FDA Approves Novel Breast Cancer Treatment

On Jan. 27, 2023, FDA announced that it had approved Stemline Therapeutics’ Orserdu (elacestrant) as a treatment for postmenopausal women or adult men with estrogen-receptor (ER) positive, HER2-negative, estrogen receptor 1 (ESR1)-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy. In addition to elacestrant, FDA also approved the Guardant360 companion diagnostic assay to identify patients with breast cancer for treatment with elacestrant.

Efficacy for elacestrant was evaluated in a randomized, open-label, active-controlled, multicenter trial (EMERALD [NCT03778931]) that enrolled 478 postmenopausal women and men with ER-positive, HER2-negative advanced or metastatic breast cancer. Additionally, 228 patients in this population had ESR1 mutations. Patients were randomized (1:1) to receive elacestrant 345 mg orally once daily or the investigator’s choice of endocrine therapy.

The major efficacy outcome measure was progression-free survival (PFS). According to an agency press release, a statistically significant difference in PFS was observed in the full population and in the subgroup of patients with ESR1 mutations. In patients with ESR1 mutations, PFS was 3.8 months for patients treated with elacestrant vs. 1.9 months in those treated with a different endocrine therapy.

The recommended elacestrant dose is 345 mg taken orally with food once daily until disease progression or unacceptable toxicity. Prior to this approval, elacestrant was granted priority review and fast track designation.

Source: FDA