Tosk discovers and develops new drugs to block the adverse effects of drugs with dose-limiting side effects and to block the activity of cancer genes. Tosk's most advanced drug, TK-90, has successfully completed Phase 2 studies in head and neck cancer patients receiving high doses of chemotherapy. Tosk has two other drugs in development for cancer therapy side effect prevention and one to block KRAS gene activity which drives as many as 30% of all cancers.