SinoMab BioScience Limited announced that Phase III clinical trial of SinoMab's product SM03 (Suciraslimab) for rheumatoid arthritis (RA) in China (Study No.: SM03-RA-III) has completed unblinding and initial statistical analysis and achieved the primary endpoint, marking a significant step towards Suciraslimab's commercial launch. Suciraslimab is a global first-in-target anti-CD22 monoclonal antibody for the treatment of rheumatoid arthritis, and it is also the first-in-class anti-CD22 naked monoclonal antibody that has completed phase III clinical trial and reached the primary endpoint. The Phase III clinical trial is a randomized, multi-centre, double-blind, placebo-controlled study to confirm the clinical efficacy and safety in patients with moderate-to-severe active RA who had an inadequate response to methotrexate (MTX).

The primary endpoint of the phase III trial is to measure the percentage of participants with ACR 20 response at week 24. ACR20 is a composite measure for the assessment of rheumatoid arthritis improvement by the American College of Rheumatology, defined as a minimum 20% improvement in the number of tender and number of swollen joints compared to the patient's own baseline, and at least 20% improvement in three of the following five measurements: including three visual scoring scale (VAS, which refers to doctors' overall assessment of disease activity, patients' general assessment of disease activity, patients' assessment of pain conditions), the patient's health assessment questionnaire (HAQ-DI) and the level of acute phase reactant (blood sediment or C-reaction protein) tested by laboratories. The Phase III study results showed that Suciraslimab was effective in suppressing disease activity and alleviating symptoms of active RA patients receiving MTX therapy.

Relevant study result shall be published in academic journals and academic conferences. As a self-developed global first-in-target and first-in-class product of the Company, Suciraslimab demonstrates clinical efficacy for the treatment of RA and via the modulation of B cell activity, it has the potential for the treatment of other immunological diseases. By adopting a novel mechanism of action, which differentiates itself from the current treatments available in the market, Suciraslimab offers a new option for RA patients to obtain long-term treatment benefits, addressing the limitations of currently available treatments in terms of efficacy, safety, and in particular, deficiency in long-term post-drug resistance against mature RA targets.