Leading Drug Repurposing Efforts
The Center for Cytokine Storm Treatment & Laboratory (CSTL) and the Castleman Disease Collaborative Network (CDCN), under the leadership of Dr. David Fajgenbaum, are committed to the discovery of new uses for existing drugs to save patients’ lives. There are ~1,500 drugs currently FDA approved to treat ~2,500 of the ~10,000 human diseases. No treatments exist for over 7,000 diseases, many of which are rare and deadly.
The CSTL and CDCN have pioneered the following approach to drug repurposing for idiopathic multicentric Castleman disease (iMCD) and other rare diseases: 1) perform in-depth studies of high-quality biospecimens to identify cell types, signaling pathways, and genes/proteins that may be involved in a given disease, 2) validate the discovery using an orthogonal method, 3) utilize bioinformatic tools and drug databases to identify drugs already FDA-approved for another condition that modulate the target, 4) administer the drug off-label (giving a drug for a use other than what it is approved for) or through a clinical trial, and 5) systematically track the impact of the drug on the given disease.
Figure 1: Drug repurposing candidates are preliminarily identified through laboratory investigation of drug targets, mining of published literature, and high-throughput drug screens. While the success rate of high-throughput drug screens has been low historically, the basic understanding of SARS-CoV-2 biology, as well as the large number of efforts, likely increases the potential for success. These candidates can be validated and refined through orthogonal in vitro and in vivo studies. Observational studies of widely used drugs are often performed to search for associations between drug exposure and outcomes. Open-label, single-arm, or preferably, randomized controlled trials are then performed to investigate efficacy (and safety) and determine if the drug should be adopted in clinical practice and/or given regulatory approval for the new indication.