Systematic review examines CE/BZA for menopause symptoms in endometriosis
Bottom line
Version 1
A new systematic review in Climacteric looked at whether conjugated estrogens/bazedoxifene, or CE/BZA, might help manage vasomotor symptoms in premenopausal and menopausal patients with a history of endometriosis. The review followed PRISMA guidance and was prospectively registered in PROSPERO, but the evidence base appears to be very limited: published literature on CE/BZA in this setting is largely made up of case reports and small case series rather than randomized trials. That matters because CE/BZA is already an FDA-approved combination for moderate-to-severe menopausal vasomotor symptoms in women with a uterus, marketed as Duavee, but it is not specifically approved for endometriosis-related management decisions. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, this is mainly a signal about how early-stage evidence can outpace clinical certainty. The review adds to interest in bazedoxifene’s tissue-selective estrogen activity and its theoretical appeal in patients with endometriosis who need symptom relief, but the current evidence remains too thin to support broad conclusions on safety, recurrence risk, or long-term outcomes in this subgroup. Clinicians reading across translational or comparative literature should keep in mind that CE/BZA carries standard boxed estrogen warnings, including risks related to endometrial cancer, cardiovascular disorders, and probable dementia, and labeling says it should be used for the shortest duration consistent with treatment goals. (dailymed.nlm.nih.gov)
What to watch: Whether this review prompts prospective studies, registry data, or formal menopause-society guidance specific to patients with prior endometriosis. (pubmed.ncbi.nlm.nih.gov)
Key facts
- Study type
- Systematic review
- Journal
- Climacteric
- Topic
- Conjugated estrogens/bazedoxifene for vasomotor symptoms in patients with endometriosis
- Evidence base
- Mostly case reports and small case series
- Randomized trials
- None identified
- FDA-approved product
- Duavee
- Approved uses
- Moderate-to-severe menopausal vasomotor symptoms in women with a uterus, and prevention of postmenopausal osteoporosis
- Not specifically approved for
- Endometriosis-related management
- Label warning
- Boxed warnings for endometrial cancer, cardiovascular disorders, and probable dementia
Version 2
A systematic review newly published in Climacteric is drawing attention to conjugated estrogens/bazedoxifene as a possible option for vasomotor symptom management in premenopausal and menopausal patients with endometriosis, a group that often presents a therapeutic dilemma because estrogen exposure can help symptoms of menopause while also raising concern about endometriosis persistence or reactivation. Based on the available record, though, the review lands in a familiar place: there’s clinical interest, but the published evidence is still sparse and mostly low level. (pmc.ncbi.nlm.nih.gov)
That context matters. Endometriosis has traditionally been viewed as a premenopausal disease, yet symptoms and residual disease can persist into natural or surgical menopause, making hormone therapy decisions unusually complex. A prior systematic review on menopause management in women with a history of endometriosis also found the literature limited, with concerns centered on recurrence, malignant transformation, and uncertainty around the safest hormone strategies. (pubmed.ncbi.nlm.nih.gov)
CE/BZA has attracted interest because it combines conjugated estrogens with bazedoxifene, a selective estrogen receptor modulator intended to provide endometrial protection without a progestin in women with a uterus. In the U.S., Duavee is approved for treatment of moderate-to-severe vasomotor symptoms associated with menopause and for prevention of postmenopausal osteoporosis, not for treatment of endometriosis itself. The current DailyMed label, updated April 28, 2026, includes boxed warnings on endometrial cancer, cardiovascular disorders, and probable dementia, and advises use for the shortest duration consistent with treatment goals and risks. (dailymed.nlm.nih.gov)
The rationale for studying CE/BZA in endometriosis is not coming out of nowhere. Earlier preclinical work reported regression of endometriosis in a murine model treated with bazedoxifene plus conjugated estrogens, and a 2018 case series described use of bazedoxifene/conjugated estrogens with leuprolide in reproductive-aged women with endometriosis. More broadly, CE/BZA has established efficacy for menopausal symptom relief in postmenopausal women, including improved menopause-related symptoms in a prior meta-analysis, which helps explain why investigators are revisiting it for harder-to-manage subgroups. (pmc.ncbi.nlm.nih.gov)
What’s missing is the kind of evidence most clinicians would want before changing practice. The review’s own framing suggests there were no randomized controlled trials to analyze, requiring appraisal tools more appropriate for case reports and case series. That means any apparent benefit should be interpreted cautiously: signals of symptom relief or tolerability may be real, but they don’t yet answer the bigger questions around recurrence of endometriosis, durability of benefit, comparative effectiveness versus conventional menopausal hormone therapy, or outcomes in patients with surgical versus spontaneous menopause. (pmc.ncbi.nlm.nih.gov)
Expert-style commentary in the surrounding literature has generally emphasized the same tradeoff. Reviews of CE/BZA in menopause have described it as a tissue-selective estrogen complex that can relieve vasomotor symptoms while limiting stimulation of the endometrium, and pooled gynecologic safety analyses from phase 3 trials have supported endometrial protection in studied postmenopausal populations. But those data come from menopause trials, not endometriosis-specific cohorts, so applying them to patients with prior or residual endometriosis is still an inference rather than a proven conclusion. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, this paper is less about immediate practice change and more about evidence literacy. It’s a reminder that mechanistic appeal, early case-based experience, and regulatory approval in one indication don’t automatically translate into confidence in a more complex subgroup. For clinicians who follow human women’s health research as a window into comparative endocrinology, pain biology, or translational reproductive medicine, the review highlights an area where patient need is clear but the evidence hierarchy is still thin. (pmc.ncbi.nlm.nih.gov)
What to watch: The next meaningful development would be prospective cohort studies or randomized trials, especially those that track symptom control, endometriosis recurrence, imaging findings, and adverse events over time, along with any updated guidance from menopause or gynecology societies on hormone therapy in patients with a history of endometriosis. (pubmed.ncbi.nlm.nih.gov)