Dicerna Pharmaceuticals, Inc. has announced the presentation of preclinical data demonstrating the promise of DCR-PH1, the Company's therapeutic candidate for the treatment of primary hyperoxaluria type 1 (PH1), a rare inherited liver disorder that often results in progressive and severe kidney damage.
The research was presented at the 11th International Primary Hyperoxaluria Workshop in Chicago by Eduardo Salido, Ph.D., Professor of Pathology at the University of La Laguna in Santa Cruz de Tenerife, Spain.
The preclinical studies showed that DCR-PH1 provides potent and long-term inhibition of HAO1, a gene implicated in the pathogenesis of PH1. In a genetically modified mouse model of PH1, researchers reported a 97 percent reduction of the HAO1 transcript in the liver after a single dose of DCR-PH1 and a significant reduction in urinary oxalate levels, a key marker of the disease. In mice treated with DCR-PH1, urinary oxalate levels returned to near baseline levels, similar to normal mice.
"Physicians, patients and families managing PH1 currently have limited to no effective treatment for this severe and progressive disease," noted Craig B. Langman, M.D., chair of the workshop and the Isaac A. Abt, M.D., Professor of Kidney Diseases, and Head, Kidney Diseases, at the Ann & Robert H. Lurie Children's Hospital of Chicago and the Feinberg School of Medicine of Northwestern University. "Based on these encouraging preclinical data, we look forward to beginning clinical trials to determine the potential role of DCR-PH1 in the treatment of PH1."
PH1 occurs when a liver enzyme called AGT does not function properly due to a genetic defect, inducing the liver to over-produce a metabolite called oxalate. While oxalate has no clinical effect in a healthy population, it is concentrated in the urine by the kidneys of patients with PH1, forming calcium oxalate crystals that can lead to chronic and painful cases of kidney stones, scarring of the kidney and end-stage renal disease.
DCR-PH1 is engineered to address the pathology of PH1 by targeting and destroying the messenger RNA (mRNA) produced by HAO1, a gene that encodes glycolate oxidase, a protein involved in producing oxalate. By reducing oxalate production, this approach is designed to prevent the complications of PH1.
"Our preclinical studies indicate that inhibition of the gene HAO1 prevents expression of glycolate oxidase, as expected, and may therefore reduce significantly the abnormally high oxalate production found in patients with PH1," commented Dr. Salido. "By blocking production of glycolate oxidase in the liver, DCR-PH1 may prevent the severe kidney damage that is characteristic of PH1."
"Dr. Salido's data lend further support to the use of the Dicer Substrate RNAi technology platform, which we believe improves upon existing RNAi technologies in the treatment of rare, genetically defined diseases involving the liver," stated Pankaj Bhargava, M.D., Chief Medical Officer of Dicerna. "We look forward to initiating clinical trials of DCR-PH1 to validate these preclinical findings in humans."