FDA-approved drug screening in patient-derived organoids demonstrates potential of drug repurposing for rare cystic fibrosis genotypes.

BACKGROUND: Preclinical cell-based assays that recapitulate human disease play an important role in drug repurposing. We previously developed a functional forskolin induced swelling (FIS) assay using patient-derived intestinal organoids (PDIOs), allowing functional characterization of CFTR, the gene mutated in people with cystic fibrosis (pwCF). CFTR function-increasing pharmacotherapies have revolutionized treatment for approximately 85% of people with CF who carry the most prevalent F508del-CFTR mutation, but a large unmet need remains to identify new treatments for all pwCF. METHODS: We used 76 PDIOs not homozygous for F508del-CFTR to test the efficacy of 1400 FDA-approved drugs on improving CFTR function, as measured in FIS assays. The most promising hits were verified in a secondary FIS screen. Based on the results of this secondary screen, we further investigated CFTR elevating function of PDE4 inhibitors and currently existing CFTR modulators. RESULTS: In the primary screen, 30 hits were characterized that elevated CFTR function. In the secondary validation screen, 19 hits were confirmed and categorized in three main drug families: CFTR modulators, PDE4 inhibitors and tyrosine kinase inhibitors. We show that PDE4 inhibitors are potent CFTR function inducers in PDIOs where residual CFTR function is either present, or created by additional compound exposure. Additionally, upon CFTR modulator treatment we show rescue of CF genotypes that are currently not eligible for this therapy. CONCLUSION: This study exemplifies the feasibility of high-throughput compound screening using PDIOs. We show the potential of repurposing drugs for pwCF carrying non-F508del genotypes that are currently not eligible for therapies. ONE-SENTENCE SUMMARY: We screened 1400 FDA-approved drugs in CF patient-derived intestinal organoids using the previously established functional FIS assay, and show the potential of repurposing PDE4 inhibitors and CFTR modulators for rare CF genotypes.

Limited premature termination codon suppression by read-through agents in cystic fibrosis intestinal organoids.

Premature termination codon read-through drugs offer opportunities for treatment of multiple rare genetic diseases including cystic fibrosis. We here analyzed the read-through efficacy of PTC124 and G418 using human cystic fibrosis intestinal organoids (E60X/4015delATTT, E60X/F508del, G542X/F508del, R1162X/F508del, W1282X/F508del and F508del/F508del). G418-mediated read-through induced only limited CFTR function, but functional restoration of CFTR by PTC124 could not be confirmed. These studies suggest that better read-through agents are needed for robust treatment of nonsense mutations in cystic fibrosis.

A bioassay using intestinal organoids to measure CFTR modulators in human plasma.

Treatment efficacies of drugs depend on patient-specific pharmacokinetic and pharmacodynamic properties. Here, we developed an assay to measure functional levels of the CFTR potentiator VX-770 in human plasma and observed that VX-770 in plasma from different donors induced variable CFTR function in intestinal organoids. This assay can help to understand variability in treatment response to CFTR potentiators by functionally modeling individual pharmacokinetics.

Isolated lung perfusion with melphalan: pharmacokinetics and toxicity in a pig model.

BACKGROUND: In patients with unresectable lung cancer or pulmonary metastases, isolated lung perfusion (ILP) has been described as an alternative method to deliver high-dose chemotherapy to the lungs, thereby minimizing systemic toxicity. Pharmacokinetics of ILP have not been extensively investigated. Therefore, we studied the feasibility of ILP with melphalan in a pig model with emphasis on pharmacokinetics and acute lung damage. METHODS: Five pigs underwent ILP with melphalan. Blood and tissue samples were obtained for determination of melphalan levels. Tissue biopsies were taken for microscopic evaluation of lung damage. RESULTS: During ILP, no hemodynamic effects of importance were noted. No systemic leakage of melphalan was observed in any of the animals. Compared with normal lung tissue, microscopic examination of lung tissue after perfusion without melphalan showed pulmonary edema. Directly after melphalan perfusion additional hemorrhagic areas were seen; however, electron microscopy displayed no irreversible endothelial damage. CONCLUSION: This study on pigs proved to be a well reproducible model for ILP with melphalan. Pharmacokinetics show a safety profile with no systemic toxicity, which could justify further patient studies, necessary to determine its effect on pulmonary metastases in humans, especially in case of adjuvant therapy after surgical resection or in unresectable disease.