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A new breast cancer clinical trial looks at a de-escalated treatment option for patients with early stage triple negative breast cancer.

MAC29 OptimICE-pCR: De-escalation of Therapy in Early-Stage TNBC Patients who Achieve pCR after Neoadjuvant Chemotherapy with Checkpoint Inhibitor Therapy

The international study CCTG MAC29 (OptimICE-pCR) is investigating whether treatment with immunotherapy versus observation in people with early-stage triple-negative breast cancer (TNBC) who had a good response after initial treatment with chemotherapy and immunotherapy is really necessary.

The investigators want to determine if observation after surgery is as effective as completing 6 more months of immunotherapy in TNBC patients who have completed standard treatment including immunotherapy before surgery, and who have had a good response.

“This is an important trial which we will be conducting with our US colleagues as part of the National Cancer Trials Network. This trial has the potential to change the management of patients with early stage TNBC with less therapy, fewer side effects, less financial cost to patients and better quality of life, without compromising outcomes,” says Dr. Lois Shepherd, CCTG Senior Investigator.

The usual approach for early-stage triple-negative breast cancer patients is to continue to receive immunotherapy after surgery. If the study shows that observation after surgery is just as effective, future patients may be able to avoid the additional weeks of treatment and its associated side effects.

“This study provides an opportunity for this patient group to have a conversation with their oncology team about de-escalating treatments by way of observation or continuing with additional immunotherapy. In both cases, patients will be followed by the study team regularly,” says Michelle Audoin, a breast cancer survivor and CCTG patient representative. “Trial participants will help oncologists better understand how to treat and monitor early stage TNBC patients.”

This trial may help researchers determine if observation will result in the same risk of cancer coming back as pembrolizumab after surgery in in this patient population who achieve pathologic complete response after preoperative chemotherapy with pembrolizumab.

•    For more information, please visit the MAC29 patient information page 
•    For trial specific information please visit the CCTG MAC29 members page


Dr. Stephen Chia Breast Committee Co-Chair
Dr. Stephen Chia
MAC29 Study Chair
Lois Sheherd CCTG Senior Investigator
Dr. Lois Shepherd CCTG Senior Investigator
Patient Representative Michelle Audoin
Michelle Audoin CCTG Patient Representative