Regulus Therapeutics Inc. announced positive topline safety and PK data from its Phase 1 SAD clinical trial of RGLS8429. Additionally, the Company announced the initiation of its Phase 1b MAD clinical trial of RGLS8429. Summary of Results from Phase 1 SAD Study: The Phase 1 SAD study demonstrated that RGLS8429 has a favorable safety and PK profile.  RGLS8429 was well-tolerated with no serious adverse events reported.

Among the 32 subjects treated with RGLS8429 or placebo, there were nine adverse events all of which were mild, except one (sinus infection) which was graded moderate in severity.  Preliminary results suggest plasma exposure is dose proportional across the four doses tested and compare favorably to the PK data from the first-generation compound, RGLS4326. Phase 1b MAD Study Initiated: The phase 1b MAD study is a double-blind, placebo-controlled study in patients with ADPKD.  The primary objectives of the MAD study are to assess safety, tolerability, and pharmacokinetics of RGLS8429 and to evaluate the efficacy of RGLS8429 treatment across three different dose levels, including changes in polycystins, cystic kidney volume (htTKV), and overall kidney function. The first planned dose level to be tested in patients with ADPKD is 1 mg/kg dosed every other week for three months.

Topline data from the first cohort of patients is expected in 1H 2023.