rfanni, when Forteo was being studied in R
Osteosarcoma, a found in rats that were given very large doses 3 to 60 times the dose given in humans. Repeat studies in monkeys did not reveal the risk of cancer. The rats developed a rare form of osteosarcoma so the FDA constructed a black box warning and approved the use of Forteo for less two years max.
The Wisker rat was also found to be predisposed to devloping this type of cancer.
After market studies found no evidence or connection to Forteo use and bone cancer. And a surveillance study involving over 75,000 patients from 2009–2019 found no cases of osteosarcoma.
The suspicion of osteosarcoma with Forteo use was dispelled, the black box removed and now we can take Forteo for many years.
I have found that even some endocrinologists are unaware of the black box removal or the extended studies.