Introduction
Psimei Pharmaceuticals plc, founded in 2001, is a biopharmaceutical product development company working in the field of oncology. Its core focus is the treatment of cancer cells using a technique called Photon Activation Therapy (PAT).

PAT is the use of conventional radiotherapy to activate PsiMei’s patented boron-based drugs.

Radiation Therapy and PAT
Radiation therapy is one of the most common treatments for cancer and is used in more than half of all cancer cases. Worldwide, it has been estimated that over 200,000 patients undergo radiotherapy on a daily basis, with approximately 5,000,000 patients being treated every year. According to the World Health Organization (WHO), around 6 million people died from cancer in 2000 and it is estimated they will increase to 10 million per year by 2020.

However, conventional radiotherapy only has, on average, a 40% cure rate. The effectiveness of radiotherapy is held back by unwanted normal tissue damage and unacceptable side effects, which limit its efficacy.

PAT, when used in conjunction with PsiMei’s products, generates long-lived free radicals that can kill cancer cells. As boron-based drugs can localize at high concentrations in tumors, the effect of PAT is to amplify radiotherapy. Studies to date with PAT have used existing radiotherapy equipment, so it is not anticipated that any new capital investment will be required by oncology centres wishing to utilize the approach.

PP200
PsiMei’s lead product is PP200. This compound has been shown to generate 90% true cure rates in animal models. Its toxicology package and clinical program have been reviewed by the FDA and MHRA. Subject to final cGMP manufacture and additional toxicology testing of its final formulation, PsiMei plans to enter PP200 into Phase I clinical trials in 2008.