van Eijk RPA, et al. - The physicians investigated whether plasma creatinine could monitor disease progression and serve as a surrogate endpoint in amyotrophic lateral sclerosis (ALS) clinical trials. They found plasma creatinine to be an inexpensive and easily accessible biomarker that demonstrated less variability between patients with ALS over time. It was predictive for the patient’s functional status, muscle strength and mortality risk. Therefore, plasma creatinine seemed to have potential to increase the power to detect treatment effects and could be incorporated in future ALS clinical trials as a potential surrogate outcome.