Sermonix Pharmaceuticals shares PK, baseline data tied to Lasofoxifene trials

Sermonix Pharmaceuticals broadly shared the three poster presentations examining clinical data tied to Sermonix’s Evaluation of Lasofoxifene, which Sermonix licensed globally from Ligand, in ESR1 Mutations studies. The presentations were initially shared last week at the 2023 San Antonio Breast Cancer Symposium. One poster addressed pharmacokinetics of lasofoxifene as a monotherapy and in combination with Eli Lilly and Company’s CDK4/6 inhibitor abemaciclib. Key takeaways included: PK data for lasofoxifene 5 mg/day were consistent with previous clinical trials, resulting in similar steady-state concentrations in patients across several studies. Addition of abemaciclib to lasofoxifene did not appear to alter the PK of lasofoxifene in ELAINE-2 compared with monotherapy in ELAINE-1, suggesting little to no drug-drug interaction. Abemaciclib concentrations in ELAINE-2 were consistent with previous monotherapy data, suggesting no impact of lasofoxifene on abemaciclib PK. A second poster discussed baseline genomic alterations and the activity of lasofoxifene and abemaciclib during the ELAINE-2 study. Key results/conclusions included: In 26 of the 29 patients enrolled, ESR1 mutations were identified at baseline by the Guardant360 CDx test. The profiling demonstrated that other genomic alterations are frequently detected concurrently with ESR1 mutations in the endocrine-resistant setting, in line with previous findings among patients with hormone receptor-positive mBC.Co-alterations in ESR1 and other genes associated with treatment resistance did not appear to compromise the efficacy of lasofoxifene plus abemaciclib in ELAINE-2. A third poster offered a trial-in-progress update on ELAINE-3, a 400-patient Phase 3 study assessing the efficacy and safety of lasofoxifene in combination with abemaciclib in treating locally advanced or ER+/HER2- mBC with an ESR1 mutation. ELAINE-3 enrollment is now underway.