Regulus Therapeutics Inc. announced it has completed enrollment in the second cohort of patients in the ongoing Phase 1b MAD study of RGLS8429 for the treatment of ADPKD. The Company expects to begin dosing the third cohort following a review of all available cohort 2 safety data, which is planned for October 2023. About ADPKD Autosomal Dominant Polycystic Kidney Disease (ADPKD), 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.

RGLS8429 was well-tolerated with no serious adverse events reported and plasma exposure was approximately linear across the four doses tested and is similar to the PK data from the first-generation compound. In April 2023, Regulus announced completion of enrollment for the first cohort of patients in the Phase 1b MAD study and after review of all available safety data, advanced to the second cohort where patients will receive 2 mg/kg of RGLS8429 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.