Sept 5 (Reuters) - Dutch drug developer ProQR Therapeutics NV said on Tuesday its interim analysis showed that an early-stage trial of an experimental treatment for a rare form of childhood blindness was successful in improving vision.
Based on what the company called "encouraging" results, ProQR said it would stop enrolling patients in the study and progress to a mid-stage trial, which is expected to start in the first half of 2019.
The early trial tested the RNA-based drug, QR-110, in 10 patients with a certain genetic mutation that resulted in an eye disorder called Leber's congenital amaurosis 10.
There are no approved treatments for the condition, which primarily affects the retina and causes severe visual impairment beginning in infancy.
There are at least 2,000 patients in Europe and the United States with the specific mutation, the company estimates.
After three months of treatment, about 60 percent of subjects showed a clinically meaningful response with improvements in vision and the ability to navigate, ProQR said.
"These results are very encouraging for our broader pipeline," Chief Executive Officer Daniel de Boer told Reuters, adding that the company was testing other drugs with similar mechanism.
De Boer said the company did not plan to partner with another firm to develop the drug.
ProQR is developing treatments for other rare eye diseases, including Usher syndrome and Stargardt's disease, that affect vision.
The company is separately testing treatments for lung disease cystic fibrosis and skin disorder dystrophic epidermolysis bullosa. (Reporting by Tamara Mathias in Bengaluru; Editing by Anil D'Silva)