2056 - IMpassion130: Results from a global, randomised, double-blind, phase 3 study of atezolizumab (atezo) + nab-paclitaxel (nab-P) vs placebo + nab-P in treatment-naive, locally advanced or metastatic triple-negative breast cancer (mTNBC)

Background

mTNBC is the breast cancer subtype with worst prognosis and is typically treated with chemo. Atezo (anti–PD-L1) combined with nab-P (A+nab-P) demonstrated safety and clinical activity in mTNBC (Pohlmann AACR 2018). Here we report final PFS and initial interim OS results from IMpassion130, a ph 3, double-blind, randomised study evaluating 1L A+nab-P in mTNBC

Methods

Eligible patients (pts) with histologically documented mTNBC, ECOG PS 0-1 and tumour tissue for PD-L1 testing were randomised 1:1 to IV atezo 840 mg or placebo (P) on d1 and 15 (q2w) + nab-P 100 mg/m² on d1, 8 and 15 of a 28-d cycle until progression. Stratification factors were prior taxanes, liver mets and tumour PD-L1 status on immune cells (positive: ≥1%). Co-primary endpoints (EPs) were PFS (ITT and PD-L1+ pts) and OS (ITT and, if significant, PD-L1+ pts). Key secondary EPs were ORR and DOR.

Results

At data cutoff 17 Apr 2018, median follow-up was 12.9 mo. In the A+nab-P and P+nab-P arms, respectively (n = 451 each), median age was 55 and 56 y; 57% and 60% had ECOG PS 0 and 63% each had prior (neo)adjuvant treatment. Efficacy data are in the Table. All-cause AEs occurred in 99% (G3-4, 49%) and 98% (G3-4, 42%) of evaluable pts in the A+nab-P and P+nab-P arms (n = 452, 438), respectively. Nausea, cough, neutropenia, pyrexia and hypothyroidism were ≥5% higher with A+nab-P. 3/6 G5 AEs in A+nab-P and 1/3 in P+nab-P pts were related to either atezo, P or nab-P. G3-4 AEs of special interest occurred in 8% of A+nab-P and 4% of P+nab-P pts.

Conclusions

IMpassion130 met its co-primary PFS EP in ITT and PD-L1+ pts, with clinically meaningful OS benefit seen at interim OS analysis in PD-L1+ pts. A+nab-P was well tolerated, with a safety profile consistent with each agent. This first positive ph 3 mTNBC immunotherapy study highlights A+nab-P as a new therapy for untreated PD-L1+ pts.

Clinical trial identification

NCT02425891

Editorial Acknowledgement

Medical writing support provided by Ashley J. Pratt, PhD, CMPP, of Health Interactions.