RCT: Camrelizumab Increases Pathological Complete Response in Early or Locally Advanced Triple-Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) accounts for approximately 15% of all breast malignancies and is known for its aggressive clinical course and limited therapeutic options. Neoadjuvant chemotherapy has become standard of care for many patients with stage II or III TNBC, aiming to downstage tumors and enhance surgical outcomes. Recent trials suggest that adding immune checkpoint inhibitors, such as anti–programmed death 1/ligand 1 (PD-1/PD-L1) agents, to anthracycline- and platinum-based regimens can further improve response rates. Camrelizumab, a humanized monoclonal anti–PD-1 antibody, has shown antitumor activity in various malignancies, including advanced TNBC. This study, the CamRelief trial, evaluated whether camrelizumab combined with intensive chemotherapy (nab-paclitaxel plus carboplatin followed by dose-dense anthracycline-cyclophosphamide) increases pathological complete response (pCR) in patients with early or locally advanced TNBC.

Objective: To determine if the addition of camrelizumab to a platinum-containing neoadjuvant chemotherapy regimen significantly improves pCR in operable or locally advanced TNBC compared with placebo plus the same chemotherapy backbone.

Methods: This randomized, double-blind, phase 3 trial enrolled 441 female patients aged 18 to 75 years from 40 Chinese centers. Eligible participants had stage II or III TNBC (T2N0-1M0/T3N0M0 or T2N2-3M0/T3N1-3M0) and an Eastern Cooperative Oncology Group performance-status score of 0 or 1. Patients were randomized 1:1 to receive camrelizumab (200 mg) or placebo plus chemotherapy. Chemotherapy consisted of nab-paclitaxel (100 mg/m^2) and carboplatin (area under the curve, 1.5) on days 1, 8, and 15 every 28 days for 16 weeks, then epirubicin (90 mg/m^2) and cyclophosphamide (500 mg/m^2) every two weeks for 8 weeks. Camrelizumab or placebo was administered every two weeks during the 24 weeks of chemotherapy. The primary end point was pCR (ypT0/Tis ypN0), assessed by a local pathologist masked to treatment assignment, at the time of surgery. Secondary end points included event-free survival, disease-free survival, distant disease-free survival, and safety.

Results: Of the 441 randomized patients, 89.2% in the camrelizumab-chemotherapy group and 91.3% in the placebo-chemotherapy group proceeded to surgery. Pathological complete response was observed in 56.8% (95% CI, 50.0%-63.4%) of patients receiving camrelizumab-chemotherapy vs 44.7% (95% CI, 38.0%-51.6%) of those receiving placebo-chemotherapy (rate difference, 12.2% [95% CI, 3.3%-21.2%]; 1-sided P = .004). Serious adverse events occurred more frequently with camrelizumab-chemotherapy (34.7% vs 22.8%), including decreased neutrophil count, decreased platelet count, and decreased white blood cell count, but most immune-related events (eg, reactive capillary endothelial proliferation, hypothyroidism) were low grade and manageable. Longer-term outcomes (event-free survival, disease-free survival, distant disease-free survival) remain immature at a median follow-up of 14.4 months, with hazard ratios of 0.80 (95% CI, 0.46-1.42), 0.58 (95% CI, 0.27-1.24), and 0.62 (95% CI, 0.29-1.33), respectively.

Conclusions: In patients with early or locally advanced TNBC, adding camrelizumab to a platinum-containing, dose-dense anthracycline-cyclophosphamide regimen significantly increased pCR rates compared with placebo plus the same chemotherapy backbone. Safety profiles were consistent with known effects of camrelizumab and dose-dense chemotherapy, with no unexpected toxicities detected.

Implications for Practice: These findings support the integration of camrelizumab into an intensive neoadjuvant regimen for TNBC, potentially offering higher rates of tumor eradication across various nodal stages. Clinicians should, however, anticipate and monitor immune-related adverse events, particularly in higher-risk populations. Given the toxicity profile, patient selection and vigilant supportive care are important.

Study Strengths and Limitations: Strengths include the randomized, double-blind design and the inclusion of higher-risk, node-positive cohorts (including N3). The dose-dense chemotherapy backbone further strengthens the applicability of results in more advanced operable disease. Limitations involve the short follow-up time, which precludes conclusive survival analyses, and the study’s restriction to a single geographic population.

Future Research: Longer follow-up is necessary to determine if improved pCR translates into sustained survival benefits. Biomarker-driven approaches, including further PD-L1 and immunogenomic analyses, may refine patient selection. Studies in broader populations and direct comparisons with other checkpoint inhibitors will help define the optimal immunotherapy-partner regimens in TNBC.

Reference:

Chen L, Li H, Zhang H, et al. Camrelizumab vs Placebo in Combination With Chemotherapy as Neoadjuvant Treatment in Patients With Early or Locally Advanced Triple-Negative Breast Cancer: The CamRelief Randomized Clinical Trial. JAMA. Published online December 13, 2024. DOI: http://doi.org/10.1001/jama.2024.23560

Joensuu H. Neoadjuvant Camrelizumab for Triple-Negative Breast Cancer. Editorial. JAMA. Published online December 13, 2024. DOI: http://doi.org/10.1001/jama.2024.25927