Tyrosine Kinase Inhibitors (TKIs) in Trastuzumab Emtansine (T-DM1) Resistant HER2-positive Metastatic Breast Cancer: A Real-world Study

Study Overview
=================
Brief Summary
-----------------
This is a real world study to evaluate the efficacy and safety of tyrosine kinase inhibitors after T-DM1 progression.

Detailed Description
-----------------
HER2-positive breast cancers account for 15%-20% of all breast cancers. The development of HER2 targeted therapies have greatly improved the survival of HER2-positive breast cancer patients. Trastuzumab emtansine (T-DM1) has shown great effectiveness in treating HER2-positive metastatic breast cancer, but therapies subsequent to T-DM1 progression are still controversial. Here, we investigated efficacy and safety of tyrosine kinase inhibitors (TKIs) based therapy in T-DM1 resistant HER2-positive metastatic breast cancer.

Official Title
-----------------
Tyrosine Kinase Inhibitors (TKIs) Based Therapy in Trastuzumab Emtansine (T-DM1) Resistant HER2-positive Metastatic Breast Cancer: A Real-world Study

Conditions
-----------------
Breast Cancer

Intervention / Treatment
-----------------
* Drug: TKIs


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Female and 18-70 years old Metastatic or locally recurrent HER2-positive breast cancer Patients received TKIs-based therapy after T-DM1 failure in treatment for metastasis Complete and accurate medical data Exclusion Criteria: - Incomplete medical data

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Observational Group<br>Patients receive TKIs after T-DM1 progression. | Drug: TKIs<br>* tyrosine kinase inhibitors based therapy<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression Free Survival (PFS) | Progression-free survival estimated using Kaplan-Meier methods is defined as the time from the date of informed consent to the earlier of death or disease progression. Patients alive without disease progression are censored at the date of last disease evaluation. Progressive disease (PD) based on RECIST 1.1 is at least a 20% increase in the sum of longest diameter (LD) of target lesions taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions. Equivocal progression of non-target lesions also qualifies as PD. | 2 years | 
| Objective Response Rate (ORR) | The overall response rate is defined as the percentage of patients with a best overall response of CR or PR relative to the appropriate analysis set | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Number of Participants Who Experienced Adverse Events (AE) | Safety will be assessed by standard clinical and laboratory tests (haematology, serum chemistry). AE grade were defined by the NCI CTCAE (National Cancer Institute Common Terminology Criteria for Adverse Events). | 2 years |