NCT06731140

Reverse HER2-negative Immune Resistant Breast Cancer

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 10 (estimated)
• Sponsor: Fudan University · Academic / Other
• Sex: Female
• Age: 18 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

This is a Phase II, open-label study evaluating the efficacy and safety of combined treatment (retinoic acid) with immune checkpoint inhibitor in HER2-negative breast cancer patients who progressed during previous immune checkpoint inhibitors.

Detailed description

This is a Phase II, open-label study evaluating the efficacy and safety of combined treatment (retinoic acid) with immune checkpoint inhibitors in metastatic HER2-negative breast cancer patients who progressed during or following previous immune checkpoint inhibitors. HER2-negative breast cancers include luminal breast cancers and triple-negative breast cancers. Current clinical studies on immunotherapy for luminal breast cancer are limited, with inconsistent results across trials. The KEYNOTE-028 study reported an objective response rate (ORR) of only 12% for pembrolizumab in PD-L1-positive, previously treated advanced luminal breast cancer patients, demonstrating limited efficacy. The GIADA phase II trial revealed a pathological complete response (pCR) rate of 16.3% with neoadjuvant chemotherapy followed by immunotherapy in luminal breast cancer. Additionally, trials such as NCT02779751 and NCT03051659 also indicated limited clinical benefits from immunotherapy. However, the I-SPY2 platform showed that combinations like olaparib, paclitaxel, and immunotherapy or wP-AC chemotherapy with immunotherapy could improve pCR rates in high-risk patients. Despite advancements, immunotherapy benefits are limited in luminal breast cancer compared to other cancers, with advanced-stage patients more likely to develop resistance. Recent clinical studies on advanced triple-negative breast cancer have shown that immunotherapy combined with chemotherapy demonstrates superior clinical efficacy compared to traditional chemotherapy alone. Phase III trials such as IMPassion130 and Keynote-522 have confirmed that PD-1/PD-L1 inhibitors used with chemotherapy significantly improve progression-free survival, overall survival, and pathological complete response rates. However, compared to other malignancies, triple-negative breast cancer patients still show relatively low overall response rates to immunotherapy: treatment-naïve patients achieve objective response rates of only 10-20% with immunotherapy monotherapy, though this improves to 56% when combined with chemotherapy, extending median progression-free survival to 7.2 months. Unfortunately, efficacy decreases significantly in later treatment lines, with objective response rates falling to just 10.6-15.9% after multiple previous treatments. Thus, strategies to overcome immunotherapy resistance or increase the sensitivity of immunotherapy efficacy are urgently needed for HER2-negative breast cancer patients. The preclinical results of our center show that retinoic acid can enhance the anti-tumor immune response by promoting the peroxidation of macrophages, increasing the infiltration and function of cytotoxic CD8+ T cells, inhibiting the growth of tumors in mice. Based on the preclinical study, the investigators designed this study to enroll metastatic HER2-negative breast cancer patients who have progressed during or following immunotherapy, and to explore the efficacy of retinoic acid combined with immunotherapy at a clinical level, providing new strategies of combined treatment for HER2-negative breast cancer patients.

Conditions

• HER2 Negative Breast Cancer

Interventions

Type	Name	Description
DRUG	Retinoic Acid	Retinoic acid 20mg tid, p.o.
DRUG	anti-PD-1 antibody and chemotherapy	PD-1 antibody SHR1210 200mg q2w chemotherapy (whether and which should be given depends on the treatment regimen before enrollment)

Timeline

• Start date: 2025-02-12
• Primary completion: 2026-10-01
• Completion: 2027-10-01
• First posted: 2024-12-12
• Last updated: 2025-11-17

Locations

1 site across 1 country: China