Chicago, Illinois—Findings from a 2nd interim analysis to be presented at the 2019 ASCO Annual Meeting confirm the clinically meaningful overall survival (OS) benefit of using atezolizumab plus nab-paclitaxel in treatment-naïve patients with PD-L1–positive, metastatic triple-negative breast cancer (mTNBC).

In the IMpassion130 clinical trial, Peter Schmid, MD, Clinical Director, Breast Cancer Centre, St. Bartholomew Cancer Centre and Honorary Consultant Medical Oncologist at Barts Hospital, United Kingdom, and colleagues assessed the use of atezolizumab plus nab-paclitaxel versus placebo plus nab-paclitaxel in patients with mTNBC.

Patients in the study were randomized in a 1:1 ratio to receive atezolizumab 840 mg or placebo on days 1 and 15 plus nab-paclitaxel 100 mg/m2 on days 1, 8, and 15 of each 28-day cycle until disease progression occurred.

The co-primary end points of the study were PFS (in ITT and PD-L1–positive patients) and OS (in ITT and, if significant, PD-L1–positive patients).

During the first interim analysis, the primary progression-free survival (PFS) was found to be significantly improved with atezolizumab plus nab-paclitaxel in the intent-to-treat (ITT) population and PD-L1–positive patients compared with placebo plus nab-paclitaxel.

Findings from the 2nd interim OS analysis of IMpassion130 will be reported at ASCO 2019.

As of January 2, 2019, which was the point of data cutoff, 9% and 3% of patients in the atezolizumab plus nab-paclitaxel and placebo plus nab-paclitaxel arms were still receiving therapy.

Although statistical significance was not observed in ITT patients, Dr Schmid and his co-investigators reported a 7-month improvement in median OS in PD-L1–positive patients atezolizumab plus nab-paclitaxel versus placebo plus nab-paclitaxel (25 months vs 18 months; hazard ratio, 0.71; 95% CI, 0.54-0.93).

According to a 4.5-month safety update, atezolizumab plus nab-paclitaxel remained tolerable.

“The 2nd IMpassion130 interim OS analysis was consistent with the 1st analysis, confirming clinically meaningful OS benefit with atezo + nP [atezolizumab plus nab-paclitaxel] in previously untreated PD-L1+ mTNBC,” Dr Schmid et al concluded.—Hina Khaliq

Schmid P, Adams S, Rugo HS, et al. IMpassion130: updated overall survival (OS) from a global, randomized, double-blind, placebo-controlled, Phase III study of atezolizumab (atezo) + nab-paclitaxel (nP) in previously untreated locally advanced or metastatic triple-negative breast cancer (mTNBC). Presented at: the 2019 ASCO Annual Meeting; May 31-June 4, 2019; Chicago, IL. Abstract 1003.