Triple negative breast cancer (TNBC) is infamous for poor prognosis and limited treatment options. Where HER2 targeting treatment has greatly improved survival in HER2 positive breast cancer, and hormonal therapies have been efficient in HR+ breast cancer cases, TNBC still has high unmet needs. Immunomedics’ Sacituzumab gained accelerated approval in April this year based on the results of phase I/II trial IMMU-132-01. Phase III confirmatory trial ASCENT was ongoing to validate safety and efficacy in heavily pretreated patients.
Sacituzumab govitecan is an antibody drug conjugate, targeting the TROP-2 receptor and releasing SN-38. Immunomedics had halted the ASCENT trial earlier than expectations in April 2020 after receiving the Data Safety Monitoring Committee recommendation based on early compelling evidence of efficacy. Results from the trial were announced in ESMO virtual conference 2020 as Late Breaking Abstract #17.
Despite enrolling heavily pretreated patients, Sacituzumab managed to double the survival with a median OS 12.1 mos vs 6.7 mos for chemotherapy, HR 0.48. It must be noted that Sacituzumab is the first ADC to boost survival in TNBC. The response rates were also higher with the experimental arm, ORR 35% vs 5%, CBR 45% vs 9%. Treatment was well tolerated with no new safety concerns. Branded as Trodelvy, the FDA label for Sacituzumab contains black box warning for severe neutropenia and diarrhea.
These exceptional results establish Sacituzumab as the preferred treatment option in the third line. Immunomedics will file for full approval by end of this year. Marketing authorization application to EMA will be initiated in early 2021. DelveInsight’s analyst forecast for TNBC estimates sales more than $ 800 Mn in seven major markets (US, EU5, and Japan) by 2030.
Gilead has acquired Immunomedics, in a $21 billion last week to be part of its expanding oncology portfolio. Sacituzumab is next evaluating the frontline setting in TNBC with Roche’s Tecentriq. Other indications for which sacituzmab is being evaluated include HR+, HER2 negative breast cancer, Urothelial cancer, NSCLC, and ovarian cancer.