Rapid Fire Best of the Best Poster Oral Clinical Oncology Society of Australia Annual Scientific Meeting 2022

Evaluation of quality of life as an early surrogate of overall survival: an analysis from phase 3 immunotherapy trials (#117)

Adel Shahnam 1 , Udit Nindra 2 , Rina Hui 1 , Ashley M Hopkins 3 , Michael J Sorich 3
  1. Medical Oncology, Westmead Hospital, Sydney, NSW, Australia
  2. Medical Oncology, Liverpool Hospital, Sydney, NSW, Australia
  3. College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia

Aims

Improvement of overall survival (OS) is the benchmark to evaluate treatment efficacy but requires time to mature. Measures such as progression free survival (PFS) and objective response rate (ORR) are used as radiological surrogates of OS. However, PFS and ORR do not take into account the patients clinical status. We explored quality of life (QoL) measures as an early surrogate of OS and evaluate their correlation when combined with PFS and/or ORR for patients treated with immunotherapy.  


Methods

We utilised published phase 3 RCTs of immunotherapies in solid malignancies that reported OS, PFS, ORR, QoL measures of time to deterioration (TTD) of global health status (GHS) or TTD of physical function (PF) by 31st of January 2022.  Spearman’s test and regression analysis was utilised to assess the relationship between PFS, ORR ratio, TTD GHS and TTD PF with OS. Multivariate regression was performed to assess the effect on the strength of correlation of adding QoL measures to established OS surrogates .

 

Results

43 studies were included. The regression coefficient of determination (R2) of the relationship of PFS and ORR ratio to OS was 0.46 and 0.29 respectively. TTD of GHS and PF was statistically associated with OS with TTD PF having a higher R2 (0.46) on regression. On multivariate regression, the model that contained PFS and TTD PF substantially improved correlation  with OS (R2 = 0.76) than PFS alone. Importantly, PFS was poorly correlated with TTD PF (R2 = 0.02) suggesting TDD PF is independent of PFS as a surrogate of OS.

 

Conclusion

When both TDD PF and PFS were utilized together, there was an improved and strong correlation with OS. This suggests the potential predictive value of incorporating both clinical (PRO) and radiological (PFS or ORR) surrogates into models to predict OS in patients treated with immunotherapy.