BOLERO-4An Open-label, Phase II, Single-arm Study of Everolimus in Combination With Letrozole in the Treatment of Postmenopausal Women With Estrogen Receptor Positive HER2 Negative Metastatic or Locally Advanced Breast Cancer

This was an open-label, phase II, multicenter, international, single-arm study for postmenopausal women with ER+/HER2- metastatic or locally advanced breast cancer. This study was comprised of 2 phases: - Core Phase: from first participant first visit to 24 months after enrollment of the last participant (and upon approval of amendment 5 dated 14-Feb-2017), up to approximately 4 years. The main purpose of the amendment 5 was to implement an Extension Phase up to 3 years. During the core phase, all enrolled participants received everolimus in combination with letrozole in the first line setting until disease progression or any other reason for which the participant might be discontinued. Only those participants who had disease progression in the first line setting were offered second line treatment (everolimus in combination with exemestane). Participants who discontinued first line treatment due to reasons other than disease progression were not eligible for second line treatment. The participants who were treated in the second line setting continued treatment until disease progression, unacceptable toxicity or withdrawal of consent. - Extension Phase: Participants that were still benefiting from everolimus at the end of the Core Phase (and upon approval of amendment 5 dated 14-Feb-2017) were transitioned to the Extension phase of the study. Participants were continued on their existing line of treatment (everolimus plus letrozole or everolimus plus exemestane) in the extension, up to 3 years or until progression or any other reason for which the participant might be discontinued. Participants entering the Extension Phase on first line treatment and deemed to no longer be clinically benefiting were not offered second line treatment in the context of the study This study included a randomized, open-label sub-study for participants in countries where the alcohol-free 0.5mg/5ml dexamethasone oral solution was commercially available who experienced a stomatitis event: at the first onset of symptoms suggestive of stomatitis, participants were to contact the study site and based on preliminary confirmation of diagnosis, participants were asked to visit the study site within 24 hours. Upon confirmation of stomatitis, participants in countries where the alcohol-free 0.5 mg/5 mL dexamethasone oral solution was commercially available (US sites only) were randomly assigned in a 1:1 ratio to take either 0.5 mg/5 mL dexamethasone mouth rinse or the standard of care used to treat stomatitis at the participant's center. All participants who experienced stomatitis (regardless of inclusion in the sub-study) were instructed to fill out the Oral Stomatitis Daily Questionnaire (OSDQ) at home every day until the participant recovered. For subsequent episodes of stomatitis, participants were instructed to contact the physician. If part of the randomized set upon telephone confirmation, they were instructed to utilize the same treatment they were assigned to after the first episode and complete the OSDQ booklet.