title: Design, power, and interpretation of studies in the standard murine model of ALS.
abstract: Identification of SOD1 as the mutated protein in a significant subset of familial amyotrophic lateral sclerosis (FALS) cases has led to the generation of transgenic rodent models of autosomal dominant SOD1 FALS. Mice carrying 23 copies of the human SOD1(G93A) transgene are considered the standard model for FALS and ALS therapeutic studies. To date, there have been at least 50 publications describing therapeutic agents that extend the lifespan of this mouse. However, no therapeutic agent besides riluzole has shown corresponding clinical efficacy. We used computer modeling and statistical analysis of 5429 SOD1(G93A) mice from our efficacy studies to quantify the impact of several critical confounding biological variables that must be appreciated and should be controlled for when designing and interpreting efficacy studies. Having identified the most critical of these biological variables, we subsequently instituted parameters for optimal study design in the SOD1(G93A) mouse model. We retested several compounds reported in major animal studies (minocycline, creatine, celecoxib, sodium phenylbutyrate, ceftriaxone, WHI-P131, thalidomide, and riluzole) using this optimal study design and found no survival benefit in the SOD1(G93A) mouse for any compounds (including riluzole) administered by their previously reported routes and doses. The presence of these uncontrolled confounding variables in the screening system, and the failure of these several drugs to demonstrate efficacy in adequately designed and powered repeat studies, leads us to conclude that the majority of published effects are most likely measurements of noise in the distribution of survival means as opposed to actual drug effect. We recommend a minimum study design for this mouse model to best address and manage this inherent noise and to facilitate more significant and reproducible results among all laboratories employing the SOD1(G93A) mouse.
authors.affiliation: ALS Therapy Development Institute, Cambridge, Massachusetts 02142, USA. sscott@als.net
authors.forename: Sean
authors.initials: S
authors.lastname: Scott
authors.forename: Janice E
authors.initials: JE
authors.lastname: Kranz
authors.forename: Jeff
authors.initials: J
authors.lastname: Cole
authors.forename: John M
authors.initials: JM
authors.lastname: Lincecum
authors.forename: Kenneth
authors.initials: K
authors.lastname: Thompson
authors.forename: Nancy
authors.initials: N
authors.lastname: Kelly
authors.forename: Alan
authors.initials: A
authors.lastname: Bostrom
authors.forename: Jill
authors.initials: J
authors.lastname: Theodoss
authors.forename: Bashar M
authors.initials: BM
authors.lastname: Al-Nakhala
authors.forename: Fernando G
authors.initials: FG
authors.lastname: Vieira
authors.forename: Jeyanthi
authors.initials: J
authors.lastname: Ramasubbu
authors.forename: James A
authors.initials: JA
authors.lastname: Heywood
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology / Q000235:genetics* / Q000401:mortality; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D012107:Research Design; D013045:Species Specificity; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1; D016019:Survival Analysis
chemical_list: C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1