Validation of the Functional Assessment of Cancer Therapy-Ovarian (FACT-O) Symptom Index (FOSI) in a phase II clinical trial of pertuzumab in patients with advanced ovarian cancer

Abstract

16021 Background: The FOSI is a very brief(8-item) index derived from the FACT-O to measure symptom response to treatment for ovarian cancer(OC). We evaluated its performance in a single arm Phase II clinical trial. Methods: The FOSI was administered to patients with advanced OC participating in a single arm Ph II clinical trial of pertuzumab(Gordon et al, JCO (2006) v24:4324;2006)). Pertuzumab, a humanized HER2 antibody is the first in a new class of investigational agents known as HER dimerization inhibitors(HDIs). Patients completed the FOSI at D1 of each 3 week cycle, up to 17 cycles. Validation analyses focused on data from the first 4 cycles and included Cronbach's alpha coefficients plus cross-sectional and longitudinal comparisons of groups defined by ECOG performance status (PS). Results: 62 patients completed the FOSI at baseline (B), 54 at cycle 2, 44 at cycle 3 and 27 at cycle 4. The FOSI showed acceptable internal consistency reliability with alphas of 0.73 to 0.80. The FOSI differentiated patients with PS 0 from those with PS =1 at each cycle (Table). There was a difference in FOSI scores in patients with worsened PS from those whose PS improved or was unchanged at cycle 2 only (p<0.001). The ES (mean change/ SD of change scores) for the group with worsened PS was -0.77. The minimally important difference was estimated to be 2–3 points. Conclusions: The FOSI is a valid symptom measure in this population of OC patients, demonstrating acceptable reliability, validity and responsiveness to clinical change. [Table: see text] No significant financial relationships to disclose.