Addition of Atezolizumab to Adjuvant Chemotherapy in Triple-Negative Breast Cancer

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The addition of atezolizumab to postsurgery chemotherapy may not benefit patients with triple-negative breast cancer, according to findings recently presented by McArthur et al at the 2024 European Breast Cancer Conference (EBCC; Abstract 1LBA).


Triple-negative breast cancer is often more challenging to treat and more likely to metastasize. Previous studies have suggested that adding immunotherapy to chemotherapy prior to surgery may improve survival in this patient population.

“We know from a previous trial that including the immunotherapy treatment atezolizumab with chemotherapy prior to surgery is beneficial for patients with triple-negative breast cancer. The ALEXANDRA/IMpassion030 trial is the first study to look at the role of chemotherapy with or without atezolizumab postsurgery for early-stage triple-negative breast cancer,” explained lead study author Heather McArthur, MD, Associate Professor in the Department of Internal Medicine and Clinical Director of the Breast Cancer Program at the Harold C. Simmons Comprehensive Cancer Center at UT Southwestern Medical Center.

Study Methods and Results

In a final analysis of the phase III ALEXANDRA/IMpassion030 trial, researchers examined the outcomes of 2,199 patients with stage II or III triple-negative breast cancer who resided in 31 different countries and were randomly assigned to receive postsurgical chemotherapy plus atezoliumab or chemotherapy alone.

After monitoring the patients for an average of 32 months, the researchers found no improvement in terms of disease-free survival among those treated with atezolizumab following surgery compared with those not treated with atezolizumab. They noted that 12.8% (n = 141) of the patients who received atezolizumab vs 11.4% (n = 125) of those who did not experienced recurrence or mortality—equating to a hazard ratio of 1.11 among the patients given atezolizumab and chemotherapy.

Further, the researchers found no benefit when assessing different subgroups, including patients whose cancer had spread to their lymph nodes and those with PD-L1–positive cancer—which is used as a marker of tumors that are more likely to respond to immunotherapy.

The researchers reported that regarding unwanted side effects, the safety of atezolizumab was consistent with other trials of the therapy. Compared with patients in the chemotherapy-alone group, those given atezolizumab and chemotherapy experienced a higher rate of serious side effects (54.3% vs 44.1%).


“The results of this final analysis are important because they show that including the immunotherapy drug atezolizumab alongside chemotherapy does not help when it’s given to patients following surgery. By extension, this also highlights the importance of treating triple-negative breast cancer with chemotherapy and immunotherapy prior to surgery, as per the current standard of care,” Dr. McArthur emphasized.

“We always hope that testing new treatment approaches will improve patients’ outcomes. However, it’s just as important to know when a new treatment added to one that is already in use is not beneficial, as in this case, to make sure patients aren’t subjected to a treatment that doesn’t work and may cause more side effects,” underscored Fiorita Poulakaki, MD, PhD, FEBS, CEBS, Head of the Department of Breast Surgery at Athens Medical Center Hospital, Greece; Vice President of Europa Donna–the European Breast Cancer Coalition; and Co-Chair of the 2024 EBCC, who was not involved in the research. “The results of this final analysis show that chemotherapy with atezolizumab after surgery does not improve disease-free survival for early-stage triple-negative breast cancer. This research therefore highlights the importance of the current approach of treating triple-negative breast cancer with chemotherapy and immunotherapy to shrink the tumor before surgery. This is vital information for surgeons and medical oncologists who treat patients with this aggressive type of cancer,” she concluded.

Disclosure: This trial was funded by Hoffmann–La Roche, Breast International Group, the Frontier Science & Technology Research Foundation, and Alliance Foundation Trials.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.