The photosensitiser rostaporfin [Purlytin™, SnET2, tin ethyl etiopurpurin, Sn(IV) etiopurpurin, PhotoPoint SnET2] was developed by Miravant Medical Technologies (USA) for use in the company's PhotoPoint™ photodynamic therapy. The therapy relies on low power, non-thermal light produced by a solid-state diode laser, sourced from the device co-developing partner, Iredex Corporation.Mirvant is currently undergoing discussions for potential licensing agreements with leading ophthalmology companies for rostaporfin.In June 2002, Miravant and Bausch & Lomb signed a non-binding letter on intent. The companies are expected to jointly review phase III clinical data concerning rostaporfin. Following the review Bausch & Lomb may negotiate an exclusive worldwide license to develop and commercialise the agent for ophthalmological indications. Previously, in June 1995, Miravant granted Pharmacia & Upjohn (now Pfizer) an exclusive worldwide license for development and marketing of rostaporfin. However, this agreement was terminated in March 2002, at which time Miravant regained the rights to all assets related to rostaporfin. In April 2000, Monsanto merged with Pharmacia & Upjohn to form Pharmacia Corporation. Subsequently, on 16 April 2003, Pharmacia Corporation was acquired by, and merged into, Pfizer.Preclinical studies had been underway for other vision-threatening eye diseases, as it also has potential in the treatment of diabetic retinopathy and glaucoma. The US FDA had granted fast-track status to rostaporfin for the treatment of age-related macular degeneration in 1998.