PSA and risk for prostate cancer in men taking dutasteride

According to further analysis of data from the REDUCE trial, “… men who are taking dutasteride can be confident that the drug does not weaken the ability of PSA to find cancer if it develops. Rather, the drug enhances the ability to find cancer if PSA levels are rising.”

The new data reported by Andriole et al. are published on line in the Journal of Urology, and there is an extensive media release from Washington University School of Medicine.

It has been known for some time that increases in PSA level in men being treated for benign prostatic hyperplasia (BPH) with a 5α-reductase inhibitor like dutasteride tended to be highly indicative for prostate cancer risk. The current study basically confirms this knowledge, based on data from the 8,000+ patients enrolled in the REDUCE trial.

In this 4-year-long study, men with a PSA level of between 2.5 and 10.0 ng/ml and an initial prostate biopsy that was negative for prostate cancer were treated either with 0.5 mg dutasteride once daily or with a placebo. The recent re-analysis has shown that:

  • The final PSA level before final biopsy and the change from month 6 to final PSA level performed better for the diagnosis of Gleason score 7-10 tumors in men who received dutasteride vs placebo.
  • Increases in PSA level were associated with a higher likelihood of biopsy detectable, Gleason score 7-10 and clinically significant prostate cancer.
  • Percentage decreases in PSA level from baseline to month 6 in the dutasteride arm did not predict prostate cancer overall or Gleason score 7-10 cancer.

Andriole and his colleagues conclude that in men with a previously negative prostate biopsy, PSA performed better during the 4-year study as a marker of prostate cancer in men who received dutasteride as compared to men receiving placebo. However, the authors do not suggest that men take dutasteride just to get a more accurate readout of PSA levels attributable to cancer. Dutasteride is associated with a series of side effects, just like every other drug. Rarely, those side effects may be serious.

2 Responses

  1. It’s worth noting the Editors note in the UW article: “Editor’s note: Dr. Andriole is a consultant for GlaxoSmithKline, the manufacturer of Avodart and the study’s sponsor.”

    Both GSK (Avodart) and Merck (Proscar) have spent a lot of time, money, and effort to “rebrand” their BPH products as prostate cancer-specific drugs. This study indicates that Avodart can limit fluctuating PSA in lesser prostate cancers I guess. The finasteride study from more than a year ago did a similar thing. (The findings there indicate that Proscar can prevent or delay the onset of prostate cancer even though the same study did indicate that there was a higher prevalence of more aggressive prostate cancer in the non-placebo arm.)

    Collectively I view the findings of both studies as cautiously as possible. If all a 5-ARI is doing is hindering detection then is that a good thing? I can see why then that the recent FDA review for dutasteride labeling was rejected — it lacks supporting data. There is plenty missing as to the efficacy of these claims but there is mucho dinero at stake.

    But I would suggest a marketing plan that favors Merck — “Use our product if you don’t have prostate cancer. Their product only hinders detection, our product prevents cancer.”

    Yea. And putting a million men on drugs that they don’t need may possibly only truly affect bottom lines, too.

  2. Tony:

    Finasteride has been available as a generic product for years, so Merck has nothing to gain. Dutasteride will be available as a generic in the not too distant future too, so GSK’s opportunity was always limited.

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