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Background: Ivarmacitinib (SHR0302), a selective Janus kinase (JAK) 1 inhibitor, has shown efficacy in patients with active ankylosing spondylitis (AS).
Objectives: We reported the efficacy of Ivarmacitinib treatment in AS patients stratified by demographics and baseline disease characteristics.
Methods: This post-hoc analysis used data from the phase II/III trial (NCT04481139). Patients with active AS received Ivarmacitinib 4 mg (n=187) or placebo (n=186) from week 0 to week 12. Efficacy outcomes were compared between Ivarmacitinib and placebo, stratified by patient demographics and baseline disease characteristics.
Results: When stratified by patient demographics, the Ivarmacitinib 4 mg group showed significant improvement in Assessment of SpondyloArthritis international Society 20% improvement (ASAS20) in subgroups of age<40 years, male, female, BMI<24 kg/m 2 , and BMI≥24 kg/m 2 compared to placebo (all P <0.05, Table 1). Additionally, the Ivarmacitinib 4 mg group demonstrated higher ASAS20 response rates in subgroups of AS duration <5 and ≥5 years, with and without history of biological/JAK inhibitors, with total back pain and night pain VAS score ≤60 and >60, when stratified by baseline disease characteristics (all P <0.05, Table 2). Notably, the improvements were pronounced in patients with age<40 years, BMI<24 kg/m 2 , AS duration <5 years, and without a history of biological/JAK inhibitors.
Conclusion: Ivarmacitinib significantly improves treatment response in active AS across subgroups, especially in those with younger age, lower BMI, shorter disease duration, and without a history of biological/JAK inhibitors.
REFERENCES: NIL.
Comparisons of ASAS20 response at W12 based on subgroups of demographics.
| Items | Placebo | Ivarmacitinib 4 mg | P value |
|---|---|---|---|
| Age | |||
| <40 years | 43 (30.5) | 72 (50.0) | 0.001 |
| ≥40 years | 11 (24.4) | 19 (44.2) | 0.051 |
| Sex | |||
| Male | 42 (28.8) | 69 (45.7) | 0.003 |
| Female | 12 (30.0) | 22 (61.1) | 0.006 |
| BMI | |||
| <24 kg/m 2 | 29 (29.6) | 51 (52.6) | 0.001 |
| ≥24 kg/m 2 | 25 (28.4) | 40 (44.4) | 0.026 |
Data were shown using n (%).
ASAS20, Assessment of SpondyloArthritis international Society 20% improvement; W12, 12 weeks; BMI, body mass index.
Comparisons of ASAS20 response at W12 based on subgroups of baseline disease characteristics.
| Items | Placebo | Ivarmacitinib 4 mg | P value |
|---|---|---|---|
| AS duration | |||
| <5 years | 16 (26.7) | 33 (61.1) | <0.001 |
| ≥5 years | 38 (30.2) | 58 (43.6) | 0.025 |
| History of biological/JAK inhibitors | |||
| No | 40 (31.5) | 66 (52.4) | 0.001 |
| Yes | 14 (23.7) | 25 (41.0) | 0.044 |
| Total back pain VAS score | |||
| ≤60 | 23 (31.1) | 31 (49.2) | 0.030 |
| >60 | 31 (27.7) | 60 (48.4) | 0.001 |
| Night pain VAS score | |||
| ≤60 | 27 (28.1) | 40 (47.1) | 0.008 |
| >60 | 27 (30.0) | 51 (50.0) | 0.005 |
Data were shown using n (%).
ASAS20, Assessment of SpondyloArthritis international Society 20% improvement; W12, 12 weeks; AS, ankylosing spondylitis; JAK, Janus kinase; CRP, C-reactive protein; VAS, visual analogue scale.
Acknowledgements: NIL.
Disclosure of Interests: None declared.
© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (