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CTRI Number  CTRI/2025/11/097495 [Registered on: 17/11/2025] Trial Registered Prospectively
Last Modified On: 15/11/2025
Post Graduate Thesis  No 
Type of Trial  Interventional 
Type of Study   Drug 
Study Design  Single Arm Study 
Public Title of Study   A study to check whether a lower fixed dose of trastuzumab deruxtecan (T-DXd) works safely and effectively for patients with HER2-low advanced or metastatic breast cancer that has stopped responding to hormone treatment. 
Scientific Title of Study   A Phase II Study of Flat-Dose Trastuzumab Deruxtecan (T-DXd) in Endocrine Refractory HER2-low advanced unresectable/metastatic Breast Cancer (FaiTH-Low) 
Trial Acronym  FaiTH-Low 
Secondary IDs if Any  
Secondary ID  Identifier 
NIL  NIL 
 
Details of Principal Investigator or overall Trial Coordinator (multi-center study)  
Name  Prabhat Bhargava 
Designation  Professor of Medical Oncology Department  
Affiliation  Tata Memorial Centre  
Address  1135, Homi Bhabha Block, Department of Medical Oncology, Tata Memorial Centre, Dr. Ernest Borges Marg, Parel, Mumbai.

Mumbai
MAHARASHTRA
400012
India 
Phone  7276174221  
Fax    
Email  bhargava611@gmail.com  
 
Details of Contact Person
Scientific Query  
Name  Prabhat Bhargava 
Designation  Professor of Medical Oncology Department  
Affiliation  Tata Memorial Centre  
Address  1135, Homi Bhabha Block, Department of Medical Oncology, Tata Memorial Centre, Dr. Ernest Borges Marg, Parel, Mumbai.

Mumbai
MAHARASHTRA
400012
India 
Phone  7276174221  
Fax    
Email  bhargava611@gmail.com  
 
Details of Contact Person
Public Query  
Name  Prabhat Bhargava 
Designation  Professor of Medical Oncology Department  
Affiliation  Tata Memorial Centre  
Address  1135, Homi Bhabha Block, Department of Medical Oncology, Tata Memorial Centre, Dr. Ernest Borges Marg, Parel, Mumbai.

Mumbai
MAHARASHTRA
400012
India 
Phone  7276174221  
Fax    
Email  bhargava611@gmail.com  
 
Source of Monetary or Material Support  
ICMR  
 
Primary Sponsor  
Name  ICMR  
Address  V. Ramalingaswami Bhawan, Ansari Nagar, New Delhi - 110029, India 
Type of Sponsor  Government funding agency 
 
Details of Secondary Sponsor  
Name  Address 
NIL  NIL 
 
Countries of Recruitment     India  
Sites of Study  
No of Sites = 1  
Name of Principal Investigator  Name of Site  Site Address  Phone/Fax/Email 
Dr Prabhat Bhargava  Tata Memorial Centre  1135,11th Floor Homi Bhabha Block, Department of Medical Oncology, Dr. Ernest Borges Marg, Parel, Mumbai.
Mumbai
MAHARASHTRA 		 07276174221

bhargava611@gmail.com 
 
Details of Ethics Committee  
No of Ethics Committees= 1  
Name of Committee  Approval Status 
Institutional Ethics Commitee  Approved 
 
Regulatory Clearance Status from DCGI  
Status 
Not Applicable 
 
Health Condition / Problems Studied  
Health Type  Condition 
Patients  (1) ICD-10 Condition: 8||Other Procedures,  
 
Intervention / Comparator Agent  
Type  Name  Details 
Comparator Agent  Not Applicable  Not Applicable 
Intervention  Trastuzumab Deruxtecan (T-DXd)   T-DXd comes as a 100mg vial. The 100 mg vial is to be reconstituted slowly with 5 mL of Sterile Water for Injection, USP into each vial to obtain a final concentration of 20 mg/mL. The reconstituted T DXd is to be diluted in an intravenous infusion bag containing 100 mL of D5W. It is to be mixed in an infusion bag made of polyvinyl chloride or polyolefin, which includes polyethylene and polypropylene bags. It should be protected from light. It is infused with an infusion set made of polyolefin or polybutadiene and a 0.20 or 0.22-micron in-line polyethersulfone (PES) or polysulfone (PS) filter. Each dose will be infused over 30- 90 minutes.  
 
Inclusion Criteria  
Age From  18.00 Year(s)
Age To  80.00 Year(s)
Gender  Both 
Details  1. Patients (above 18 years age) with unresectable/metastatic ER-positive and HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer.
2. Refractory to endocrine therapy.
3. Prior treatment with 1–2 chemotherapy lines in the metastatic setting.
4. No prior anti-HER2 therapy.
5. ECOG performance status 0–1
 
 
ExclusionCriteria 
Details  1. Patients with triple-negative breast cancer (TNBC) will be excluded.
2. Has a medical history of myocardial infarction within 6 months before enrollment.
3. Has a history of symptomatic congestive heart failure.
4. Has a history of (noninfectious) interstitial lung disease (ILD)/pneumonitis that required steroids, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at Screening.
5. Has spinal cord compression or clinically active central nervous system metastases, defined as untreated and symptomatic, or requiring therapy with corticosteroids or anticonvulsants to control associated symptoms. However, subjects with treated brain metastases that are no longer symptomatic and who require no treatment with corticosteroids or anticonvulsants may be included in the study if they have recovered from the acute toxic effect of radiotherapy. A minimum of 2 weeks must have elapsed between the end of whole brain radiotherapy and study enrollment.
 
 
Method of Generating Random Sequence   Not Applicable 
Method of Concealment   Not Applicable 
Blinding/Masking   Not Applicable 
Primary Outcome  
Outcome  TimePoints 
Evaluating Progression-Free Survival (PFS) with a flat 100 mg dose of Trastuzumab Deruxtecan (T-DXd).  For the enrolled participants, progression-free survival will be assessed from the time of enrollment in the study till the patient has confirmed disease progression with radiological/lab investigation evidence.  
 
Secondary Outcome  
Outcome  TimePoints 
Assess overall response rate (ORR), disease control rate (DCR), overall survival (OS), and quality of life (QoL).
Analyze the incidence and severity of adverse events.
Determine the cost-effectiveness of the treatment.
 		 For the enrolled participants, the overall response rate, disease control rate, overall survival rate, and quality of life will be assessed from the time of enrollment in the study till the patient has confirmed disease progression with radiological/lab investigation evidence.  
 
Target Sample Size   Total Sample Size="32"
Sample Size from India="32" 
Final Enrollment numbers achieved (Total)= "Applicable only for Completed/Terminated trials"
Final Enrollment numbers achieved (India)="Applicable only for Completed/Terminated trials" 
Phase of Trial   Phase 2 
Date of First Enrollment (India)   22/12/2025 
Date of Study Completion (India) Applicable only for Completed/Terminated trials 
Date of First Enrollment (Global)  Date Missing 
Date of Study Completion (Global) Applicable only for Completed/Terminated trials 
Estimated Duration of Trial   Years="4"
Months="0"
Days="0" 
Recruitment Status of Trial (Global)   Not Yet Recruiting 
Recruitment Status of Trial (India)  Open to Recruitment 
Publication Details   N/A 
Individual Participant Data (IPD) Sharing Statement

Will individual participant data (IPD) be shared publicly (including data dictionaries)?  

Response - NO
Brief Summary  

Study Title: A Phase II Study of Flat-Dose Trastuzumab Deruxtecan in Endocrine Refractory HER2 Low Advanced Unresectable/Metastatic Breast Cancer FaiTH Low.

Introduction: Breast cancer is one of the most common cancers worldwide. HER2 low advanced or metastatic breast cancer patients have a poorer prognosis after becoming endocrine resistant. Trastuzumab Deruxtecan , an antibody-drug conjugate , has shown promising efficacy in treating HER2-low cancers. This study explores the effectiveness of a flat 100 mg dose compared to the historical standard 5.4 mg per kg dose. 

Hypothesis: A flat 100 mg dose of TDXd can provide similar efficacy to the standard weight-based dose while improving safety, reducing costs, and enhancing accessibility for patients. 

Study Objectives:

Primary Objective: Evaluate Progression Free Survival with a flat 100 mg dose of TDXd

Secondary Objectives: Assess overall response rate , disease control rate, and overall survival

Adverse Event Incidence and  Severity with graded according to CTCAE v 5.0. 

Quality of Life : Assessments with EORTC QLQ C30 

Study Design Type: Single-arm Simon Phase II trial. 

Participants: HER2 low, ER positive endocrine refractory metastatic breast cancer patients post 1 line of chemotherapy. 

Duration: 24 months of accrual and 12 months of follow up. 

Sample Size: 32 patients 11 in Stage I expansion to 21 if efficacy is observed.

Dosing: Flat-dose 100 mg IV infusion every 3 weeks. 

Eligibility Criteria Inclusion Criteria: Patients more than18 years with unresectable or metastatic ER positive and HER2 low with IHC 1 positive or IHC 2 positive  or ISH Non-amplified  breast cancer.

Refractory to endocrine therapy. Prior treatment with 1 to 2 chemotherapy lines in the metastatic setting. No prior anti HER2 therapy. ECOG performance status 0 to 1. 

Exclusion Criteria: Patients with triple-negative breast cancer TNBC will be excluded. Severe heart disease, recent myocardial infarction, or symptomatic heart failure. Interstitial lung disease  or significant pulmonary conditions. Active CNS metastases requiring steroids. 

Data Management and Statistical Plan Kaplan Meier curves will analyze survival outcomes. Descriptive statistics for toxicity and response rates. Intent-to-treat analysis will be conducted. 

Anticipated Risks: Potential side effects include neutropenia, nausea, ILD, fatigue, and cardiac toxicity. 

Benefits: Potential comparable efficacy at a lower dose with fewer toxicities and cost reductions, making treatment more accessible.

Ethical Considerations and  Patient Confidentiality Conducted per ICMR guidelines and the Declaration of Helsinki. Informed consent is required.

Confidentiality was maintained with de identified data storage. This trial aims to establish a cost effective, safer alternative to standard dose TDXd for HER2 low breast cancer patients while maintaining treatment efficacy.

 
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