The frequency of gastrointestinal adverse events with daily IR risedronate and the DR doses in this study is consistent with previous studies of daily, weekly, and monthly dosing with risedronate [11–13].

Table 2 Summary of adverse events   Risedronate 5 mg IR daily 35 mg DR FB weekly 35 mg DR BB weekly (N = 307) (N = 307) (N = 308) n click here (%) n (%) n (%) Adverse events 211 (68.7) 222 (72.3) 238 (77.3) Serious adverse events 22 (7.2) 20 (6.5) 21 (6.8) Deaths 1 (0.3) 0 (0.0) 0 (0.0) Withdrawn due to an adverse event 25 (8.1) 28 (9.1) 19 (6.2) Most common adverse events associated with withdrawal  Gastrointestinal disorder 11 (3.6) 17 (5.5) 13 (4.2) Most common adverse events  Influenza 19 (6.2) 22 (7.2) 18 Fulvestrant (5.8)  Nasopharyngitis 16 (5.2) 21 (6.8) 26 (8.4)  Arthralgia 24 (7.8) 21 (6.8) 19 (6.2)  Back pain 18 (5.9) 21 (6.8) 19 (6.2) Adverse events of special interest  Clinical Entinostat vertebral fracture 1 (0.3) 0 (0.0) 2 (0.6)  Clinical nonvertebral fracture 5 (1.6) 9 (2.9) 10 (3.2)  Upper gastrointestinal tract adverse events 45 (14.7) 48 (15.6) 61 (19.8)  Diarrhea 15 (4.9) 27 (8.8) 18 (5.8)  Abdominal

pain 9 (2.9) 16 (5.2) 15 (4.9)  Upper abdominal paina 7 (2.3) 9 (2.9) 23 (7.5)  Constipation 9 (2.9) 15 (4.9) 16 (5.2)  Selected musculoskeletal adverse eventsb 46 (15.0) 48 (15.6) 53 (17.2)  Adverse events potentially associated with acute C-X-C chemokine receptor type 7 (CXCR-7) phase reactionc 4 (1.3) 7 (2.3) 4 (1.3) a p value = 0.0041 bIncludes arthralgia, back pain, bone pain, musculoskeletal pain, musculoskeletal discomfort, myalgia, and neck pain cIncludes symptoms of influenza-like illness or pyrexia with a start date within the first 3 days after the first dose of study drug and duration of 7 days or less Other adverse events of special interest for bisphosphonates include clinical fractures, musculoskeletal

adverse events, and acute phase reaction adverse events. Clinical fractures are defined as all nonvertebral fractures and symptomatic, radiographically confirmed vertebral fractures that occurred after randomization and were reported as adverse events. Acute phase reactions are defined as influenza-like illness and/or pyrexia starting within 3 days following the first dose of study drug and having a duration of 7 days or less. Clinical vertebral and nonvertebral fractures occurred infrequently. The numeric differences noted were not statistically significant, and the types of fractures were similar among the treatment groups. Musculoskeletal adverse events were reported by similar proportions of subjects across treatment groups (Table 2). No cases of acute phase reaction or osteonecrosis of the jaw were reported. Small decreases in serum calcium and the expected reciprocal increases in serum iPTH 1–84 were seen within the first few weeks of treatment, as expected upon initiation of antiresorptive therapy.