Long-term use of burosumab for the treatment of tumor-induced osteomalacia.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by tumoral overproduction of FGF-23. Due to local recurrence, we describe the long-term efficacy and safety profile of burosumab, an anti-FGF-23 monoclonal antibody, in a TIO patient after three unsuccessfully surgical attempts. INTRODUCTION: TIO is a rare paraneoplastic syndrome caused by tumoral overproduction of fibroblast growth factor 23 (FGF23), resulting in hyperphospaturia, hypophosphatemia, and osteomalacia. Surgery is the only definitive treatment, but tumor can locally recur, even after years from primary surgery. Furthermore, some tumors cannot be removed by surgery due to their location. METHODS: We describe the case of a 54-year-old woman affected by recurrent TIO who, after three unsuccessful surgical attempts of tumor removal, was treated with burosumab, an anti-FGF-23 monoclonal antibody. RESULTS: The patient was referred to our Bone Unit after experiencing several fractures in different sites, both traumatic and non-traumatic. At the time of first evaluation, at the age of 46, serum-phosphate (SP) was 1.2 mg/dL (reference range (RR) 2.5-4.5), 24-h urinary phosphate was 842 mg (RR 400-1000), and intact-FGF-23 was 117 pg/mL (RR 25-45). Imaging showed a metabolic pre-sacral lesion that firstly underwent to exploratory laparotomy. Then, patient underwent to surgical excision of tumor. After 18 months of well-being, tumor relapsed and even the subsequent surgery was not able to completely remove it. Since 2015, patient was maintained in phosphorus supplements and 1,25(OH)2vitamin D3, but SP levels never normalized. In September 2019, she was started on burosumab, initially at the dose of 0.3 mg/kg/month, progressively increased to the current 0.8 mg/kg/month, with great improvement of pain, physical performance, and normalization of SP levels. Burosumab was temporary and cautionary discontinued for COVID-19 pneumonia, with a worsening of SP. After restart of burosumab, biochemistry returned to normal. CONCLUSIONS: To our knowledge, this is the first European patient affected by TIO treated with burosumab for more than 2 years. Burosumab is a promising therapy in the medical treatment of TIO refractory or not eligible for definitive surgery, with good efficacy and safety profile.

Safety profile of drugs used in the treatment of osteoporosis: a systematical review of the literature.

The range of osteoporosis treatments is increasingly large and, like any disease, the pharmacological management of patients should involve a risk/benefit evaluation to attain the greatest reduction in risk of fracture with the lowest incidence of adverse events. The aim of this review is to critically appraise the literature about the safety issues of the main pharmacological treatments of osteoporosis. This document is the result of a consensus of experts based on a systematic review of regulatory documents, randomized controlled trials, metaanalyses, pharmacovigilance surveys and case series related to possible adverse drug reactions to osteoporosis treatment with calcium and vitamin D supplements, bisphosphonates, strontium ranelate, selective estrogen receptor modulators, denosumab, and teriparatide. As expected, randomized controlled trials showed only the most common adverse events due to the samples size and the short observation time. Case series and observational studies are able to provide data about uncommon side effects, but in some cases a sure cause-effect relationship needs still to be confirmed. Consistently with methodological limitations, the newer drugs have a tolerance profile that has not been fully explored yet. Osteoporosis treatments showed an overall good tolerance profile with rare serious adverse events that, however, must be well known by the clinician who prescribes these drugs. The concern about possible adverse events should be weighed against the reduction of morbidity and mortality associated with a significant fracture risk reduction.

Regional differences of vitamin D deficiency in rheumatoid arthritis patients in Italy.

Vitamin D deficiency is very common in patients with rheumatoid arthritis (RA). Aim of this study was to evaluate the prevalence of vitamin D deficiency among the different Italian regions and whether these variations are associated with different severity of the disease. The study includes 581 consecutive RA patients (464 women), not taking vitamin D supplements, from 22 Italian rheumatology centres uniformly distributed across Italy. Together with parameters of disease activity (disease activity score 28), functional impairment (activities of daily living and health assessment questionnaire disability index) and mean sun exposure time, all patients had serum 25-hydroxyvitamin D (25OHD) measured in a centralized laboratory. Vitamin D deficiency (25OHD level <20 ng/mL) was very frequent among RA patients; its prevalence was 60%, 52% and 38% in southern, central and northern Italy, respectively. Mean disease activity and disability scores were worse in southern regions of Italy. These scores were inversely related to 25OHD levels and this correlation remained statistically significant after adjusting for both body mass index (BMI) and sun exposure time. However, disease severity remained significantly higher in southern regions versus central-northern Italy after adjustment also for serum 25OHD levels, age and BMI. In RA Italian patients there are significant regional differences in the prevalence of vitamin D deficiency explained by different BMI, and sun exposure time, and inversely associated with disease activity and disability scores.

Unbalanced diet to lower serum cholesterol level is a risk factor for postmenopausal osteoporosis and distal forearm fracture.

The purpose of this study was to assess whether dietary changes aimed at reducing serum cholesterol can increase the risk of osteoporosis (OP) and fracture. The study group consisted of 311 postmenopausal women with high serum cholesterol levels and following a diet low in dairy products (calcium intake estimated at less than 300 mg/day) for 27.3 +/- 29.1 months. This sample was compared with a case-control group of 622 healthy postmenopausal women paired for age and age at menopause and with a calcium intake estimated at more than 1 g/day. Bone mineral density was measured at the lumbar spine by dual-energy X-ray absorptiometry. Prevalence of OP was significantly higher in women with a low dairy calcium intake (42.1% vs 22.3%; p < 0.0001), as was the number of Colles' fractures occurring after menopause (4.5% vs 1.6%; p = 0.008). Multiple logistic regression analyses demonstrated that a diet low in dairy calcium was a risk factor for OP (OR = 2.52, 95% CI 1.84-3.45) and Colles' fracture (OR = 2.72, 95% CI 1.18-6.26). In the low dairy calcium group, diet duration significantly influenced the risk of OP (OR = 1.13, 95% CI 1.01-1.25 for 1 year of diet). No differences in further risk factors for coronary heart disease were found between the groups, but the proportion of women physically active was lower in the women with high serum cholesterol levels. A diet that severely limits calcium intake from dairy products in an attempt to correct raised serum cholesterol levels is a risk factor for postmenopausal OP and Colles' fracture. Dietary intervention methods to lower serum cholesterol in postmenopausal women should maintain an adequate calcium intake by providing calcium from low-fat dairy products or calcium supplements.

Comparison of plasma and synovial concentrations of synthetic salmon calcitonin after a single intravenous dose.

The plasma and synovial fluid concentrations of synthetic salmon calcitonin in 10 patients with knee joint effusions have been compared after a single i.v. dose of 200 I.U. calcitonin. Plasma and synovial fluid concentrations of calcitonin were measured using a specific RIA before and 30 and 60 min after administration. Calcitonin was not detectable at zero time in plasma or in synovial fluid. Plasma calcitonin concentrations 60 min after administration were significantly lower than at 30 min, while the synovial fluid concentration remained relatively constant. The results show that synthetic salmon calcitonin penetrates into the articular cavity after a single i.v. dose of 200 I.U. and that a steady concentration persists there over 60 min.