COMPliance and Arthralgia in Clinical Therapy: the COMPACT trial, assessing the incidence of arthralgia, and compliance within the first year of adjuvant anastrozole therapy.

BACKGROUND This prospective study evaluated the relationship between arthralgia and compliance during the first year of adjuvant anastrozole therapy in postmenopausal women with hormone receptor-positive early breast cancer. PATIENTS AND METHODS COMPliance and Arthralgia in Clinical Therapy (COMPACT) was an open-label, multicenter, noninterventional study conducted in Germany. Patients had started adjuvant anastrozole 3-6 months before the study start. The primary end points were arthralgia, compliance, and the relationship between compliance and arthralgia, assessed at specific time points. RESULTS Overall, 1916 patients received upfront anastrozole. Mean arthralgia scores were increased from baseline at each visit up to 9 months. Compliance with anastrozole therapy gradually decreased over time from baseline to 9 months (P<0.001). At 9 months, investigators estimated that >95% of patients were compliant versus patient reports of <70%. There was a significant association between arthralgia mean scores and noncompliance at 6 months (P<0.0001), 9 months (P<0.0001), and overall (P<0.0001). Over time, new events or impairment of existing arthralgias were reported in 14% (3 months), 11% (6 months), and 9% (9 months) of patients. CONCLUSION Arthralgia is important in the clinical management of women with early breast cancer and may contribute to noncompliance and clinical outcomes. CLINICALTRIALSGOV IDENTIFIER NCT00857012.