OBJECTIVES: Combination therapies are an essential driver of drug spending. To contain the financial impact on the statutory health insurance (SHI) in Germany, the SHI Financial Stabilization Act (GKV-Finanzstabilisierungsgesetz – GKV-FinStG) introduced a 20% lump-sum discount on reimbursed drug combinations in October 2022. However, it remains unclear how drug combinations will be identified for billing purposes and how they will be distinguished from monotherapies and therapy sequences. We investigate the impact of different approaches to identifying drug combinations based on 2017 to 2021 claims data of large German SHI funds.

METHODS: As examples, we consider approved (two-)drug combinations for treating melanoma, renal cell carcinoma, and multiple myeloma. Drug combinations are classified as highly certain (same day + 1/same hospital stay), less certain (up to 30 days), and uncertain (>30 days) depending on the timespan between the dispenses of two or more considered prescriptions.

RESULTS: The influence of the chosen identification approach varies significantly between indications. For melanoma, 85% of all consecutive dispenses of combination partners can be identified as combination therapy with a high degree of certainty. In contrast, for multiple myeloma, the identification of drug combinations is associated with considerable uncertainty (identification rate with high certainty: 55%). Accepting a timespan of up to 30 days, four out of five consecutive dispenses across all investigated indications are identified as a combination. In 2021, potential savings from the lump-sum combination discount would have ranged from €38.5 million to €55.2 million across all indications, depending on the identification approach chosen.

CONCLUSIONS: The analyses show that implementing the lump-sum combination discount is subject to significant uncertainties. However, they also show that a pragmatic definition of combination therapy (e.g., as "parallel" administration of two agents to a patient within 30 days) could reasonably compromise uncertainty and implementation costs.