Texaphyrins: a new approach to drug development

The texaphyrins are prototypical metal-coordinating expanded porphyrins. They represent a burgeoning class of pharmacological agents that show promise for an array of medical applications. Currently, two different water-soluble lanthanide texaphyrins, namely motexafin gadolinium (Gd-Tex, 1) and motexafin lutetium (Lu-Tex, 2), are involved in multi-center clinical trials for a variety of indications. The first of these agents, XCYTRIN(R) (motexafin gadolinium) Injection, is being evaluated as a potential X-ray radiation enhancer in a randomized Phase III clinical trial in patients with brain metastases. The second, in various formulations, is being evaluated as a photosensitizer for use in: (i) the photodynamic treatment of recurrent breast cancer (LUTRIN(R) Injection; now in Phase IIb clinical trials); (ii) photoangioplastic reduction of atherosclerosis involving peripheral and coronary arteries (ANTRIN(R) Injection; now in Phase II and Phase I clinical trials, respectively); and (iii) light-based age-related macular degeneration (OPTRIN(R) Injection; currently under Phase II clinical evaluation), a vision-threatening disease of the retina. In this article, these developments, along with fundamental aspects of the underlying chemistry are reviewed. Copyright (C) 2001 John Wiley & Sons, Ltd.