Claritas Pharmaceuticals, Inc. announced that it has completed toxicology studies of R-107 in canines. On March 12, 2021, Claritas announced strongly positive data from toxicology studies in rodents, and the Company is announcing equally positive data from toxicology studies in dogs. These canine toxicology studies were performed by Covance Laboratories, Inc., under full Good Laboratory Practice (GLP) compliance, which is an FDA prerequisite to initiation of Phase 1 clinical studies in humans. Covance is considered to be the world's premier comprehensive drug development company, is FDA audited and approved to perform pre-clinical safety and toxicology studies and was named the "Global Contract Research Organization (CRO) Company of the Year" in 2020 by Frost & Sullivan. The completion of these toxicology studies in dogs will provide appropriate regulatory support for both injectable and oral formulations of R-107, as well as for any topical formulations of R-107 where the drug may be absorbed into the blood and systemic exposure may consequently occur. Claritas is currently developing R-107 as a therapy for vaccine-resistant COVID-19, as well as for the treatment of influenza, and other viral diseases. The canine studies at Covance evaluated four dose levels of R-107: 60, 75, 90, and 150 milligrams per kilogram of body weight given daily as a singular intramuscular injection, the same route of administration that is planned for the initial clinical studies in humans. In addition, R-107 was also administered as a repeat daily injection for 7 consecutive days, a length of time consistent with the anticipated duration of therapy in the clinical setting of COVID-19 infection. At all dose levels tested, R-107 was well tolerated by the animals. Given that the intended therapeutic dose of R-107 in humans is only 10-15 milligrams per kilogram of body weight, the results of these completed toxicology studies are expected to provide at least a 5-fold safety margin for human use. This level of safety margin substantially exceeds the standard requirement of regulatory agencies, such as the FDA. In addition, the canine studies successfully measured the plasma levels of R-107 and its metabolites, including the therapeutically active payload metabolite, R-100. The plasma levels of both R-107 and R-100 were found to be linearly related to the dose level of R-107, a correlation that will simplify the selection of the optimal dosing regimen when the drug reaches the stage of clinical testing. R-107 is a liquid, nitric oxide-releasing molecular prodrug that can be administered by injection, in contrast to nitric oxide gas therapy which requires a special type of delivery device and complex administration by trained respiratory therapists. When administered by injection, R-107 is slowly hydrolyzed by the blood, thereby releasing its active payload, R-100, which in turn steadily and slowly releases nitric oxide. This depot-like action of R-107 results in a sustained delivery of nitric oxide to tissues throughout the body, allowing for a smooth delivery of the active drug over 24 hours following a single dose of R-107.