Health care policies, drug costs, and time toxicities in biologics for HER2-positive breast cancer: cost minimization analysis of direct and indirect costs.

Background: Trastuzumab and pertuzumab, available as subcutaneous (s.c.) or intravenous (i.v.), are established treatments in human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Subcutaneous formulations are costlier but offer benefits such as reduced administration time, patient convenience, and decreased reliance on hospital resources. Policy changes in Singapore in September 2022 may have increased out-of-pocket cost for s.c. formulations. Materials and methods: This study examines the utilization trends and cost impact of s.c. versus i.v. HER2 therapies from the individual, health care, and societal perspectives. A retrospective cohort study at a tertiary cancer institute analysed drug utilization trends before and after policy changes. Cost minimization analysis compared i.v. and s.c. formulations. Results: From March 2022 to October 2023, a total of 3642 doses of trastuzumab and pertuzumab were administered. The utilization of s.c. pertuzumab/trastuzumab/hyaluronidase rose from 0 to 87 doses/month, with a consequent decline in the usage of i.v. pertuzumab/trastuzumab. Utilization of i.v. trastuzumab biosimilar remained steady. Although estimated direct costs of s.c. dual HER2 blockade is 11% more than i.v. pertuzumab/trastuzumab biosimilar, incorporation of indirect costs including patient time and cost savings with s.c. infusions in the community settings demonstrated s.c. dual HER2 blockade to be 5.5% cheaper than i.v. pertuzumab/trastuzumab biosimilar. Conclusion: Dual HER2 therapy use remains high in Singapore, reflecting the priority of treatment efficacy. Indirect cost savings may offset the higher direct costs. Reducing time toxicity and extending care to the community is pivotal to cancer patients with constrained timeframes. These findings provide valuable insights for decision making in health care policy and negotiations with drug companies to ensure s.c. formulations are affordable.