Total patient group
Thirty-one patients were examined at baseline, n=29 after 3 and n=28 after 6 and 12 months (3 patients lost to follow-up). The patients included (24 females) revealed a mean age of 60.1±14.9 years and mean disease duration of 14.9±7.1 years. 96.8% of the patients were rheumatoid factor (RF-IgM) positive and 93.6% ACPA positive.
Regarding prior treatment, 28 patients had received other biologicals (TNFα- or IL6- inhibitors). Reasons for discontinuing previous drug treatment were nonresponse (40.0%), insufficient effectiveness (46.7%), contraindications (16.7%) and adverse events (46.7%). 17 patients had already received Rituximab before being included in the study.
Additionally, concomitant therapies such as NSAIDs, glucocorticoids and DMARDs were used by all patients within one year as follows: NSAIDs: at baseline: 71.0% (n=22), after 12 months: 64.3% (n=18); Glucocorticoids (prednisone equivalent): at baseline: 87.1% (mean daily dosage à 7.4 mg), after 12 months 75% (mean daily dosage à 4.9 mg); DMARDs (mostly methotrexate, followed by: leflunomide, sulfasalazine, hydroxychloroquine, azathioprine): 61.3%, after 12 months 50.0%.
In the total study population, mean DAS28 decreased from 5.1±1.2 to 4.3±1.1 (p= 0.003) and mean patient’s global VAS (range 0-100mm) from 54.8±17.2 to 41.3±16.2 (p=0.001), respectively. Mean CRP was significantly reduced from 10.7±9.6 to 5.7±8.0 (p=0.023) over the period of 12 months.
The imaging parameters US7 GS synovitis score (range 0-27) and US7 GS tenosynovitis score (range 0-7) presented a significant decrease during one year (mean 13.3±7.7 to 9.7±6.6; p=0.005 and mean 1.4±1.6 to 0.8±1.2; p=0.008).
FOI in PVM increased in a course of 12 months (mean 9.8±6.9 to 13.2±9.8, p=0.111), while FOI in phases 1, 2, and 3 decreased (phase 1: mean 9.1±11.1 to 4.8±9.7, p=0.704, phase 2: mean 31.8±15.2 to 30.1±15.6, p=0.182, phase 3: mean 10.4±8.6 to 9.0±7.2, p=0.537) not significantly (Supplementary Table 1).
Patients with RTX re-therapy
Of the total 31 patients, n=14 received a re-therapy with RTX (45.2%) within 12 months: n=3 after 6 months, n=4 after 7 months, n=5 after 9 months, and n=2 after 10 months. The parameters DAS28 and patient’s global VAS decreased significantly in this group (mean of DAS28 at baseline 5.1, after 12 months 3.9; p=0.004; mean patient’s global VAS at baseline 59.6mm, after 12months 45mm; p=0.042).
FOI in PVM singularly significantly increased (mean 7.8±4.3 to 15.2±10.4; p=0.013; range 0-90) in comparison to the other imaging parameters (see Table 1).
Prediction for RTX re-therapy
The likelihood for a RTX re-therapy (after 6 months) was analyzed by considering the predictive value of the change between baseline and 3-months or 6-months follow-up in clinical and patient reported parameters. The change in DAS28, ESR and CRP as well as patient reported parameters were not associated with the initiation of a RTX re-therapy (AUC close to 0.5). On the other side, the likelihood of a RTX re-therapy was significantly predicted by the change between baseline and 6-months follow-up in the imaging parameters US7 GS synovitis score (AUC = 0.73) and FOI in PVM (AUC = 0.78). (see Table 2).
Patients without RTX re-therapy
Seventeen patients of the total patient group did not receive a re-therapy with RTX during the observed 12 months. In this group, a significant decrease between baseline and 12-months follow-up was shown for the patient’s global VAS, US7 GS synovitis, US7 GS tenosynovitis, US7 PD tenosynovitis, and FOI in phase 2. (Table 1). However, the clinical parameters did not change significantly in this group. The ESR after 12 months was significantly higher than in the group with re-therapy (p=0.033). Regarding FOI, signal enhancement in phase 2 was reduced in a significant manner (mean 33.9±15.8 to 28.2±17.3; p=0.008). PVM remained stable in this group.