5F-DF-203-L-LYSINAMIDE (Phortress) is an experimental antitumor agent with potent and selective activity against human-derived carcinomas of breast, ovarian and renal origin. The mechanism of action of Phortress is distinct from all classes of chemotherapeutic agents currently in the clinic, and involves metabolic activation by cytochrome P450 (CYP) 1A1 to electrophilic species, which generate DNA adducts in sensitive tumors only. Phortress is in phase I clinical trials for the treatment of solid tumours. The compound was co-developed by Pharminox, University of Nottingham and Cancer Research UK.

Norcyclobenzaprine (aka desmethylcyclobenzaprine) is one of the major metabolites of cyclobenzaprine which is a muscle relaxant marketed under the brand name Flexeril. Both cyclobenzaprine and norcyclobenzaprine are known to be potent antagonists of the serotonin 2a receptor.