Postsurgery Immunotherapy Doesn’t Improve Survival in Breast Cancer
Adding atezolizumab immunotherapy to postsurgery chemotherapy doesn’t have the same benefits as the pre-surgery regimen
MILAN, ITALY — Patients with triple-negative breast cancer do not benefit from the addition of atezolizumab to their postsurgery chemotherapy treatment, according to the results of a large Phase 3 clinical trial. Triple-negative breast cancer—so-called because the cancer cells are not fuelled by estrogen, progesterone, or the HER2 protein—is harder to treat and more likely to spread to other parts of the body.
Previous research has suggested that adding an immunotherapy treatment to chemotherapy before surgery can improve survival for this group of patients. The new results show that including atezolizumab (a type of immunotherapy) with chemotherapy after surgery does not bring the same benefits.
Effect of atezolizumab therapy on triple-negative breast cancer
The ALEXANDRA/IMpassion030 study is a Phase 3 clinical trial that included 2,199 people from 31 different countries with stage two or three triple-negative breast cancer. Following resection, half of the patients were randomly assigned to be treated with chemotherapy plus atezolizumab, with the other half treated with chemotherapy.
Heather McArthur, MD, MPH, an 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 in Dallas, Texas, USA, said, “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.”
Patients have been monitored for an average of 32 months. Researchers found no improvement for patients treated with atezolizumab after surgery compared to those not treated with atezolizumab in terms of survival and remaining free of cancer. Among the patients taking atezolizumab, 141 (12.8 percent) had a recurrence or died. Among patients not taking atezolizumab, 125 (11.4 percent) had a recurrence or died. This equates to a hazard ratio of 1.11 for patients taking atezolizumab.
Researchers also found no benefit when looking at different sub-groups, such as patients whose cancer has spread to the lymph nodes and patients with PD-L1 positive cancer, which is used as a marker of cancers that are more likely to respond to immunotherapy.
Findings of the Phase 3 clinical trial
McArthur said, “This is a large international clinical trial looking at treatment for patients with triple-negative breast cancer. The results of this final analysis are important because they show that including the immunotherapy drug atezolizumab alongside chemotherapy does not help when 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, per the current standard of care.”
The final analysis also showed that the safety of atezolizumab, in terms of unwanted side effects, was consistent with other trials of the treatment. Among the patients treated with atezolizumab and chemotherapy, 54.3 percent experienced serious side effects. Among those treated with chemotherapy alone, 44.1 percent experienced serious side effects.
Fiorita Poulakaki, MD, PhD, FEBS, CEBS, head of the Breast Surgery Department at Athens Medical Center Hospital, Greece, and vice president of Europa Donna, the European Breast Cancer Coalition, who was not involved with the research said, “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 clinicians and medical oncologists who treat patients with this aggressive type of cancer.”
- This press release is supported by the European Organisation for Research and Treatment of Cancer