|| EMAS 2003 Bucharest 24 – 28 May 2003
|Asian studies highlight differences and similarities in the menopause experience
Menopausal problems among Asian women remain underestimated, said Professor Khunying Limpaphayom (Chulalongkorn University Hospital, Bangkok, Thailand). She said that although there were a number of differences between East and West, there were also many similarities. And she warned that menopausal problems were an important health issue in Thailand and other Asian countries and would become even more critical as the population aged further.
Limpaphayom said that studies show that hot flushes, although less severe than elsewhere, affected up to 37.7 percent of Thai women. Reports of urogenital symptoms were highly variable, probably reflecting differences in women's ability to discuss such complaints.
However, one important difference was highlighted: a high prevalence of nontypical symptoms in Thai women, including numbness, pins and needles, joint and muscle pain, forgetfulness and skin dryness. National surveys in Thailand also show the prevalence of osteoporosis of the spine and femoral neck to be around 20 percent and 12 percent respectively.
Expanding on the role of HRT, Dr. Kittisak Wilawan of the Pramongkutklao Hospital, Bangkok, said that use of HRT in Thailand was less than 5 percent. Wilawan added: "The main reasons for not using HRT are cancer concern and uncertainty on information of benefit and risk. The main indications for HRT initiation comprise of osteoporosis, vasomotor and genital symptoms respectively. Decision is primarily relied on medical advice."
In the wake of the WHI results, the Thai Menopause Society recommends that its members reconsider benefit and risk associated with the use of HRT after 4-5 years and carry out regular safety monitoring if treatment is continued.
Introducing STEARs, a new class of treatments
Ongoing research into the mechanism of action and clinical profile of tibolone, an alternative menopausal therapy that exerts selective estrogenic activity, has led to demands for a class title that accurately describes what it does and differentiates it appropriately from estrogen-containing hormonal therapies. Accordingly, the term STEAR (selective tissue estrogenic activity regulator) has been introduced.
Launching the class title at the EMAS conference, Dr. Lenus Kloosterboer (R&D at tibolone manufacturer Organon, The Netherlands) said: "Tibolone prevents bone loss and relieves climacteric symptoms in postmenopausal women. These effects are due to the estrogen receptor activation of its two 3-OH metabolites. However, estrogen activity is not expressed in the endometrium and the breast. As a result, estrogen-like stimulation of the endometrium and the breast is not observed."
He said that that the new class title had been developed with the support of external experts to encompass the main property of tibolone, which is estrogenic activity expressed in a tissue selective way.
He added that other future members of this class should be efficacious in preventing hot flushes, vaginal atrophy and bone loss, without compromising the breast and the endometrium. In addition to these minimum requirements, he pointed out that tibolone demonstrates additional features, such as beneficial effects on mood and libido as a result of its mild androgenic effects.
Future SERMs in the pipeline
Research for new SERMs [selective estrogen receptor modulators] that are more potent and more selective than raloxifene, the first SERM to enter the market, is fierce. Two potential second-generation compounds-lasofoxifene (Pfizer) and basedoxifene (Wyeth)-are currently undergoing phase III trials.
During a plenary lecture, Dr. Paola Albertazzi (Centre for Metabolic Bone Disease, Hull, UK), said that lasofoxifene entered phase III trials towards the end of 2000 for the treatment of postmenopausal osteoporosis. The move follows phase II trials showing that it increases bone mineral density as effectively as the leading estrogen replacement therapy and reduced LDL levels. Albertazzi said that it was likely that its efficacy in relation to hip fracture-not shown for raloxifene-would be a major question.
Basedoxifene is also under evaluation for the prevention of osteoporosis. Albertazzi said there was much interest in its use with conjugated equine estrogens, saying: "Due to its antiproliferative effect on the uterus, it is currently being tested in combination with estrogen in the attempt to maintain the clinical benefit of estrogen without the need for progestogen to prevent endometrial stimulation."
She suggested that raloxifene, which is licensed for the prevention of osteoporosis, should not be viewed as an alternative to HRT in early postmenopausal women: "Raloxifene induces hot flushes. This therapy should not be given as an alternative to HRT in early menopausal women. It should be used for older women for whom hot flushes are not a problem."
Strategies to prevent osteoporosis without estrogen
Gynecologists are increasingly having to provide treatments for the management of postmenopausal osteoporosis that are free of estrogen for patients who cannot or will not consider HRT, said Dr. John Stevenson (Imperial College London, UK), reviewing the options during a symposium organized by the British Menopause Society.
He said that while bisphosphonates have marked anti-resorptive activity, they are poorly absorbed from the gastrointestinal tract and needed to be taken fasting. Newer compounds such as alendronate and risedronate are more efficacious than etidronate and have been shown to reduce the incidence of both osteoporotic hip and spine fractures, he said. Stevenson added that gastrointestinal side effects could be reduced, although not avoided, by once-weekly dosing regimens.
Describing tibolone as an alternative to traditional HRT, he said that there was good evidence that it was very active on the bone, adding "A number of studies show that tibolone is very effective in preventing postmenopausal bone loss and causes an early increase in bone mineral density. Therefore it is very likely that it will prevent the development of osteoporosis. However, fracture data is not available yet." Nevertheless, he added he would be "surprised" if the effect would not translate into fracture reduction. This is currently under investigation in the LIFT study, a randomized placebo-controlled global study evaluating tibolone (1.25 mg) in the prevention of osteoporotic fractures in women diagnosed with osteoporosis.
Stevenson also said that calcitonin and SERMs [selective estrogen receptor modulators] appeared effective in preventing spinal fractures but lacked efficacy in preventing hip fractures. Finally, he commented that parathyroid hormone, which has to be given by daily injection, has been shown to produce striking increases in bone density. He suggested that it may prove to be particularly useful in combination with antiresorptive agents.