SAN ANTONIO –
This news organization spoke with SABCS program director Virginia Kaklamani, MD, leader of the Breast Cancer Program at UT Health, San Antonio, and Jason A. Mouabbi, MD, of the University of Texas MD Anderson Cancer Center, Houston, about their top five picks on HR-positive disease – the research they were most excited about and what the findings could mean for clinical practice and patient outcomes.
1. Addressing an unmet need
Data from the phase 3 CAPItello-291 clinical trial showed that the addition of the investigational AKT inhibitor capivasertib to fulvestrant resulted in statistically significant and clinically meaningful improvement in progression-free survival (PFS) among 708 patients with HR-positive, HER2-negative advanced breast cancer, compared with those who received placebo plus fulvestrant (GS3-04).
For patients treated with capivasertib plus fulvestrant, median PFS was 7.2 months, compared with 3.6 months for those who received placebo plus fulvestrant (hazard ratio, 0.60). Among patients assigned to the capivasertib group, 41% had tumors with AKT pathway mutations. In this group, the median PFS was 7.3 months vs. 3.1 months in the placebo cohort. The objective response rate among patients with measurable disease was 23% overall in the capivasertib group, compared with 12.2% in the placebo arm; it was 28.8% vs. 9.7% among the patients with AKT alterations.
Dr. Mouabbi noted that the study “met its primary endpoint” and that, importantly, it “addresses an area of unmet need.”
“The study’s treatment targets the PI3K/AKT/mTOR pathway, which is a very active pathway in hormone-positive metastatic breast cancer,” Dr. Mouabbi explained. He noted, “We’ve always wanted to tackle that pathway effectively, and it looks like this drug can do that.”
2. Next-generation SERD
Data from the phase 2 SERENA-2 trial offers evidence that camizestrant, a next-generation selective estrogen-receptor degrader (SERD), improved PFS compared with fulvestrant for patients with HR-positive, HER2-negative breast cancer (GS3-02).
Overall, 240 patients were randomly assigned to receive camizestrant monotherapy at various doses or fulvestrant at 500 mg. Among patients who received camizestrant 75 mg, median PFS was 7.2 months; among those who received camizestrant 150 mg, PFS was slightly longer, at 7.7 months vs. 3.7 months for patients treated with fulvestrant. Compared with fulvestrant, camizestrant reduced the risk of disease progression by 42% at 75 mg (HR, 0.58) and by 33% at 150 mg (HR, 0.67). In a subgroup of patients with ESR1 mutations, camizestrant reduced the risk of disease progression by 67% in the group that received 75 mg and by 45% in the group that received 150 mg, compared with fulvestrant (median PFS, 6.3, 9.2, and 2.2 months, respectively).
“In this trial, camizestrant looks like a more beneficial treatment in the target group,” said Dr. Kaklamani. “This is significant because it means that camizestrant could be used in the future in HR-positive metastatic breast cancer instead of fulvestrant.” In addition, “camizestrant is taken orally and is much more convenient for patients, unlike fulvestrant, which is taken intramuscularly.”