Treatment options were scarce for advanced or metastatic triple-negative breast cancer. Yet, the efficacy of combination therapy with atezolizumab and nab-paclitaxel was illustrated in patients with metastatic triple-negative breast cancer.1 Following the publication of findings in the New England Journal of Medicine, the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) approved atezolizumab combined with nab-paclitaxel for the frontline use in triple-negative subgroup of breast cancer patients.2-3
Triple-negative breast cancer is defined by the lack of expression of hormone receptors and human epidermal growth factor receptor type 2 (HER2). This type of breast cancer accounts for approximately 12-17% of diagnosed breast cancers.4 Compared to other non-triple-negative breast cancers, triple-negative breast cancer has a higher recurrence rate within the first three years after diagnosis.5
Limited treatment options are available for advanced or metastatic triple-negative breast cancer patients. Previously recommended initial treatment for advanced or metastatic triple-negative breast cancer by the European Society for Medical Oncology (ESMO) included anthracycline-taxane chemotherapy, which was followed by carboplatin or other platinum regimen.6 However, recent findings demonstrating the efficacy of atezolizumab, an antibody against programmed death-ligand 1 (PD-L1), plus nab-paclitaxel in metastatic triple-negative breast cancer patients may impact clinical management of the disease in the near future.1
The IMpassion130 was a phase 3, double-blind, randomized, placebo-controlled study.1 A total of 902 patients documented with triple-negative breast cancer were randomized 1:1 and administered either with atezolizumab plus nab-paclitaxel or placebo plus nab-paclitaxel until disease progression or an unacceptable level of toxic effects occurred.1 Primary end points of the study were progression-free survival (PFS) and overall survival (OS).1 Combination therapy with atezolizumab and nab-paclitaxel prolonged PFS of locally advanced or metastatic triple-negative breast cancer patients, while OS was not significantly different between both groups.1 Atezolizumab plus nab-paclitaxel group presented a prolonged median PFS of 7.2 months, as opposed to 5.5 months in the placebo plus nab-paclitaxel group (progression or death HR=0.80, 95% CI: 0.69-0.92, p=0.002).1 In the PD-L1-positive subgroup, a significantly lower risk of progression or death was observed with atezolizumab–nab-paclitaxel than with placebo–nab-paclitaxel (median PFS 7.5 months vs. 5.0 months, HR=0.62, 95% CI: 0.49-0.78, p<0.001).1
The safety profile of combination therapy with atezolizumab and nab-paclitaxel was consistent with clinical trial observations of other combination of atezolizumab plus chemotherapy, with no new adverse events reported.1 Although discontinuation rate of either agent was higher in the atezolizumab plus nab-paclitaxel group than the placebo plus nab-paclitaxel group, dose intensity of nab-paclitaxel was not compromised.1
Based on these results, the European Commission (EC) has approved the use of combination of atezolizumab with nab-paclitaxel in adult patients with PD-L1-positive (≥1%) metastatic or locally advanced triple-negative breast cancer who do not have prior exposure to chemotherapy for metastatic diseases.3
1. Schmid P, Adams S, Rugo HS, et al. Atezolizumab and nab-paclitaxel in advanced triple-negative breast cancer. N Engl J Med. 2018;379(22):2108-21.
2. FDA approves atezolizumab for PD-L1 positive unresectable locally advanced or metastatic triple-negative breast cancer. U.S. Food and Drug Adminstration. (Accessed September 12, 2019, at https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-atezolizumab-pd-l1-positive-unresectable-locally-advanced-or-metastatic-triple-negative)
3. CHMP post-authorisation summary of positive opinion for Tecentriq (X-17-II-22). European Medicines Agency. (Accessed September 12, 2019, at https://www.ema.europa.eu/en/documents/smop/chmp-post-authorisation-summary-positive-opinion-tecentriq-x-17-ii-22_en.pdf)
4. Foulkes WD, Smith IE, Reis-Filho JS. Triple-negative breast cancer. N Engl J Med. 2010;363(20):1938-48.
5. Dent R, Trudeau M, Pritchard KI, et al. Triple-negative breast cancer: clinical features and patterns of recurrence. Clin Cancer Res. 2007;13(15 Pt 1):4429-34.
6. Lebert JM, Lester R, Powell E, et al. Advances in the systemic treatment of triple-negative breast cancer. Curr Oncol. 2018;25(Suppl 1):S142-S150.