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Investors - Regulus Therapeutics Regulus Therapeutics Reports First Quarter 2021 Financial Results and Recent Updates Regulus Therapeutics Demonstrates Target Engagement in First - Ever Study of RGLS4326 in Patients with Autosomal Dominant Polycystic Kidney Disease ( ADPKD ) Second Cohort Underway with Data Expected Mid - 2021 SAN DIEGO , May 13 , 2021 / PRNewswire / -- Regulus Therapeutics Inc. ( Nasdaq : RGLS ) , a biopharmaceutical company focused on the discovery and development of innovative medicines targeting microRNAs ( the " Company " or " Regulus " ) , today reported financial results for the first quarter ended March 31 , 2021 and provided a corporate update . " We are excited about the data we recently announced from the first cohort of our phase 1b clinical trial of RGLS4326 for the treatment of patients with ADPKD where we saw mean increases of greater than 50 % and 20 % in Polycystin 1 ( PC1 ) and Polycystin 2 ( PC2 ) , respectively . PC1 and PC2 are the products of the PKD1 and PKD2 genes , and are depressed in patients with this disease . The trends for both suggest that with continued therapy , higher levels of these proteins may be attainable and less frequent dosing required . Additionally , RGLS4326 was well tolerated by all nine patients with no serious adverse events reported " , stated Jay Hagan , CEO of Regulus . " Data from the first cohort provides the safety and pharmacokinetic data needed to complete the modeled safety margins . We plan to submit these data to FDA this summer in the context of our discussions regarding the remaining partial clinical hold requirements . " Program Updates RGLS4326 for ADPKD : In February 2021 , the Company completed enrollment in the first cohort of a Phase 1b clinical study for RGLS4326 in patients with ADPKD ( The " Phase 1b " ) . The Phase 1b is an adaptive design , open- label , multiple dose study in up to three cohorts of patients with ADPKD . The study is designed to evaluate the safety , pharmacokinetics , and changes in levels of PC1 and PC2 in patients with ADPKD administered RGLS4326 every other week for a total of four doses . The dose level for the first cohort is 1 mg / kg of RGLS4326 and the dose level for the second cohort is 0.3 mg / kg . The third and final cohort will be dosed at a level to be determined based on the results of the first two cohorts . In May 2021 , the Company announced top - line results from the first cohort of patients with ADPKD in its ongoing Phase 1b clinical trial of RGLS4326 . In the first cohort , nine patients were enrolled and received 1 mg / kg of RGLS4326 subcutaneously every other week for four doses . Safety , pharmacokinetics , and certain disease related biomarkers were evaluated through the course of the study . The biomarkers included : PC1 and PC2 , kidney injury marker 1 ( KIM - 1 ) , neutrophil gelatinase - associated lipocalin ( NGAL ) , as well as urea and creatinine and were chosen to evaluate changes in disease related measures . Measured levels of PC1 and PC2 increased greater than 50 % and 20 % , respectively by the end of study compared to baseline levels . Regulus believes these initial data demonstrate that RGLS4326 engages the target miR - 17 leading to increased expression of the PKD1 and PKD2 genes and the resultant increases in measured polycystin levels . Measured levels of PC1 and PC2 have been shown to inversely correlate with disease severity and are believed to be directly linked to the underlying genetic drivers of the disease . The overall trend in polycystin showed increasing levels of both PC1 and PC2 over time with a sustained effect suggesting less frequent dosing could be utilized . Importantly , at the time of the analysis , patient mutational status was not known and may further contribute to understanding differences in response rates . Approximately 85 % of patients with ADPKD are reported to have a mutation in the PKD1 gene , while the remaining 15 % have a mutation in the PKD2 gene . Additionally , the PKD1 gene has one predicted binding site for miR - 17 while the PKD2 gene has two predicted binding sites for miR - 17 , potentially contributing to different response rates between the biomarkers . RGLS4326 was well tolerated by all nine patients with no serious adverse events reported . All reported adverse events were mild and generally transient in nature . Overall , the pharmacokinetic profile of RGLS4326 in patients with ADPKD was similar to that observed in a prior healthy volunteer study . Concentrations of RGLS4326 in plasma were greater in patients ( Cmax 3 ug / mL ) relative to healthy volunteers ( Cmax 2 ug / mL ) , suggesting a lower dose in patients could achieve the desired exposure in the kidney , the target organ of interest . - Data from this first cohort is planned to be submitted for presentation at PKD Connect in June 2021 and at Kidney Week , the American Society of Nephrology annual meeting being held in November 2021 . Corporate Highlights