Teriparatide Did Not Increase Adult Osteosarcoma Incidence in a 15-Year US Postmarketing Surveillance Study

The Osteosarcoma Surveillance Study was initiated in the United States in 2003 to monitor for a potential association between the osteoporosis treatment teriparatide and osteosarcoma. Osteosarcoma occurs at a background incidence rate of approximately 2.5 cases per million per year in US adults aged 40 years or older. For this study, incident cases of osteosarcoma diagnosed between January 1, 2003, and December 31, 2016, were identified through participating cancer registries in the United States. Information on prior exposure to medications and possible risk factors was obtained by self-report (or proxy report) in telephone interviews. Exposure information was verified through medical record abstraction for a sample of patients. A standardized incidence ratio was estimated to compare the observed and expected numbers of osteosarcoma patients with a prior history of teriparatide treatment. Interviews were completed for 24% (1173) of patients diagnosed with osteosarcoma between 2003 and 2016; three reports of teriparatide use before diagnosis were identified. Based on the background incidence rate, the expected number of osteosarcoma cases among patients treated with teriparatide was 4.17. Given the three observed cases, the standardized incidence ratio was 0.72 (90% confidence interval [CI], 0.20 to 1.86). Demographic characteristics were similar for interviewed and noninterviewed patients. Agreement was >90% between self-reported and chart-recorded exposure to osteoporosis medications. Mean age of interviewed patients was 61 years; 53% of patients were male, 84% were white, and 5% were Hispanic. The prevalence of suspected risk factors for development of osteosarcoma among the osteosarcoma cohort was 19% for history of radiation and 4% for history of Paget's disease of bone. These findings showed that the incidence of osteosarcoma associated with teriparatide use during the 15-year surveillance period was no different than would be expected based on the background incidence rate of osteosarcoma. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Primary Bone Tumors: Challenges and Opportunities for CAR-T Therapies

Primary malignant bone tumors are rare, occur in all age groups, and include distinct entities such as osteosarcoma, Ewing sarcoma, and chondrosarcoma. Traditional treatment with some combination of chemotherapy, surgery, and radiation has reached the limit of efficacy, with substantial room for improvement in patient outcome. Furthermore, genomic characterization of these tumors reveals a paucity of actionable molecular targets. Against this backdrop, recent advances in cancer immunotherapy represent a silver lining in the treatment of primary bone cancer. Major strategies in cancer immunotherapy include stimulating naturally occurring anti-tumor T cells and adoptive transfer of tumor-specific cytotoxic T cells. Chimeric antigen receptor T cells (CAR-T cells) belong to the latter strategy and are an impressive application of both insights into T cell biology and advances in genetic engineering. In this review, we briefly describe the CAR-T approach and discuss its applications in primary bone tumors. © 2019 American Society for Bone and Mineral Research.

Scoliosis in Fibrous Dysplasia/McCune-Albright Syndrome: Factors Associated With Curve Progression and Effects of Bisphosphonates

Scoliosis is a complication of fibrous dysplasia/McCune-Albright syndrome (FD/MAS); however, risk factors and long-term outcomes are unknown. Bisphosphonates are commonly used; however, it is unknown whether their use decrease the risk of progressive scoliosis. Clinical data from the National Institutes of Health (NIH) cohort study was reviewed. Cobb angles were measured, and variables associated with scoliosis progression were identified. Of 138 subjects with available radiographs, 84 (61%) had scoliosis, including 55 (65%) classified as mild (Cobb angle >10 to ≤30 degrees), 11 (13%) as moderate (>30 to ≤45 degrees), and 18 (22%) as severe (>45 degrees). Total skeletal disease burden was highly associated with scoliosis severity (p < 0.0001). Endocrinopathies associated with scoliosis included fibroblast growth factor 23 (FGF23)-mediated hypophosphatemia (p < 0.001) and hyperthyroidism (p < 0.001). Bone turnover markers, including osteocalcin and NTX-telopeptides, were associated with severe scoliosis (p < 0.01). Associations were identified between Cobb angle and functional metrics, including leg length discrepancy (p < 0.01), hip range of motion (p < 0.05), and strength of the gluteus medius and maximus (p < 0.01). Longitudinal analyses were conducted in 69 subjects who had serial radiographs over a median 4.9-year period (range, 0.9 to 14.7 years). Twenty-two subjects were treated with bisphosphonates; there was no difference in Cobb angle progression compared to untreated subjects (0.10 versus 0.53 degrees/year, p = 0.36). Longitudinal data was available for 10 of 12 subjects treated with spinal fusion; one had instrumentation failure, but in nine subjects Cobb angles were stable with 6.1 years of follow-up (range, 0.9 to 14.7 years). Two fatalities from scoliosis-associated restrictive lung disease occurred in subjects managed non-operatively. Scoliosis occurs frequently in patients with polyostotic FD, and may be potentially fatal. The primary risk factor for progressive scoliosis is total skeletal disease burden. Treatable features that contribute to scoliosis progression include leg length discrepancy, FGF23-mediated hypophosphatemia, and hyperthyroidism. Current data do not support routine use of bisphosphonates to prevent progression of spinal curvature. Spinal fusion is frequently effective in providing long-term stability, and may be lifesaving. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Osteosarcoma in a Patient With Pseudohypoparathyroidism Type 1b Due to Paternal Uniparental Disomy of Chromosome 20q

It is assumed that a persistent high level of parathyroid hormone (PTH) might have a relation with bone malignancy. However, there has been no report of osteosarcoma associated with pseudohypoparathyroidism type 1b (PHP1b), which is accompanied by high PTH. PHP1b is the result of resistance to PTH in certain end-organ tissues, especially the kidney; the response in bone is unaffected because it normally expresses stimulatory G protein equally from both parental alleles. A 21-year-old male, presenting with gum swelling at the right mandible, was referred to a dental clinic. A curative surgical resection by segmental mandibulectomy was performed and the pathologic findings of the mass were consistent with osteoblastic osteosarcoma. His laboratory results showed a low calcium level despite high PTH, and he did not have any features of Albright hereditary osteodystrophy; therefore, PHP1b was suspected. Multiplex ligation-dependent probe amplification and microsatellite marker analyses of chromosome 20 confirmed the diagnosis and identified paternal uniparental disomy of chromosome 20q (patUPD20). To the best of our knowledge, this is the first report of osteosarcoma in a patient with PHP1b due to patUPD20. © 2017 American Society for Bone and Mineral Research.

Assessment of Bone Fragility in Patients With Multiple Myeloma Using QCT-Based Finite Element Modeling

Multiple myeloma (MM) is a malignant plasma cell disease associated with severe bone destruction. Surgical intervention is often required to prevent vertebral body collapse and resulting neurological complications; however, its necessity is determined by measuring lesion size or number, without considering bone biomechanics. Finite element (FE) modeling, which simulates the physiological loading, may improve the prediction of fragility. To test this, we developed a quantitative computed tomography (QCT)-based FE model of the vertebra and applied it to a dataset of MM patients with and without prevalent fracture. FE models were generated from vertebral QCT scans of the T₁₂ (T₁₁ if T₁₂ was fractured) of 104 MM patients, 45 with fracture and 59 without, using a low-dose scan protocol (1.5 mm slice thickness, 4.0 to 6.5 mSv effective dose). A calibration phantom enabled the conversion of the CT Hounsfield units to FE material properties. Compressive loading of the vertebral body was simulated and the stiffness, yield load, and work to yield determined. To compare the parameters between fracture and nonfracture groups, t tests were used, and standardized odds ratios (sOR, normalized to standard deviation) and 95% confidence intervals were calculated. FE parameters were compared to mineral and structural parameters using linear regression. Patients with fracture showed lower vertebral stiffness (-15.2%; p = 0.010; sOR = 1.73; 95% CI, 1.11 to 2.70), yield force (-21.5%; p = 0.002; sOR = 2.09; 95% CI, 1.27 to 3.43), and work to yield (-27.4%; p = 0.001; sOR = 2.28; 95% CI, 1.33 to 3.92) compared to nonfracture patients. All parameters correlated significantly with vBMD (stiffness: R²  = 0.57, yield force: R²  = 0.59, work to yield: R²  = 0.50, p < 0.001), BV/TV (stiffness: R²  = 0.56, yield force: R²  = 0.58, work to yield: R²  = 0.49, p < 0.001), and Tb.Sp (stiffness: R²  = 0.51, yield force: R²  = 0.53, work to yield: R²  = 0.45, p < 0.001). FE modeling identified MM patients with compromised mechanical integrity of the vertebra. Higher sOR values were obtained for the biomechanical compared to structural or mineral measures, suggesting that FE modeling improves fragility assessment in these patients. © 2016 American Society for Bone and Mineral Research.