The following is a summary of “Trastuzumab Duocarmazine in Pretreated Human Epidermal Growth Factor Receptor 2–Positive Advanced or Metastatic Breast Cancer: An Open-Label, Randomized, Phase III Trial (TULIP),” published in the October 2024 issue of Oncology by Turner et al.      

Human epidermal growth factor receptor 2 (HER2)–targeted treatment is the standard of care for HER2-positive (HER2+) breast cancer, but most patients develop progressive disease despite persistent HER2 expression.  

Researchers conducted a prospective study to compare trastuzumab duocarmazine (T-Duo) with physician’s choice (PC) in patients with advanced HER2 + breast cancer.  

They conducted an open-label, randomized phase III trial, assigning 437 patients (2:1) to trastuzumab duocarmazine (n = 291) or PC (n = 146) after progression during or after ≥2 HER2-targeted therapies or after trastuzumab emtansine (T-DM1). The main endpoint was progression-free survival (PFS) assessed by a blinded independent central review.  

The results showed the median PFS of 7.0 months (95% CI, 5.4 to 7.2) for T-Duo compared to 4.9 months (95% CI, 4.0 to 5.5; HR, 0.64 [95% CI, 0.49 to 0.84]; P=.002) for PC. The median OS was 20.4 months (T-Duo) vs. 16.3 months (PC; HR, 0.83 [95% CI, 0.62 to 1.09]; P=.153). The objective response rate was 27.8% (T-Duo) compared to 29.5% (PC), with other efficacy endpoints favoring T-Duo.  

They concluded that treatment with T-Duo significantly improved PFS in patients with advanced HER2+breast cancer, although tolerability was affected by ocular toxicity.  

Source: ascopubs.org/doi/10.1200/JCO.24.00529