molecules of the month

The PTC Therapeutics oral, brain-penetrant tubulin-binding agent, PTC596, is in Ph. I clinical studies for advanced solid tumors (starting dose of 200 mg PO BIW). We recently highlighted encequidar, a P-gp inhibitor co-dosed with paclitaxel to render paclitaxel orally bioavailable. A directly orally bioavailable tubulin-binder would circumvent the need for two drugs and reduce potential drug-drug interactions. One of the 2020 small molecule FDA approvals, cedazuridine, similarly induces a DDI to render the traditional IV chemo agent decitabine orally available. The adoption of “oral chemo” combination regimens may catalyze the development of single agent oral chemotherapies such as PTC596 as well. A topical synthetic tubulin inhibitor (tirbanibulin) was also approved last year for actinic keratosis. It will be interesting to watch if synthetic tubulin-binders will…