Also this month, Nature Medicine published a paper describing the use of a novel intranasal delivery technology, developed by Intradigm, to deliver siRNAs targeting SARS-related genes in rhesus monkeys.
According to the company, a collaboration with Chinese biotech firm Top Genomics and several academic institutions has yielded data indicating that the siRNAs have both a prophylactic and therapeutic effect against the infection in the monkeys.
In the study, two siRNAs called SC2 and SC5 targeting two different genes in the SARS genome were administered as a single agent intranasally to a rhesus macaque model of the disease. Doses ranged from 10 to 40 mg/kg.
"The studies … included two control groups and three treatment groups using prophylactic, concurrent, or early post exposure regimens, with a large number of animals in each group," the company said.
"Observations of SARS-like symptoms, measurements of SCV RNA presence, and lung histopathology and immunohistochemistry consistently showed siRNA-mediated anti-SARS efficacy by either prophylactic or therapeutic regimens," the Nature Medicine papers authors note. "The siRNAs used provided relief from SCV infection-induced fever, diminished SCV viral levels, and reduced acute diffuse alveoli damage."
Additionally, there were no signs of siRNA-induced toxicity or off-target effects, Intradigm said.
According to Intradigm, the work was conducted in collaboration with researchers from Sun Yat-Sen University; Top Genomics of Guangzhou; the Institute of Laboratory Animal Science; the Chinese Academy of Medical Sciences and Peking Union Medical College; Guangzhou Institute of Respiratory Diseases of Guangzhou Medical College; and Hong Kong University.
Martin Woodle, CSO of Intradigm, told RNAi News this week that Top Genomics holds the Chinese market rights to the SARS drug under a long-standing partnership between the companies. Although Intradigm holds the rights in other territories, he said that the company is currently focusing its internal efforts on its RNAi-based anti-cancer drug ICS-283, which is delivered systemically and expected to enter phase I testing in mid-2006.
Intradigm is, however, considering applications in various disease areas for the intranasal delivery technology used in the SARS study for future efforts, Woodle noted. The company is also open to potential partnerships for the technology.
Doug Macron ([email protected])