Table 3.
Characterization of failure of infliximab therapy in primary nonresponders
| Case no. | Trough (μg/ml)a | DAS28-ESR | HAQ | CRP (mg/dl) | ESR (mm/h) | Anti-CCP Abs (U/ml) | IgM RF (IU/ml) | SJC28 (SJC66) | TJC28 (TJC68) | EULAR response | Reason for lack of efficacy |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | <0.1 | 7.2 | 2.63 | 3.8 | 65 | 907 | 86 | 13 (13) | 13 (23) | None | Rapid clearance |
| 2 | <0.1 | 8.6 | 2.75 | 11.7 | 91 | Negative | Negative | 22 (40) | 24 (46) | None | Rapid clearance |
| 3 | <0.1 | 7.2 | 3.00 | 8.4 | 81 | 112 | 404 | 10 (17) | 12 (19) | None | Rapid clearance |
| 4 | <0.1 | 6.4 | 2.00 | 4.5 | 47 | 254 | Negative | 9 (11) | 9 (11) | None | Rapid clearance |
| 5 | 0.38 | 5.8 | 1.25 | 2.0 | 42 | 151 | 95 | 7 (7) | 7 (7) | None | Rapid clearance |
| 6 | 0.5 | 7.5 | 3.00 | 6.5 | 94 | 770 | 196 | 13 (25) | 16 (28) | None | Rapid clearance |
| 7b | 4.71 | 5.3 | 1.65 | 0.5 | 75 | 127 | 45 | 2 (15) | 4 (16) | Moderate | Residual type |
| 8 | 5.77 | 5.8 | 1.75 | 2.0 | 38 | Negative | 21 | 3 (9) | 7 (16) | None | Residual type |
| 9 | 7.11 | 6.1 | 1.50 | 0.5 | 30 | 464 | 134 | 9 (9) | 10 (12) | None | Residual type |
DAS28 disease activity score for 28 joints, HAQ health assessment questionnaire score, CRP C-reactive protein, ESR erythrocyte sedimentation rate, anti-CCPAbs anti-cyclic citrullinated peptide antibodies, RF rheumatoid factor, SJC28 swollen joint count in 28 joints, TJC28 tender joint count in 28 joints, EULAR European League Against Rheumatism
aThe trough concentrations in case 5 and those in cases 7 and 8 were obtained immediately before the 2nd and 4th infusions of infliximab, respectively; those in the other patients were obtained immediately before the 3rd infusion. Values of the other markers were determined at the end of infliximab therapy
bCase 7 achieved a moderate response as defined by the EULAR criteria at week 14, but failed to achieve a 20% clinical improvement as defined by the American College of Rheumatology (ACR) criteria