HER2陽性進行乳がんに対するイネテタマブとカメレリズマブおよびチデロンの併用療法：前治療歴のある患者を対象とした第2相単群前向き試験

The efficacy and safety of anti-HER2 therapy and immune checkpoint inhibitors combined with chemotherapy to treat HER2-positive advanced breast cancer that has failed standard HER2-directed therapies is unknown. This study evaluated the efficacy and safety of a novel, fully China-developed combination therapy-comprising inetetamab (an anti-HER2 monoclonal antibody), camrelizumab (an anti-PD-1 antibody), and utidelone (a microtubule inhibitor)-in this treatment-refractory population.

The ICU study (NCT04681287) was a single-arm, multicentre, phase 2 trial conducted at five centres in China. Patients with HER2-positive MBC who had experienced progression on prior trastuzumab and TKIs were enrolled. The primary endpoint was the 3-month progression-free survival (PFS) rate in the per-protocol population.

A total of 48 patients with a median of three previous systemic therapies for advanced disease (range, 1-4) were enrolled (median follow-up duration 43.0 months). The 3-month PFS rate in 46 patients was 71.67% (95% CI: 59.7-85.9). The most common any-grade treatment-emergent adverse events (TEAEs) were peripheral neuropathy (87.2%, two events were grade 3) and reactive cutaneous capillary endothelial proliferation (57.4%, all grade 1-2). There were no grade 4 or 5 TEAEs.

The combination of inetetamab, camrelizumab, and utidelone demonstrated promising efficacy and a manageable safety profile in heavily pretreated patients with HER2-positive MBC. These findings support this regimen as a viable treatment option in this setting and warrant further investigation in randomized controlled trials.

The study was registered at ClinicalTrials.gov with the identifier NCT04681287.