C5aR1 antagonist PMX53 showed no detrimental toxicity in human clinical trials of refractory rheumatoid arthritis [276], and PMX205 with its greater access to the brain than PMX53 [277], is in development for clinical trials by Alsonex Pharmaceuticals for neurodegenerative diseases, including motor neuron disease and ALS. This evidence concerns the gene C5AR1 and amyotrophic lateral sclerosis.