Yervoy discounts cannot be applied retroactively, as per the terms and conditions outlined by Bristol Myers Squibb. The company's access support program specifies that patients must meet certain criteria and enroll before receiving any financial assistance for Yervoy. Once enrolled, patients may be eligible for various forms of support, but these discounts are typically not retroactive. It is important for patients to review the specific terms and conditions provided by Bristol Myers Squibb to understand the eligibility requirements and limitations of any discounts or assistance programs for Yervoy treatment [2]. The Drug Patent Watch website provides information on Yervoy as a biologic drug, but it does not specifically address the retroactive application of discounts [1]. The article from the National Center for Biotechnology Information discusses the clinical efficacy and safety of Yervoy in the treatment of advanced melanoma but does not mention anything about discounts or their retroactive application [3].

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/YERVOY
[2] https://www.bmsaccesssupport.com/assets/commercial/us/bmsaccesssupport/en/pdf/IVs-Terms-and-Conditions.pdf
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10242360/