FDA Grants Approval to Elacestrant for ER+/HER2– Advanced Metastatic Breast Cancer

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Patients with estrogen receptor–positive, HER2-negative metastatic breast cancer can now receive elacestrant as treatment following the FDA’s approval of the agent.

The FDA has granted approval to elacestrant (Orserdu) for the treatment of postmenopausal women or adult men with estrogen receptor (ER)–positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer with progression after at least 1 line of therapy, according to a press release from the FDA.1

The FDA has also approved the Guardant360 CDx assay as a companion diagnostic for identifying patients who are suitable to receive treatment with elacestrant.

Approval of elacestrant was supported by data from the phase 3 EMERALD trial (NCT03778931), in which investigators compared elacestrant with standard of care (SOC) endocrine therapy among patients with ER­–positive, HER2-negative breast cancer.

Topline data indicated that the median progression-free survival (PFS) was 3.8 months (95% CI, 2.2-7.3) for elacestrant among patients with ESR1 mutations and 1.9 months (95% CI, 1.9-2.1) for patients receiving fulvestrant or other aromatase inhibitors (HR, 0.55; 95% CI, 0.39-0.77; 2-sided P = .0005).

The FDA has approved a recommended dose of 345 mg of oral elacestrant taken with food once a day until disease progression or unacceptable toxicity.

According to data from the EMERALD trial published in the Journal of Clinical Oncology, the primary end point PFS favored patients receiving elacestrant compared with those in the SOC arm in the overall population (HR, 0.70; 95% CI, 0.55-0.88; P = .002) and among patients with an ESR1 mutation (HR, 0.55; 95% CI, 0.39-0.77; P = .0005).2

The 6 and 12-month PFS rates for those with an ESR1 mutation and in the overall cohort in each respective arm were 34.3% vs 20.6% (95% CI, 14.1%-26.7%) and 22.3% (95% CI, 15.2%-29.4%) vs 9.5% (95% CI, 4.0%-14.8%). Among patients with an ESR1 mutation, the 6-month and 12-month PFS rates in each respective cohort were 40.8% (95% CI, 30.1%-51.4%) vs 19.1% (95% CI, 10.5%-27.8%) and 26.8% (95% CI, 16.2%-37.4%) vs 8.2% (95% CI, 1.3%-15.1%).

Investigators of the trial enrolled a total of 477 patients, with 239 patients receiving elacestrant and 238 receiving SOC endocrine therapy. The median age of patients was 63 years, and 47.8% (n = 228) of patients had detectable ESR1 mutations. A total of 43.4% (n = 207) of patients received 2 prior lines of endocrine therapy, and baseline characteristics were well-balanced between both treatment cohorts.

Common adverse effects (AEs) occurring in the elacestrant and SOC arms, respectively, included nausea (35.0% vs 18.0%), fatigue (19.0% vs 18.8%), and vomiting (19.0% vs 8.3%). The most common grade 3 or 4 AEs observed in the elacestrant arm included nausea (2.5%), back pain (2.5%), and increased alanine transaminase (2.1%). A total of 6.3% of patients in the elacestrant arm and 4.4% in the SOC arm discontinued treatment due to AEs.

References

  1. FDA approves elacestrant for ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer. News release. FDA. January 27, 2023. Accessed January 27, 2023. bit.ly/3kQrxHq
  2. Bidard FC, Kaklamani VG, Neven P, et al. Elacestrant (oral selective estrogen receptor degrader) versus standard endocrine therapy for estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer: results from the randomized phase III EMERALD trial. J Clin Oncol. Published online May 18, 2022. doi:10.1200/JCO.22.00338

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