Proteostasis Therapeutics, Inc. announced the presentation of results from an ex vivo study of the Company’s proprietary cystic fibrosis transmembrane conductance regulator (CFTR) modulators in organoids from individuals with CF who are ineligible for the current standard of care CFTR modulator therapies due to their genotype, a population of approximately 2,300 adults in Europe alone. The results, outlined in a poster entitled “Intestinal Organoid Models as a Path for Personalized Therapy Development in Cystic Fibrosis,” will be presented at the Keystone Symposia on Tissue Organoids taking place on January 19-23, 2020 in Vancouver, BC, Canada. The study remains on track for collecting tissue samples from up to 500 CF patients with less common genotypes by the end of First Quarter 2020 for assaying as organoids and for testing responsiveness to investigational CFTR modulators, including Proteostasis’ CFTR potentiator, corrector and amplifier, dirocaftor (DIR), posenacaftor (POS) and nesolicaftor (NES), respectively. Data from the organoid study will be used to select a subset of patients for a confirmatory clinical trial, known as the CHOICES trial (Crossover trial based on Human Organoid Individual response in CF - Efficacy Study). This organoid program is a strategic initiative funded by the European Commission, which has invited a select number of drug developers and leading researchers in CF to build a roadmap for personalized therapeutics in CF. Based on the outcome of the study, this transition from precision to personalized medicine for the treatment of CF could begin in patients with less common mutations. The organoid study seeks to measure the ex vivo responsiveness to the PTI CFTR modulators in tissue samples collected via a rectal suction procedure. The rectal tissue is developed into an organoid or a miniaturized organ that is genetically identical to the patient donor and shares the same micro-anatomy as the organ from which they were derived. Organoid cultures from more than 370 adult CF patients have been established to date. Based on initial genotype analysis, approximately 85% of enrolled patients carry genotypes that lead to CFTR protein synthesis making them eligible for ex vivo study with DIR, POS and NES. Data from the organoid study will be used to select a subset of patients for the confirmatory CHOICES clinical trial.