The Menarini Group and Stemline Therapeutics, Inc. a wholly-owned subsidiary of the Menarini Group, focused on bringing transformational oncology treatments to cancer patients, presented results from phase 1b/2 ELEVATE and ELECTRA clinical studies evaluating ORSERDU® (elacestrant) in combination with other treatments. Both the ELEVATE and ELECTRA studies were designed with the objective to overcome different resistance mechanisms and enhance patient outcomes with combination treatment options. Data was presented at the 2023 San Antonio Breast Cancer Symposium (SABCS), December 5-9, 2023.

The ELEVATE study is evaluating elacestrant in combination with inhibitors of the PI3K/AKT/mTOR pathway (everolimus and alpelisib) and cell-cycle pathway inhibitors (palbociclib, ribociclib, and abemaciclib). Results reported at SABCS 2023 include all combination data from Cohort 1 of the phase 1b portion of the study, with the therapies showing predictable safety profiles that were consistent with prior studies. Additional cohorts are currently under evaluation to assess pharmacokinetics (PK) and determine the recommended phase 2 dose (RP2D) for each combination.

The ELECTRA study is evaluating elacestrant in combination with abemaciclib. Phase 1b of this study will also determine the recommended phase 2 dose (RP2D) of this combination in patients regardless of metastases sites.  Phase 2 will evaluate the benefit of the combination in patients with ER+/HER2- advanced or metastatic breast cancer with brain metastases since both compounds have demonstrated the ability to cross the blood-brain barrier. Results reported at SABCS 2023 include the three dose cohorts of the phase 1b portion of the study, showing a tolerable and manageable safety profile with favorable preliminary efficacy in these patients, regardless of the site of their metastases.

The three cohorts have been completed with no patients experiencing dose limiting toxicities. No discontinuations have been observed for any patient beyond the observation period due to toxicity. Most common adverse events were diarrhea, nausea, and neutropenia/neutrophil count decreased.

Only neutropenia was associated with grade 3 events with the combination; managed with standard dose reduction for abemaciclib.