F. Valleggi

Selective estrogen receptor modulators for postmenopausal osteoporosis : Current state of development

Selective estrogen receptor modulators (SERMs) are structurally different compounds that interact with intracellular estrogen receptors in target organs as estrogen receptor agonists and antagonists. These drugs have been intensively studied over the past decade and have proven to be a highly versatile group for the treatment of different conditions associated with aging, including hormone-responsive cancer and osteoporosis. Tamoxifen and toremifene are currently used to treat advanced breast cancer and also have beneficial effects on bone mineral density and serum lipids in postmenopausal women. Raloxifene is the only SERM approved worldwide for the prevention and treatment of postmenopausal osteoporosis and vertebral fractures. However, although these SERMs have many benefits, they may also be responsible for some potentially very serious adverse effects, such as thromboembolic disorders and, in the case of tamoxifen, uterine cancer. These adverse effects represent a major concern given that long-term therapy is required to prevent osteoporosis. Moreover, both preclinical and clinical reports suggest that tamoxifen, toremifene and raloxifene are considerably less potent than estrogen.The search for the ‘ideal’ SERM, which would have estrogenic effects on bone and serum lipids, neutral effects on the uterus, and antiestrogenic effects on breast tissue, but none of the adverse effects associated with current therapies, is currently under way. Ospemifene, lasofoxifene, bazedoxifene and arzoxifene, which are new SERM molecules with potential greater efficacy and potency than previous SERMs, are currently under investigation for use in the treatment and prevention of osteoporosis. These drugs have been shown to be comparably effective to conventional hormone replacement therapy in animal models of osteoporosis, with potential indications for an improved safety profile. Clinical efficacy data from ongoing phase III trials are awaited so that a true understanding of the therapeutic potential of these compounds can be obtained.

The Effects of Recombinant TSH on Bone Turnover Markers and Serum Osteoprotegerin and RANKL Levels

OBJECTIVE Recently it was found that thyrotropin (TSH) receptors are present both in osteoclast and osteoblast and that TSH can modulate bone remodeling independent of thyroid hormones. The aim of this study was, firstly, to evaluate the effects of acute administration of TSH on bone remodeling markers both in men and in women and, secondly, to evaluate if these effects are mediated by variations in serum osteoprotegerin (OPG) and receptor activator of nuclear factor-KB ligand (RANKL). DESIGN We studied 30 thyroidectomized patients (10 premenopausal and 10 postmenopausal women, 10 men) affected by thyroid carcinoma on l-thyroxine therapy. Eighty age- and sex-matched subjects were used as controls. A blood sample was drawn from each patient at baseline and 3 and 5 days after recombinant human TSH (rhTSH) administration, in preparation for (131)I whole body scan, to assess serum bone markers and serum OPG and RANKL levels. MAIN OUTCOME At baseline, postmenopausal women and men had significantly higher values of bone turnover markers and serum OPG compared to control subjects. In all thyroidectomized patients serum RANKL was lower than in controls. After rhTSH administration, serum N-terminal propeptide of type-I procollagen (PINP), a marker of bone formation, increased significantly in postmenopausal women, while serum RANKL significantly increased after 3 days in postmenopausal patients and men returning to baseline values at day 5. Serum OPG levels did not change significantly. CONCLUSIONS The low serum TSH observed in thyroidectomized patients on l-thyroxine therapy is associated with an increase of bone turnover in postmenopausal women and men that is associated with an increase of OPG and a decrease of serum RANKL levels. The acute TSH administration results in an increase of PINP, an index of osteoblastic activity, associated with an increase of serum RANKL. The lack of this response in premenopausal women suggests an influence of estrogen status on bone reactivity to TSH.

Comparison of Different Intravenous Bisphosphonate Regimens for Paget's Disease of Bone

This randomized study compared different intravenous bisphosphonates in PDB. Zoledronate was superior with respect to pamidronate in achieving biochemical remission, with therapeutic response maintained in most patients at 15 mo. Single neridronate and zoledronate infusion showed a similar efficacy in up to 90% of patients nonresponders to pamidronate.

Ospemifene use in postmenopausal women

Background: Selective estrogen receptor modulators (SERMs) are structurally different compounds that interact with intracellular estrogen receptors in target organs as estrogen agonists and antagonists. These drugs have been intensively studied over the past decades and have proven to be a highly versatile group for the treatment of different conditions associated with menopause, including hormone-responsive cancer and osteoporosis. However, currently available SERMS are also responsible for side effects such as thromboembolic disorders, or gynecological symptoms (especially vaginal dryness and hot flushes). Objective/methods: The purpose of this article is to review the clinical trials of ospemifene, a new SERM in Phase III development for the treatment of vulvar and vaginal atrophy. The medical literature was reviewed for appropriate articles containing the terms ‘ospemifene’ and ‘SERMs’. Results/conclusions: The recently released results from a pivotal Phase III study in postmenopausal women demonstrated statistically significant improvements of ospemifene 60 mg/day in symptoms of vulvar and vaginal atrophy over the use of non-hormonal vaginal lubricant. Ospemifene also appeared to be well tolerated, with few patients experiencing side effects. The additional positive results on bone and the breast observed in preclinical studies need to be clinically confirmed to extend the therapeutic potential of this new SERM.

Corretto uso dei marcatori del rimodellamento osseo

RiassuntoImarker del turnover osseo rappresentano un mezzo di valutazione dinamica dello scheletro che aggiungono informazioni alla valutazione statica fornita dalla densitometria ossea. Numerosi studi hanno dimostrato che esiste un’associazione fra i marker ed il rischio di frattura, ma ancora è difficile trasferire questi dati nella gestione del singolo paziente. Probabilmente il maggior potenziale dei marker risiede nel loro utilizzo per il monitoraggio della terapia dell’osteoporosi, soprattutto quando vengono utilizzati farmaci antiriassorbitori, sia per la valutazione della compliance dei pazienti che per la valutazione dell’effetto terapeutico.