This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
GALAXY is a phase 1/2, non-randomized parallel-design treatment study evaluating targeted antibody-drug conjugates in patients with breast cancer characterized by HER2 ultra-low or no expression.
| Feature | GALAXY |
|---|---|
| Condition | Breast Cancer |
| Phase | 1/2 |
| Design | Parallel, non-randomized, open-label |
| Primary purpose | Treatment |
| Enrollment | 56 |
| Interventions | SHR-A1811; TROP2 ADC |
| Primary endpoints | Occurrence of adverse events (AEs)- Phase 1; Objective Response Rate (ORR)- Phase 2 |
2. Clinical Question
The clinical question is whether targeted antibody-drug conjugates can be evaluated for safety and antitumor activity in patients with advanced breast cancer with HER2 ultra-low or no expression.
Population
Patients with breast cancer with HER2 ultra-low or no expression.
Intervention
SHR-A1811 or TROP2 ADC.
Comparator
No randomized comparator; the registry describes a non-randomized design.
Primary questions
What adverse events occur during Phase 1, and what is the objective response rate during Phase 2?
3. Trial Design
SHR-A1811
A targeted antibody-drug conjugate intervention.
TROP2 ADC
A targeted antibody-drug conjugate intervention.
4. Endpoints
| Endpoint | Time frame | Description |
|---|---|---|
| Occurrence of adverse events (AEs)- Phase 1 | Up to follow-up period, approximately 24 months | Occurrence of AEs in Phase 1 graded according to CTCAE v5.0 |
| Objective Response Rate (ORR)- Phase 2 | Until progression, assessed up to approximately 24 months | The proportion of patients who have a CR or PR, as determined by the Investigator at local site per RECIST 1.1. |
5. Statistical Methodology
The registry describes a phase 1/2 non-randomized treatment study. The statistical framework therefore focuses on safety evaluation in Phase 1 and response assessment in Phase 2 rather than randomized treatment-effect estimation.
Safety analysis
The Phase 1 primary endpoint measures occurrence of adverse events graded according to CTCAE v5.0. Safety analyses in early-phase studies commonly summarize the frequency, severity, and timing of observed adverse events.
Objective response rate analysis
The Phase 2 primary endpoint is ORR, defined as the proportion of patients achieving complete response or partial response according to investigator assessment using RECIST 1.1. ORR is typically summarized as a proportion with confidence intervals to describe statistical uncertainty.
6. Planned Analysis
No results are posted on ClinicalTrials.gov for the primary endpoints. The registry specifies that Phase 1 will measure occurrence of adverse events and Phase 2 will measure objective response rate.
For a response endpoint, interpretation depends on the number of responders, the analysis population definition, assessment timing, and uncertainty around the observed proportion.
7. Statistical Methods Explained
Why is ORR used in early-phase oncology studies?
Objective response rate provides a direct measure of tumor shrinkage activity and can be assessed before long-term outcomes such as survival are mature.
What does RECIST 1.1 contribute to response analysis?
RECIST 1.1 provides standardized criteria for determining whether tumor measurements meet definitions such as complete response or partial response.
Why is this trial not analyzed like a randomized trial?
The registry describes a non-randomized design. Without random allocation, comparisons between groups may be affected by differences in patient characteristics rather than treatment alone.
Why are confidence intervals important for ORR?
A response percentage alone does not describe precision. Confidence intervals indicate the uncertainty associated with estimating a response rate from a finite number of patients.
Why is CTCAE grading used?
CTCAE v5.0 provides a standardized framework for classifying adverse-event severity across clinical studies.
8. Limitations
- Non-randomized design: Treatment groups are not assigned randomly, limiting causal comparisons between interventions.
- No posted efficacy results: The registry does not currently report ORR estimates or safety event summaries.
- Early-phase setting: Phase 1/2 studies are generally designed to evaluate safety and preliminary activity rather than provide definitive comparative evidence.
- Sample size: The planned enrollment of 56 participants provides a limited population for estimating treatment effects precisely.
- Response assessment: Investigator assessment per RECIST 1.1 depends on imaging evaluation and assessment timing.
9. Why This Trial Matters Statistically
GALAXY illustrates several important concepts in early-phase oncology statistics: safety monitoring, response-rate estimation, non-randomized treatment evaluation, and the interpretation of antibody-drug conjugate studies.
| Concept | How it appears in GALAXY |
|---|---|
| Early-phase design | Phase 1/2 structure combining safety and response objectives |
| Safety analysis | Adverse events graded according to CTCAE v5.0 |
| Binary endpoint analysis | ORR based on CR and PR assessments |
| RECIST methodology | Investigator assessment using RECIST 1.1 |
| Non-randomized inference | Interpretation without randomized comparator groups |
10. Sources
- ClinicalTrials.gov: NCT05824325.
Continue through the Clinical Biostats knowledge graph
Clinical trial methods connect study design, endpoints, statistical analysis, and interpretation into a broader framework for understanding biomedical research.
11. Record Summary
GALAXY is a phase 1/2 non-randomized clinical trial evaluating SHR-A1811 and TROP2 ADC in advanced breast cancer with HER2 ultra-low or no expression. The statistical focus is on safety evaluation in Phase 1 and objective response rate assessment in Phase 2. ClinicalTrials.gov currently reports the trial design and endpoint framework but does not report primary endpoint results.