PD06-07: COMPliance and Arthralgias in Clinical Therapy (COMPACT): Assessment of the Incidence and Severity of Arthralgia, Treatment Costs and Compliance within the First Year of Adjuvant Anastrozole Therapy.
Authors: Hadji P , Blettner M , Bolten WW , Harbeck N , Hindenburg H-J , Jackisch C , König K , Lueck H-J , Rief W , Zaun S , Klein P , Kreienberg R 
Published: June 2012

Introduction: Aromatase inhibitors (AI) are well established as adjuvant endocrine treatment for postmenopausal (PMP) women with HR+ early breast cancer (EBC). However, according to retrospective data, compliance to adjuvant endocrine therapy for EBC may drop to below 70% after one year and to as low as 50% by year 4. In clinical trials, AI are significantly more frequently associated with arthralgia than tamoxifen. Yet, prospective real world data on the effects of AI-associated arthralgia on patient compliance, patient outcomes as well as treatment costs of arthralgia are lacking.

Methods: COMPACT is an open, prospective, non-interventional study assessing the incidence and severity of arthralgia, treatment costs, and compliance within the first year of adjuvant anastrozole therapy in PMP women with HR+ EBC. The study is sponsored by AstraZeneca Germany and supported by three major German health insurance funds [GWQ ServicePlus AG, DAK, TK]. Patients on adjuvant treatment for 3–6 months were enrolled at 620 breast centres and practices throughout Germany and stratified by, a) initial adjuvant anastrozole therapy or, b) switch from tamoxifen to anastrozole. All patients receive regular standardized information about EBC from baseline to week 20 to support treatment compliance. Data on patient demographics, occurrence of and treatment of arthralgia, and quality of life will be collected at baseline, 3, 6 and 9 months. Primary endpoints are scaled data on arthralgia, assessed with a visual analogous scale (VAS) via patient questionnaire, and compliance to anastrozole in both strata, assessed by patient and investigator questionnaire. Secondary endpoints include the incidence of arthralgia, treatment costs, reasons for non-compliance, and the influence of arthralgia on clinical outcome. For a subgroup of patients data on arthralgia treatment and compliance will be validated with corresponding data of the participating health insurance funds.

Results: Between April 2009 and February 2011, 2313 patients were recruited, 2007 receiving upfront anastrozole and 306 patients on switch therapy. Preliminary baseline data for 2313 patients show the following patient characteristics: mean age 64.5 years, mean BMI 27.7. Only 16.8% of patients had received hormone replacement therapy prior to their cancer. 41.5% of patients had concomitant symptoms relating to skeleton or musculature, and 11.9% stated arthralgias existing prior to anastrozole treatment. 13.1% reported a worsening of pre-existing arthralgias or new arthralgia after starting on anastrozole treatment.

Conclusion: COMPACT aims to provide valid real world data on the incidence and severity of AI-associated arthralgia, treatment modalities and treatment costs. Our results will help to understand and better counsel patients about AI-associated arthralgia to improve adherence to AI-treatment, breast cancer outcomes, and therapy costs.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-07.