Sacituzumab govitecan-hziy approved in patients with metastatic triple-negative breast cancer (TNBC) who received 2 prior therapies for metastatic disease.
An antibody-drug conjugate the targets the human trophoblast cells surface antigen 2 (TROP-2) which which is expressed in most types of breast cancer.
A humanized anti-TROP-2 antibody with an SN-38 payload covalently attached by means of a pH sensitive hydrolyzable linker.
The SN–38 moiety is a topoisomerase I inhibitor.
Progression free and overall survival were significantly better with Sacituzumab govitecan-hziy than with single agent chemotherapy among patients with metastatic triple negative breast cancer.
ASCENT trial randomization of patients with unresectable locally advanced or mTNBC who relapsed after 2 or more prior systemic therapies: receive 10 mg/kg as an intravenous infusion of sacituzumab govitecan on days 1 and 8 of a 21-day cycle and 262 patients assigned to receive physician’s choice of single agent chemotherapy.
Patients receiving the drug demonstrated a statistically significant and clinically meaningful 59% improvement in progression free status, which was extended to 5.6 months versus 1.7 months with chemotherapy and extended overall survival to 12.1 months from 6.7 months which represents a 52% reduction in the risk of death.
Tradename Trodelvy
A novel antibody-drug conjugate that consists of three components: the antibody that targets the surface protein Trop-2, a hydrolysable linker; and SN-38 the toxic payload.
It is a targeted therapy.
SN-38 is an active metabolite of Irinotecan a topoisomerase inhibitor 1.
SN-38 is more powerful than Irinotecan.
It has a high drug to antibody ratio of 7.6 to 1.
Trop-2 is an antigen expressed in the majority of breast cancers, including triple negative breast cancer.
Approval based on positive results from a single-arm, multicenter phase II study which was designed to evaluate objective response rate (ORR) and duration of response (DOR) of the agent in patients with metastatic TNBC.
Phase III ASCENT study compared Sacituzumab circuit to standard chemotherapy in patients with triple negative breast cancer.
The median progression free survival was 5.6 months with Sacituzumab and 1.7 months with standard of care.
The objective response rate was 39% versus 5%, respectively.
In the ASCENT study the median overall survivor was 12.1 months with Sacituzumab, versus 6.7 months with standard chemotherapy.
Sacituzumab Govitecan Becomes First ADC Approved for TNBC.
The FDA’s decision was supported by efficacy data from the single-arm phase 1/2 IMMU-132-01 trial (NCT01631552), which showed that sacituzumab govitecan induced durable responses in the 108 patients with mTNBC who were treated with the ADC.
The overall response rate was 33.3% and the median duration of response was 7.7 months.
Triple-negative breast cancer response rate with standard chemotherapy is in the range of 10% to 15%, and the median progression-free survival is 3 to 4 months with standard therapies in the later-line setting.
Patients receive sacituzumab govitecan intravenously on day 1 and day 8, every 21 days until disease progression or unacceptable toxicity.
This was a very heavily pretreated patient population: the overall response rate was 33.3% and the median duration of response was 7.7 months.
These results compared to historical data with standard chemotherapy, nearly double what you see with that of standard chemotherapy.
TROPiCS trial randomized patients with HR positive metastatic breast cancer, who had received at least 2 to 4 prior lines of chemotherapy, and patients also received therapy treatment with CDK 4/6 inhibitors.: sacituzimab improved median progression free survival from 4 to 5.5 months and overall survival from 11.2 to 14.1 months.
Patients treated with sacituzimab tgfr hormone positive disease responded, regardless of TROP-2 expression levels, negating the need for TROP-2 expression testing.
Neutropenia is the most common adverse event with sacituzumab govitecan.
The incidence of any grade of neutropenia was 64%., and the incidence of grade 4 neutropenia was 13%.
The incidence of febrile neutropenia with this agent was 6%.
Common adverse events: nausea, neutropenia, diarrhea, fatigue, alopecia, anemia, vomiting, constipation, rash, decreased appetite, and abdominal pain.
Overall, the recommended dose of sacituzumab govitecan is 10 mg/kg weekly on days 1 and 8 of a 21-day treatment cycle until disease progression or toxicity.
Adverse events are related to SN-38 back bone toxicity and consist of neutropenia,,anemia, nausea, allopecia and diarrhea.
The use of GCS factor May be needed for severe neutropenia, and prophylaxis with loperamide can usually control diarrhea.
Diarrhea occurs typically within the first few days of therapy, and neutropenia is usually seen in the first couple of cycles.
It is a new standard of care for patients who receive prior treatment for metastatic triple negative breast cancer.
Studies show that in a population of hormonally receptive positive HER2 negative patients previously treated with endocrine chemotherapy the drug achieved clinical activity similar to that reported in heavily pre-treated patients with metastatic triple negative breast cancer who had an overall response rate of 33% and duration of responsive 7.7% with a median progression free survival of 5.5 months.