Atezolizumab and Nab-Paclitaxel Prolonged PFS in Metastatic Triple-Negative Breast Cancer

Atezolizumab plus nab-paclitaxel significantly prolonged progression-free survival (PFS) among patients with metastatic triple-negative breast cancer, with an even greater benefit observed for patients in the PD-L1–positive subgroup, according to preliminary results from the IMpassion130 trial that were presented at the 2018 ESMO Congress in Munich, Germany, and published online in The New England Journal of Medicine.^1,2

With a median follow-up of slightly more than 1 year, the median progression-free survival was 7.2 months with the combination compared with 5.5 months for placebo plus nab-paclitaxel in the intention-to-treat analysis (hazard ratio [HR] for progression or death = 0.80; P = .002). Patients with PD-L1–positive tumors assigned to atezolizumab plus nab-paclitaxel had a 2-month increase in PFS compared with placebo plus nab-paclitaxel (7.5 vs 5.0 months; HR = 0.62; P < .001).

“A benefit with atezolizumab–nab-paclitaxel in patients with PD-L1–positive tumors that was shown in our trial provides evidence of the efficacy of immunotherapy in at least a subset of patients,” the researchers wrote in NEJM. “It is important for patients’ PD-L1 expression status on tumor-infiltrating immune cells to be taken into consideration to inform treatment choices for patients with metastatic triple-negative breast cancer.”

Patients with untreated, metastatic triple-negative breast cancer were randomly assigned to receive atezolizumab plus nab-paclitaxel or placebo plus nab-paclitaxel. The 2 primary end points were PFS and overall survival (OS). PD-L1 positivity was defined as expression on tumor-infiltrating immune cells of 1% or greater.

At first interim analysis, in the intent-to-treat group, median OS was 21.3 months with the combination compared with 17.6 months for placebo plus nab-paclitaxel (HR = 0.84; P = .08). Among those with PD-L1–positive tumors, the median overall survival was 25.0 months compared with 15.5 months, respectively.

The safety of atezolizumab plus nab-paclitaxel was consistent with the known toxic effects of each agent.

Disclosure: This study was supported by F. Hoffman-La Roche/Genentech, a member of the Roche Group.

Read more of Cancer Therapy Advisor‘s coverage of the ESMO 2018 meeting by visiting the conference page.

References

1. Schmid P. Impassion130: Results from a global, randomized, double-blind phase 3 study of atezolizumab (atezo) = nab-paclitaxel (nab-P) vs placebo + nab-P in treatment-naïve, locally advanced or metastatic triple-negative breast cancer (mTNBC). Presented at: the ESMO 2018 Congress; Munich, Germany: October 20, 2018. Abstract LBA1_PR.
2. Schmid P, Adams S, Rugo HS, et al. Atezolizumab and nab-paclitaxel in advanced triple-negative breast cancer [published online October 20, 2018] N Engl J Med. doi: 10.1056/NEJMoa1809615