OBJECTIVES: The KEYNOTE-355 trial showed that programmed death receptor 1 (PD-1) inhibitor pembrolizumab, in the combined positive score (CPS) ≥10 population and combined with chemotherapy (nab-paclitaxel, paclitaxel or gemcitabine), improves survival over placebo + chemotherapy for previously untreated locally recurrent inoperable or metastatic TNBC. Based on those findings, pembrolizumab was approved in Colombia for that population. Likewise, atezolizumab plus nab-paclitaxel (A+NP), is another treatment option available for 1L metastatic TNBC. This study evaluated cost-effectiveness of pembrolizumab + nab-paclitaxel versus A+NP in CPS ≥10 population from a third payer perspective in Colombia.

METHODS:: A three-state cohort-based partitioned survival model projected costs and outcomes over 47 years with 3% annual discounting. Health state occupancy was modeled using KEYNOTE-355 Kaplan–Meier curves for progression-free survival (PFS) and overall survival (OS). Indirect comparator (A+NP) was compared with pembrolizumab + nab-paclitaxel through a network meta-analysis using data from Impassion130 trial. Costs for initial and subsequent treatments, disease and adverse events management, and terminal care were included using public drugs and procedures lists prices. Time-on-treatment (ToT) for pembrolizumab + nab-paclitaxel was taken from KEYNOTE-355. The model used A+NP PFS as proxy for its ToT and assumed atezolizumab treatment duration of 2 years (equal to pembrolizumab + nab-paclitaxel).

RESULTS: The analysis showed that pembrolizumab + nab-paclitaxel is dominant as compared to A+NP. With pembrolizumab combination therapy, patients accrued 0.846 additional life-years (LY) and 0.706 additional quality-adjusted life-years (QALYs), with reduced total costs of COP $2,022,278 over A+NP. The probability of being cost effective is 72.50% at willingness to pay threshold of COP $69,150,201.

CONCLUSIONS: The results of this study suggest that compared to atezolizumab + nab-paclitaxel, pembrolizumab + nab-paclitaxel is a cost-saving option in first line treatment of patients with locally recurrent inoperable or metastatic TNBC whose tumors expressed PD-L1 (CPS ≥10).