Krystal Biotech Announces Positive Interim Clinical Update from KB407 Phase 1 CORAL-1 Study with Confirmation of Wild-Type CFTR Delivery to the Lungs of Patients with Cystic Fibrosis

Core Insights - The company announced a positive interim clinical update from the highest dose cohort of the CORAL-1 study, confirming successful lung delivery and expression of wild-type CFTR protein in cystic fibrosis patients following inhaled administration of KB407 [1][2][13] - The CORAL-3 study design has been submitted to the FDA, with enrollment expected to start in the first half of 2026 [1][13] Clinical Study Details - KB407 is being evaluated in the CORAL-1 study, which is a multi-center Phase 1 study with three dose escalation cohorts [4] - As of January 6, 2026, seven patients have been dosed in the highest dose cohort, with successful bronchoscopies yielding biopsies suitable for molecular analysis [6][12] - The percentage of conducting airway cells transduced with KB407 ranged from 29.4% to 42.1% across six patients with successful bronchoscopies [7][9] Patient Demographics and Results - Among the four modulator ineligible patients, all biopsies were positive for CFTR or viral marker expression, indicating widespread dissemination of KB407 [9] - For modulator eligible patients, the percentage of conducting airway cells positive for viral markers ranged from 31.4% to 36.8% [11] Safety Profile - Inhaled KB407 was well tolerated in the highest dose cohort, with most adverse events being mild to moderate [12] - One serious adverse event of asthma exacerbation was reported but deemed procedure-related and not related to KB407 [12] Future Plans - The company is moving forward with the CORAL-3 study, designed to evaluate the safety and efficacy of repeat KB407 administration [13] - The company expects to align on the CORAL-3 study design with the FDA in the first quarter of 2026 and start enrollment in the second quarter of 2026 [13]