A phase 1b study evaluating the effect of elacestrant treatment on estrogen receptor availability and estradiol binding to the estrogen receptor in metastatic breast cancer lesions using 18F-FES PET/CT imaging

Table 5 Grade 3 adverse events, serious adverse events, and adverse events leading to discontinuation

Adverse event (AE), n (%)	Elacestrant dose cohort
Adverse event (AE), n (%)	200/400 mg (N = 8)	400 mg (N = 8)	Overall (N = 16)
Grade 3 AEs^a	1 (12.5)	3 (37.5)	4 (25.0)
Anemia	0	1 (12.5)	1 (6.3)
Circulatory collapse	0	1 (12.5)	1 (6.3)
Esophagitis	1 (12.5)	0	1 (6.3)
Cystitis	0	1 (12.5)	1 (6.3)
Pulmonary embolism	0	1 (12.5)	1 (6.3)
Serious AEs	1 (12.5)	2 (25.0)	3 (18.8)
Esophagitis	1 (12.5)	0	1 (6.3)
Amnesia	0	1 (12.5)^b	1 (6.3)
Circulatory collapse	0	1 (12.5)^b	1 (6.3)
Presyncope	0	1 (12.5)^b	1 (6.3)
Pulmonary embolism	0	1 (12.5)^c	1 (6.3)
Dyspnea	0	1 (12.5)^c	1 (6.3)
AEs leading to elacestrant discontinuation	3 (37.5)	0	3 (18.8)
Esophagitis	1 (12.5)	0	1 (6.3)
Nausea	1 (12.5)^d,e	0	1 (6.3)
Fatigue	1 (12.5)^d,e	0	1 (6.3)
Anorexia	1 (12.5)^d,e	0	1 (6.3)
Cough	1 (12.5)^d,f	0	1 (6.3)
Upper extremity peripheral edema	1 (12.5)^d,f	0	1 (6.3)

^aThere were no grade 4 AEs
^bThese events occurred in the same patient
^cThese events occurred in the same patient
^dThese events occurred during treatment with elacestrant 400 mg
^eGrade 2 nausea, fatigue, and anorexia occurred in the same patient
^fGrade 2 cough and grade 1 upper extremity peripheral edema occurred in the same patient

ISSN: 1465-542X