Shares of Regulus Therapeutics (RGLS, Financials) fell 24% to $0.89 as of 12:39 p.m. GMT-5 on Wednesday following the company's announcement of interim results from its Phase 1b multiple-ascending dose clinical trial for farabursen, a treatment for autosomal dominant polycystic kidney disease.

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The business also said that the U.S. Food and Drug Administration's End-of-Phase 1 meeting went well and that agreement on important components of a proposed Phase 3 pivotal study was obtained.

With exploratory biomarker data showing a decrease in the height-adjusted total kidney volume growth rate, the interim analysis of the fourth cohort in the Phase 1b study revealed that farabursen remained displaying a mechanistic dosage response. Assessing the safety, tolerability, pharmacokinetics, and pharmacodynamics of the medication in adult ADPKD patients, the research is a double-blind, placebo-controlled experiment.

For three months, 26 individuals in the fourth cohort had a fixed dosage of 300 mg farabursen every other week. Researchers noted a decrease in urine polycystin 1 and 2 levels among the first 14 participants examined, proteins linked to illness severity. Safety records from all 26 patients revealed the medication was well tolerated, according to the business.

Regulus said the effects on polycystin biomarkers were comparable to those seen in the third group at 3 mg/kg, a level the firm feels delivers ideal kidney exposure. Conditional probability studies point to a strong chance of reaching the desired htTKV effectiveness threshold.

December saw the business visit the FDA for an end-of- phase 1 meeting. Regulus claims the government approved the non-clinical and clinical pharmacology programs as well as the acceptance of the chemical, manufacturing, and controls program. Under a 2:1 randomizing pattern, the planned Phase 3 trial is scheduled to include a single active dosage and placebo given every other week. For possible expedited approval, the FDA approved a 12-month htTKV endpoint; for possible complete approval, a 24-month estimated glomerular filtration rate endpoint.

Regulus officials claimed the most recent findings support farabursen's potential as ADPKD therapy. Later this year, the business intends to move the medicine into a major Phase 3 study.

Among the most prevalent monogenic diseases and a main cause of end-stage renal failure, ADPKD results from mutations in the PKD1 or PKD2 genes. With an estimated worldwide frequency of up to seven million, the disorder afflicters over 160,000 persons in the United States. Usually advancing to renal failure, the condition causes cysts in the kidneys to grow.

Designed to block miR-17, a target associated to ADPKD development, farabursen is an experimental oligonucleotide treatment. Preclinical investigations have shown possible advantages for the medication in renal function and disease severity decreases as well as other aspects.