Fracture rates and economic outcomes in patients with osteoporosis prescribed risedronate gastro-resistant versus other oral bisphosphonates: a claims data analysis

Cost-effectiveness of weekly gastro-resistant risedronate 35 mg, compared with weekly alendronate 70 mg tablets, in the treatment of postmenopausal osteoporosis in Spain

Aim: To estimate the cost-effectiveness of treating postmenopausal osteoporosis (PMO) with weekly gastro-resistant risedronate 35 mg gastro-resistant tablets (RIS-GR), compared with weekly alendronate 70 mg tablets (ALN) in Spain. Methods: A probabilistic analysis (second-order Monte Carlo simulation) was performed with a time horizon of 5 years, from the perspective of the Spanish National Health System. The bone fracture probabilities were obtained from a cohort study of 3614 women from USA with PMO treated with RIS-GR (1807) or ALN (1807) (Thomasius, 2022). The pharmacological cost and the cost of fractures were obtained from Spanish sources (€ 2022). The utilities of patients with and without fracture (quality-adjusted life years [QALYs]) were obtained from the medical literature. Results: Compared with ALN, treatment with RIS-GR can avoid 79 fractures (between 75 and 82) every 1000 patients treated, and 0.0119 QALYs would be gained (between 0.0098 and 0.0140) per patient. Additionally, GR-RIS would generate a cost saving per patient of €1994 (€1437-2904) with a probability of 99.7%. The scenario analyses confirmed the stability of the base case results. Conclusion: According to this study, RIS-GR would be the dominant treatment (lower costs with QALY gain) compared with ALN.

Fracture risk in women with osteoporosis initiated on gastro-resistant risedronate versus immediate release risedronate or alendronate: a claims data analysis in the USA

The study results indicate that women with osteoporosis initiated on gastro-resistant risedronate have a lower risk of fracture than those initiated on immediate release risedronate or alendronate. A large proportion of women discontinued all oral bisphosphonate therapies within 1 year of treatment start.

PURPOSE

Using a US claims database (2009-2019), we compared risk of fractures between women with osteoporosis initiated on gastro-resistant (GR) risedronate and those initiated on (a) immediate release (IR) risedronate or (b) immediate release alendronate.

METHODS

Women aged ≥ 60 years with osteoporosis who had ≥ 2 oral bisphosphonate prescription fills were followed for ≥ 1 year after the first observed bisphosphonates dispensing (index date). Fracture risk was compared between the GR risedronate and IR risedronate/alendronate cohorts using adjusted incidence rate ratios (aIRRs), both overall and in subgroups with high fracture risk due to older age or comorbidity/medications. Site-specific fractures were identified based on diagnosis codes recorded on medical claims using a claims-based algorithm. Persistence on bisphosphonate therapy was evaluated for all groups.

RESULTS

aIRRs generally indicated lower fracture risk for GR risedronate than IR risedronate and alendronate. When comparing GR risedronate to IR risedronate, statistically significant aIRRs (p < 0.05) were observed for pelvic fractures in the full cohorts (aIRRs = 0.37), for any fracture and pelvic fractures among women aged ≥ 65 years (aIRRs = 0.63 and 0.41), for any fracture and pelvic fractures among women aged ≥ 70 years (aIRRs = 0.69 and 0.24), and for pelvic fracture among high-risk women due to comorbidity/medications (aIRR = 0.34). When comparing GR risedronate to alendronate, statistically significant aIRRs were observed for pelvic fractures in the full cohorts (aIRR = 0.54), for any fracture and wrist/arm fractures among women aged ≥ 65 years (aIRRs = 0.73 and 0.63), and for any fracture, pelvic, and wrist/arm fractures among women aged ≥ 70 years (aIRRs = 0.72, 0.36, and 0.58). In all cohorts, ~ 40% completely discontinued oral bisphosphonates within 1 year.

CONCLUSIONS

Discontinuation rates of oral bisphosphonate therapy were high. However, women initiated on GR risedronate had a significantly lower risk of fracture for several skeletal sites than women initiated on IR risedronate/alendronate, particularly those aged ≥ 70 years.

Novel formulations of oral bisphosphonates in the treatment of osteoporosis

Oral bisphosphonates are a key intervention in the treatment of osteoporosis and in reducing the risk of fragility fractures. Their use is supported by over 3 decades of evidence; however, patient adherence to oral bisphosphonates remains poor in part due to complex dosing instructions and adverse events, including upper gastrointestinal symptoms. This problem has led to the development of novel oral bisphosphonate formulations. Buffered, effervescent alendronate is dissolved in water and so seeks to reduce upper gastro-intestinal adverse events, and gastro-resistant risedronate aims to reduce the complexity of dosing procedure (e.g. fasting prior to consumption) whilst still maintaining the efficacy of fracture risk reduction. Clinical trials and real-world data have been employed to demonstrate some benefits in terms of reduced upper gastro-intestinal adverse events, adherence, persistence and health economic outcomes. This report describes the result of an ESCEO (European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis) expert working group, which explores where oral bisphosphonates sit in current clinical practice guidelines, review their risk-benefit profile and the consequences of poor adherence before exploring novel oral bisphosphonate formulations and their potential clinical and health economic impact. Further research is required but there are signs that these novel, oral bisphosphonate formulations may lead to improved tolerance of oral bisphosphonates and thus, improved adherence and fracture outcomes.

Aminobisphosphonates: Reconsideration 25 years after their approval for the treatment of osteoporosis

Aminobisphosphonates are widely used in the treatment of osteoporosis. They have a high affinity for hydroxyapatite, binding primarily to resorbing surfaces, but also to forming surfaces and to some extent to resting surfaces. They inhibit osteoclasts, thereby decreasing remodelling units. Consequently, they increase bone mass and reduce stress risers. This decreases the risk of fractures. If this decrease is sufficient, they can be temporarily withdrawn (drug holidays), which prevents serious complications (atypical femoral fracture). They probably reduce mortality. Virtually all patients with osteoporosis can benefit from them at some point in the course of their disease (at the beginning of treatment or after the administration of anabolics, selective estrogen receptor modulators or denosumab). If well tolerated orally, alendronate and risedronate are preferable. Otherwise, zoledronate is preferred. Their efficacy vs. cost-safety-convenience ratio makes aminobisphosphonates reference drugs in the field of osteoporosis.

An open-label randomized study of the relative absorption of gastro-resistant risedronate taken fasted or with food versus immediate-release risedronate

Patients with osteoporosis often take oral bisphosphonates with food, rendering these medications ineffective. This study compared the relative absorption of four formulations of gastro‐resistant (GR; formulations 1–4) risedronate 35 mg versus immediate‐release (IR) risedronate 35 mg taken fasted. Secondarily, it compared the relative absorption of GR formulations administered fed and fasted, and determined the site of disintegration. Healthy participants (N = 160) were randomized to one of nine treatment groups: IR risedronate taken fasted (group A) or formulations 1–4 taken fasted or fed (groups B–I). Fasted groups fasted for 8 h pre‐dose and 4 h post‐dose. Fed groups fasted for 7.5 h, then took risedronate with breakfast. Urine was collected until 72 h post‐dose and analyzed using liquid chromatography. From each group, up to seven participants underwent scintigraphic monitoring to assess tablet disintegration. The percentage of total dose recovered in urine (A’_e) was ~0.5% for group A. The A’_e of formulations 1–4 taken fasted was 0.220% (90% confidence interval 0.124–0.389), 0.298% (0.122–0.730), 0.154% (0.090–0.264), and 0.108% (0.051–0.231), respectively. With food, the A’_e of formulation 1 decreased least versus fasted (−27%) compared with the A’_e of formulations 2, 3, and 4 (−73%, −80%, and −65%, respectively). Formulations 1–3 disintegrated in the small intestine, formulation 4 closer to the large intestine. All GR formulations were well tolerated and in line with the known safety profile for IR risedronate. Formulation 2 had the highest absorption when taken fasted, whereas the absorption of formulation 1 was least affected by food.