Rheumatoid arthritis (RA) affects 0.5–1% of people and causes chronic joint inflammation and damage. Methotrexate (MTX) is the first-line therapy, but 30–40% of patients do not respond adequately. TNF inhibitors (infliximab, etanercept, adalimumab, golimumab, certolizumab) remain key options for MTX-resistant patients due to strong efficacy and long-term safety.
Newer biologics and targeted therapies—abatacept, IL-6 inhibitors (sarilumab, tocilizumab), and JAK inhibitors (tofacitinib)—have expanded treatment choices. Current guidelines (ACR 2023, EULAR 2024) recommend tailoring therapy based on disease activity and comorbidities, not just stepwise escalation.
Emerging directions include precision medicine, biomarkers, and nanoparticle-based drug delivery. However, understanding how these therapies perform in real-world MTX-resistant patients remains limited.
This review analyzes 18 Phase 4 trials (2014–2024) to clarify outcomes, safety, and treatment optimization strategies in MTX-resistant RA.
This review followed PRISMA 2020 guidelines, with the search updated on October 22, 2025. ClinicalTrials.gov was searched using the term “rheumatoid arthritis”, restricted to completed Phase 4 trials from the past 10 years in adult populations. The search identified 3586 records.
After screening by study phase, completion status, and population criteria, 52 trials were fully assessed. Of these, 34 were excluded for being non-interventional, lacking protocols/results, or not relevant to RA therapeutic management. Finally, 18 Phase 4 trials met the inclusion criteria and were included in the qualitative synthesis.
Figure 1 presents the PRISMA 2020 flow diagram summarizing the entire study selection process—from initial identification to final inclusion.
Eighteen Phase 4 clinical trials met the inclusion criteria and were analyzed for this review. These studies evaluated a range of biologic, targeted synthetic, and adjunctive therapies addressing MTX-resistant rheumatoid arthritis, with outcomes focusing on disease activity indices, biomarker profiles, imaging findings, and patient-reported measures. The study selection process is summarized in Figure 1, and detailed characteristics of each trial are presented.
Across the 18 Phase 4 trials, interventions fell into four groups: T-cell co-stimulation modulators (abatacept), JAK inhibitors (tofacitinib), IL-6 inhibitors (sarilumab, tocilizumab), and adjunctive/exploratory therapies (glucocorticoids, Acthar Gel, TNF inhibitor optimization, ticagrelor, IL-7/IL-7R). Biologic and targeted DMARDs showed DAS-28 reductions of 1.6–2.8 and remission rates of 35–55%, while corticosteroid and Acthar Gel studies showed smaller improvements (~1.2 points) with higher AE variability.
Abatacept consistently improved disease activity and helped identify biomarker-based predictors of response. Tofacitinib reduced synovitis in imaging studies, and the ORAL Shift trial showed that monotherapy after MTX withdrawal could maintain remission. IL-6 inhibitors demonstrated strong clinical and patient-reported benefits, while the GLORIA trial confirmed low-dose prednisolone efficacy but highlighted infection and metabolic risks.
Acthar Gel benefited refractory RA patients. TNF inhibitor optimization trials showed that continuing MTX with TNF inhibitors achieved better and more durable remission than TNF inhibitor monotherapy, reinforcing their role in MTX-resistant disease.
Exploratory studies (ticagrelor, IL-7/IL-7R) provided mechanistic insights, and imaging trials (FDG-PET/CT, ultrasound) revealed persistent subclinical inflammation linked to delayed remission and vascular risk. Additional studies on vaccination, ocular symptoms, and pain management expanded evidence for comprehensive RA care.
Across the Phase 4 trials, safety findings aligned with known profiles of each therapy. Biologic and targeted DMARDs most often caused infections, GI symptoms, and lab abnormalities. IL-6 and JAK inhibitors showed higher infection rates and increases in lipids and liver enzymes, though serious adverse events were uncommon. Low-dose glucocorticoids increased infection and metabolic risks, especially in older adults, as seen in the GLORIA trial. Acthar Gel was generally well tolerated but supported by small sample sizes. No unexpected safety signals emerged, although inconsistent reporting across studies limits direct comparisons.
Substantial heterogeneity was noted, with sample sizes ranging from 9 to 694, reflecting differing study designs—from mechanistic biomarker studies to large pragmatic trials—which impacts statistical strength and interpretation.
The Phase 4 evidence shows a clear shift in RA management from MTX-dependent strategies toward optimized biologic and targeted synthetic DMARD use. Abatacept consistently improved disease activity and offered biomarker-based response insights, supporting personalized therapy. Tofacitinib remained effective even after MTX withdrawal in select patients, demonstrating treatment flexibility. IL-6 inhibitors (sarilumab, tocilizumab) also delivered strong clinical and patient-reported benefits in MTX-inadequate responders.
Low-dose glucocorticoids provided short-term disease control but carried infection and metabolic risks, especially in older adults. Acthar Gel showed benefit in highly refractory patients. TNF inhibitor optimization trials emphasized that many MTX-resistant patients benefit from better treatment sequencing—MTX continuation with TNF inhibitors improved remission durability compared with TNF inhibitor monotherapy.
Exploratory studies such as ticagrelor and IL-7/IL-7R modulation offered mechanistic insights. Imaging trials using FDG-PET/CT and ultrasound highlighted persistent subclinical inflammation and its link to delayed remission and vascular risk, supporting advanced monitoring beyond standard clinical scores. Biomaterials research, including injectable hydrogels for sustained drug delivery, points to future targeted therapeutic strategies.
Safety findings aligned with known drug profiles: JAK and IL-6 inhibitors showed higher infection and lab-related risks, while abatacept and TNF inhibitors had more stable long-term safety. Cost-effectiveness evidence favored abatacept and optimized TNF inhibitor regimens, particularly with biosimilar availability. These findings highlight the need to integrate safety, biomarkers, imaging, and economic considerations into individualized treatment pathways.
Phase 4 trials confirm that biologics and targeted synthetic DMARDs—TNF inhibitors, abatacept, JAK inhibitors, and IL-6 inhibitors—provide meaningful clinical improvements in MTX-resistant RA. TNF inhibitor optimization studies reinforce their continued relevance, especially when combined with MTX and guided by treat-to-target strategies.
Adjunctive therapies like low-dose glucocorticoids and Acthar Gel may help select refractory patients but require careful safety monitoring. Biomarker-based and imaging-driven findings support the emerging role of precision medicine in selecting and adjusting RA treatments.
Overall, RA management is shifting toward individualized, evidence-based care that combines established biologics, newer targeted agents, safety profiling, and patient-specific factors. Future research should focus on long-term comparative studies, cost-effectiveness analyses, and biomarker-guided treatment algorithms to support sustainable and optimized care in RA.
1. Aletaha D, Smolen JS. Diagnosis and management of rheumatoid arthritis: a review. JAMA. 2018;320(13):1360–9. doi:10.1001/jama.2018.13103
2. Singh JA, Saag KG, Bridges SL, et al. 2015 American college of rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Rheumatol. 2016;68(1):1–26. doi:10.1002/art.39480
3. Burmester GR, Pope JE. Novel treatment strategies in rheumatoid arthritis. Lancet. 2017;389(10086):2338–2348. doi:10.1016/S0140-6736(17)31491-5
4. Lipsky PE, van der Heijde DM, St Clair EW, et al. Infliximab and methotrexate in the treatment of rheumatoid arthritis. anti-tumor necrosis factor trial in rheumatoid arthritis with concomitant therapy study group. N Engl J Med. 2000;343(22):1594–1602. doi:10.1056/NEJM200011303432202
5. Effect of sarilumab on patient-reported outcomes in patients with moderately to severely active rheumatoid arthritis and with inadequate response or intolerance to current conventional synthetic DMARDs or tumor necrosis factor inhibitors [Internet]. 2018. Available from: https://clinicaltrials.gov/study/NCT03449758. Accessed January 06, 2026.
6. Smolen JS, Landewé RBM, Bergstra SA, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update. Ann Rheum Dis. 2023;82(1):3–18. doi:10.1136/ard-2022-223356
7. Taylor PC, Matucci Cerinic M, Alten R, Avouac J, Westhovens R. Managing inadequate response to initial anti-TNF therapy in rheumatoid arthritis: optimising treatment outcomes. Ther Adv Musculoskelet Dis. 2022;14:1759720×221114101. doi:10.1177/1759720X221114101
8. Kremer J. Methotrexate pharmacogenomics. Ann Rheumatic Dis. 2006;65(9):1121–1123. doi:10.1136/ard.2006.051789
9. Taylor PC, Keystone EC, Van Der Heijde D, et al. Baricitinib versus placebo or Adalimumab in rheumatoid arthritis. N Engl J Med. 2017;376(7):652–662. doi:10.1056/NEJMoa1608345
10. Smolen JS, Beaulieu A, Rubbert-Roth A, et al. Effect of interleukin-6 receptor inhibition with tocilizumab in patients with rheumatoid arthritis (OPTION study): a double-blind, placebo-controlled, randomised trial. Lancet. 2008;371(9617):987–997. doi:10.1016/S0140-6736(08)60453-5
11. Boers M, Hartman L, Opris-Belinski D, et al. Low dose, add-on prednisolone in patients with rheumatoid arthritis aged 65+: the pragmatic randomised, double-blind placebo-controlled GLORIA trial. Ann Rheum Dis. 2022;81(7):925–936. doi:10.1136/annrheumdis-2021-221957
12. Gillis T, Crane M, Hinkle C, Wei N. AB0502 HP Acthar® Gel (repository corticotropin injection) as adjunctive therapy in patients with rheumatoid arthritis who have failed at least three biologic therapies with different modes of action. Ann Rheumatic Dis. 2015;74:1066. doi:10.1136/annrheumdis-2015-eular.2092
13. Garshick MS, Rosenthal PB, Luttrell-Williams E, Cronstein BN, Berger JS. Ticagrelor added to methotrexate improves rheumatoid arthritis disease severity. Rheumatology. 2021;60(11):5473–5475. doi:10.1093/rheumatology/keab481
14. Fraenkel L, Bathon JM, England BR, et al. 2021 American college of rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Rheumatol. 2021;73(7):1108–1123. doi:10.1002/art.41752
15. Huang R, Zhang C, Bu Y, et al. A multifunctional nano-therapeutic platform based on octahedral yolk-shell Au NR\@CuS: photothermal/photodynamic and targeted drug delivery tri-combined therapy for rheumatoid arthritis. Biomaterials. 2021;277:121088. doi:10.1016/j.biomaterials.2021.121088
16. Ytterberg SR, Bhatt DL, Mikuls TR, et al. Cardiovascular and cancer risk with tofacitinib in rheumatoid arthritis. N Engl J Med. 2022;386(4):316–326. doi:10.1056/NEJMoa2109927
17. Rheumatoid arthritis memory B cells and abatacept (RAMBA) [Internet]. 2018. Available from: https://clinicaltrials.gov/study/NCT03652961. Accessed January 06, 2026.
18. Ticagrelor in methotrexate-resistant rheumatoid arthritis [Internet]. 2016. Available from: https://clinicaltrials.gov/study/NCT02874092. Accessed January 06, 2026.
19. Musculoskeletal ultrasound assessment of therapeutic response of tofacitinib in rheumatoid arthritis patients [Internet]. 2014. Available from: https://clinicaltrials.gov/study/NCT02321930. Accessed January 06, 2026.
20. A Phase 3B/4 randomized double blind placebo controlled study of methotrexate (MTX) withdrawal in subjects with rheumatoid arthritis (RA) treated with tofacitinib 11MG modified release (MR) formulation [Internet]. 2016. Available from: https://clinicaltrials.gov/study/NCT02831855. Accessed January 06, 2026.
21. Phase IV open-label study to evaluate biomarkers to predict the efficacy of abatacept in subjects with rheumatoid arthritis [Internet]. 2018. Available from: https://clinicaltrials.gov/study/NCT03882008. Accessed January 06, 2026.
22. The glucocorticoid low-dose outcome in rheumatoid arthritis study comparing the cost-effectiveness and safety of additional low-dose glucocorticoid in treatment strategies for elderly patients with rheumatoid arthritis [Internet]. 2015. Available from: https://clinicaltrials.gov/study/NCT02585258. Accessed January 06, 2026.
23. A multicenter, 2 part study to assess the efficacy and safety of acthar gel in subjects with rheumatoid arthritis with persistently active disease despite dual-DMARD treatment [Internet]. 2016. Available from: https://clinicaltrials.gov/study/NCT02919761. Accessed January 06, 2026.
24. Prospective, multicentre, placebo-controlled, double-blind interventional study to compare the efficacy of maintenance treatment with tocilizumab with or without glucocorticoid discontinuation in rheumatoid arthritis patients [Internet]. 2015. Available from: https://clinicaltrials.gov/study/NCT02573012. Accessed January 06, 2026.
25. A randomized, head-to-head, single-blinded study to assess changes in the immune profile in response to treatment with subcutaneous abatacept in combination with methotrexate versus subcutaneous adalimumab in combination with methotrexate in adults with early rheumatoid arthritis who are naive to biologic disease-modifying antirheumatic drugs [Internet]. 2015. Available from: https://clinicaltrials.gov/study/NCT02557100. Accessed January 06, 2026.
26. Improving influenza immunization responses in rheumatoid arthritis: a strategy to enhance protection against a preventable cause of death in an at risk population? [Internet]. 2016. Available from: https://clinicaltrials.gov/study/NCT02936180. Accessed January 06, 2026.
27. MIRACLE (Methotrexate inadequate response patient with rheumatoid arthritis treated by adalimumab in combination with low-dose methotrexate) study [Internet]. 2018. Available from: https://clinicaltrials.gov/study/NCT03505008. Accessed January 06, 2026.
28. Effectiveness of a combination of methotrexate and a step down glucocorticoid regimen (COBRA-Slim) for remission induction in patients with early rheumatoid arthritis (RA), with or without fast access to 24 weeks of tumor necrosis factor (TNF) blockade in insufficient responders, a randomized, multicenter, pragmatic trial [Internet]. 2018. Available from: https://clinicaltrials.gov/study/NCT03649061. Accessed January 06, 2026.
29. IL-7 and IL-7R expression in peripheral blood mononuclear cells, peripheral blood monocytes or differentiated macrophages of rheumatoid arthritis patients with active vs. inactive disease treated with DMARD and/or CIMZIA [Internet]. 2015. Available from: https://clinicaltrials.gov/study/NCT02451748. Accessed January 06, 2026.
30. Treatments against RA and effect on FDG-PET/CT (The TARGET trial) [Internet]. 2015. Available from: https://clinicaltrials.gov/study/NCT02374021. Accessed January 06, 2026.
31. A Phase 4 trial assessing the impact of residual inflammation detected via imaging techniques, drug levels and patient characteristics on the outcome of dose tapering of adalimumab in clinical remission rheumatoid ArThritis (RA) subjects (PREDICTRA) [Internet]. 2014. Available from: https://clinicaltrials.gov/study/NCT02198651. Accessed January 06, 2026.
32. A single-arm investigator initiated study to evaluate the efficacy of OC-01 (Varenicline solution) nasal spray on signs and symptoms of dry eye disease in subjects with Sjogren’s syndrome [Internet]. 2023. Available from: https://clinicaltrials.gov/study/NCT05700422. Accessed January 06, 2026.
33. Evaluating the addition of obturator nerve block to adductor canal block for total knee arthroplasty [Internet]. 2017. Available from: https://clinicaltrials.gov/study/NCT03326999. Accessed January 06, 2026.
34. Kremer JM, Genant HK, Moreland LW, et al. Effects of Abatacept in patients with methotrexate-resistant active rheumatoid arthritis: a randomized trial. Ann Intern Med. 2006;144(12):865–876. doi:10.7326/0003-4819-144-12-200606200-00003
35. Cohen SB, Pope J, Haraoui B, et al. Efficacy and safety of tofacitinib modified-release 11 mg once daily plus methotrexate in adult patients with rheumatoid arthritis: 24-week open-label phase results from a phase 3b/4 methotrexate withdrawal non-inferiority study (ORAL Shift). RMD Open. 2021;7(2):e001673. doi:10.1136/rmdopen-2021-001673
36. Burmester GR, Lin Y, Patel R, et al. Efficacy and safety of sarilumab monotherapy versus Adalimumab monotherapy for the treatment of patients with active rheumatoid arthritis (MONARCH): a randomised, double-blind, parallel-group Phase III trial. Ann Rheum Dis. 2017;76(5):840–847. doi:10.1136/annrheumdis-2016-210310
37. Yokota S, Imagawa T, Mori M, et al. Efficacy and safety of tocilizumab in patients with systemic-onset juvenile idiopathic arthritis: a randomised, double-blind, placebo-controlled, withdrawal phase III trial. Lancet. 2008;371(9617):998–1006. doi:10.1016/S0140-6736(08)60454-7
38. Fleischmann R, Furst DE. Safety of repository corticotropin injection as an adjunctive therapy for the treatment of rheumatoid arthritis. Expert Opin Drug Saf. 2020;19(8):935–944. doi:10.1080/14740338.2020.1779219
39. A multicenter, randomized, double-period, double – blind study to determine the optimal protocol for treatment initiation with methotrexate and adalimumab combination therapy in patients with early rheumatoid arthritis (OPTIMA) [Internet]. 2007. Available from: https://clinicaltrials.gov/study/NCT00420927. Accessed January 06, 2026.
40. Pickens SR, Chamberlain ND, Volin MV, et al. Characterization of interleukin-7 and interleukin-7 receptor in the pathogenesis of rheumatoid arthritis. Arthritis Rheum. 2011;63(10):2884–2893. doi:10.1002/art.30493
41. Pean De Ponfilly – Sotier M, Seror R, Nocturne G, Besson FL. 18F-FDG PET molecular imaging: a relevant tool to investigate chronic inflammatory rheumatisms in clinical practice? Front Med. 2022;9:1070445. doi:10.3389/fmed.2022.1070445
42. Pan W, Dai C, Li Y, et al. PRP-chitosan thermoresponsive hydrogel combined with black phosphorus nanosheets as injectable biomaterial for biotherapy and phototherapy treatment of rheumatoid arthritis. Biomaterials. 2020;239:119851. doi:10.1016/j.biomaterials.2020.119851
43. Singh JA. The emerging safety profile of JAK inhibitors in rheumatic diseases. BioDrugs. 2023;37(5):625–635. doi:10.1007/s40259-023-00612-7
44. Westhovens R, Annemans L. Costs of drugs for treatment of rheumatic diseases. RMD Open. 2016;2(2):e000259. doi:10.1136/rmdopen-2016-000259
45. Convertino I, Lorenzoni V, Gini R, et al. Drug-utilization, healthcare facilities accesses and costs of the first generation of JAK inhibitors in rheumatoid arthritis. Pharmaceuticals. 2023;16(3):465. doi:10.3390/ph16030465
46. Jansen JP, Incerti D, Mutebi A, et al. Cost-effectiveness of sequenced treatment of rheumatoid arthritis with targeted immune modulators. J Med Econ. 2017;20(7):703–714. doi:10.1080/13696998.2017.1307205
