Q-TWiST Analysis to Assess Benefit-Risk of Sacituzumab Govitecan in Previously Treated Patients With Metastatic Triple-Negative Breast Cancer.

Abstract

In ASCENT, sacituzumab govitecan (SG) showed significantly longer overall survival and progression-free survival than chemotherapy of physician's choice with similar rates of treatment-emergent adverse events (TEAEs) in previously treated patients with metastatic triple-negative breast cancer (mTNBC). We assessed the benefit-risk of SG versus chemotherapy by integrating patient preferences (health utilities) with clinical benefits in this analysis. Quality-adjusted Time Without Symptoms of disease progression or Toxicity of treatment (Q-TWiST) methodology was used to compare treatments where survival was partitioned into three health states using the intention-to-treat ASCENT population: (1) toxicity (grade ≥3 TEAE after random assignment and before disease progression), (2) TWiST (progression-free period without grade ≥3 TEAE), and (3) relapse (disease progression until death or end of follow-up, whichever came first). Health state utilities were derived from published literature. Q-TWiST was calculated as utility-weighted sum of mean health state durations. The established threshold for relative Q-TWiST improvement considered clinically important is 10% and clearly clinically important is 15%. SG had significantly longer Q-TWiST (8.3 months; 95% CI, 7.6 to 9.1 months) than chemotherapy (4.8 months; 95% CI, 4.3 to 5.4 months) in patients with mTNBC, a difference of 3.5 months (95% CI, 2.6 to 4.4 months; <i>P</i> < .0001). Relative Q-TWiST improvement with SG was 39.5%, exceeding the clearly clinically important threshold. Q-TWiST benefits of SG over chemotherapy increased over the available 31-month follow-up. Restricted mean time with toxicity was numerically higher with SG versus chemotherapy; this difference stabilized with longer follow-up. The Q-TWiST analysis supports a positive benefit-risk ratio for SG versus chemotherapy in patients with previously treated mTNBC. Net benefits of SG continued to accrue over time.