A New Use for Microdosing
There is a fundamental difference between the Presage approach and the traditional use of the term “microdosing,” which the FDA defines as being less than 1/100th of the effective dose used to treat human patients. Though Presage does deliver microdoses of the drugs being testing with the CIVO™ microinjection device, the company has revolutionized the predictive value of these small doses by employing them in an entirely different way.
In the past, microdosing has primarily referred to the systemic delivery of microdoses of drugs to a small cohort of patients before the drugs advanced to traditional human trials. Such early “Phase 0” trials in humans were enabled by the 2006 FDA Guidance on Exploratory IND Studies to evaluate small doses of drugs in the body with minimal risk to the patients. However, the results obtained with such low systemic drug concentrations translated poorly to systemic clinical studies. As a result, systemic microdosing in Phase 0 is not commonly employed in drug development today.
In contrast, Presage uses microinjection to deliver the small doses of each drug or combination of drugs directly into a tumor, concentrating the dose in a small mass of the patient, thereby achieving pharmacologically relevant concentrations of the drugs. For the first time, multiple drugs can be assessed in the only model of human cancer that really matters: the human patient.