Sacituzumab govitecan should become the new standard of care in women with previously treated metastatic triple-negative breast cancer (mTNBC), according to discussion at ESMO 2020.
A phase 3 study, presented at the ESMO Virtual Congress 2020, randomised 529 women to either sacituzumab or their physician’s chemotherapy of choice.
The drug is a first-in-class conjugate of an anti–Trop-2 antibody linked to the chemotherapy drug SN-38.
The study showed a significant improvement in PFS with sacituzumab over physicians’ chemotherapy treatment of choice (5.6 v 1.7 months; HR 0.41; p<0.0001).
Similarly for overall survival, there was a doubling of OS (12.1 v 6.7 months; HR 0.48; p<0.001) with sacituzumab compared to other treatments.
Speaking in a highlights session, medical oncologist Dr Aditya Bardia from Massachusetts General Hospital, said the objective response rate was also higher with sacituzumab (35% v 5%; p<0.0001).
Dr Bardia said the drug was well tolerated with a manageable safety profile.
Common adverse events included neutropenia, anaemia, diarrhoea, nausea, fatigue and alopecia. However treatment discontinuation rates due to adverse events were very low at 4.7% for the sacituzumab group and 5.4% for the control group.
“ASCENT is the first phase 3 study of a Trop-2-directed antibody drug conjugate in pretreated metastatic triple-negative breast cancer to demonstrate a significant improvement over standard chemotherapy with improvements in median PFS, median OS, and objective response rates.”
“This study confirms that sacituzumab govitecan should be considered as a new standard of care for patients with pretreated metastatic triple-negative breast cancer.”
Dr Bardia said sacituzumab govitecan (TRODELVY) was granted accelerated approval by the US FDA earlier this year for adult patients with metastatic triple-negative breast cancer who have received at least two prior therapies for metastatic disease.
Commenting on the study in the ESMO session, Dr Fatima Cardoso, director of the Breast Unit of the Champalimaud Cancer Clinical in Lisbon (Portugal) voiced criticism over the ASCENT being halted early due to “compelling evidence of efficacy”.
“It’s not clear to me why the trial had to be stopped. For the current patients if there is no crossover, there is no benefit in stopping the trial. And for future patients it is better to have the final results sufficiently powered,” she said.
“This is a moderate benefit even so, not a substantial breakthrough, so it is very important not to stop trials too early.”
Dr Cardoso, lead author on the ESO-ESMO guidelines for the management of advanced breast cancer, concluded that in her opinion sacituzumab should now be considered a new treatment option for patients previously treated with two or more lines of therapy.