Trial results for the Phase 2 study of Trastuzumab Deruxtecan (T-DXd) in HER2-positive locally advanced or metastatic breast cancer were posted on ClinicalTrials.gov on 2026-03-12. The trial, identified as NCT05744375, was terminated early after enrolling only 2 participants, leading to limited efficacy and safety data.
Background
Trastuzumab Deruxtecan is an antibody-drug conjugate. This specific study aimed to evaluate its efficacy, safety, and tolerability in HER2-positive locally advanced or metastatic breast cancer patients who were resistant to prior trastuzumab plus pertuzumab plus taxane therapy due to early relapse.
Trial design
The study, NCT05744375, was a national, multicenter, Phase 2, single-arm clinical trial. It was designed to investigate Trastuzumab Deruxtecan in patients with Locally Advanced Breast Cancer and Metastatic Breast Cancer. The trial was terminated, having enrolled a total of 2 participants. The main objective was to evaluate the antitumor activity of Trastuzumab Deruxtecan in the first-line treatment of HER2-positive breast cancer patients resistant to trastuzumab-pertuzumab based therapy.
Key results
Due to the early termination of the trial and low enrollment, comprehensive efficacy and safety data are limited. For the Trastuzumab Deruxtecan (T-DXd) group, the following measurements were reported:
- Objective Response Rate (ORR): 1 participant
- Progression-Free Survival (PFS): NA month (95% Confidence Interval)
- Overall Survival (OS): NA month (95% Confidence Interval)
- Time to Treatment Response (TTR): 1.9 month
- Duration of Response (DoR): NA month (95% Confidence Interval)
- The Number of Participants Who Experienced Adverse Events (AE) Related to Study Treatment: 2 Participants
- Changes From Baseline in the Global Health Status Score (GHS): 58.33 units on a scale and 62.5 units on a scale
- Time to Deterioration (TTD) in Quality of Life (QoL): NA month (95% Confidence Interval)
- Progression-Free Survival 2 (PFS2): NA month (95% Confidence Interval)
- Progression-Free Survival 3 (PFS3): NA month (95% Confidence Interval)
What this means
The early termination of this Phase 2 trial and the enrollment of only 2 participants severely limit the ability to draw definitive conclusions regarding the efficacy and safety of Trastuzumab Deruxtecan in this specific patient population. The reported data, including several 'NA' values for key survival and response duration endpoints, do not provide sufficient evidence to assess the drug's activity in HER2-positive locally advanced or metastatic breast cancer patients resistant to prior trastuzumab-pertuzumab based therapy. Further research would be needed to understand the potential role of Trastuzumab Deruxtecan in this setting.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT05744375, titled 'Trastuzumab Deruxtecan in First-line HER2-positive Locally Advanced/MBC Patients Resistant to Trastuzumab+Pertuzumab,' were posted on 2026-03-12 on clinicaltrials.gov.