ProQR Announces a Proof-of-Concept Nasal Potential Difference Study of QR-010 is Open for Enrollment

ProQR Therapeutics N.V.

today announced that PQ-010-002 is open for enrollment. The primary objective of PQ-010-002 is to estimate the effect of topical administration of QR-010 on the nasal mucosa in the restoration of CFTR function, as measured by Nasal Potential Difference (NPD). PQ-010-002 is an open-label, exploratory study evaluating the effect of QR-010 in ∆F508 homozygous (carry two allelic copies) and compound heterozygous (carry one copy of the ∆F508 mutation and one other disease causing mutation) cystic fibrosis (CF) patients. QR-010 is a novel investigational RNA therapeutic designed to repair the genetic mutation in the mRNA of CF patients due to the ∆F508 mutation. "We are excited to announce that the second clinical study of QR-010 is now open and enrolling," said Noreen R. Henig, MD, Chief Development Officer of ProQR. "This study is an important proof-of-concept study that will test the activity of QR-010 in the treatment of CF. In animal models of CF, QR-010 showed the ability to restore CFTR mediated NPD to normal or wild-type levels. Repeating the same test in individuals with CF will provide an important first signal of the therapeutic potential of QR-010." PQ-010-002 is a 28-day study conducted in up to 5 sites located in the US and Europe that are experienced in conducting NPD measurements. NPD is a well-accepted diagnostic test for CF and recently has been used to assess therapeutic benefit in clinical trials of investigational agents. The study will enroll at least 16 people with CF that are either homozygous or compound heterozygous for the ∆F508 mutation. NPD and sweat chloride measurements will be done before and after local treatment in the nose with QR-010 three times a week for four weeks. "RNA-based therapeutics are a novel approach to the treatment of the gene mutations that cause CF. The preclinical nasal potential difference studies of QR-010 in the mouse models of CF are quite compelling. The proof-of-concept study of QR-010 will support the understanding of QR-010's impact on CFTR function in patients with CF with the common ∆F508 CFTR mutation," said John P. Clancy, Professor of Pediatrics and Research Director, Division of Pulmonary Medicine, Cincinnati Children's Hospital and a member of the Cystic Fibrosis Foundation Therapeutic Development Network's leadership team. PQ-010-002 will be conducted in parallel with PQ-010-001, the ongoing Phase 1b safety and tolerability study of QR-010 in CF patients homozygous for the ∆F508 mutation. In addition to safety and tolerability, PQ-010-001 will assess pharmacokinetics and exploratory clinical efficacy endpoints. In the Phase 1b study, QR-010 is delivered to the lungs via inhalation. "We are very proud of our teams that have moved QR-010 from an interesting idea to two enrolling clinical studies in just three years," said Daniel A. de Boer, Chief Executive Officer of ProQR. "We are committed to bringing important new therapies to patients with CF and these studies are important steps in understanding the potential of QR-010."