Cost-utility analysis of adjuvant trastuzumab therapy for HER2-positive early-stage breast cancer in the Philippines

BACKGROUND: Breast cancer is the leading malignancy among Filipino women, with about 23.50% of cases characterized by human epidermal growth factor receptor-2 (HER2) overexpression. Trastuzumab, in addition to standard chemotherapy, is currently recommended as primary treatment for HER2-positive early-stage breast cancer (EBC) in the adjuvant settings, and has been listed in the Philippine National Formulary (PNF) since 2008, but with no current evidence yet on its value for money, to date. Hence, despite several policy enablers, its accessibility remains to be limited in the Philippines. We performed an economic evaluation to assess the cost-effectiveness and budget impact of adjuvant trastuzumab therapy for HER2-positive EBC in the Philippines, using healthcare system and societal perspectives, in aid of guiding coverage decisions. METHODS: A Markov model-based cost-utility and budget impact analyses were conducted to estimate the total costs incurred and outcomes gained in using 1 year of adjuvant trastuzumab added to standard chemotherapy versus standard chemotherapy alone, over a lifetime horizon. We discounted both costs and outcomes at 3.5% per annum. Parameters were estimated using country survival data, systematic review and meta-analysis of the relative treatment effect, local and international cost data, and published utility data. Univariate and probabilistic sensitivity analyses were used to account for parameter uncertainty. RESULTS: Trastuzumab therapy was dominated with an incremental cost-effectiveness ratio (ICER) at PHP 453,505 per QALY gained from a healthcare system perspective or PHP 458,686 per QALY gained from a societal perspective, with 10% cost-effectiveness probability at the country cost-effectiveness threshold of PHP 120,000 per QALY gained. National implementation will cost an additional amount of PHP 13,909 million in year one alone, plus about PHP 2000 to 3000 million annually for the succeeding fiscal years. CONCLUSION: At its current cost, 1 year of adjuvant trastuzumab therapy compared to standard chemotherapy alone for HER2-positive EBC does not represent value for money in the Philippines. Its current cost will have to significantly lower down by one-half to achieve cost-effectiveness.