Quantitative medical cost-effectiveness analysis of molecular-targeting cancer drugs in Japan

In Japan, both incidence and mortality rates of cancers have continuously increased and medical costs are growing more rapidly than the overall economy of Japan. However, there is no consensus threshold for cost-effectiveness in medical care, and few studies have investigated cost-effectiveness of medical care in Japan. The present study was to determine the direct costs of molecular-targeting drugs that were recently approved in Japan through simple and quantitative calculations. Thus, we calculated an incremental cost-effectiveness ratio (ICER) and the cost per life-year gained (LYG) by using reported data from randomized clinical trials for various cancers.

Between 2008 and 2011, we reviewed seven molecular-targeting drugs that were approved for treatment of five cancers in Japan. These drugs included Bevacizumab, sorafenib, sunitinib, temsirolimus, Lapatinib, and panitumumab. Direct cost, ICER, and LYG of the drugs were estimated from the randomized phase III clinical trial data referred to in package leaflets. Effectiveness was defined as the prolongation of both median overall survival (OS) and progression-free survival (PFS). Costs were calculated as those of molecular-targeting drugs. Subsequently, ICER was based on 1-month increases in both OS and PFS periods and 1% increases in OS, and LYG was determined.

Direct costs ranged from ¥724,804 ($9,060) to ¥1,506,628 ($18,833). ICERs of the drugs ranged from ¥724,804 ($9,060) to ¥1,506,628 ($18,833) for a 1-month increase in OS. For each month of PFS, ICERs ranged from ¥372,243 ($4,653) to ¥7,399,877 ($92,498). The costs of Bevacizumab and sorafenib for treatment of HCC per 1% increase in OS were ¥376,657 ($4,708) and ¥313,733 ($3,922), respectively. LYG ranged from ¥8,697,650 ($108,721) to ¥18,079,530 ($225,994).

Some molecular-targeting drugs are not cost-effective. Considering ethical and moral issues, we should establish economic endpoints to approve new drugs in Japan.