The addition of dual immunotherapy treatment to standard chemotherapy has shown promising results in patients with treatment resistant, early-stage triple negative breast cancer.

Primary results of the CHARIOT clinical trial have been presented at the American Society of Clinical Oncology (ASCO) international conference. This was a world-first Australian clinical trial developed by Breast Cancer Trials (BCT) researchers that was open to both women and men diagnosed with triple negative early breast cancer. The trial recruited 34 patients at eight participating institutions throughout Australia.

Triple negative breast cancer is the breast cancer subtype with the poorest prognosis; it is more likely to spread beyond the affected breast. Patients whose cancer shrinks and disappears, with no evidence of cancer in their breast or lymph nodes (based on pathology), after receiving chemotherapy prior to breast surgery (neoadjuvant chemotherapy) have the greatest chance of long-term survival. However, those patients who have evidence of residual cancer in the breast after neoadjuvant chemotherapy have a high chance of relapse and death from breast cancer within three years.

The purpose of the CHARIOT clinical trial was to see if using two immunotherapy drugs (nivolumab and ipilimumab) together with standard chemotherapy (paclitaxel) before surgery, was safe and effective and could stimulate the body’s immune system to kill the cancer cells. And, if continuing treatment with one of these drugs (nivolumab) after surgery can keep the immune system active to eradicate any residual cancer cells.

The trial found that in patients with early-stage triple negative breast cancer who did not respond to standard neoadjuvant chemotherapy, the addition of nivolumab and ipilimumab resulted in a promising response rate with 24% of participants achieving a complete disappearance of their cancer within the breast and lymph nodes by the time of surgery. This treatment was able to be delivered safely, with some patients experiencing known and expected side effects of immunotherapy. These side effects were able to be successfully treated.

Professor Sherene Loi is the Study Chair of the CHARIOT clinical trial, Board Director at BCT and Head of the Translational Breast Cancer Genomics and Therapeutics Laboratory at the Peter MacCallum Cancer Centre. She says longer term follow up is needed to help determine the overall effectiveness of this treatment approach and the benefits to patients.

“CHARIOT was a phase II clinical trial that aimed to examine the safety and efficacy of dual immunotherapy in these high-risk patients, where standard chemotherapy has not been effective in reducing their tumour,” Professor Loi said.

“While we have seen some promising results in the pathological response rate of this treatment, the survival benefits of adding ipilimumab to treatment is currently unclear. So the study will now continue the future follow-up of patients to determine event free survival (EFS) and overall survival (OS).”

Founded in 1978, Breast Cancer Trials conducts a multicentre national and international clinical trials research program, for the treatment and prevention of breast cancer. Supported by the generosity of donors and other funding bodies, the research program involves 835 researchers in 109 institutions across Australia and New Zealand.

For more information about Breast Cancer Trials, visit www.breastcancertrials.org.au.

Contact: BCT Communications Manager, Anna Fitzgerald – 0400 304 224 or anna.fitzgerald@bctrials.org.au

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