Adherence to Oral Anticancer Drugs (OAD) in Patients (pts) with Metastatic Renal Cancer (mrcc): First Results of the Prospective Observational Multicenter IPSOC Study (investigating Patient Satisfaction with Oral Anti-cancer Treatment).

4622 Background: Patient adherence to oral therapy is a critical issue in cancer treatment. The aim of this study is to investigate the prevalence and severity of non-adherence to OAD in mRCC and to identify factors predictive of non-adherence. Methods: Prospective observational multicenter trial performed at 11 Belgian academic and non-academic centers. All pts with mRCC starting OADs (sunitinib, pazopanib, everolimus or sorafenib) are eligible for the study. Pts are contacted by phone at baseline and at 1, 3, 6 and 12 months. At each contact, pts are asked to complete questionnaires investigating 1) medication adherence (MMAS), 2) patient satisfaction with treatment (CTSQ) and with treatment education (PS-CaTE), 3) the extent of information desire (EID), 4) quality of life (FACT-G and FKSI) and 5) the role of the pharmacist (SWiP). Adherence is measured using an electronic medication event monitoring system (MEMS, Aardex). Results: Between 02/2011 and 11/2011, 49 pts (m: 33, f: 16) with a median age of 63 years (range 25 - 87) have participated in the IPSOC study. Twenty-nine pts (64%) were treated with an OAD in first-line, 15 pts (33%) in second-line. With a median follow-up of 131 days (range 2 - 313) 45 pts (92%) claimed to be fully adherent to their treatment (based on MMAS and CTSQ data). Four patients indicated to have missed at least one dose, of whom two indicated they occasionally forgot their medication and two others interrupted treatment because of side effects. Based on MEMS data, mean adherence, defined as the percentage of days with at least the prescribed number of dosage taken, was 98.91%. Conclusions: The IPSOC study, the first to examine adherence to OAD among mRCC pts, shows that mRCC pts are almost fully adherent to treatment recommendations. This seems to be in contrast to adherence data for other, long-lasting, anti-cancer treatments. Further investigations will focus on the question whether extensive counseling and participation in side-effect programs contribute to the high percentage of adherence in this study.