Yosuke Yoshida1,2, Masayuki Kaneko3, Mamoru Narukawa3. 1. Department of Clinical Medicine (Pharmaceutical Medicine), Graduate School of Pharmaceutical Sciences, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo, 108-8641, Japan. dl17406@st.kitasato-u.ac.jp. 2. MSD K.K., a Subsidiary of Merck & Co., Inc, Kenilworth, NJ, USA. dl17406@st.kitasato-u.ac.jp. 3. Department of Clinical Medicine (Pharmaceutical Medicine), Graduate School of Pharmaceutical Sciences, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo, 108-8641, Japan.
Abstract
BACKGROUND: Although it is suggested that the endpoints originated from the concept of tumor shrinkage dynamics, such as early tumor shrinkage and depth of response, are strongly associated with overall survival (OS) in patients with metastatic colorectal cancer (mCRC), they are yet to be validated as a single surrogate endpoint of OS by themselves. This study aimed to investigate the impact of advantage in tumor response on the correlation between treatment effects on progression-free survival (PFS) and OS in mCRC patients. METHODS: Based on an electronic search, we identified randomized controlled trials of first-line therapy for mCRC. The impact of advantage in objective response rate (ORR) on the correlation between treatment effects on PFS and OS was evaluated based on Spearman correlation coefficients (rs). RESULTS: Forty-seven trials with a total of 24,018 patients were identified. The hazard ratio for PFS showed a relatively higher correlation with that for OS (rs = 0.63) when the trials were limited to those that demonstrated a larger difference in ORR, compared to the case for trials that demonstrated a smaller difference (rs = 0.32). This tendency was also observed in the subgroup analysis stratified by the types of treatment agents (targeted or non-targeted). CONCLUSIONS: The magnitude of advantage in tumor response was suggested to contribute to a better prediction of OS benefit based on PFS in patients with mCRC. The accuracy of OS estimation in mCRC is expected to be improved by considering the degree of tumor shrinkage in conjunction with PFS.
BACKGROUND: Although it is suggested that the endpoints originated from the concept of tumor shrinkage dynamics, such as early tumor shrinkage and depth of response, are strongly associated with overall survival (OS) in patients with metastatic colorectal cancer (mCRC), they are yet to be validated as a single surrogate endpoint of OS by themselves. This study aimed to investigate the impact of advantage in tumor response on the correlation between treatment effects on progression-free survival (PFS) and OS in mCRC patients. METHODS: Based on an electronic search, we identified randomized controlled trials of first-line therapy for mCRC. The impact of advantage in objective response rate (ORR) on the correlation between treatment effects on PFS and OS was evaluated based on Spearman correlation coefficients (rs). RESULTS: Forty-seven trials with a total of 24,018 patients were identified. The hazard ratio for PFS showed a relatively higher correlation with that for OS (rs = 0.63) when the trials were limited to those that demonstrated a larger difference in ORR, compared to the case for trials that demonstrated a smaller difference (rs = 0.32). This tendency was also observed in the subgroup analysis stratified by the types of treatment agents (targeted or non-targeted). CONCLUSIONS: The magnitude of advantage in tumor response was suggested to contribute to a better prediction of OS benefit based on PFS in patients with mCRC. The accuracy of OS estimation in mCRC is expected to be improved by considering the degree of tumor shrinkage in conjunction with PFS.