This is a randomized, double-blind, placebo-controlled, multicenter clinical study to evaluate the efficacy and safety of GR1501 injection in Radiographic Axial Spondyloarthritis, as well as a confirmatory clinical trial of immunogenicity.~This clinical trial was divided into four stages, namely screening period (W-4~W0), core treatment period (W0~W16), maintenance treatment period (W16~W32), and follow-up period (W32~W48).~target population： radiographic axial spondyloarthritis who had a inadequate response to NSAIDs or have a history of intolerance to NSAIDs.~primary outcome measure:percentage of participants achieving an ASAS20 response in week 16.
The purpose of this trial is to demonstrate the clinical efficacy of GR1501 at week 16; and to demonstrate safety and tolerability of GR1501 compared to placebo in patients with Radiographic Axial Spondyloarthritis at week 16 and long term safety up to Week 48。 The main question it aims to answer is whether GR1501 injection was superior to placebo in the proportion of subjects with ASAS20 response at week 16 in patients with Radiographic Axial Spondyloarthritis.