A Survey on Japanese Drug Pricing and Treatment Costs of Cancer Chemotherapy Drugs: The Case of Monoclonal Antibodies

OBJECTIVES: Under the NHI drug pricing rules, prices of cancer chemotherapy drugs vary greatly depending on approved indications and drug price revisions. Therefore, drug treatment costs may differ significantly even among drugs with similar clinical efficacy. To compare the drug treatment costs of bevacizumab and ramucirumab, monoclonal antibody agents indicated for metastatic colorectal cancer.

METHODS: Using publicly available data from the Japanese health agencies (Chuikyo and PMDA), we investigated methods of pricing newly listed drugs, histories of indication expansions, and drug price revisions. The drug costs of metastatic colorectal cancer were also calculated using the latest NHI drug prices.

RESULTS: Bevacizumab was calculated as a drug for the treatment of metastatic colorectal cancer in 2007 using the cost accounting method (400 mg 191299 yen). On the other hand, the drug price of ramucirumab was calculated in 2015 as a drug for the treatment of metastatic gastric cancer under the comparable drug method I with bevacizumab as the comparator drug, and the drug price was further increased with a foreign price adjustment (500 mg, 355450 yen). Furthermore, the price of bevacizumab was significantly reduced to 107607 yen in 2024 (a 44% decrease) due to repricing twice for market expansions and the launch of biosimilars. Therefore, the cost of bevacizumab for an adult weighing 60 kg every two weeks was 86,130 yen versus 362,032 yen for ramucirumab, a difference of approximately 4.2 times.

CONCLUSIONS: Even for drugs with no clear difference in indication or therapeutic effect, drug price calculation rules may result in large price differences. Especially for cancer chemotherapy drugs, the difference is too large to be ignored because of their high price. When considering treatment regimens, after understanding the reasons for drug price differences, cost-effectiveness should also be considered from the perspectives of individual patients and society.