OBJECTIVES: For orphan drugs an additional benefit is granted by market authorization of the European Medicines Agency.[1] Although an additional benefit is granted companies have to demonstrate the extent of additional benefit as basis for subsequent reimbursement price negotiations by submitting a simplified dossier to the Federal Joint Committee (Gemeinsamer Bundesausschuss).[2] The objective of this analysis was to assess whether the additional benefit extent of orphan drugs does impact rebate size of price negotiations. The hypothesis indicated an inversely proportional association between additional benefit extend and negotiated rebate size. METHODS: In a first step the orphan drug market was analyzed and substances affected by an assessment of additional benefit extent were identified within the German healthcare market. Association between additional benefit extent and rebate size of negotiations was analyzed by Spearman correlation. Data were collected from public available information of the Federal Joint Committee as well as price information from the German pharmacy pricing data base LAUER-TAXE.[3] In a second step of the analysis a survey was conducted and market access experts of orphan drug manufacturers were interviewed. RESULTS: By February 2016, 84 orphan drugs with orphan drug designation were identified in the European Union. 19 were distributed in the outpatient German healthcare market and underwent additional benefit extent assessment and price negotiations. Association between additional benefit extent and rebate size could only be identified if the category “not quantifiable additional benefit” was excluded. CONCLUSIONS: There is only limited association between the extent of additional benefit and rebate size for orphan drugs. This is caused by a large rebate range for orphan drugs for which the additional benefit extend was not quantifiable.