1. Ruxolitinib and exemestane for estrogen receptor positive, aromatase inhibitor resistant advanced breast cancer
- Author
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Makhlin, Igor, McAndrew, Nicholas P, Wileyto, E Paul, Clark, Amy S, Holmes, Robin, Bottalico, Lisa N, Mesaros, Clementina, Blair, Ian A, Jeschke, Grace R, Fox, Kevin R, Domchek, Susan M, Matro, Jennifer M, Bradbury, Angela R, Feldman, Michael D, Hexner, Elizabeth O, Bromberg, Jacqueline F, and DeMichele, Angela
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Oncology and Carcinogenesis ,Clinical Trials and Supportive Activities ,Cancer ,Breast Cancer ,Estrogen ,Clinical Research ,6.1 Pharmaceuticals ,Evaluation of treatments and therapeutic interventions ,Clinical sciences ,Oncology and carcinogenesis ,Epidemiology - Abstract
Circulating IL-6, an activator of JAK/STAT signaling, is associated with poor prognosis and aromatase inhibitor (AI) resistance in hormone-receptor positive (HR+) breast cancer. Here we report the results of a phase 2 single-arm Simon 2-stage trial combining Ruxolitinib, an oral selective inhibitor of JAK1/2, with exemestane, a steroidal AI, in patients with HR+ metastatic breast cancer (MBC) after progression on non-steroidal AI (NSAI). Safety and efficacy were primary objectives, and analysis of inflammatory markers as predictors of response was a key secondary objective. Twenty-five subjects enrolled. The combination of ruxolitinib and exemestane was safe, though anemia requiring transfusion in 5/15 (33%) at the 25 mg dose in stage 1 led to a reduction to 15 mg twice daily in stage 2 (with no additional transfusions). Clinical benefit rate (CBR) in the overall study population was 24% (95% CI 9.4-45.1); 6/25 patients demonstrated stable disease for ≥6 months. Median progression-free survival was 2.8 months (95% CI 2.6-3.9). Exploratory biomarkers revealed high levels of systemic inflammation and 60% harbored a high-risk IL-6 genotype. Pharmacodynamics demonstrated modest on-target inhibition of phosphorylated-STAT3 by ruxolitinib at a tolerable dose. Thus, ruxolitinib combined with exemestane at a tolerable dose was safe but minimally active in AI-resistant tumors of patients with high levels of systemic inflammation. These findings highlight the need for more potent and specific therapies targeting inflammation in MBC.
- Published
- 2022