SABCS 2022: Camizestrant Versus Fulvestrant for Hormone Receptor–Positive, HER2-Negative Breast Cancer

By: Julia Fiederlein Cipriano
Posted: Thursday, January 5, 2023

In the phase II SERENA-2 trial, both the 75- and 150-mg dose levels of camizestrant exhibited a statistically significant and clinically meaningful progression-free survival benefit versus fulvestrant in postmenopausal patients with advanced estrogen receptor–positive, HER2-negative breast cancer, according to Mafalda Oliveira, MD, PhD, of Vall d’Hebron University Hospital, Barcelona, and colleagues. The results, which were presented during the 2022 San Antonio Breast Cancer Symposium (SABCS; Abstract GS3-02), suggested treatment with this next-generation oral selective estrogen receptor degrader was also well tolerated.

“The results of this study support further development of camizestrant in hormone receptor–positive breast cancer,” commented Dr. Oliveira in a press release from the American Association for Cancer Research.

Patients who were previously treated with no more than one endocrine therapy and/or chemotherapy regimen were randomly assigned to receive 500 mg of fulvestrant or 75, 150, or 300 mg of camizestrant. The 75-mg camizestrant arm, 150-mg camizestrant arm, and fulvestrant arm comprised 74, 73, and 73 patients, respectively; the 300-mg camizestrant arm was discontinued early.

The median durations of progression-free survival in the overall, ESR1-mutated, and ESR1 wild-type populations were 7.2, 6.3, and 7.2 months with 75 mg of camizestrant; 7.7, 9.2, and 5.8 months with 150 mg of camizestrant; and 3.7, 2.2, and 7.2 months with fulvestrant, respectively.

Treatment-emergent adverse events of grade 3 or higher were reported in 12.2% of the 75-mg camizestrant arm, 21.9% of the 150-mg camizestrant arm, and 13.7% of the fulvestrant arm. Adverse events leading to discontinuation of treatment occurred in 2.7%, 0%, and 0% of patients treated with 75 mg of camizestrant, 150 mg of camizestrant, and fulvestrant, respectively. Photopsia (18.4%) and (sinus) bradycardia (13.6%) were the most common adverse events considered by the investigator to be causally related to camizestrant. The most frequently reported fulvestrant-related adverse events were hot flush (2.7%) and myalgia (2.7%).

Disclosure: For full disclosures of the study authors, visit sabcs.org.

2022 San Antonio Breast Cancer Symposium