Highest benefit of neoadjuvant nivolumab in breast tumours with high PD-L1 expression and/or low ER expression

The benefit of neoadjuvant nivolumab is highest in patients with high PD-L1 expression and low oestrogen receptor (ER) expression, according to the results of an exploratory biomarker analysis of CheckMate 7FL.

Recently, results from the phase 3 CheckMate 7FL trial (NCT04109066) showed the benefit of the addition of nivolumab to neoadjuvant chemotherapy and adjuvant endocrine therapy in patients with newly diagnosed high-risk, high-grade ER-positive/HER2-negative primary breast cancer [1]. In the overall population, pathological complete response (pCR) rates with nivolumab were significantly improved compared with controls (24.5% vs 13.8%; OR 2.05; 95% CI 1.29–3.27; P=0.0021). The benefit of nivolumab was greater in the PD-L1-positive population (combined positive score [CPS] ≥1%).

Dr Sherene Loi (Peter MacCallum Cancer Centre, Australia) presented the results of an exploratory biomarker analysis of CheckMate 7FL [2]. “The aim of this biomarker study was to further define the patients who had greater magnitude of benefit with the addition of nivolumab to neoadjuvant chemotherapy in the CheckMate 7FL trial,” explained Dr Loi.

With respect to PD-L1 expression, the pCR rate benefit of nivolumab was greater with increased CPS scores. The between-group difference in pCR increased from 5.7% in patients with CPS <1 to 52.3% in patients with CPS ≥20. In addition, a greater benefit of nivolumab was observed in patients with tumours containing >5% stromal tumour-infiltrating cells (TILs).

High expression of ER was negatively correlated with a pCR rate benefit of nivolumab: nivolumab benefit was the highest in patients with low (<50%) ER expression, Dr Loi showed. In addition, low expression of progesterone receptor (PR) was associated with a greater benefit of nivolumab. No association between nivolumab benefit and Ki67 proliferation index was observed.

“This exploratory analysis shows that the nivolumab benefit on pCR rates was the highest in patients with tumours with higher PD-L1 expression, stromal TILs ≥5%, and low expression of ER and PR,” concluded Dr Loi. Additional exploratory and correlative analyses are ongoing to further refine the patient subpopulation with primary ER-positive/HER2-negative breast cancer who could benefit from the addition of nivolumab to neoadjuvant chemotherapy.

1. Loi S, et al. Abstract LBA20, ESMO 2023, 20–24 October, Madrid, Spain.
2. Loi S, et al. Biomarker results in high-risk estrogen receptor‑positive, human epidermal growth factor receptor 2‑negative primary breast cancer following neoadjuvant chemotherapy ± nivolumab: an exploratory analysis of CheckMate 7FL. Abstract GS01-01, SABCS 2023, 5–9 December, San Antonio, TX, USA.

 

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Posted on 11 January, 202411 January, 2024