Previously treated patients with advanced non-small-cell lung cancer (NSCLC) ought to receive pembrolizumab at a dose of 2 mg/kg once every 3 weeks (Q3W), authors of an evaluative study of the drug suggest.1
In this phase 1 study, a group of 449 patients was split into 3 cohorts, 55 patients received pembrolizumab 2 mg/kg Q3W, 238 received 10 mg/kg Q3W, and 156 received 10 mg/kg at Q2W. The overall response rate for the 55 patients receiving 2 mg/kg Q3W was 15% [95% CI, 7%-28%], whereas the latter groups responded at average rates of 25% and 21%, respectively.
The authors determined the relationship between the total drug exposure over 6 weeks (measured at a steady state) and longitudinal change in tumor size (measured by adding longest diameters) by regression and non-linear mixed effects modeling. The flat exposure-response relationship of the models suggested that the lowest evaluated dose (2 mg/kg Q3W) achieves optimal efficacy.
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It was concluded that doses larger than 2 mg/kg Q3W evaluated in the study were not clinically beneficial for patients with advanced NSCLC, despite the relatively small sample size of the first cohort. Adverse effects did not differ significantly among the 3 cohorts.
- Chatterjee M, Turner DC, Felip E, Lena H, Cappuzzo F, Horn L, et al. Systematic evaluation of pembrolizumab dosing in patients with advanced non-small-cell lung cancer [published online ahead of print April 26, 2016]. Ann Oncol. doi: 10.1093/annonc/mdw174.