Trial results for trastuzumab deruxtecan in combination with tucatinib for HER2-positive breast cancer were posted on ClinicalTrials.gov on 2025-07-31. The Phase 2 study (NCT04539938) showed a confirmed objective response rate (cORR) of 51.4% and a median overall survival (OS) of 28.4 months.
Background
The trial investigated the combination of tucatinib and trastuzumab deruxtecan in participants diagnosed with HER2-positive breast cancer that was either metastatic or could not be completely removed with surgery.
Trial design
The Phase 2 study (NCT04539938) was a completed trial that enrolled 70 participants. The study focused on individuals with HER2 Positive Breast Cancer. All participants in the trial received both tucatinib and trastuzumab deruxtecan as interventions.
Key results
The trial reported the following key measurements for the total participant group:
- Confirmed Objective Response Rate (cORR) per Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 according to investigator assessment: 51.4% of participants.
- Median Progression-Free Survival (PFS) per RECIST v1.1 according to investigator assessment: 11.5 months.
- Median Duration of Response (DOR) per RECIST v1.1 according to investigator assessment: 11.9 months.
- Disease Control Rate (DCR) per RECIST v1.1: 94.3% of participants.
- Median Overall Survival (OS): 28.4 months.
Regarding safety, the study reported:
- Number of participants with Treatment Emergent Adverse Events (TEAEs): 70 participants.
- Number of participants with Serious Adverse Events (SAEs): 25 participants.
What this means
The results from this Phase 2 trial suggest that the combination of tucatinib and trastuzumab deruxtecan demonstrates clinical activity in patients with HER2-positive breast cancer. The observed confirmed objective response rate and median overall survival indicate potential benefit for this patient population. The safety profile included 70 participants experiencing Treatment Emergent Adverse Events and 25 participants experiencing Serious Adverse Events.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04539938, titled "A Study of Tucatinib Plus Trastuzumab Deruxtecan in HER2+ Breast Cancer," were posted on 2025-07-31 on clinicaltrials.gov.