The encouraging results of the phase III ASCENT trial suggest that sacituzumab govitecan has clearly earned a place in the treatment algorithm for advanced triple-negative breast cancer, said the study’s invited discussant, Fatima Cardoso, MD, Director of the Breast Unit at the Champalimaud Clinical Center in Lisbon and President of the Advanced Breast Cancer (ABC) Global Alliance.

Fatima Cardoso, MD

“A 4-month benefit in progression-free survival and, more importantly, a 5.5-month benefit in overall survival are quite good in triple-negative breast cancer,” Dr. Cardoso noted. It is particularly impressive, she said, in light of the number of previous lines of treatment in this study: a median of 4 prior lines and as many as 17, “which is remarkable for this subtype,” she pointed out.

Apart from the usual hematologic toxicities, almost 60% of patients experienced some nausea or diarrhea, “all grades of which affect quality of life,” noted Dr. Cardoso. Fatigue and alopecia also occurred, but few patients discontinued the study because of these or other side effects. Clinicians using this drug “should focus on education, prophylaxis, and early management of side effects,” she advised.

Study Drawbacks

Dr. Cardoso thought the study would have been stronger had it made overall survival the primary endpoint. “This is important in the metastatic setting, especially in triple-negative disease, where median overall survival is quite low and where each line of treatment, especially after the second line, has a short duration,” she commented. “My plea is for studies to ensure that overall survival is at least a co-primary endpoint.”

In addition, Dr. Cardoso was disappointed to see the study stopped early. “It’s better to finish a trial and have the final results sufficiently powered,” especially when the benefit is “moderate and not a breakthrough,” she said. “Don’t stop trials too early, especially with new agents that are not commercially available.”

These points aside, Dr. Cardoso affirmed that sacituzumab govitecan is beneficial in managing advanced triple-negative breast cancer. “We should now add this drug to the guidelines for patients pretreated with two or more lines of therapy.” 

DISCLOSURE: Dr. Cardoso has served as a consultant or advisor to Amgen, Astellas Pharma, AstraZeneca, Celgene, Daiichi Sankyo, Eisai, GE Healthcare, Genentech, GlaxoSmithKline, MacroGenics, Medscape, Merck Sharp & Dohme, Merus, Mundipharma, Mylan, Novartis, Pfizer, Pierre Fabre, Prime Oncology, Roche, Samsung Bioepis, Sanofi, Seattle Genetics, and Teva and has been reimbursed for travel, accommodations, or other expenses by AstraZeneca, Pfizer, and Roche.