Radius Health, Inc. (“Radius”) and Menarini Group (“Menarini”) shared details about the elacestrant data of the EMERALD study. These results were presented at the San Antonio Breast Cancer Symposium. The data was presented by Dr. Aditya Barhia, MD as a “Late Breaker”, and shared in an oral presentation.
The EMERALD trial (NCT03778931) was a multicenter, international, randomized and controlled phase 3 trial that evaluated elacestrant monotherapy versus SoC in the treatment of ER+/HER2-advanced or mBC. Patients who had received one or two prior lines of Endocrine Therapy (ET) were eligible for the trial. All patients had to have progressed on an ET plus CDK4/6 inhibitors prior. One line of chemotherapy was permitted.
EMERALD met its primary objectives: progression-free survival for the entire population and PFS for patients with Estrogen Receptor-1 mutations.
Dr. Aditya BARDIA, MD, breast medical-oncologist at Mass General Cancer Center Harvard Medical School, and principal investigator of EMERALD commented that patients with advanced or metastatic ER+/HER2- breast cancer have few treatment options because of endocrine resistance to earlier treatment lines. Dr. Bardia said, “Elacestrant–as the first oral SERD–has the potential to be the new standard in care due to its performance vs. SoC in both the general population and the ESR1 subgroup.” Elacestrant, an oral monotherapy, will be an effective and safe option for patients, their families and healthcare providers going forward.
Elcin Barker Ergun is the Chief Executive Officer at the Menarini Group. She said, “We are extremely happy with the results of the EMERALD research. Data from the EMERALD study clearly show that elacestrant is an oral option that can be tolerated and effective vs. SoC and fulvestrant in 1/3 line for patients with advanced or metastatic breast carcinoma, as well as patients with tumors harboring ESR1 mutations. This subgroup of cancers can be difficult to treat. Given the positive safety and efficacy findings, we plan to submit regulatory submissions in the United States of America and the European Union in 2022. We thank all patients, their families, and healthcare professionals who participated in this important clinical trial.
Menarini will pursue combination studies and begin activity in new therapeutic lines, such as the adjuvant setting. This will allow elacestrant fully to address the unmet needs of ER+/HER2-patients. FDA granted elacestrant fast track status in 2018.
Test Results:
All patients were required to receive CDK 4/6 inhibitors. A study of the patient population revealed that 69.4% had visceral metastasis, and 22.2% had received chemotherapy. EMERALD met both primary outcomes, which measured PFS for elacestrant monotherapy vs. soC in the overall population and mESR1 patients:
— Overall Population – Lower risk of death or progression compared to SoC by 30% (HR=0.697; 95% CI: 0.5552, 0.880] P=0.0018
— Extended median PFS of 2.79 months, compared to SoC of 1.91
– 12 month probability of PFS was 22.3% (95 CI 15.2%, 29.4%) for elacestrant and 9.4% (95%CI 4.0%, 14.8%), for SoC.
— Comparable to fulvestrant elacestrant had a 32% lower risk of death or progression (HR=0.684; 95% CI: 0.521, 0.897] P=0.0049).
— ESR1 Mutation Population
– Lower risk of death or progression compared to SoC by 45% (HR=0.546; 95% CI: 0.3387, 0.768] P=0.0005)
— Extended median PFS of 3.78 months, versus 1.87 SoC
– 12 month probability of PFS 26.8% (95%CI: 16.2%,37.4%) with elacestrant, vs. 8.2% (95%CI: 1.3%-15.1%) with SoC
– Elacestrant had a 50% lower risk of death or progression than fulvestrant (HR=0.504; 95% CI: 0.3341, 0.741; P=0.0005)
— Both patient populations had similar results. Results in key subgroups such as visceral metastases and number of prior lines were consistent with overall outcome
Overall Survival (OS) is a key secondary endpoint in the EMERALD trial. Pre-specified interim analyses indicate a trend favoring SoC over elacestrant in both patient groups. Final analysis is expected in the latter half of 2022 or early twenty-three.
Safety Results:
Elacestrant was tolerated well and had a positive safety profile, consistent with other ETs.
— TEAEs that lead to discontinuation are rare in the SoC and elacestrant arms (6.3%, 4.4%)
— Grade 3 and higher TRAE was 7.2% for elacestrants and 3.1% soC
— Grade 3 and higher adverse events in elacestrants: nausea, vomiting, and diarrhea were respectively 2.5%, 0.8%, and 0%
Data are being systematically analyzed and further results will be published in peer-reviewed journals.
About the Elacestrant (RAD1901), EMERALD Phase3 Study
Elacestrant, a selective estrogen receptor-degrader (SERD), is licensed to Menarini Group and is currently being evaluated for its potential use as an oral treatment once daily in advanced ER+/HER2- breast cancer patients. The compound can be used alone or in combination with other treatments for breast cancer, according to studies done prior to EMERALD. The EMERALD Phase 3 trial, which is randomized, open-label, active-controlled, evaluates elacestrant in ER+/HER2-metastatic breast cancer patients. The study included 477 patients who had received one to two lines of endocrine treatment, including a 4/6 inhibitor and cyclin-dependentkinase (CDK). The study involved 477 patients who had received prior treatment with one or two lines of endocrine therapy, including a cyclin-dependent kinase (CDK) 4/6 inhibitor. Patients were randomly assigned to either an approved hormonal agent or elacestrant. The primary endpoint is progression-free survival (PFS), in both the general patient population as well as in patients with ESR1 mutations. Evaluation of overall survival (OS), objective rate (ORR) and duration of response are secondary endpoints.
