This study will evaluate whether adding QL1706 (iparomlimab and tuvonralimab) to neoadjuvant endocrine therapy improves tumor response in patients with hormone receptor-positive (HR-positive), human epidermal growth factor receptor 2-negative (HER2-negative) breast cancer who have had a poor response to neoadjuvant chemotherapy. Approximately 40 participants whose tumors have decreased by less than 40% on magnetic resonance imaging after two cycles of neoadjuvant TAC chemotherapy will be randomly assigned in a 1:1 ratio to receive either an aromatase inhibitor plus a CDK4/6 inhibitor or the same treatment combined with QL1706. Premenopausal and perimenopausal participants will also receive ovarian function suppression. The main outcome is the objective response rate during the study treatment period. Pathological response, changes in Ki-67, treatment safety, and changes in the tumor immune microenvironment will also be evaluated.
Patients with HR-positive/HER2-negative breast cancer may have an inadequate response to neoadjuvant chemotherapy, and an optimal subsequent neoadjuvant treatment strategy for this population has not been established. QL1706 is a bifunctional combination antibody consisting of iparomlimab, which targets programmed cell death protein 1 (PD-1), and tuvonralimab, which targets cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Simultaneous inhibition of these immune checkpoints may enhance antitumor immune activity. This study will explore whether the addition of QL1706 to endocrine therapy and CDK4/6 inhibition improves tumor response in patients who have had a poor early response to neoadjuvant chemotherapy. This is an exploratory, open-label, prospective, randomized controlled study. Approximately 40 women with stage IIB-IIIC HR-positive/HER2-negative early or locally advanced breast cancer will be enrolled. Eligible participants must have received two cycles of neoadjuvant TAC chemotherapy and have a reduction in tumor size of less than 40% on magnetic resonance imaging. Participants will be randomly assigned in a 1:1 ratio to the experimental arm or the active comparator arm. Participants in the active comparator arm will receive an aromatase inhibitor plus a CDK4/6 inhibitor. Participants in the experimental arm will receive the same treatment combined with QL1706 at 5 mg/kg by intravenous infusion on Day 1 of each 3-week cycle for six cycles. Premenopausal and perimenopausal participants will receive ovarian function suppression. Surgery will be performed after completion of neoadjuvant treatment based on clinical assessment. The primary outcome is the objective response rate according to Response Evaluation Criteria in Solid Tumors version 1.1. Secondary outcomes include breast pathological complete response, total pathological complete response, Miller-Payne grade, residual cancer burden class, changes in Ki-67 expression, and the incidence of immune-related and other adverse events. Exploratory analyses will assess changes in the tumor immune microenvironment, including immune-cell infiltration and the expression of PD-1, programmed death-ligand 1, and CTLA-4, using blood and tumor specimens collected at protocol-specified time points.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
40
Iparomlimab and tuvonralimab (QL1706) will be administered intravenously at 5 mg/kg on Day 1 of each 3-week cycle for six cycles.
Participants will receive exemestane, anastrozole, or letrozole. The specific aromatase inhibitor, dose, and administration schedule will be selected according to the applicable prescribing information or clinical guidelines and will be continued throughout the approximately 18-week neoadjuvant treatment period.
Participants will receive abemaciclib or ribociclib. The specific CDK4/6 inhibitor, dose, and administration schedule will be selected according to the applicable prescribing information or clinical guidelines and will be continued throughout the approximately 18-week neoadjuvant treatment period.
Premenopausal and perimenopausal participants will receive ovarian function suppression with goserelin, leuprorelin, or triptorelin. The specific agent, dose, and administration schedule will follow the applicable prescribing information or clinical guidelines.
Objective Response Rate (ORR)
The proportion of participants whose best overall response is complete response (CR) or partial response (PR), as assessed by computed tomography or magnetic resonance imaging according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1). ORR will be calculated as the number of participants achieving CR or PR divided by the total number of participants included in the efficacy analysis, multiplied by 100%.
Time frame: From randomization through the preoperative assessment after six treatment cycles, approximately 18 weeks
Breast Pathological Complete Response Rate (bpCR)
Time frame: At surgery after completion of six treatment cycles, approximately 18 weeks after randomization
Total Pathological Complete Response Rate (tpCR)
Time frame: At surgery after completion of six treatment cycles, approximately 18 weeks after randomization
Miller-Payne Grade
Pathological response of the primary breast tumor will be assessed using the Miller-Payne grading system, which ranges from Grade 1 to Grade 5. Grade 1 indicates no or minimal reduction in tumor cells, whereas Grade 5 indicates no identifiable malignant cells at the primary tumor site. A higher grade indicates a better pathological response to treatment.
Time frame: At surgery after completion of six treatment cycles, approximately 18 weeks after randomization
Residual Cancer Burden (RCB) Class
Residual cancer burden will be assessed in the resected breast and regional lymph nodes and classified as RCB-0, RCB-I, RCB-II, or RCB-III. RCB-0 indicates no residual invasive cancer, whereas RCB-III indicates extensive residual disease. A higher RCB class indicates a greater residual tumor burden and a worse pathological response to treatment.
Time frame: At surgery after completion of six treatment cycles, approximately 18 weeks after randomization
Incidence of Immune-Related Adverse Events
Time frame: From the first dose of study treatment through 30 days after the last dose, approximately 22 weeks
Change From Baseline in Ki-67 Expression
Ki-67 expression will be assessed by immunohistochemistry in tumor tissue obtained at baseline and at surgery and reported as the percentage of positively stained tumor cells (range, 0% to 100%). Change from baseline will be calculated as the value at surgery minus the baseline value and reported in percentage points (possible range, -100 to 100). A negative value indicates a reduction in Ki-67 expression, with a more negative value indicating greater suppression of tumor cell proliferation.
Time frame: From baseline to surgery after completion of six treatment cycles, approximately 18 weeks
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