<qa>  What is the primary outcome of ASAS20?Efficacy of the treatment is measured by reduction in the signs and symptoms of axial spondyloarthritis at weeks 12 and 24. If the primary outcome of ASAS20 ASsessment in Ankylosing Spondylitis response criteria, improvement of at least 20 in patient reported symptoms is not met at the week 12, the dose of methotrexate or corresponding placebo will be increased to 20 mg per week during weeks 12 to 24. 