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PR04 trial results

10 May 2007

An MRC CTU-led trial has found that oral clodronate does not prevent bone metastases in men at risk.

PR04 was a trial for men who were within 3 years after initial diagnosis with prostate cancer and who did not have bone metastases. The aim of this trial was to see whether addition to the standard therapy of a first general bisphosphonate drug called sodium clodronate (Loron520) could delay or prevent the development of symptomatic bone metastases. Consenting patients were therefore randomly assigned to receive either daily oral sodium clodronate or placebo for a maximum of 5 years. A total of 508 patients were recruited to the trial between June 1994 and December 1997 from various hospitals across the UK and one in New Zealand.

After a median follow up of almost 10 years the data from this trial has now been analysed and the results have been published in the Journal of the National Cancer Institute [1]. The authors of this paper found that the addition of sodium clodronate did not lead to any benefit in symptomatic bone-metastases free survival or in overall survival and have thus concluded that adjuvant sodium clodronate does not modify the natural history of non-metastatic prostate cancer.


  1. Oral Sodium Clodronate for Nonmetastatic Prostate Cancer — Results of a Randomized Double-Blind, Placebo-Controlled Trial: Medical Research Council PR04 (ISRCTN61384873). Malcolm D. Mason, Matthew R. Sydes, John Glaholm, Ruth E. Langley, Robert A. Huddart, Michael Sokal,Mark Stott, Anne C. Robinson, Nicholas D. James, Mahesh K. B. Parmar, David P. Dearnaley. J Natl Cancer Inst 2007;99:1-13.