HUNTINGTON’S DISEASE: Enrollment in Phase 1/2a Study of IONIS-HTT Rx in Patients with HD Completed and Open-Label Extension Study to Open in 2H 2017; Anti-Sense Drug Designed to Reduce Production of All Forms of HTT, Including Mutant HTT

On June 22, 2017, Ionis Pharmaceuticals, Inc. (NASDAQ: IONS) announced completion of enrollment in the Phase 1/2a randomized, placebo-controlled, dose escalation study of IONIS-HTTRx in patients with Huntington's disease (HD). Dosing in the final patient cohort continues, and Ionis plans to report top-line results from this study around year-end 2017. The safety and tolerability profile of IONIS-HTTRx in the completed cohorts of the Phase 1/2a study supports its continued development. Patients who complete the Phase 1/2a study will be eligible to participate in an open-label extension (OLE) study that Ionis plans to initiate in the next several months. Roche, Ionis' partner for this drug, continues to advance and support the program. IONIS-HTTRx is the first therapy in clinical development targeting the cause of HD by reducing the production of the toxic mutant huntingtin protein (mHTT) from the mutated huntingtin gene. "We are encouraged by the safety profile of IONIS-HTTRx we have observed to date in the completed dosing cohorts in the Phase 1/2a study. Upon completion and full analysis of this study, the next step for this program will be to conduct a study to investigate whether decreasing mutant huntingtin protein with IONIS-HTTRx can slow the progression of this terrible disease," said C. Frank Bennett, PhD, Senior Vice President of Research at Ionis Pharmaceuticals. "We believe that IONIS-HTTRx, which is designed to reduce the production of all forms of the huntingtin (HTT) protein – the known cause of HD, represents the most promising opportunity to address this significant unmet medical need.