From the Guidelines
Forteo (teriparatide) carries a small but notable risk of osteosarcoma, a rare bone cancer, which was observed in rat studies when the medication was given at high doses for extended periods, but the actual incidence of osteosarcoma linked to Forteo in humans has been extremely low, with only a handful of cases reported worldwide despite millions of patients using the medication 1. The risk of cancer associated with Forteo (teriparatide) treatment for osteoporosis is a critical consideration in clinical practice.
- The medication works by stimulating new bone formation, which is why there are theoretical concerns about stimulating bone tumor growth, but real-world evidence has been largely reassuring regarding this specific safety concern 1.
- Patients with increased risk factors for osteosarcoma, such as Paget's disease of bone, unexplained elevations in alkaline phosphatase, open epiphyses, or prior radiation therapy involving the skeleton, should not use Forteo 1.
- The benefit of Forteo in reducing fracture risk in severe osteoporosis typically outweighs this small cancer risk for most eligible patients, especially when the medication is used as recommended for no more than 2 years total lifetime exposure 1.
- It is essential to weigh the potential benefits of Forteo against the risks, particularly in patients with a history of cancer or those at increased risk of osteosarcoma, and to consider alternative treatments, such as bisphosphonates, in these cases 1.
From the FDA Drug Label
5 WARNINGS AND PRECAUTIONS 5. 1 Osteosarcoma An increase in the incidence of osteosarcoma (a malignant bone tumor) was observed in male and female rats treated with teriparatide. Osteosarcoma has been reported in patients treated with teriparatide in the post marketing setting; however, an increased risk of osteosarcoma has not been observed in observational studies in humans There are limited data assessing the risk of osteosarcoma beyond 2 years of teriparatide use
The risk of cancer, specifically osteosarcoma, associated with Forteo (teriparatide) treatment for osteoporosis is a potential concern, as it has been observed in rats and reported in some patients. However, no increased risk of osteosarcoma has been observed in adult humans treated with teriparatide. It is essential to note that there are limited data assessing the risk of osteosarcoma beyond 2 years of teriparatide use 2.
From the Research
Risk of Cancer with Forteo Treatment
The risk of cancer associated with Forteo (teriparatide) treatment for osteoporosis has been a topic of interest due to initial findings from pre-approval animal studies indicating an increased risk of osteosarcoma. However, subsequent human studies have not shown a significant increase in this risk.
Key Findings
- A case series study published in 2021 3 explored the use of teriparatide in patients with a history of radiotherapy, which is a relative contraindication due to the potential increased risk of osteosarcoma. The study found that teriparatide may be beneficial in select cases where osteoporosis is severe and other treatment options are not suitable.
- A review of teriparatide and osteosarcoma risk published in 2022 4 discussed the history of the drug's approval, the science behind its potential risks, and the elimination of the boxed warning regarding osteosarcoma risk. The review highlighted that real-world studies have shown no increase in osteosarcoma risk in patients using teriparatide compared to unexposed groups.
- Other studies have also investigated the safety and efficacy of teriparatide in various patient populations, including postmenopausal women, men with idiopathic or hypogonadal osteoporosis, and patients with glucocorticoid-induced osteoporosis 5, 6.
Osteosarcoma Risk
- A long-term cancer surveillance study published in 2021 7 found no incident cases of osteosarcoma among patients treated with teriparatide, with a crude incidence rate of 0 cases per million person-years.
- The study's findings are consistent with other research indicating that the risk of osteosarcoma associated with teriparatide treatment is low 4, 6.
Considerations for Patients
- Patients with osteoporosis should discuss the potential benefits and risks of teriparatide treatment with their healthcare provider, taking into account their individual risk factors and medical history.
- The decision to use teriparatide should be based on a careful assessment of the potential benefits and risks, including the risk of osteosarcoma 3, 4.