AstraZeneca is to begin Phase III testing of its novel prostate cancer treatment ZD4054 later this year after data released this week suggested the drug boosts survival in patients with hormone resistant disease.

The oral drug extended patients' lives by seven months, bringing their survival time to about 2 years, compared with just under 1.5 years for those on placebo, according to the results of the Phase II EPOC study released at the European Cancer Conference in Barcelona.

The study involved 312 men whose cancer no longer responded to hormone therapy but who had yet to start chemotherapy.

The researchers noted that ZD4054 did not stop the disease progressing. However, they said the differences in survival times were encouraging given the limited treatment options in such patients.

Nick James, Professor of Clinical Oncology at the Institute for Cancer Studies in Birmingham, UK, who led the study, said: "Currently, the only licensed treatment option for metastatic patients shown to improve survival in men with hormone resistant prostate cancer is chemotherapy with docetaxel. The results from the EPOC study suggest that ZD4054 10mg once daily may have the potential to increase the median overall survival time for men with asymptomatic or mildly symptomatic metastatic HRPC."

The updated Phase II data revealed that patients who received ZD4054 10mg once daily survived 24.5 months, and patients who received ZD4054 15mg once-daily survived 23.5 months. Those on placebo lived for only 17.3 months from the start of the trial.

New trials to begin this year

To further evaluate the potential of ZD4054, the Phase III trial programme ENTHUSE, consisting of three studies, will begin this year. The first of these trials is aimed at investigating the efficacy of ZD4054 in metastatic HRPC, while the second will look at its role in non-metastatic HRPC patients. A third trial will study ZD4054 in combination with docetaxel (Taxotere) for the treatment of metastatic HRPC.

Some analysts have predicted that ZD4054 could eventually generate $1 billion a year in sales for AstraZeneca.

Prostate cancer primarily affects men over the age of 50.3 and is the most commonly diagnosed male cancer in many western countries. Worldwide, more than 670,000 men are diagnosed with prostate cancer every year, and its incidence is increasing. HRPC affects approximately 60,000 new patients in the US alone each year. Michael Day