarker Development: MCC as Translational Endpoint
A separate observational study involving 25 adults with confirmed PCD showed consistently low MCC values across genotypes, reinforcing MCC as a potential translational biomarker for future disease-modifying studies. The correlation between protein restoration and MCC improvement in RCT1100-103 further supports MCC’s role as a clinically meaningful endpoint.
Leadership Perspective
Chief Executive Officer Shehnaaz Suliman said the data demonstrated successful lung delivery and downstream biologic activity of an inhaled genetic medicine in PCD patients. Chief Medical Officer John Matthews described the findings as a foundational advance for the PCD field.
Conference Spotlight and Future Direction
ReCode also presented the RCT1100 program during an oral session at the ATS 2026 Respiratory Innovation Summit in Orlando. The early findings support continued clinical development of inhaled mRNA therapies for PCD and provide initial evidence that restoring mucociliary clearance may translate into broader disease-modifying benefit in future studies.
Reference
ReCode Therapeutics Achieves a First: Proof of Activity in Primary Ciliary Dyskinesia Patients
About the Writer
Mahathi Palivela (LinkedIn) is pursuing PharmD and has a strong interest in Clinical Pharmacy and Patient safety. She is passionate about handling and analyzing patient data, and translating clinical insights into clear, meaningful summaries. She aims to apply this interest in Medical Writing and Pharmacovigilance, focusing on improving patient outcomes through careful data interpretation and communication.