Background/Purpose

The GO-FORTH, phase 2/3 clinical trial was conducted to examine the efficacy and safety of Golimumab (GLM) plus MTX in Japanese patients (pts) with active RA despite MTX therapy (NCT00727987). In treatment for RA, it has been recommended to assess the clinical disease activity at least every 3 months according to the treat to target (T2T) recommendation. Therefore, predictors of long-term efficacy with GLM treatment using clinical data at baseline and 3 months would seem to be extremely important.

Objective

To assess the predictability of using clinical data at baseline and week 12 (W12) after GLM treatment in GO-FORTH study, for achievement of each remission criteria after 1-year.

Methods

GO-FORTH was a multicenter, randomized, double-blind, placebo-controlled study in pts with active RA despite MTX therapy. Pts were randomized to Placebo (PBO), GLM50 mg or GLM 100 mg q4 wks combined with MTX (6-8 mg/ week). Data of all pts who were randomized to GLM 50 mg or GLM 100mg as active treatment were used for analysis. Several definitions of remission at week 52 (W52) were used and defined as: DAS remission (DAS28ESR <2.6), HAQ remission (HAQ <0.5) and radiographic remission (‡™TSS <=0). Akaike Information Criteria (AIC) were calculated to assess predictability with all possible predictors using univariate logistic regression model. Area under the curves (AUC) were calculated to assess the performance of possible predictors using receiver operating characteristics (ROC) curves. Cutoff values were also calculated using Euclidean method. The correlations between possible predictors were carefully considered to determine predictor.

Results

DAS28ESR score at W12 was chosen based on the values of AIC as a possible predictor of DAS remission at W52. HAQ score at W12 was also chosen as a possible predictor of HAQ remission at W52. Similar trends were observed in the both scores at baseline.  The cutoff point (AUC) of DAS28ESR for DAS remission with GLM 50 mg and GLM 100 mg at W12 were 3.0 (0.876) and 3.5 (0.863), then cutoff point of HAQ score for HAQ remission with them were 0.625 (0.880) and 0.500 (0.958), respectively (see table). The results of baseline and PPVs/ NPVs for each determined predictors were also calculated as table shown. Both potential predictors showed larger AUC and smaller cutoff values at W12 than those at the baseline. There were no noticeable differences between GLM 50mg and GLM 100mg in the potential predictors. Predictors for radiographic remission were not specified by this analysis.

Conclusion

These analyses suggest that DAS28ESR and HAQ score at baseline and W12 can be predictors for DAS remission and HAQ remission at W52 in Japanese pts treated with GLM combined with MTX individually. In particular in terms of DAS remission, it seems to be important to achieve LDA within 3 months to maintain long term clinical remission.