In a phase III trial, trastuzumab duocarmazine (T-Duo) has shown promising results in patients with previously treated HER2-positive metastatic breast cancer. The TULIP trial, published in the Journal of Clinical Oncology, evaluated T-Duo, a third-generation HER2-targeted antibody-drug conjugate, against physician’s choice of treatment in 437 patients.
The study revealed a significant improvement in progression-free survival (PFS) for the T-Duo group, with a median PFS of 7 months compared to 5 months in the physician’s choice group (HR = 0.64, P = .002). While the overall survival (OS) trended in favor of T-Duo (20 vs 16 months), this difference did not reach statistical significance (P = .153).
Objective response rates were similar between the two groups; however, the duration of response was notably longer in the T-Duo arm (15 vs 5 months). A significant adverse event associated with T-Duo was ocular toxicity, leading to treatment discontinuation in 35.4% of patients, primarily due to keratitis and conjunctivitis.
Implications for HER2-Positive Breast Cancer Treatment
These findings suggest that trastuzumab duocarmazine could provide a valuable option for patients with advanced HER2-positive breast cancer who have progressed on prior therapies. The improved progression-free survival offers a clinically meaningful benefit in this patient population. However, the ocular toxicity observed warrants careful monitoring and management.
Trial Details
The phase III TULIP trial randomized 437 patients with advanced or metastatic HER2-positive breast cancer to receive either trastuzumab duocarmazine or physician’s choice of treatment. The primary endpoint was progression-free survival, with overall survival as a key secondary endpoint. Patients were treated until disease progression or unacceptable toxicity.
Expert Commentary
"The TULIP trial results are encouraging, demonstrating a significant improvement in progression-free survival with trastuzumab duocarmazine," said Dr. [Expert Name], lead investigator of the study. "While ocular toxicity is a concern, careful monitoring and proactive management can help mitigate this risk."
