Adding nivolumab to neoadjuvant chemo improves response rate for high risk ER+ HER2− breast cancer

Prof Sherene Loi - Peter MacCallum Cancer Centre, Melbourne, Australia

I presented the CheckMate 7FL study. This was a randomised prospective multicentre phase III study investigating the benefit of nivolumab, which is a PD-1 inhibitor, in combination with neoadjuvant chemotherapy followed by adjuvant endocrine therapy in patients with newly diagnosed oestrogen receptor positive HER2 negative breast cancer.

In this study patients needed to be classified as high risk. So we defined that as clinically node positive or large T3/T4 tumours and they had to be grade 3 as determined by their local pathologist. These patients were randomised to receive nivolumab or placebo in combination with four cycles of weekly paclitaxel followed by four cycles of AC followed by surgery. Then they went on to have adjuvant endocrine therapy with nivolumab or placebo for completion of one year.

This trial recruited 521 patients. It had to be cut short from the original 1,000 patients because of the approval of adjuvant abemaciclib. You can’t combine adjuvant abemaciclib with adjuvant nivolumab. So originally we were going to look at pCR as well as long-term event free survival but the study was cut short to just look at pCR because of this issue.

The results were in the overall population that the addition of nivolumab increased the pCR rate by around 10%. This is a really good outcome because we haven’t seen anything increase the pCR rate in this group of breast cancer patients, which is the commonest risk type cancer patient. In patients that were designated as PD-L1 positive by SP142, a specific assay, their pCR rate was increased dramatically by over 20%, from 20% to 44%. So this is a massive increase in pCR rate and I think it’s going to be clinically significant for these patients but we need to follow them long term to see if this increase in pCR rate translates to event free survival.