Cost-efficiency and expanded access modeling of conversion to biosimilar trastuzumab-dkst with or without pertuzumab in metastatic breast cancer

Abstract

Aims: To investigate the cost-efficiency and budget-neutral expanded access of biosimilar intravenous trastuzumab-dkst versus reference intravenous (trastuzumab-IV) and subcutaneous trastuzumab (trastuzumab-SC) (with/without pertuzumab) in metastatic breast cancer (MBC). Methods: Economic simulation modeling in a panel of 1,000 MBC patients to estimate: 1) cost-savings by conversion from trastuzumab-IV or trastuzumab-SC to trastuzumab-dkst at 10-100% conversion rates in 3 weight groups: first quartile (Q1:62.2 kg), median (73.1 kg), third quartile (Q3:88.6 kg), and 2) budget-neutral expanded access to trastuzumab-dkst from cost-savings. Results: In monotherapy, conversion (%) from trastuzumab-IV generates one-year cost-savings from $2,272,189 (Q1;10%) to $31,506,804 (Q3;100%) and from trastuzumab-SC monotherapy savings range from $2,071,277 (Q3;10%) to $35,775,475 (Q1;100%). In combination with pertuzumab, trastuzumab-dkst is cost-efficient in all patient weights with one-year savings over trastuzumab-IV up to $32,662,714 (Q3;100%) and over trastuzumab-SC up to $35,322,461 (Q1;100%). Savings from conversion from trastuzumab-IV monotherapy could provide between 3,087 (Q1;10%) and 30,911 (Q3;100%) additional trastuzumab-dkst doses—enough to treat 58 to 583 patients for one year. Conversion from trastuzumab-SC monotherapy could provide between 1,559 (Q3;10%) and 48,598 (Q1;100%) additional trastuzumab-dkst doses or 38 to 918 additional one-year treatments with trastuzumab-dkst. In combination with pertuzumab, conversion from trastuzumab-IV could provide from 311 (Q1;10%) to 3,939 (Q3;100%) maintenance doses (pertuzumab + trastuzumab-dkst) or 17 to 210 additional one-year regimens (all agents). Savings from conversion from trastuzumab-SC could expand access to 226 (Q3;10%) to 4,782 (Q1;100%) additional maintenance doses or 12 to 254 one-year regimens. Conclusions: This first cost-efficiency and expanded access study of biosimilar therapeutic cancer agents shows that trastuzumab-dkst is cost-efficient over trastuzumab-IV and trastuzumab-SC across all patient weights in both monotherapy and combination with pertuzumab and paclitaxel. These cost savings could provide more patients with trastuzumab-dkst treatment on a budget-neutral basis.