This clinical trial is focused on studying cystic fibrosis, a genetic condition that affects the lungs and digestive system. The trial will test a new treatment called SPL84, which is a solution for inhalation. This treatment is designed to help people with a specific genetic mutation known as the 3849 +10 Kb C->T mutation in the CFTR gene. The purpose of the study is to evaluate the safety and tolerability of SPL84 when given in increasing doses through inhalation.

Participants in the study will use a device called the Aerogen InnoSpire Go nebulizer to inhale the medication. This device helps deliver the treatment deep into the lungs. The study will compare the effects of SPL84 with a placebo solution, which looks like the treatment but does not contain the active substance. The trial will monitor participants for any side effects and changes in their health, including lung function and overall well-being.

The study will take place over several months, during which participants will receive multiple doses of SPL84. Researchers will collect information on how the body processes the medication and its impact on symptoms of cystic fibrosis. The goal is to determine the most suitable dose that is both safe and effective for patients with this genetic mutation. Participants will be closely monitored throughout the study to ensure their safety and to gather valuable data on the treatment’s potential benefits.