Finasteride Has Little Impact on Sexual Function in Men
The drug finasteride had a minimal effect on the sexual function of men who took it to prevent prostate cancer.
Some studies have found a link between finasteride and sexual dysfunction in men. But these studies were smaller, short-term, and did not consider variation among individuals when evaluating the impact of finasteride on sexual function.
Carol Moinpour, Ph.D., of the Fred Hutchison Cancer Research Center in Seattle and colleagues investigated sexual dysfunction in more than 17,000 men who participated in the Prostate Cancer Prevention Trial during a 7-year period.
Finasteride only slightly increased sexual dysfunction compared with a group not taking the drug, and the effect decreased over time.
“Our data show that the effects of finasteride treatment are clinically far less relevant than natural sources of variability in this heterogeneous population and suggest that finasteride would cause little or no sexual dysfunction for most men who might take it,” the authors write.
Contact: Dean Forbes, communications department, Fred Hutchison Cancer Research Center, (206) 667-2896, dforbes@fhcrcc.org
Surrogate Endpoints Inconsistently Used in Clinical Trials
In a commentary, Cornelis Punt, M.D., Ph.D., of the University Nijmegen Medical Center in The Netherlands and colleagues discuss the inconsistent use of surrogate endpoints in clinical trials and propose guidelines for future studies.
Overall survival is considered the gold standard endpoint for cancer treatment trials. But the time and money required to conduct a trial using overall survival as the endpoint has led researchers to consider other endpoints that can act as surrogates for overall survival.
Looking at 52 studies of phase III clinical trials of colon cancer treatment, the researchers found that eight other endpoints were used in addition to overall survival. Moreover, the definitions of these endpoints varied widely among studies.
A panel of clinical trial experts reached a consensus on definitions for the endpoints and determined if and when they should be used in future trials. Six of the endpoints were selected as relevant to treatment trials: disease-free survival, time to recurrence, time to treatment failure, relapse-free survival, cancer-specific survival, and overall survival.
“After considering all six endpoints, the panel selected disease-free survival…as the most appropriate primary endpoint for future trials of adjuvant treatment for colon cancer or for any type of cancer. This endpoint was selected because it includes all clinically relevant events, has little opportunity for bias, is observed earlier than overall survival, and is likely to be statistically sensitive to real treatment benefits,” the authors write.
Contact: Cornelis Punt, +31243610353, c.punt@onco.umcn.nl
New Trial Design May Better Test Targeted Therapies
A new design for phase III trials will allow researchers to more efficiently evaluate the effectiveness of targeted therapies.
Many cancer drugs that target specific molecules only benefit a subset of patients who have high enough levels of the target molecule. Often, though, phase III clinical trials are designed without knowledge of this threshold, so the trial includes patients who will not respond to the treatment. That means the drug’s effect on the group of responsive patients could be missed.
Wenyu Jiang, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues propose a different trial design that combines the usual test for response to treatment in all patients with the identification and validation of a cutoff point for a molecular target. They tested the design in a simulated trial and also used it to analyze data from an existing prostate cancer trial.
In the simulation trial, the new design allowed the researchers to see when the drug was effective in the overall population, as well as when it was effective in only a smaller subset with elevated levels of the target molecule.
“The procedure we have proposed allows drug development to be optimized by combining definitive testing for overall effect with biomarker validation,” the authors write.
Contact: NCI press office, 301-496-6641, ncipressofficers@mail.nih.gov
Also in the June 26 JNCI:
- http://www.eurekalert.org/emb_releases/2007-06/jotn-ln062107.php
- http://www.eurekalert.org/emb_releases/2007-06/jotn-ti062107.php
- http://www.eurekalert.org/emb_releases/2007-06/jotn-cc062107.php
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