Treatment Boosts Cure Rate for Most Common Form of Breast Cancer in Trial

A Peter Mac-led international clinical trial has shown adding an immunotherapy drug to the chemotherapy that patients receive ahead of surgery can dramatically improve breast cancer cure rates.

The Phase III CheckMate-7FL trial involved 510 people with the “ER+/HER2-” sub-type which accounts for around 70% of all breast cancers. These patients receive chemotherapy to shrink their tumour making it easier to surgically remove.

This trial assessed adding an infusion of the drug nivolumab – or a placebo – to the pre-surgery phase and then assessing how patients respond overall, and the practise changing results have just published in Nature Medicine.

Professor Sherene Loi, who led the trial, said adding nivolumab led to around a doubling in the number of patients who achieved the best possible outcome known as a pathological complete response (pCR).

“These patients are considered to be likely cured because their tumour was removed and samples of breast and lymph node tissue collected at the same time also show no detectable cancer cells,” explains Prof Loi.

“The number of patients who achieved this pCR improved significantly as a result of nivolumab, an exciting result that points to a new treatment paradigm in this most common type of breast cancer.”

Overall, pCR rates were 25% in the trial participants treated with nivolumab versus 14% in the placebo group.

In a sub-group of who patients with tumours that had the “PD-L1” biomarker – indicating heightened responsiveness to nivolumab - the pCR rate was 44% in the nivolumab group compared to 20% who received the placebo.

PD L1 is a protein known to reduce an immune cell’s anti-cancer activity, and nivolumab works by blocking the receptor where PD L1 could bind to an immune cell so preserving its anti-cancer activity.

There were no new safety signals identified in the trial however there were five deaths in the nivolumab treatment aim – and two were related to nivolumab toxicity. There were no deaths in the placebo arm.

ER+/HER2− breast cancer accounts for 70% of the around 2.3 million cases of breast cancer diagnosed worldwide in 2020.

Prof Loi adds while these patients generally have better outcomes than other types of breast cancer, this can vary and there is a more aggressive type of ER+/HER2- breast cancer in young women that is more likely to recur.

“It seems that these may be the most responsive to immunotherapy and chemotherapy,” she also says.

Reference: Loi S, Salgado R, Curigliano G, et al. Neoadjuvant nivolumab and chemotherapy in early estrogen receptor-positive breast cancer: a randomized phase 3 trial. Nat Med. 2025. doi: 10.1038/s41591-024-03414-8

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