years after its original introduction, and then only for secondary prevention. In another case, AstraZeneca was accused of marketing rosuvastatin (Crestor) without providing hard endpoint data, relying instead on surrogate endpoints. The company countered that rosuvastatin had been tested on larger groups of patients than any other drug in the class, and that its effects should be comparable to the other statins. Cancer Progression Free Survival is a prominent example in Oncology contexts. There are examples of cancer drugs approved on the basis of progression-free survival failed to show subsequent improvements in overall survival in subsequent studies. In breast cancer, Bevacizumab (Avastin) initially gained approval from the Food and Drug Administration, but subsequently had its license revoked. More patient focused surrogate endpoints may offer a more meaningful alternative such as Overall Treatment Utility. Infectious disease In HIV/AIDS medicine, CD4 counts and viral loads are used as surrogate markers for drug approval for clinical trials. In hepatitis C medicine, the surrogate endpoint "Sustained Virological Response" has been used for the approval of expensive drugs known as Direct Acting Antivirals. The validity of this surrogate endpoint for predicting clinical outcomes has been challenged. For several vaccines (anthrax, hepatitis A, etc), the induction of detectable antibodies in blood is used as a surrogate marker for vaccine effectiveness, as exposure of individuals to an actual pathogen is considered unethical. Criticism There have been a number of instances when studies using surrogate markers have been used to show benefit from a particular treatment, but later, a repeat study looking at endpoints has not shown a benefit, or has even shown a harm. In 2021, the FDA came under heavy criticism for the approval of an alzheimer's drug called Aduhelm based on a surrogate endpoint that was later shown to be based on fraudulent data. See also FDA Accelerated Approval Program based on surrogate endpoints References Medical terminology Epidemiology Biomarkers Medical statistics Clinical trials