Is the Juice Worth the Squeeze? Overall Survival gain per unit treatment time as a metric of clinical benefit of systemic treatment in incurable cancers

Abstract

Introduction Novel systemic therapeutic options such as enzyme inhibitors and monoclonal antibodies have transformed the practice of medical oncology in the recent past. However, survival gains remain modest in most cases. Quantifying the magnitude of benefit against financial and non-financial toxicity of treatment is pivotal in deciding treatment. We describe a novel metric which can be used to assess effectiveness novel therapeutics for incurable cancers. Methods The median overall survival was divided by the median duration of treatment to obtain the overall survival gain per treatment time which was the primary end-point of the study. This parameter was compared with the European Society of Medical Oncology Magnitude of clinical benefit scale (ESMO-MCBS) score. Spearman's rank correlation coefficient was used to test the association between the novel metric and the ESMO-MCBS scores. Results Data were available for 30 drugs across 60 indications. The median overall survival per unit treatment time ranged from 0.68 (range 0.2-0.51). Only 18/60 indications had a ratio greater than 1 while 13/60 indications had a ratio less than 0.5. The median treatment duration was not mentioned in 11 indications and median progression free survival was substituted for the analysis. The ESMO-MCBS score was available for 49 of the indications. The Spearman's rank correlation coefficient was 0.44575 and showed a statistically significant association between survival gain per unit treatment time and the ESMO-MCBS score (p = 0.00133). Conclusions Along with other metrics, the ratio of survival gain over treatment duration is a useful parameter to assess effectiveness of novel therapeutics in the palliative setting.