Phase 4
Completed N=245
Evaluating the Dose Timing (Morning vs Evening) of Endocrine Therapy and Its Effects on Tolerability and Compliance
Source: ClinicalTrials.gov NCT04864405 ↗Enrolled (actual)
245
Serious AEs
—
Results posted
Jan 2026
Primary outcomePrimary: Change in Endocrine Toxicity and Tolerability at 12 Weeks — -2.2; -5.0 units on a scale
◆ Published Evidence
Emerging
5citations · ~5 / year
A pragmatic, multicenter, randomized trial comparing morning versus evening dosing of adjuvant endocrine therapy (REaCT-CHRONO Study).
Summary
Endocrine therapy is an established treatment for hormone receptor-positive breast cancer, but can cause significant side effects with deterioration in quality of life. The side effects of all forms of endocrine therapy are well recognized and can lead to treatment non-persistence or non-compliance. Chronotherapy, also called chronotherapeutics, is defined as the administration of a medication in coordination with circadian rhythm in order to minimize side effects and yield a greater efficacy. The investigators propose to perform a pragmatic, multi-centre, open-label, randomized clinical trial to establish the optimal timing (morning vs. evening) of administering endocrine therapy based on side effects and benefits in early stage breast cancer patients.
Linked Publications (2)
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A pragmatic, multicenter, randomized trial comparing morning versus evening dosing of adjuvant endocrine therapy (REaCT-CHRONO Study).
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Does the Time of Day at Which Endocrine Therapy Is Taken Affect Breast Cancer Patient Outcomes?
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Change in Endocrine Toxicity and Tolerability at 12 Weeks |
-2.2; -5.0 | — |
| SECONDARY Change in Endocrine Toxicity and Tolerability |
-0.3; -0.5; -1.6; -2.3; -2.2; -5.0 | — |
| SECONDARY Change in Health Related Quality of Life Scores |
1.9; 1.2; 1.4; 0.9; 2.3; -0.6 | — |
| SECONDARY Number of Participants Who Were Compliant With ET |
103; 100; 105; 105; 103; 95 | — |
| SECONDARY Cost-effectiveness |
— | — |
Eligibility Criteria
Inclusion Criteria
- Patients with an early stage or locally advanced hormonal receptor positive breast cancer
- Plan to receive endocrine therapy
- 18 years of age or older
- Able to provide oral consent
- Willing and able to complete questionnaires as per study protocol
Exclusion Criteria
- Metastatic cancer
- Previous endocrine therapy for breast cancer
- Plan to receive adjuvant abemaciclib
Data sourced from ClinicalTrials.gov (NCT04864405) and the linked publication. Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication. Informational only — not medical advice.