Formulation and Specifications: Injection: 100mg/vial, 160mg/vial
Indications: Single agent is indicated for the adjuvant treatment of HER2-positive early-stage breast cancer patients with residual invasive lesions despite receiving paclitaxel-based neoadjuvant therapy in combination with trastuzumab.
Key points for rational drug use:
1. Emtrastuzumab (T-DM1) and trastuzumab are different drugs, and substitution in clinical application is prohibited.
2. Patients receiving adjuvant therapy with T-DM1 should meet the following requirements: (1) Should be confirmed as HER2-positive by HER2 testing in a qualified pathology laboratory. (2) Complete a neoadjuvant regimen based on trastuzumab (H) and paclitaxel. (3) Failure to achieve pathologic complete remission on pathologic evaluation after neoadjuvant therapy. Pathologic complete remission (pCR) is defined as no invasive carcinoma in the primary breast and negative regional lymph nodes, i.e. ypT0/Tis ypN0. pCR cannot be diagnosed after neoadjuvant therapy with only residual intramamammary cholangiocarcinoma or only residual ITC in the lymph nodes.
3. The recommended dose of T-DM1 is 3.6 mg/kg administered by intravenous infusion every 3 weeks (21 days as a cycle). Patients with early stage breast cancer should receive a total of 14 cycles of treatment unless disease recurs or uncontrollable toxicity occurs. Dose adjustments should be made promptly in the event of adverse reactions according to the instructions, and the dose reduction regimen is listed below. After dose reduction, the T-DM1 dose should not be increased.
| Dose reduction regimen | Dose level |
| Starting dose | 3.6mg/kg |
| 3mg/kg | |
| Second dose reduction | 2.4mg/kg |
| Treatment discontinued |
4. In clinical practice, past history, physical examination, electrocardiogram, and echocardiogram LVEF should be assessed at baseline before starting T-DM1, and LVEF should be monitored every 3 months during use. if the patient has asymptomatic cardiac insufficiency, the monitoring frequency should be higher. Treatment should be suspended when: (1) LVEF <45% and LVEF should be assessed repeatedly within 3 weeks. if LVEF <45% is confirmed, treatment should be discontinued. (2) LVEF of 45% to <50% and ≥10% decline relative to baseline should be suspended and LVEF assessed repeatedly within 3 weeks. if LVEF remains <50% and does not recover to <10% relative to baseline, treatment should be discontinued. (3) LVEF of 45% to <50% and a decrease of <10% relative to baseline may be continued and LVEF assessed repeatedly within 3 weeks.(4) LVEF ≥50% may be continued. (5) Symptomatic congestive heart failure, grade 3 to 4 left ventricular systolic dysfunction or grade 3 to 4 heart failure, or grade 2 heart failure with LVEF <45% should be discontinued.
5. It is recommended that platelet counts be monitored prior to each T-DM1 dose: (1) If grade 2 to 3 (25 to 75) × 109/L at the planned treatment date, treatment should be delayed until platelet counts return to ≤ grade 1 (≥ 75 × 109/L) at the same dose level. If a patient requires two doses of delayed dosing due to thrombocytopenia, treatment should be considered at one lower dose level. (2) If platelets are reduced to grade 4 (<25×109/L), treatment should be delayed until platelet counts recover to ≤grade 1 (≥75×109/L) and then lowered by one dose level. (3) Patients who develop thrombocytopenia (platelet count <100×109/L) and those on anticoagulation therapy should be monitored closely during treatment with this product. (4) The vast majority of thrombocytopenia can be recovered after suspension or dose reduction and discontinuation treatment according to the instructions. If the effect of conventional platelet-raising therapy is not satisfactory, a specialist hematologist should be consulted as soon as possible, and if necessary, targeted tests such as bone marrow aspiration, thrombopoietin antibody and platelet antibody test should be given to clarify the possible causes and then provide symptomatic treatment.
The results of two international multicenter phase III clinical studies suggest that T-DM1 can significantly prolong the progression-free survival and overall survival of patients with HER2-positive advanced breast cancer who have failed trastuzumab therapy compared with lapatinib combined with capecitabine and physician-selected treatment regimens, and that T-DM1 can be a second- and second-line treatment option for patients with HER2-positive advanced breast cancer.