AACR 2020: Lapatinib-Based First-Line Treatment in Metastatic Breast Cancer
Posted: Thursday, April 30, 2020
Based on international phase III trial data presented at the 2020 American Association for Cancer Research (AACR) Virtual Annual Meeting (Abstract CT212), first-line treatment of paclitaxel, trastuzumab, and lapatinib was found to be tolerated, with gastrointestinal toxicity as the predominant adverse event. However, a progression-free survival benefit in patients with HER2-positive metastatic breast cancer did not reach statistical significance; although the study was underpowered for this endpoint.
According to Denis M. Collins, PhD, of Dublin City University, and colleagues, “The addition of a HER2-targeted [tyrosine kinase inhibitor] to trastuzumab-containing chemotherapy regimens warrants investigation in HER2-positive [metastatic breast cancer].”
The international study included 75 patients who were randomly assigned to receive either 80 mg/m2 of paclitaxel for 3 out of a 4-week cycle plus 8 mg/kg of trastuzumab on the first day of each cycle. This was followed by 4 mg/kg every 2 weeks or a combination of paclitaxel and trastuzumab plus 1,000 mg of lapatinib daily. Patients continued treatment until disease progression, unacceptable toxicity, or withdrawal of consent. A total of 65 patients, including 31 in the lapatinib group, were evaluable for progression-free survival. The lapatinib group experienced a numerically higher median progression-free survival, although it did not reach the threshold for statistical significance (24.0 vs. 19.3 months). Similarly, no meaningful difference was noted in overall survival.
The most common adverse events were gastrointestinal disorders, with diarrhea occurring twice as often with lapatinib (88% vs. 42%). The lapatinib group also experienced a higher incidence of grade 3 and 4 adverse events (61.8% vs. 50.0%) as well as adverse event–related deaths (2 vs. 0).
Disclosure: For full disclosures of the study authors, visit abstractsonline.com.
