Q-TWiST Analysis of Patients Receiving Temsirolimus or Interferon Alpha for Treatment of Advanced Renal Cell Carcinoma

Abstract

For patients with advanced cancers, it is important that treatment improves the quality as well as the quantity of survival. This quality-adjusted time without symptoms of progression or toxicity (Q-TWiST) analysis provides a combined measure of both the overall survival interval and the quality of survival for patients with advanced renal cell carcinoma (RCC) receiving temsirolimus, interferon (IFN)-alpha or the combination of these agents, using data from a phase III clinical trial. Overall survival was partitioned into three distinct health states: time with serious toxicity (TOX), time after progression (REL) and time without symptoms of progression or toxicity (TWiST). Health states were quality weighted by patient-reported EQ-5D measures collected while receiving treatment. All 626 patients from the trial were included in computation of health-state durations. EQ-5D questionnaires were obtained from 260 patients upon progression and from 230 after a grade 3 or 4 adverse event, and from 278 patients in the TWiST state. Patients receiving temsirolimus had 38% longer TWiST than those receiving IFNalpha (6.5 vs 4.7 months, respectively; p = 0.0005). Patients receiving temsirolimus had 25% longer quality-adjusted survival in terms of Q-TWiST than those receiving IFNalpha (7.0 vs 5.6 months, respectively; p = 0.0015). Differences between the combination (temsirolimus + IFNalpha) and IFNalpha groups were not statistically significant. Threshold utility analysis indicated that temsirolimus was the preferred alternative for all possible utility weights for REL and TOX health states. Temsirolimus resulted in significantly longer Q-TWiST (quality-adjusted survival) in patients with advanced RCC than IFNalpha therapy.