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.

Tumor induced osteomalacia: A single center experience on 17 patients.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome due to a phosphaturic tumor, which overproduces Fibroblast Growth Factor 23 (FGF-23), causing hyperphosphaturia, hypophosphatemia, low 1,25(OH)2D and osteomalacia. Tumor localization is critical, diagnostic delay ranges from 2.5 to 28 years and to date surgical removal is considered effective treatment. We retrospectively evaluated patients with definite diagnosis of TIO referred to a tertiary Rheumatology Center between September 2000 and May 2020, investigating clinical management and disease outcome. We included 17 patients: 10 (58.8%) were females, mean age at diagnosis was 55.3 ± 13.9 years (mean ± standard deviation), with a diagnostic delay from symptoms onset to tumor detection of 6.6 ± 6.25 years. Biochemical data were: serum phosphorus 1.3 ± 0.4 mg/dL (Reference Range: 2.5-4.6), serum 1,25(OH)2D 31.8 ± 22.9 ng/mL (RR: 25-86), intact FGF-23, 358.9 ± 677 pg/mL (RR: 25-45); 24 h-Urine Phosphorus was increased in only 2 patients, while tubular reabsorption of phosphate (TRP) was decreased in all patients confirming a renal phosphate wasting. In 2013 68Ga- DOTA-based PET/CT was introduced in routinely practice and diagnostic delay was consistently reduced (from 8.6 ± 7.9 to 4.3 ± 2.4 years). Thirteen patients underwent surgery, one patient underwent radiofrequency ablation; 3 patients, not eligible for surgery, were treated only with supplements of phosphorus and calcitriol. One was started on Burosumab after several unsuccessful surgical attempts. After surgery or ablation, 8 patients had complete remission, 3 TIO persistence, and 3 had overtime relapse. Relapses were observed only in patients who previously underwent closed biopsy. To our knowledge, this is the widest European cohort of TIO patients in the last two decades. We confirm a usual diagnostic delay and recommend a stepwise diagnostic approach. Tumor biopsy is not recommended due to the potential cell spilling. Surgery is generally considered a definitive treatment, even though other approaches have been successful in curing TIO. Active surveillance on possible recurrence is always needed. Burosumab appears a promising therapy.

A clinical overview of bone marrow edema.

Bone marrow edema (BME) is a descriptive term which identifies a specific magnetic resonance imaging (MRI) pattern that can be observed in a number of clinical entities, which are often characterized by pain as their main symptom, but show significant differences in terms of histopathological findings, causal mechanisms and prognosis. Bone marrow lesions in the subchondral bone of subjects with knee osteoarthritis (OA) seem to be associated with pain and progression of cartilage damage over time. Some histopathological studies of advanced OA have shown a prevalent fibrosis and bone marrow necrosis. BME of the subchondral bone in rheumatoid arthritis is associated with an infiltrate of inflammatory cells and osteoclasts and has a predictive value of further development of erosions. In spondyloarthritis, BME of the sacroiliac joints identifies an active sacroiliitis and is associated with histological inflammation and radiographic progression, whereas the relationship between BME lesions of the spine and syndesmophyte development is still controversial. BME syndromes (BMES), such as transient osteoporosis of the hip, regional migratory osteoporosis, and transient post-traumatic BMES, are characterized by a BME pattern on MRI and a self-limiting course. The potential evolution of BMES toward osteonecrosis is still controversial.

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.

[The role of rank-ligand inhibition in the treatment of postmenopausal osteoporosis]. / Il ruolo dell'inibizione del rank-ligando nel trattamento dell'osteoporosi postmenopausale.

Osteoporosis is a skeletal disease affecting millions of people worldwide in which a decreased bone mass and a microarchitectural deterioration compromise bone strength leading to bone fragility and increased susceptibility to fracture. Bone turnover increases at menopause, with osteoclast-mediated bone resorption exceeding bone formation. Recent discoveries in bone biology have demonstrated that RANKL, a cytokine member of the tumor necrosis factor superfamily, is an essential mediator of osteoclast formation, function and survival. Denosumab is a fully human monoclonal antibody with a high affinity and specificity for human RANKL. By binding to its target, denosumab prevents the interaction of RANKL with its receptor RANK on osteoclasts and their precursors and inhibits osteoclast-mediated bone resorption. Administered as a subcutaneous injection every six months, denosumab has been shown to decrease bone turnover and to increase bone mineral density in postmenopausal women with low bone mass and osteoporosis. In these patients denosumab significantly reduced the risk of vertebral fractures, hip fractures and nonvertebral fractures. In all clinical trials published to date, denosumab was well tolerated with an incidence of adverse events, including infections and malignancy, generally similar to subjects receiving placebo or alendronate. The denosumab therapeutic regimen consisting in a subcutaneous injection every 6 months may increase patient compliance and persistence with a further benefit from treatment. By providing a new molecular target for osteoporosis treatment, denosumab is a promising drug for the treatment of postmenopausal osteoporosis and the prevention of fragility fractures.

Osteoporosis with vertebral fractures in young males, due to bone marrow mastocytosis: a report of two cases.

Male osteoporosis in young patients is an unusual condition, always worth investigating as a possible manifestation of secondary osteoporosis. Mastocytosis is a clonal disorder of mast cells with heterogeneous presentations; when pathologic cells accumulate only in the bone marrow, vertebral fractures and systemic osteoporosis may represent the sole clinical presentation at the onset of the disease. We report on two young male patients who came to our attention because of multiple dorsal and lumbar vertebral fractures, with no other signs of systemic mastocytosis (SM). Lumbar and femoral dual x-ray absorptiometry showed reduced bone mineral density values; biochemical investigations did not report significant anomalies, suggestive of secondary osteoporosis. One of the patients underwent iliac crest bone biopsy, which was not diagnostic. A vertebral intralesional CT-guided bone biopsy was performed in both patients, which allowed the diagnosis of SM. Our experience pointed out that bone biopsy still remains the gold standard for the diagnosis of SM. However, iliac crest biopsy can be not significant because of circumscribed bone marrow involvement: in these cases only intralesional bone biopsy could be diagnostic.

Association between iron overload and osteoporosis in patients with hereditary hemochromatosis.

SUMMARY: In 87 patients with hereditary hemochromatosis, osteoporosis was detected in 25%, and osteopenia in 41%. Bone mineral density was independently associated with BMI, ALP levels, hypogonadism/menopause, and the amount of iron removed to reach depletion, but not with cirrhosis. Osteoporosis is influenced by iron overload in hemochromatosis. INTRODUCTION: To analyze prevalence, clinical characteristics and genetic background associated with osteoporosis in a retrospective study in Italian patients with hereditary hemochromatosis (HHC). METHODS: In 87 consecutive patients with HHC, bone mineral density was systematically evaluated by dual energy x-ray absorptiometry of the lumbar spine (n = 87) and femoral neck (n = 66). RESULTS: Osteoporosis was detected in 22 (25.3%), and osteopenia in 36 (41.4%) patients. Mean Z scores were -0.92 +/- 1.42 at lumbar spine and -0.35 +/- 1.41 at femoral neck. Lumbar spine T-score was independently associated with total ALP (p = 0.002), hypogonadism/menopause (p = 0.026), and iron overload (p = 0.033 for ferritin and p = 0.017 for iron removed). We observed a borderline significance for BMI (p = 0.069) and smoking status (p = 0.086). Lumbar spine osteoporosis was independently associated with lower BMI (OR 0.73, 95% CI 0.54-0.94), total ALP (OR 1.17, 95% CI 1-1.39 per 10 unit increase) and the amount of iron removed (OR 1.53, 95% CI 1-2.5 per 5 g increase). HFE genotypes did not differ between patients with and without osteoporosis. CONCLUSIONS: Osteoporosis is observed in a quarter of unselected patients with HHC, independently of the genetic background, and is associated with ALP, hypogonadism, body weight, and severity of iron overload.

[Guidelines for the diagnosis, prevention and treatment of osteoporosis]. / Linee guida per la diagnosi, prevenzione e terapia dell'osteoporosi Società Italiana dell'Osteoporosi, del Metabolismo Minerale e delle Malattie dello Scheletro - SIOMMMS.

UNLABELLED: The guidelines for the osteoporosis management were first drafted by a working group and then critically evaluated by the board of SIOMMMS. The most relevant points are: DEFINITION: Osteoporosis is defined as a quantitative and qualitative deterioration of bone tissue leading to increased risk of fracture. Postmenopausal and senile osteoporosis are defined as primitive. DIAGNOSIS: The cornerstone for the diagnosis of osteoporosis is the measurement of bone mineral density (BMD) by DXA (dual-energy X-ray absortiometry) at the femoral neck with T-score values <-2.5, following the WHO definition. Other DXA sites or technologies for measuring bone mass are also acceptable when the former is not accessible. A BMD evaluation is recommended to all women above 65 years of age. At younger age or in man the bone assessment is recommended only in subjects with specific risk factors. A control of bone mass measurement is seldom required before 2 years. DIFFERENTIAL DIAGNOSIS: A few biochemical tests such as serum and urinary calcium, protein electrophoresis, serum creatinine and ESR are usually sufficient to exclude most secondary types of osteoporosis. The value of the so called bone turnover markers for the diagnosis and follow-up of osteoporosis remains uncertain. Several secondary forms of osteoporosis require a specific diagnostic and therapeutic management. PREVENTION: The osteoporosis prevention should be based on the elimination of specific risk factors such as inadequate calcium and vitamin D intake, smoking and sedentary life. The use of pharmacological agents in subjects with BMD values >-2.5 is usually not justified. Pharmacological intervention: The use of drugs registered for the treatment of osteoporosis are recommended when the benefits overcome the risk. This is the case only when the risk of fracture is rather high. FRAX is recognized as a useful tool for easily estimate the long-term fracture risk. SIOMMMS with these guidelines is committed to validate and further develop this diagnostic tool.

Association of quantitative heel ultrasound with history of osteoporotic fractures in elderly men: the ESOPO study.

In order to evaluate the usefulness of calcaneal quantitative ultrasound (QUS) in the assessment of male osteoporosis, a cross-sectional, population-based study was performed. A cohort of 4,832 men, randomly selected, community-dwelling, aged 60-80 years and representative of the general older male Italian population was recruited. QUS measurements were assessed in 83 centers distributed all over Italy and equipped with an Achilles device (GE-Lunar, Madison, Wisconsin, USA). All participants were administered a questionnaire covering lifestyle variables and medical history. Low-energy fractures that had occurred since age 50 were recorded. Overall, 43 subjects reported a previous hip fracture and 455 subjects reported other non-spinal fractures. Univariate analysis showed that fractured subjects were older, with a lower level of outdoor physical activity and a more frequent history of prolonged bedridden periods in comparison with unfractured subjects. Men reporting non-spinal fractures showed a higher prevalence of smoking, while no difference was found among groups in anthropometric measures and calcium intake. QUS measurements showed that all QUS parameters were significantly lower in both fracture groups (p<0.001). Multiple logistic regression analysis demonstrated that each SD reduction in QUS measures was associated with an approximate doubling of the risk for hip fracture, independent of age and other clinical variables (broadband ultrasound attenuation [BUA]: odds ratio [OR]=2.24; 95% confidence interval [CI] 1.61-3.08; stiffness index: OR=2.19; CI 1.56-3.11; speed of sound [SOS]: OR=1.71; CI 1.18-3.24) and with an increase of the risk of other non-spinal fractures (BUA: 1.38; CI 1.22-1.59; stiffness index: OR=1.27; CI 1.17-1.38; SOS: OR=1.14; CI 0.96-1.40). It can be concluded that calcaneal QUS measurement is associated with the risk for hip fracture and any non-spinal fractures among a community-dwelling cohort of elderly men. The strength of the association between QUS measurement and fracture is similar to that observed in elderly women.

Drug-induced agranulocytosis during treatment with infliximab in enteropathic spondyloarthropathy.

Agranulocytosis is a disorder characterized by a severe decrease in the number of granulocytes in blood, that frequently occurs as an adverse reaction to some drugs. By now, there are no reports in literature of agranulocytosis caused by tumur necrosis factor-alpha blockers. We describe the case of a 20-year-old Caucasian male affected by enteropathic (Crohn's disease) spondyloarthropathy HLA B27 negative, successfully treated with infliximab. After the second infliximab infusion, he was found to have a severe transient neutropenia (0.5 x 10(9)/L). Routine serum chemistry and full blood cell count (apart from neutrophil count) were normal. Serology excluded an active infection. Bone marrow needle aspirate showed a normal trilineage differentiation. Autoantibody assessment showed negative ANA, anti-dsDNA, anti-ENA, and ANCA, but positive granulocyte-bound antibodies (GBA) and neutrophil-specific (CD 16+)-bound antibodies (anti-NA). Ten weeks after infliximab infusion, neutrophil count and GBA and anti-NA assay returned spontaneously within normal range and we observed the same progress after every successive infliximab infusion we performed. These data indicated that infliximab possibly triggered production of granulocyte and neutrophil autoantibodies with resultant autoimmune agranulocytosis.

A case of oncogenic osteomalacia detected by 111In-pentetreotide total body scan.

A case of tumor-induced osteomalacia in a 35-year-old woman suffering from severe bone pain and muscle weakness is described. This uncommon disease is characterized by a reduced serum phosphorus level with elevated urinary phosphate excretion, normocalcemia, high serum bone alkaline phosphatase and a deficiency of 1,25 dihydroxyvitamin D3. The tumors responsible for oncogenic osteomalacia are usually small, benign and commonly located in bone or soft tissues of the head and the limbs, so the diagnosis can often be difficult. In this case a 111In-pentetreotide scintigraphy was able to detect a hemangiopericytoma located in the right mascellar sinus. Removal of the tumor resulted in the reversal of clinical and biochemical abnormalities.

Intravenous clodronate in the treatment of reflex sympathetic dystrophy syndrome. A randomized, double blind, placebo controlled study.

OBJECTIVE: To evaluate the efficacy of intravenous (i.v.) clodronate in patients with reflex sympathetic dystrophy syndrome (RSDS) and to assess the urinary excretion of type I collagen crosslinked N-telopeptide (NTx) before and after the treatment. METHODS: Thirty-two patients with RSDS were randomized to receive either i.v. clodronate 300 mg daily for 10 consecutive days or placebo. Forty days later, the placebo treated patients received the clodronate treatment. Outcome measures included as a primary endpoint the visual analog scale of pain (VAS, range 0-100); secondary endpoints were a clinical global assessment (CGA, range 0-3) and an efficacy verbal score (EVS, range 0-3). Clinical and biochemical assessments were performed before the treatment, 40 (T40), 90 (T90), and 180 (T180) days later. RESULTS: At T40 the 15 patients randomized to clodronate treatment showed significant decreases of VAS and CGA (p = 0.002, p = 0.001, respectively). Compared with the placebo group (17 patients), significant differences were found in all clinical variables (VAS: p = 0.001; CGA: p = 0.001; EVS: p<0.0001). A further clinical improvement was observed throughout the study. Pooling the results of all 32 patients after clodronate treatment, at T180 the overall percentage decrease of VAS was 93.2+/-15.6%, with 30 patients significantly improved or asymptomatic. Significant inverse correlations between baseline NTx values and decreases of VAS were found at T90 (p = 0.03) and T180 (p = 0.01). No adverse events related to treatment occurred. CONCLUSION: A 10 day i.v. clodronate course is better than placebo and effective in the treatment of RSDS. NTx seems to be a predictive factor for clodronate efficacy.

Prevalence of osteoporosis by educational level in a cohort of postmenopausal women.

To evaluate whether the prevalence of osteoporosis and related risk factors might be influenced by the level of education, as has been demonstrated for many other chronic diseases, 6160 postmenopausal women at their first densitometric referral were interviewed about reproductive variables, past and current use of estrogens, prevalence of chronic diseases, and lifestyle factors such as calcium intake, physical activity, smoking and overweight. This sample was stratified by years of formal education. Densitometric evaluation was performed by dual-energy X-ray absorptiometry. Age at menarche, past exposure to oral contraceptives, use of hormone replacement therapy, prevalence of chronic diseases, physical activity, overweight and smoking showed significant trends according to the years of education. The prevalence of osteoporosis showed an inverse relationship with level of education, ranging from 18.3% for the most educated to 27.8% for the least educated women. Multiple logistic regression analysis demonstrated a predictive role toward osteoporosis by age, age at menarche and menopause, hormone replacement therapy, calcium intake, physical activity and body mass index. Using the lowest educational level as reference category, increases in educational status were associated with a significantly reduced risk for osteoporosis (OR = 0.76, 95% CI 0.65-0.90 for 6-8 years of schooling; OR = 0.68, 95% CI 0.57-0.82 for 9 years or more). This study shows differences in the prevalence of osteoporosis among educational classes and the protective role played by increases in formal education. If these results are confirmed in other population studies, public health intervention programs will have to consider the socioeconomic and cultural background of the population strata that run a greater risk of osteoporosis.

Bone and joint involvement in genetic hemochromatosis: role of cirrhosis and iron overload.

OBJECTIVE: To evaluate the frequency of arthropathy and osteoporosis in genetic hemochromatosis (GH) and to quantify potential risk factors for these 2 conditions. METHODS: Radiographic evidence of arthropathy was systematically sought in plain radiographs of 32 patients (28 men) with histologically proven GH (17 with hepatic cirrhosis). Bone mineral density was measured by x-ray absorptiometry of L2-L4 and osteoporosis was defined as a T score > or = 2.5 standard deviation below the mean. Potential risk factors investigated were age, body mass index, cirrhosis, alcohol abuse, hepatitis B and C infections, HLA phenotype, serum free testosterone levels, and the amount of iron removed by phlebotomy to reach depletion. The independent role of risk factors for the presence of osteoporosis was tested by multiple logistic regression analysis. RESULTS: Radiologic signs of arthropathy were observed in 81.3% of cases. Patients with arthropathy were older than patients without (p < 0.001), but did not differ in the frequency of cirrhosis, amount of iron removed, and HLA typing. Osteoporosis was observed in 9 patients and was positively associated with the amount of iron removed and cirrhosis. However, in multivariate analysis, cirrhosis was not independently associated with osteoporosis, but patients with higher iron removed had a greater probability to have osteoporosis [odds ratio (OR) = 3.23 for any increase of 5 g, 95% confidence interval (CI): 1.09-9.58], whereas the presence of HLA-A3 was associated with a reduction of risk (OR 0.013, 95% CI: 0.0015-1.13). CONCLUSION: These findings indicate the high prevalence of osteoarticular involvement in Italian patients with GH. Neither cirrhosis nor the amount of iron removed was associated with arthropathy. In contrast, in univariate analysis the risk of osteoporosis was significantly increased by liver cirrhosis. With multivariate analysis we found that osteoporosis was highly influenced by the degree of iron overload, playing an independent role in accelerating bone loss in patients with GH.