Processa Pharmaceuticals, Inc. provided an interim analysis from its Phase 1b study of its Next Generation Capecitabine (NGC-Cap). Thus far in the Phase 1b study, patients have received doses of NGC-Cap ranging from 75 mg once a day to 225 mg twice a day, significantly less than the 1,600 mg to 2,500 mg twice a day dose administered for FDA-approved capecitabine. More importantly, these much lower doses for NGC-Cap result in 5-FU (5-fluorouracil, the main metabolite of capecitabine that further metabolizes into desirable cancer-killing molecules called anabolites and undesirable molecules called catabolites that cause unwanted side effects) exposure up to 10 times greater than the higher FDA-approved capecitabine doses due to NGC-Cap?s unique metabolic pathway.

One would anticipate that the much greater 5-FU exposure would result in greater and/or more severe side effects when, in fact, the side effect profile for 5-FU exposures from NGC-Cap had a similar anabolite side effect profile to FDA-approved capecitabine. In addition, the side effects associated with FBAL (fluoro-beta-alanine, the primary catabolite formed from the metabolism of 5-FU), such as hand-foot syndrome, that can lead to capecitabine intolerance, were almost non-existent, likely because FBAL exposure was approximately 1% of the exposure seen after FDA-approved capecitabine administration. Important to FDA?s request that the company evaluate multiple dosage regimens to determine an Optimal Dosage Regimen, the interim analysis also shows that an improvement in the side effect profile was observed at a 5-FU NGC-Cap exposure of 5-6 times greater than FDA-approved capecitabine.

These data confirm that the metabolic pathways that regulate how NGC-Cap is processed in the body suggest NGC-Cap may offer higher efficacy at lower doses of the underlying capecitabine agent, while simultaneously offering a better safety profile from less production of the side-effect producing catabolite FBAL that causes many of the dose-limiting side effects from treatment with capecitabine alone. It is believed that NGC-Cap?s ability to inhibit the production of catabolites like FBAL is key to the success of NGC-Cap. Further clinical studies are needed to confirm these interim observations.