https://www.selleckchem.com/products/FTY720.html Results The search strategy identified 278 studies, with 31 included in the final review after inclusion and exclusion criteria were applied. Retrospective cohorts (77%) and cross-sectional analyses (16%) were most frequently encountered. Sum Diagnosis Specific was the most common costing method (39%), followed by Regression (32%). Of the 31 studies analyzed, 35% included costs that would be included in a societal model. Costs were identified for various stages and complications related to HCV disease progression. Several studies included were determined to have a high (48%) or moderate risk (42%) of bias related to COI estimates. Conclusion Cost estimates for formal, informal, and non-health care services were identified in this review, but several challenges still exist in fully quantifying HCV burden. Future modeling studies including cost inputs should critically evaluate the risk of bias based on costing methods and data sources.Objectives The Orphan Drug Act extends exclusivity of branded drugs by 7 years for each rare disease approval. By extending market exclusivity, manufacturers can forestall generic competition. We determined the prevalence of drugs with multiple orphan approvals, the duration for which manufacturers are able to maintain exclusivity using this mechanism, and the budget impact of these additional exclusivity periods on US spending on orphan drugs. Methods We analyzed a retrospective cohort of US orphan drug approvals filed between 1983 and 2017. Drug costs throughout this time period were measured using IQVIA claims data. We estimated additional years of exclusivity per drug per orphan approval using mixed-effects negative binomial regression. The budget impact analyzed potential cost-savings for exclusivity periods greater than 7 years after the initial orphan approval based on potential price reductions from the introduction of biosimilar/generic competition. Results A total of 432 branded