New drugs approved by the FDA and other regulatory bodies have a long path to approval that requires toxicology studies to prove safety, detailed evidence of safe delivery and effectiveness, with a very large body of documentation to establish manufacture and stability. An already approved drug that is repurposed (used to treat another disease) has a considerably truncated route to FDA approval.

Path to regulatory approval

The accompanying figures compare de novo and repurposed drug development. The complexity, cost and timeline is substantially simplified and truncated in a drug approval involving repurposing.

After proving effectiveness in phase 2 trials, a single positive pivotal trial is sufficient for regulatory clearance and marketing approval of most repurposed drugs, using the FDA’s 505(b)(2) regulatory pathway in the US.

All available clinical, toxicology, manufacturing information and published material can be accessed in taking the repurposed drug to the FDA, and the applicant does not have to develop all of the material.

In the case of PPS, while the chemical entity is off patent, its manufacture remains a trade secret. Paradigm works closely with the manufacturer, bene pharmaChem, in sourcing the material for formulation as ZILOSUL® and RHINOSUL®.

By working closely with the proprietary manufacturer of PPS, we are able to leverage substantial knowledge and expertise available from earlier regulatory filings.