Subgroup analysis of IMpassion130: Atezolizumab + nab-paclitaxel (nab-P) in patients (pts) with advanced triple-negative breast cancer (TNBC) in Asian countries

Abstract

Background: The global ph III IMpassion130 study (NCT02425891) in 1LmTNBC showed that PFS with atezolizumab (A) + nab‐P (A+nab‐P) was significantly better than with placebo (P) + nab‐P in ITT and PD‐L1IC+ pts; clinically meaningful OS improvement was also seeninPD‐L1 IC+ pts (Schmid et al. NEJM 2018, ASCO 2019). As region‐specific differences have been reported for efficacy and toxicity of other therapies, we report outcomes for A+nab‐P in IMpassion130 pts enrolled in Hong Kong, Japan, Singapore, South Korea, Taiwan, Thailand. Methods: Eligible pts with histologically documented advanced TNBC, ECOG PS 0‐1 and tumour tissue for PD‐L1 testing were randomised 1:1 to IV atezolizumab 840 mg or placebo ond1 and 15 (q2w) + nab‐P 100mg/m2on d1, 8 and 15 of a28‐d cycle until progression. Stratification factors were prior taxanes, liver mets and PD‐L1 expression on tumour‐infiltrating immune cells (IC, positive: >1%). Co‐primary endpoints (EPs) were PFS (ITT andPD‐L1+ pts) and OS (ITT and, if significant, PD‐L1+ pts). Key secondary EPs were ORR and DOR. Results: As of 2 Jan 2019, median follow‐up was 20.0 mo in 145 pts in Asian countries. In the A+nab‐P (n = 79) and P+nab‐P (n = 66) arms, respectively, 42% and 33% had prior (neo)adjuvanttaxane treatment (tx),29% and 17% had liver mets, and 43% and 35% werePD‐L1 IC+. Efficacy data are in the table. As of 3 Sep 2018, all‐cause, any‐grade AEs occurred in 100% (G3‐4, 44% and 39%) of safety‐evaluable pts in the A+nab‐P and P+nabP arms (n = 78,65), respectively. Serious tx‐related AEs occurred in 8% of A+nab‐P and 6% of P+nab‐P pts. G3‐4 AEs of special interest occurred in 5% of A+nab‐P and P+nab‐P pts. Conclusions: In this post‐hoc analysis, the efficacy of A+nab‐P in IMpassion130 pts in Asian countries was consistent with the previously reported global ITT and PD‐L1IC+ pts. No new safety signals were observed, and tolerability was consistent with that of the overall population.