Immune Marker Identified as Prognostic in Triple-Negative Breast Cancer

A translational, exploratory analysis of the WSG-ADAPT-TN trial revealed that the immune marker programmed cell death protein 1 (PD1) may be prognostic for survival in patients with triple-negative breast cancer (TNBC) who achieve a pathologic complete response (pCR) after neoadjuvant therapy. The results were presented at the 2018 San Antonio Breast Cancer Symposium (SABCS) in Texas.¹  

In the WSG-ADAPT-TN trial, 336 patients with TNBC were randomly assigned to receive 12 weeks of either nab-paclitaxel plus gemcitabine or nab-paclitaxel plus carboplatin in the neoadjuvant setting. Standard chemotherapy was recommended after surgery in patients who did not achieve a pCR; patients who received a pCR had the option of adjuvant chemotherapy. The primary endpoint was pCR, which has already been reported. Secondary endpoints included translational analyses, which have not been reported until now.

The translational analysis included 306 patients. None of the predictive markers evaluated were predictive for event-free survival (EFS) benefit from carboplatin plus nab-paclitaxel as compared to gemcitabine plus nab-paclitaxel. 

PD1 status (as assessed by mRNA) when combined with pCR was prognostic for survival benefit. Patients who achieved a pCR and were PD1 high had longer EFS than patients who achieved a pCR and were PD1 low (P > .001).

The effect of adjuvant chemotherapy according to PD1 status in patients who achieved a pCR was also evaluated. Patients with a pCR who received adjuvant chemotherapy and had low PD1 expression had longer EFS than patients who did not receive adjuvant chemotherapy. In patients who had a pCR and high PD1 status, no difference in survival was seen between those who received adjuvant chemotherapy and those who did not. 

The study authors wrote that patients with both pCR and high immune signature, which is defined here by PD1, had “excellent” 3-year EFS and “may be candidates for treatment de-escalation,” whereas patients with both pCR and low immune signature “may benefit from standard adjuvant poly-chemotherapy.”

Read more of Cancer Therapy Advisor‘s coverage of the SABCS 2018 meeting by visiting the conference page.

Reference

1. Gluz O, Nitz U, Liedtke C, et al No survival benefit of chemotherapy escalation in patients with pCR and “high-immune” triple-negative early breast cancer in the neoadjuvant WSG-ADAPT-TN trial. Oral presentation at: 2018 San Antonio Breast Cancer Symposium; December 4-8, 2018; San Antonio, TX. Abstract GS5-06.