1215P - Prediction of treatment effects for individual cancer patients using data from randomized clinical trials

Date 27 September 2014
Event ESMO 2014
Session Poster Display session
Topics Non-Small-Cell Lung Cancer, Locally Advanced
Presenter Rob van Kruijsdijk
Citation Annals of Oncology (2014) 25 (suppl_4): iv417-iv425. 10.1093/annonc/mdu348
Authors R.C.M. van Kruijsdijk1, F.L.J. Visseren1, L. Boni2, H.J.M. Groen3, A.C. Dingemans4, J.G. Aerts5, Y. van der Graaf6, A. Ardizzoni7, E.F. Smit8
  • 1Department Of Vascular Medicine, University Medical Center Utrecht, 3508GA - Utrecht/NL
  • 2Clinical Trials Coordinating Center, Istituto Toscano Tumori, University Hospital Careggi, Florence/IT
  • 3Department Of Pulmonary Diseases, University Hospital Groningen (UMCG), NL-9700 RB - Groningen/NL
  • 4Pulmonology, Maastricht University Medical Center (MUMC), NL-6202 AZ - Maastricht/NL
  • 5Pulmonary Diseases, Amphia Hospital/Erasmus MC, 4818CK - Breda/NL
  • 6Julius Center For Health Sciences And Primary Care, University Medical Center Utrecht, 3508GA - Utrecht/NL
  • 7Medical Oncology Unit, University Hospital, Parma/IT
  • 8Dept. Of Pulmonary Diseases, Vrije University Medical Centre (VUMC), NL-1081 HV - Amsterdam/NL

Abstract

Aim

Results from randomized clinical trials (RCTs) evaluating the efficacy of chemotherapy are typically reported as relative risk or difference in median survival on a group level. Patients are most interested in their personal expected absolute treatment effect. Translating group level estimates to individual patients in clinical practice is challenging, as absolute treatment effects can vary substantially among individuals. We propose a method for individualized treatment effect prediction using data from RCTs, to identify cancer patients who benefit from specific treatments.

Methods

Data from the NVALT7 study, a randomized phase II trial comparing pemetrexed (P) with P plus carboplatin (C) in 240 patients with non-small cell lung cancer relapsing after platinum based chemotherapy (Smit et al. J. Clin. Oncol. 2009), were analyzed. Cox proportional hazards models, including routinely available patient and tumor characteristics, were developed for individualized prediction of the absolute effects of adding C to P in terms of absolute increase in overall survival (OS), progression free survival (PFS) and risk of grade 3/4 toxicity. Models were internally validated and an external validation in the GOIRC 02 2006 randomized phase II study is planned.

Results

The predicted individual benefit in OS of adding C to P ranged from -1.2 to 10.8 months. Patients with squamous tumors, particularly those with better performance status, lower leucocyte count and longer treatment free interval, had the highest predicted median OS benefit from addition of C (3.2 months ), though with a wide range (1.4 to 10.8 months). The difference in predicted PFS for individuals ranged from 0.1 to 3.2 months. Internal validation showed a satisfactory model calibration and discrimination (c-index: 0.69/0.65 for OS/PFS). The predicted absolute risk increase (ARI) of toxicity with addition of C was similar in patients with ≤3 months predicted OS (ARI 5.0%) and those with longer predicted OS (ARI 5.2%).

Conclusions

Data from RCTs may be used to predict absolute treatment effects for individual patients before start of therapy. Individualized treatment effect predictions from validated models may guide treatment decisions in cancer patients by identifying those who benefit most in terms of OS and PFS and have low risk of toxicity.

Disclosure

E.F. Smit: EFS has received honoraria from Eli Lilly. All other authors have declared no conflicts of interest.