Regulus Therapeutics Inc. announced, after review of all available safety data, that it will advance to the second cohort of patients in the Phase 1b MAD study of RGLS8429 for the treatment of ADPKD. The Phase 1b MAD study is a double-blind, placebo-controlled trial evaluating the safety, tolerability, pharmacokinetics and pharmacodynamics of RGLS8429 in adult patients with ADPKD. The study will evaluate RGLS8429 treatment across three different dose levels, including measuring changes in polycystins, height-adjusted total kidney volume, cyst architecture, and overall kidney function.

The first cohort is being dosed at 1 mg/kg of RGLS8429 or placebo every other week for three months. No issues were identified in cohort 1 based on the review of all availableblind safety data clearing the way to advancement to cohort 2. The safety review incorporated available data from all 12 patients in the first cohort including several who had completed the dosing schedule. Patients in the second cohort will receive 2 mg/kg of RGLS 8429 or placebo every other week For three months.

The Company also recently completed the 27-week chronic toxicity study of RGLS8429 in mice. No RGLS8429-related toxicity, including CNS effects, was observed at any dose level up to the top dose of 300 mg/kg administered every other week. About ADPKD, Autosomal Dominant Polycystic Kidney Disease, caused by mutations in the PKD1 or PKD2 genes, is among the most common human monogenic disorders and a leading cause of end-stage renal disease.

The disease is characterized by the development of multiple fluid filled cysts primarily in the kidneys, and to a lesser extent in the liver and other organs. Ex excessive kidney cyst cell proliferation, a central pathological feature, ultimately leads to end-stage renal disease in approximately 50% of ADPKD patients by age 60. Approximately 160,000 individuals are diagnosed with the disease in the United States alone, with an estimated global prevalence of 4 to 7 million.