Final results from IMPROVE: a randomized, controlled, open-label, two-arm, cross-over phase IV study to determine patients’ preference for everolimus in combination with exemestane or capecitabine in combination with bevacizumab in advanced HR-positive, HER2-negative breast cancer

BACKGROUND: The objective of the IMPROVE study was patients’ preference for either endocrine-based therapy or combined chemo- and anti-angiogenic therapy in advanced HR-positive/HER2-negative breast cancer. METHODS: In this randomized, cross-over phase IV study, 77 patients were recruited in 26 sites in Germany. Patients were randomized 1:1 to receive either capecitabine plus bevacizumab (Cap+Bev) as first-line therapy followed by cross-over to everolimus plus exemestane (Eve+Exe) as second-line therapy (Arm A) or the reverse sequence (Arm B). The primary endpoint was patients’ preference for either regimen, assessed by the Patient Preference Questionnaire 12 weeks after cross-over. Key secondary endpoints included progression-free survival (PFS), overall survival (OS), safety, and quality of life (QoL). RESULTS: 61.5% of patients preferred Cap+Bev (p = 0.1653), whereas 15.4% preferred Eve+Exe and 23.1% were indecisive. Physicians showed a similar tendency towards Cap+Bev (58.1%) as the preferred regimen versus Eve+Exe (32.3%). Median first-line PFS was longer for Cap+Bev than for Eve+Exe (11.1 months versus 3.5 months). Median second-line PFS was similar between Cap+Bev and Eve+Exe (3.6 months versus 3.7 months). Median OS was comparable between Arm A (28.8 months) and Arm B (24.7 months). 73.0% and 52.6% (first−/second-line, Cap+Bev) and 54.1% and 52.9% (first−/second-line, Eve+Exe) of patients experienced grade 3/4 TEAEs. No treatment-related deaths occurred. QoL and treatment satisfaction were not significantly different between arms or treatment lines. CONCLUSIONS: Patients tended to favor Cap+Bev over Eve+Exe, which was in line with physicians’ preference. Cap+Bev showed superior first-line PFS, while QoL was similar in both arms. No new safety signals were reported. TRIAL REGISTRATION: EudraCT No: 2013–005329-22. Registered on 19 August 20