Trastuzumab Duocarmazine Improves PFS in HER2+ Advanced Breast Cancer

Results of a phase 3 trial suggest that trastuzumab duocarmazine improves progression-free survival (PFS) over chemotherapy in patients with pretreated, HER2-positive advanced breast cancer.

However, trastuzumab duocarmazine does not improve overall survival (OS) in this patient population, according to study investigator Philippe Aftimos, MD, of Institute Jules Bordet in Anderlecht, Belgium.

Dr Aftimos presented these results, from the phase 3 TULIP trial (ClinicalTrials.gov Identifier: NCT03262935), at the ESMO Congress 2023.

TULIP enrolled 437 patients with HER2-positive, locally advanced or metastatic breast cancer. Patients had received 2 or more therapies for metastatic disease or ado-trastuzumab for metastatic disease.

The patients were randomly assigned to receive trastuzumab duocarmazine at 1.2 mg/kg every 21 days (n=291) or physician’s choice of chemotherapy (n=146) until progression or unacceptable toxicity. The chemotherapy options were lapatinib plus capecitabine, trastuzumab plus capecitabine, trastuzumab plus vinorelbine, or trastuzumab plus eribulin.

The median PFS, the study’s primary endpoint, was 7.0 months in the trastuzumab duocarmazine arm and 4.9 months in the chemotherapy arm (hazard ratio [HR], 0.64; 95% CI, 0.49-0.84; P =.002).

The median OS was 21.0 months with trastuzumab duocarmazine and 19.5 months with chemotherapy (HR, 0.87; 95% CI, 0.68-1.12; P =.236). The estimated 1-year OS rates were 70% with trastuzumab duocarmazine and 68% with chemotherapy.

The rate of treatment-emergent adverse events (TEAEs) was 96.5% in the trastuzumab duocarmazine arm and 96.4% in the chemotherapy arm. The rate of grade 3 or higher TEAEs was 52.4% and 48.2%, respectively.

TEAEs of any grade that were more common in the trastuzumab duocarmazine arm than in the chemotherapy arm were eye toxicity (78.1% vs 29.9%), pneumonitis (6.6% vs 0%), and interstitial lung disease (1.0% vs 0%).

Disclosures: This research was supported by Byondis B.V. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Aftimos PG, Turner N, O’Shaughnessy J, et al. Trastuzumab duocarmazine versus physician’s choice therapy in pre-treated HER2-positive metastatic breast cancer: Final results of the phase III TULIP trial. Presented at ESMO Congress 2023. Oct. 20-24, 2023. Madrid, Spain. Abstract 386MO.

This article originally appeared on Cancer Therapy Advisor