Neither age nor previous hormone therapy had statistically significant associations with the effect of intravaginal prasterone on dyspareunia severity, according to a new subgroup analysis of clinical trial data. In a trend that did not reach statistical significance, though,said David F. Archer, MD.
“This was an unexpected finding,” he said in an interview.
In a subgroup analysis of data from two clinical trials of intravaginal prasterone (Intrarosa),and his colleagues sought to investigate whether age, time since menopause, or any previous use of hormone replacement therapy influenced prasterone’s efficacy in treating dyspareunia.
Dr. Archer and his collaborators pooled data from two prospective, randomized, double-blind, placebo-controlled trials (and ) of intravaginal prasterone dosed at 0.50%, 6.5 mg once daily for 12 weeks; he presented the subgroup analyses at the annual meeting of the North American Menopause Society in San Diego.
For each subgroup, Dr. Archer, a professor of obstetrics and gynecology at Eastern Virginia Medical School, Norfolk, and his coinvestigators compared the mean differences in dyspareunia severity score of women who received prasterone and those who received placebo.
All subgroup analyses used the endpoint of improvement in moderate to severe dyspareunia or whether dyspareunia was the most bothersome symptoms for the women participating in the study. The investigators began by looking at the subgroup of 460 women who were 56 years and older at baseline and compared them with the 180 younger participants.
The 283 older participants who received prasterone saw a decrease of 0.36 points in a dyspareunia severity score versus a 0.44 point decrease for the 123 women aged 55 and younger who received prasterone, a nonsignificant difference between subgroups. The decrease compared with placebo-takers was significant in both cases, however (P = .0003 and P =.0031, respectively).
Looking at time since menopause, Dr. Archer and his collaborators divided participants into 33 individuals who were 1 or 2 years post menopause, 86 women who were 3-5 years post menopause, and 521 women who had experienced menopause at least 6 years before study baseline.
In this analysis, 22 of the earliest postmenopause women received prasterone, seeing a 1.59 point drop in dyspareunia severity. For the 59 women in the prasterone study arms who were 3-5 year past menopause, the decrease from baseline was 0.59 points. Finally, among the 325 women who received prasterone and experienced menopause 6 or more years ago, the decrease was 0.27 points.
Although there was a numeric difference in the change in dyspareunia score severity among these groups, the differences were not statistically significant, said Dr. Archer. Again, though, those who took prasterone had a significant reduction in dyspareunia severity scores when compared with those taking placebo (P less than .0001, P = .0136, and P = .0024, respectively).
In the prasterone study arms, 184 had previously used hormone therapy, and 222 had not. After 12 weeks of intravaginal prasterone, there was no statistically significant difference between the two subgroups, with a decreases in dyspareunia severity scores of 0.45 and 0.32, respectively. The decreases in severity scores when compared with those among women who took placebo were again statistically significant for both subgroups, however (P = .0002 and P = .0057, respectively).
Prasterone is a steroid that is also known as dehydroepiandrosterone (DHEA) and is an endogenous hormone that is a precursor for estrogens and androgens. Prasterone’s mechanism of action to reduce vulvar and vaginal atrophy is not completely understood, according to the.
“The nonstatistically significant smaller effect on dyspareunia observed when treatment is initiated after a longer period after menopause suggests that a longer treatment period could be needed to achieve optimal benefit and that treatment of dyspareunia should be initiated as early as possible after menopause,” said Dr. Archer.
Dr. Archer reported grant support from and consulting relationships with several pharmaceutical companies, including Endoceutics, the producer of Intrarosa intravaginal prasterone.