Conference Coverage

No signal for CV, breast effects with bioidentical vaginal estrogen for dyspareunia



Menopausal women with dyspareunia who received a bioidentical estradiol vaginal insert experienced no cardiovascular or breast effects that would suggest significant systemic absorption.

Dr. Lisa Larkin, an internal medicine physician in private practice in Mariemont, Ohio

Dr. Lisa Larkin

The lack of sex hormone binding globulin (SHBG) changes in the subset of women who received this test bolsters support for low systemic absorption from the low-dose vaginal softgel, Lisa Larkin, MD, said at the annual meeting of the North American Menopause Society in Orlando.

These safety data show that the vaginal route for this hormone is meeting a treatment goal for many menopausal women: “One goal of vaginal estrogen is to minimize systemic absorption and potentially reduce related side effects,” Dr. Larkin said.

TX-004HR (Imvexxy) delivers bioidentical solubilized 17 beta-estradiol (E2) via a softgel vaginal insert. It is Food and Drug Administration approved in 4-mcg and 10-mcg doses for the treatment of moderate to severe dyspareunia associated with menopause.

The phase 3 clinical trial (REJOICE) of TX-004HR met the coprimary endpoints of improving vaginal physiology, lowering vaginal pH, and decreasing the severity of dyspareunia at both the 4- and 10-mcg doses, said Dr. Larkin, an internal medicine physician in private practice in Mariemont, Ohio.

Serum estradiol levels for REJOICE participants were “similar to placebo and baseline, and generally within the postmenopausal range,” she said.

The randomized, double-blind, placebo-controlled trial tested 4-, 10-, and 25-mcg doses of TX-004HR. The self-administered vaginal inserts were used once daily for 2 weeks, then twice weekly for an additional 10 weeks.

In looking at treatment emergent adverse events (TEAEs), the REJOICE investigators were particularly interested in tracking cardiovascular and breast events, Dr. Larkin said. Participants received ECGs and clinical breast exams at baseline, and at study week 12. In addition, 72 of the women had SHBG measured at baseline and at weeks 2 and 12. The trial had a high completion rate of 94% at 12 weeks. The mean age of the women was 59 years, and the mean body mass index was 26.7 kg/m2. African American women made up 12% of the study; the remainder of the women were white.

In the end, 784 menopausal women with moderate to severe dyspareunia were randomized 1:1:1:1 to placebo or to receive one of the three dose levels of TX-004HR. Overall, “no clinically significant differences in adverse events were observed between treatment and placebo groups,” Dr. Larkin said. Only headache, vaginal discharge, and vulvovaginal pruritus occurred in at least 3% of the women in any treatment arm, with no differences between those taking TX-004HR and placebo. There were no malignancies or endometrial hyperplasia among the REJOICE participants: “There was no signal of estrogenic stimulation of the endometrium,” she said.

Looking at cardiovascular-related TEAEs, the five events that occurred were judged to be mild, and mostly not related to treatment. One case of first degree atrioventricular block and one case of sinus bradycardia were reported by the same woman, who was taking the 4-mcg dose of TX-004HR. One additional woman on that dose experienced palpitations, as did one woman taking placebo. “No coronary heart disease, venous thromboembolism, or other thrombotic episodes were noted” during the REJOICE trial, Dr. Larkin said. There were no clinically significant ECG changes during the study period that were judged related to treatment. Blood pressure was mildly increased in three women, one each in the 4-mcg, 10-mcg, and placebo study arms. The elevation was considered possibly related to the study in the 4-mcg and placebo takers. Two other women in the 4-mcg group experienced mild incident hypertension, with one woman’s hypertension judged possibly related to treatment.

Blood chemistry showed incident hypercholesterolemia for one woman in the 4-mcg group and one in the placebo group, and one woman taking the 10-mcg TX-0400HR dose and two taking placebo had increases in serum triglycerides.

Seven women reported breast-related TEAEs, with five of these considered possibly or probably treatment related. One woman on the 10-mcg dose had breast tenderness; all other events were among placebo takers.

Finally, among the subset of women whose SHBG levels were tested, “no dose-related pattern was apparent, and changes with TX-004HR were comparable to changes with placebo,” said Dr. Larkin, noting that there was no suggestion of significant systemic absorption.

“These safety data, in conjunction with the improved moderate to severe dyspareunia efficacy data and minimal estradiol absorption, support a local effect of the TX-004HR vaginal insert,” she said.

The study was sponsored by TherapeuticsMD, the manufacturer of TH-004HR. Dr. Larkin disclosed that she is an advisory board member and on the speaker’s bureau for Valeant pharmaceuticals, is a consultant for TherapeuticsMD, and is an advisory board member for AMAG and Palatin Technologies.

SOURCE: Larkin L et al. NAMS 2018, Thursday concurrent session 1.

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