Teriparatide and Osteosarcoma Risk: History, Science, Elimination of Boxed Warning, and Other Label Updates.

The phase 3 trials of the bone anabolic drug teriparatide were prematurely terminated because of a preclinical finding of osteosarcoma in rats treated with high doses of teriparatide for near lifetime. Even so, results from these and subsequent clinical trials showed efficacy and tolerability. Based on the phase 3 results and additional preclinical investigations, Forteo (teriparatide) was approved for use in the United States with an indication for the treatment of osteoporosis in patients at high risk for fracture, a boxed warning regarding potential risk of osteosarcoma, a 2-year lifetime limitation of use, other risk mitigations, and a requirement to assess for risk of osteosarcoma in humans treated with teriparatide. Subsequent investigations included five real-world studies directed at assessing a connection between teriparatide and osteosarcoma risk in humans. The early studies did not identify an increased risk of osteosarcoma but were inadequate to sufficiently characterize risk, given the low incidence of this rare form of bone cancer. Learning from these efforts, two studies were undertaken using claims data to identify large cohorts of patients treated with teriparatide and assess whether these patients were found to have osteosarcoma by linking pharmacy claims data with data from cancer registries. These studies showed no increase in osteosarcoma in patients using teriparatide compared with unexposed groups, as well as to the expected population-based background incidence of the disease. Based on this real-world evidence and the totality of data collected from postmarketing use and other clinical investigations, the label was updated in 2020. The changes included addition of information from large observational studies using real-world evidence, removal of the boxed warning, and a revision of the 2-year lifetime limitation. Thus, observational studies with large sample sizes using real-world data can provide supportive evidence to facilitate regulatory decisions including the elimination of a boxed warning. © 2022 Eli Lilly and Company. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Assessing the incidence of osteosarcoma among teriparatide-treated patients using linkage of commercial pharmacy and state cancer registry data, contributing to the removal of boxed warning and other labeling changes.

BACKGROUND: Teriparatide, a recombinant human parathyroid hormone analogue, is associated with increased bone mineral density and a decreased risk of fractures. A dose-dependent increase in the incidence of osteosarcoma was observed in toxicology studies conducted in rats. The primary objective of this study was to estimate the incidence of osteosarcoma over a 10-year period among teriparatide-treated patients versus patients unexposed to teriparatide with osteoporosis and patients in the general population using national pharmacy dispensing data linked with data from participating state cancer registries (SCRs) in the US. METHODS: Patients aged 18 years or older with a dispensed teriparatide prescription formed two different cohorts: Teriparatide-Osteoporosis (Teriparatide-OP) was formed by matching teriparatide patients to unexposed patients with osteoporosis and Teriparatide-General Population (Teriparatide-GP) was formed by matching teriparatide patients to general population patients with a dispensed prescription for a medication other than teriparatide. Matching was performed using select demographics and other variables. Study cohorts were linked to SCR data to ascertain osteosarcoma status. To account for missing outcome data from non-participating SCRs, two analytic approaches were used: the first adjusted the person-time at-risk using a coverage fraction and the second restricted the analyses to patients from states with participating SCRs. RESULTS: There were 18 osteosarcoma cases across four study cohorts: the same three cases in the Teriparatide-OP and Teriparatide-GP cohorts, six cases in the Osteoporosis cohort, and nine cases in the General Population cohort. For the analysis using the coverage fraction the incidence rate ratio (IRR) comparing the Teriparatide-OP and Teriparatide-GP cohorts to the Osteoporosis and General Population cohorts was 1.0 (95% CI: 0.2, 4.5) and 1.3 (95% CI: 0.2, 5.1), respectively. When restricting the analysis to patients from states with participating SCRs, the IRR was 0.6 (95% CI: 0.1, 3.6) and 0.8 (95% CI 0.1, 4.0), respectively. CONCLUSION: The estimates of association between teriparatide and osteosarcoma were imprecise due to the small number of observed osteosarcoma cases. However, the incidence of osteosarcoma observed in each study cohort was within the expected range given background rates for the US general population. The evidence generated by this study, in conjunction with other real-world studies evaluating the risk of osteosarcoma, was used to support changes to the US teriparatide label (including removal of the black box warning regarding potential risk of osteosarcoma) and expand treatment options for patients with osteoporosis.

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).

Assessing the incidence of osteosarcoma among teriparatide users based on Medicare Part D and US State Cancer Registry Data.

PURPOSE: During preclinical testing, teriparatide caused a dose-dependent increase in the incidence of osteosarcoma in rats. This study compared the incidence rate of osteosarcoma among patients aged ≥65 years treated with teriparatide vs a matched-comparator cohort. METHODS: This population-based comparative-cohort study matched exposure details for each teriparatide user, identified via Medicare Part D prescription claims, and up to four comparators based on age, sex, zip code, date of claim for filled prescription, and number of unique therapeutic classes dispensed. Outcomes were identified via linkage with participating cancer registries. All US state cancer registries were invited to participate. RESULTS: Overall, 153 316 patients in the teriparatide cohort and 613 247 in the comparator cohort were linked to 811 osteosarcoma cases from 26 participating state cancer registries (68% of US patients aged ≥65 years diagnosed 2007-2014). Analysis on a subset of cohorts revealed they were balanced for known osteosarcoma risk factors and Charlson comorbidity index. Mean duration of teriparatide treatment was 10 months. No osteosarcoma cases were observed in the teriparatide cohort; the incidence rate in the comparator cohort was consistent with the background incidence rate among adults aged ≥65 years. The incidence rate ratio was 0.0 (95% confidence interval, 0.0-3.2). CONCLUSIONS: For US patients aged ≥65 years, incidence of osteosarcoma among those treated with teriparatide ranges from 0 to 3.2 times the incidence of osteosarcoma in those treated with other medications. Given low incidence of osteosarcoma, this range of effect is inconsistent with a large absolute increase in osteosarcoma risk.

Evaluation of dystonia in children and adolescents treated with atomoxetine within the Truven MarketScan database: a retrospective cohort study.

OBJECTIVE: Atomoxetine is a non-stimulant drug indicated for the treatment of attention-deficit/hyperactivity disorder in children aged ≥6 years, adolescents, and adults. In this retrospective cohort study, the incidence and risk of dystonia in children and adolescents treated with atomoxetine was compared to a propensity score-matched cohort of stimulant users. METHODS: Data between 1 January 2006 and 31 December 2014 from patients aged 6-17 years in the Truven Health Analytics MarketScan database were used to generate two cohorts of patients: (1) atomoxetine users and (2) stimulant (methylphenidates or amphetamines) users. A Cox proportional hazards regression model was used to compare incidence of dystonia across propensity score-matched cohorts. RESULTS: Of the 70,657 atomoxetine users, 70,655 users were propensity score-matched to a stimulant user. In the atomoxetine- and stimulant-treated cohorts, the crude incidence rates of dystonia were 54.9 (95% CI: 27.1-82.7) and 77.9 (95% CI: 49.1-106.8) per 100,000 person-years, respectively. The hazard ratio for occurrence of dystonia with atomoxetine use relative to stimulant use was 0.68 (95% CI: 0.36 - 1.28; P = 0.23). CONCLUSION: In this large retrospective cohort study, there was no significant difference in incidence or risk of dystonia among patients treated with atomoxetine compared to stimulants.