Gene Therapy: A Possible Alternative to CFTR Modulators?

A new era of targeting cystic fibrosis with non-viral delivery of genomic medicines

Cystic fibrosis (CF) is a complex genetic respiratory disorder that necessitates innovative gene delivery strategies to address the mutations in the gene. This review delves into the promises and challenges of non-viral gene delivery for CF therapy and explores strategies to overcome these hurdles. Several emerging technologies and nucleic acid cargos for CF gene therapy are discussed. Novel formulation approaches including lipid and polymeric nanoparticles promise enhanced delivery through the CF mucus barrier, augmenting the potential of non-viral strategies. Additionally, safety considerations and regulatory perspectives play a crucial role in navigating the path toward clinical translation of gene therapy.

Repeat or single-dose lentiviral vector administration to mouse lungs? It's all about the timing

Lentiviral vectors are attractive delivery vehicles for cystic fibrosis gene therapy owing to their low immunogenicity and ability to integrate into the host cell genome, thereby producing long-term, stable gene expression. Nonetheless, repeat dosing may be required to increase initial expression levels, and/or boost levels when they wane. The primary aim of this study was to determine if repeat dosing of a VSV-G pseudotyped LV vector delivered into mouse lungs is more effective than a single dose. C57Bl/6 mouse lungs were conditioned with lysophosphatidylcholine, followed one-hour later by a LV vector carrying the luciferase reporter gene, using six different short-term (≤1 wk) and long-term (>1 wk) dosing schedules. Luciferase expression was quantified using bioluminescence imaging over 12 months. Most dosing schedules produced detectable bioluminescence over the 12-month period, but the shorter intervals (≤1 wk) produced higher levels of flux than the longest interval (five doses at least 1-month apart). Ex vivo lung analysis at 12 months showed that the estimated mean flux for the group that received two doses 1-week apart was significantly greater than the single dose group and the two groups that received doses over a period greater than 1-week. These results suggest that early consecutive multiple doses are more effective at improving gene expression in mouse lungs at 12 months, than longer repeat dosing intervals.

Gene therapy for cystic fibrosis: Challenges and prospects

Cystic fibrosis (CF) is a life-threatening autosomal-recessive disease caused by mutations in a single gene encoding cystic fibrosis transmembrane conductance regulator (CFTR). CF effects multiple organs, and lung disease is the primary cause of mortality. The median age at death from CF is in the early forties. CF was one of the first diseases to be considered for gene therapy, and efforts focused on treating CF lung disease began shortly after the CFTR gene was identified in 1989. However, despite the quickly established proof-of-concept for CFTR gene transfer in vitro and in clinical trials in 1990s, to date, 36 CF gene therapy clinical trials involving ∼600 patients with CF have yet to achieve their desired outcomes. The long journey to pursue gene therapy as a cure for CF encountered more difficulties than originally anticipated, but immense progress has been made in the past decade in the developments of next generation airway transduction viral vectors and CF animal models that reproduced human CF disease phenotypes. In this review, we look back at the history for the lessons learned from previous clinical trials and summarize the recent advances in the research for CF gene therapy, including the emerging CRISPR-based gene editing strategies. We also discuss the airway transduction vectors, large animal CF models, the complexity of CF pathogenesis and heterogeneity of CFTR expression in airway epithelium, which are the major challenges to the implementation of a successful CF gene therapy, and highlight the future opportunities and prospects.

Cancer in Cystic Fibrosis: A Narrative Review of Prevalence, Risk Factors, Screening, and Treatment Challenges: Adult Cystic Fibrosis Series

Cystic fibrosis (CF) is a progressive monogenetic disorder that causes persistent pulmonary disease, but also affects other organ systems, including the digestive tract. Recent advances in treatment and care of patients with CF, including the use of new and highly effective CF transmembrane conductance regulator modulators, have led to a dramatic increase in survival. Young patients with CF now can expect to live to or beyond middle age, when cancer is more frequent. Patients with CF now are known to face an increased risk of digestive tract cancer, particularly cancer of the colon. The risk, which could be triggered by associated CF-related conditions or other genetic mechanisms, is even greater in patients who received a transplant. Also some evidence suggests that adenomatous polyps develop more frequently in patients with CF and at an earlier age than in patients without CF. To reduce the excess risk of intestinal cancer in patients with CF, the Cystic Fibrosis Foundation has developed colonoscopy-based guidelines. For nontransplanted patients, colonoscopy should begin at 40 years of age, with rescreening at 5-year intervals; the screening interval should be shortened to 3 years if adenomatous polyps are discovered. For transplanted patients, screening should start at 30 years of age, or within 2 years of the transplant operation. Before colonoscopy, it is essential for patients with CF to undergo a special, more intensive bowel preparation than normally used for those without CF. Whether the new drugs that have dramatically improved morbidity and mortality for patients with CF will alter the risk of cancer is unknown and needs to be assessed in future studies.