A meta-analysis characterizing the dose-response relationships for three oral nitrogen-containing bisphosphonates in postmenopausal women

Managing Early Onset Osteoporosis: The Impact of Premature Ovarian Insufficiency on Bone Health

Premature ovarian insufficiency is a reproductive endocrine disorder characterized by the cessation of ovarian function before the age of 40 years. Although the etiopathology of POI remains largely unknown, certain causative factors have been identified. Individuals affected by POI are at an increased risk of experiencing bone mineral density (BMD) loss. Hormonal replacement therapy (HRT) is recommended for patients with POI to mitigate the risk of decreased BMD, starting from the time of diagnosis until reaching the average age of natural menopause. Various studies have compared the dose-effect relationship of estradiol supplementation, as well as different HRT formulations on BMD. The impact of oral contraception on reduced BMD or the potential benefits of adding testosterone to estrogen replacement therapy are still subjects of ongoing discussion. This review provides an overview of the latest advancements in the diagnosis, evaluation, and treatment of POI as it relates to BMD loss.

Multiple Porous Synthetic Bone Graft Comprising EngineeredMicro-Channel for Drug Carrier and Bone Regeneration

Due to high demand but limited supply, there has been an increase in the need to replace autologous bone grafts with alternatives that fulfill osteogenic requirements. In this study, two different types of bone grafts were tested for their drug carrying abilities along with their osteogenic properties. Two different types of alendronate-loaded bone grafts, Bio-Oss (bovine bone graft) and InRoad (biphasic synthetic bone graft) were observed to see how different concentrations of alendronate would affect the sustained release to enhance osteogenesis. In this study, defected ovariectomize-induced osteoporotic rat calvarias were observed for 28 days with three different concentrations of alendronate (0 mg, 1 mg, 5 mg) for both Bio-Oss and InRoad. A higher concentration (5 mg) allowed for a more controlled and sustained release throughout the 28-day comparison to those of lower concentrations (0 mg, 1 mg). When comparing Bio-Oss and InRoad through histology and Micro-CT, InRoad showed higher enhancement in osteogenesis. Through this study, it was observed that alendronate not only brings out robust osteogenesis with InRoad bone grafts, but also enhances bone regeneration in an alendronate-concentration-dependent manner. The combination of higher concentration of alendronate and multiple porous bone graft containing internal micro-channel structure of InRoad resulted in higher osteogenesis with a sustained release of alendronate.

Real-world Adherence and Persistence with Bisphosphonate Therapy in Postmenopausal Women: A Systematic Review

PURPOSE

Bisphosphonate therapy is a well-established and effective treatment for postmenopausal osteoporosis and the prevention of osteoporotic fracture. However, poor adherence to and poor persistence with bisphosphonate therapy may reduce its benefits. Previous studies have documented the poor rates of adherence and persistence among postmenopausal women with osteoporosis. The objective of this systematic literature review was to evaluate adherence, persistence, and the impact of adherence and persistence on fracture risk in postmenopausal women with diagnosed osteoporosis.

METHODS

Articles eligible for review included observational studies of the real-world use of bisphosphonates in 23 countries and were identified by using MEDLINE, EMBASE, IMSEAR (Index Medicus for South-East Asia Region), and LILACS (Latin American and Caribbean Health Sciences Database).

FINDINGS

We identified and evaluated 10 studies that assessed bisphosphonate adherence by measuring medication possession ratio (MPR), persistence, and/or the impact of adherence and persistence on fracture risk. Mean MPR at 1 year ranged from 54% to 71% in the 3 studies that reported this assessment of adherence, and 40%-85% of patients at 1 year were adherent, defined as an MPR ≥80%, in the 8 studies that reported this end point. At 1 year, rates of persistence ranged from 28% to 74%. Rates of adherence and persistence were highest with agents requiring less frequent administration and typically declined over time. Fracture rates were significantly lower among adherent women with MPRs ≥80% compared with women with MPRs <80%.

IMPLICATIONS

Our results show that suboptimal adherence to and persistence with bisphosphonate therapy in postmenopausal women are common and increase the risk of fracture. Additional research is needed to identify and incorporate effective strategies for improving adherence to bisphosphonates in postmenopausal women.

Screening for Atypical Femur Fractures Using Extended Femur Scans by DXA

Atypical femur fractures (AFFs) are a rare but serious complication associated with the use of antiresorptive drugs such as bisphosphonates. Assessment of incomplete AFFs on extended femur scans by dual-energy X-ray absorptiometry (DXA) may prevent the development of complete fractures. The aim of this study was to evaluate the potential of extended femur scans by DXA as a screening tool for incomplete AFFs. From June 2014 until September 2016, extended femur scans were routinely performed in all consecutive patients undergoing DXA scanning who had used bisphosphonates or denosumab at any given moment in the previous year. When "beaking" was found, defined as a localized periosteal or endosteal thickening of the lateral cortex, a radiograph of the femur was performed to confirm incomplete AFF. Beaking was detected in 12 of 282 patients (4.3%) with extended scans of both femora. In 9 patients (3.2%), beaking corresponded with the radiological presence of incomplete AFFs, of whom 4 already had an X-ray made because of a previous complete AFF of the other leg. Five patients (1.8%) were newly diagnosed with 6 yet unknown incomplete AFFs. No additional X-ray was performed in 2 patients because of loss of follow-up. Beaking was explained by known soft tissue calcifications in 1 patient. The positive predictive value of beaking on extended femur scan was 83.3% in our study. Three cases in whom the new diagnosis of incomplete AFF has affected medical and surgical treatment are further discussed to illustrate the relevance of early detection. We conclude that extended femur scans by DXA can detect incomplete AFFs in patients on antiresorptive treatment and should therefore be considered a clinically relevant screening tool because early identification of AFFs has therapeutic consequences. © 2017 American Society for Bone and Mineral Research.

Bone Mass Outcomes in Patients With Osteoporosis Treated With Risedronate After Alendronate Failure: a 12-Month Follow-Up Study

Oral bisphosphonates are the drugs most frequently used for the treatment of osteoporosis. Clinicians usually switch between these drugs in clinical practice based on differences in efficacy. We aim to investigate the reasons associated with switching between oral bisphosphonates and to evaluate bone mass response and the incidence of fractures 12 mo after the exchange in a cohort of patients with osteoporosis seen at a tertiary hospital. Patients with osteoporosis who switched between oral bisphosphonates between January 2007 and December 2014 were included. Bone mass measured by dual-energy X-ray absorptiometry and the incidence of fracture were evaluated. A total of 112 patients (73.1 yr old on average, 95.5% women, 98% postmenopausal) were included. All patients were taking alendronate at the time of the switch to risedronate. In 91 patients (81.3%), the following reasons for the exchange of medication were identified: bone loss (59.8%), adverse events (11.6%), and recent fragility fracture (10.7%). One year after the switch, bone densitometry revealed bone loss in 51 patients (45.5%), bone mass maintenance in 34 (30.4%), and bone mass gain in 27 (24.1%). No new vertebral fracture was detected and no nonvertebral fracture was reported in 12 mo of follow-up. Bone mass outcomes (gain, loss, or maintenance) were not associated with the reason for switching between oral bisphosphonates. Similarly, none of the parameters evaluated could predict good densitometric response (gain or maintenance) in this scenario. Our findings suggest that the use of risedronate should not be recommended in the scenario of treatment failure or adverse events following the use of alendronate.

Non-adherence with bisphosphonates among patients with osteoporosis: impact on fracture risk and healthcare cost‏

Osteoporosis-related fractures at the spine and hip have a substantial impact on mortality, morbidity, and quality of life in older adults worldwide. Adherence to bisphosphonates is essential for effective treatment and fracture prevention. Nevertheless, numerous studies from various populations and study designs clearly indicated that adherence and persistence are poor with more than 50% of patients discontinuing therapy within one year. This is primarily explained by mild adverse effects, dosing regimens, and costs. Studies have also shown that good adherence is associated with reduced osteoporosis-related and non-related healthcare costs as soon as 2 years from therapy initiation. Nonetheless, we found only little improvement in adherence rates over the years. In light of the importance of medication adherence and the limited success of previous programs, other than reducing dosing frequency, new directions should be explored to engage patients and care givers in order to improve adherence and prevent fractures.

Methods for meta-analysis of pharmacodynamic dose-response data with application to multi-arm studies of alogliptin

Standard methods for meta-analysis of dose-response data in epidemiology assume a model with a single scalar parameter, such as log-linear relationships between exposure and outcome; such models are implicitly unbounded. In contrast, in pharmacology, multi-parameter models, such as the widely used E_max model, are used to describe relationships that are bounded above and below. We propose methods for estimating the parameters of a dose-response model by meta-analysis of summary data from the results of randomized controlled trials of a drug, in which each trial uses multiple doses of the drug of interest (possibly including dose 0 or placebo). We assume that, for each randomized arm of each trial, the mean and standard error of a continuous response measure and the corresponding allocated dose are available. We consider weighted least squares fitting of the model to the mean and dose pairs from all arms of all studies, and a two-stage procedure in which scalar inverse-variance meta-analysis is performed at each dose, and the dose-response model is fitted to the results by weighted least squares. We then compare these with two further methods inspired by network meta-analysis that fit the model to the contrasts between doses. We illustrate the methods by estimating the parameters of the E_max model to a collection of multi-arm, multiple-dose, randomized controlled trials of alogliptin, a drug for the management of diabetes mellitus, and further examine the properties of the four methods with sensitivity analyses and a simulation study. We find that all four methods produce broadly comparable point estimates for the parameters of most interest, but a single-stage method based on contrasts between doses produces the most appropriate confidence intervals. Although simpler methods may have pragmatic advantages, such as the use of standard software for scalar meta-analysis, more sophisticated methods are nevertheless preferable for their advantages in estimation.

Current perspectives on the etiology and manifestation of the "silent" component of the Female Athlete Triad

The Female Athlete Triad (Triad) represents a syndrome of three interrelated conditions that originate from chronically inadequate energy intake to compensate for energy expenditure; this environment results in insufficient stored energy to maintain physiological processes, a condition known as low energy availability. The physiological adaptations associated with low energy availability, in turn, contribute to menstrual cycle disturbances. The downstream effects of both low energy availability and suppressed estrogen concentrations synergistically impair bone health, leading to low bone mineral density, compromised bone structure and microarchitecture, and ultimately, a decrease in bone strength. Unlike the other components of the Triad, poor bone health often does not have overt symptoms, and therefore develops silently, unbeknownst to the athlete. Compromised bone health among female athletes increases the risk of fracture throughout the lifespan, highlighting the long-term health consequences of the Triad. The purpose of this review is to examine the current state of Triad research related to the third component of the Triad, ie, poor bone health, in an effort to summarize what we know, what we are learning, and what remains unknown.

Ionic complex of risedronate with positively charged deoxycholic acid derivative: evaluation of physicochemical properties and enhancement of intestinal absorption in rats

Risedronate is widely used clinically to treat osteoporosis, Paget's disease, hypercalcemia, bone metastasis, and multiple myeloma. However, its oral efficacy is restricted due to its low bioavailability and severe gastrointestinal adverse effects. This study was designed to evaluate the effect of deoxycholic acid derivatives on the permeability and oral bioavailability of risedronate by increasing its lipophilicity and affinity to bile transporters. We synthesized two bile acid derivatives, N(α)-deoxycholyl-L-lysyl-methylester (DCK) and N(α)-deoxycholyl-L-lysyl-hydroxide (HDCK) as oral absorption enhancers. After ionic complex formation with the bile acid derivatives, the complexes were characterized by powder X-ray diffraction. Their artificial membrane permeabilities and bioavailabilities in rats were investigated in comparison with pure risedronate. Complex formation with DCK or HDCK demonstrated that risedronate existed in an amorphous form in the complex. A physical complex of risedronate with DCK enhanced the apparent membrane permeability of risedronate significantly but pure risedronate was not permeable. An in vivo study revealed that the C max and AUClast of risedronate/DCK (1:2) complex were 1.92- and 2.64-fold higher than those of pure risedronate, respectively. Thus, the risedronate/DCK complex can improve the oral absorption of risedronate and patient compliance by reducing dose frequency and adverse reactions.

Osteoporosis treatment: why ibandronic acid?

INTRODUCTION

In this article, we have summarized the specific evidence on ibandronic acid (or ibandronate) efficacy, tolerability, and feasibility acquired from trials and clinical use.

AREAS COVERED

This critical review focuses on evidence from randomized controlled clinical trials, meta-analyses, surrogate markers, bridging trials, long-term extension studies, observational studies, clinical experiences in osteoporosis in addition to postmenopausal treatment adherence in clinical practice, and safety profile of ibandronic acid.

EXPERT OPINION

Pivotal studies on ibandronic acid efficacy in terms of antifracture effects on nonvertebral fractures had some intrinsic limitations. However, a large body of indirect evidence suggests that ibandronate has significantly sustained vertebral and nonvertebral antifracture efficacies in women with postmenopausal osteoporosis, in comparison to those observed with other nitrogen-containing bisphosphonates. Discrepancies in efficacy between the available bisphosphonate regimens appear to be a function of dose rather than to inherent differences in their respective therapeutic potential. Drugs or treatment regimens that minimize the risk of osteoporotic fractures and make the treatment of osteoporosis more convenient and suitable for patients are preferred: ibandronic acid marketed at oral doses of 150 mg once monthly and 3 mg quarterly as intravenous injection has these characteristics. The safety profile of ibandronic acid treatment appears to be good overall and in some cases better than that of other nitrogen-containing bisphosphonates.