The toremifene/PIN trial was designed to assess the potential of toremifene in preventing the progression of prostatic intraepithelial neoplasia (PIN) to active prostate cancer in men with a diagnosis of high grade PIN.
The study was a randomized, double-blind, placebo-controlled study, started in 2005 and it recruited a full complement of 1,590 participants. Participants were randomized to receive either toremifene 20 mg (the study drug) or placebo once daily for 36 months. They all received regular assessment for effectiveness and safety on a predetermined schedule.
Key inclusion criteria for eligibility in this trial were:
- Being male, and aged ≥ 30 years
- Having a diagnosis of high grade PIN from any previous prostate biopsy (as confirmed by the central study pathologist )
- Having had a prostate biopsy in the last 6 months that shows no evidence of cancer OR having had two prostate biopsies in the 12 months prior to screening that showed no evidence of cancer with at least one of the biopsies occurring within 6 months prior to the screening visit
- Have a serum PSA of ≤ 10 ng/mL
- Have adequate bone marrow, liver and renal function according to the trial protocol
In May 2010, the manufacturers of toremifene announced that the incidence of prostate cancer was lower in men receiving toremifene 20 mg compared to placebo but was not statistically significantly different. A relative risk reduction of 10.2 percent at 3 years of follow-up was observed. However, this level of reduction in risk was not considered to be sufficiently convincing to submit toremifene for regulatory approval for the prevention of prostate cancer in men with a prior diagnosis of high-grade PIN.