Kellier-Steele N, Krohn K, Midkiff K, Harris D, Andrews E. Post-marketing case series study of adult osteosarcoma and for(s)teo: study update from the first 12 years. Poster presented at the 22nd Annual Meeting of the International Society of Clinical Densitometry (ISCD); June 1, 2016. Galway, Ireland.

AIMS: Two retrospective post-marketing safety surveillance studies were initiated in 2003 (in the US) and 2004 [in 5 Nordic countries (Denmark, Finland, Iceland, Norway and Sweden)] to monitor for a possible association between For(s)teo treatment and osteosarcoma (OS) in adults aged 40 and older. The rarity of OS (~3/million) requires a long study duration. The objective of this presentation is to provide an update on study progress, including descriptive characteristics of the OS patients.

METHODS: Incident cases of adult OS diagnosed on or after January 1, 2003, were identified through population-based cancer registries in the US, and on or after January 1, 2004 in the Nordic countries through comprehensive cancer treatment centers and national registries. After consent, patient demographics, treatment history with For(s)teo, and exposure to known risk factors for OS were ascertained via telephone interview (US) or medical records (Nordic countries). In the US, a random sample of medical records is reviewed annually to validate self-reported information.

RESULTS: United States: Through September 30, 2015, 939 US patients diagnosed with OS from 2003-2013 have been interviewed via telephone survey. Demographic characteristics were similar for patients who did and did not consent. Among patients interviewed the mean age was 61 years; 52% were male; 85% were white, and 10% were African-American. The most common morphologic tumor types were OS, not otherwise specified (NOS) (71%); chondroblastic OS (12%); and fibroblastic OS (6%). Reported prevalence of known risk factors were history of radiation (19%) and history of Paget's disease of the bone (5%). One patient reported use of Forteo prior to the diagnosis of OS. The interim data are consistent with no increased risk among teriparatide users.

Nordic Countries: This study completed in 2014. As of December 31, 2013, records for 112 OS cases were abstracted. Mean age was 60 years; 56% were male; 100% were white. The most common morphologic tumor types were OS, NOS (84%), and chondroblastic OS (13%). Medical chart abstractions did not identify any patients with a history of For(s)teo use prior to the diagnosis of OS.

Data from these studies contribute to knowledge about the long-term safety of For(s)teo. Although there is a single case of prior For(s)teo exposure in the US, evidence of a causal relationship between For(s)teo treatment and OS in humans has not been identified.

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