THE OPTIMIZATION OF INTERFERON FOR MS STUDY: 375 MICROG INTERFERON BETA-1B IN SUBOPTIMAL RESPONDERS.

We aimed to evaluate the safety and MRI efficacy of interferon beta-1b (IFNbeta-1b) 375 microg (subcutaneously [sc] every other day [eod]) in relapsing-remitting multiple sclerosis (RRMS) patients with a suboptimal response to IFNbeta-1b 250 microg, i.e., with MRI activity or relapses. The OPTimization of Interferon for MS (OPTIMS) study was a prospective multicenter randomized phase 2 trial comprising a 6-month run-in phase (to identify suboptimal responders) and a 6-month randomized phase of open-label clinical and blinded MRI follow-up. During run-in all patients were treated with IFNbeta-1b 250 microg sc eod; during the study phase suboptimal treatment responders were randomized either to IFNbeta-1b 250 or 375 microg sc eod. Primary outcome was the proportion of patients without MRI activity during study Months 9-12 according to the intention-to-treat principle. 216 RRMS patients entered the study: 83 suboptimal responders were identified and randomized, 7 refused to continue treatment, 76 were included in the analysis. More patients treated with 375 microg had no MRI activity at Months 9-12 (30/36 vs.16/40; relative risk, 0.28; 95 % confidence interval, 0.08-0.47; p = 0.0001). Sensitivity analysis ("worst case scenario") confirmed the results. No new or unexpected adverse events were observed, but there was a trend towards more withdrawals in the 375 microg group. Increasing the dose of IFNbeta-1b from 250 microg to 375 microg is a successful strategy for reducing subclinical signs of disease activity in RRMS patients. Further studies are needed to show whether this dose may also improve clinical efficacy

MRI activity and neutralising antibody as predictors of response to interferon beta treatment in multiple sclerosis.

Objective: To prospectively validate MRI activity and neutralising anti-interferon antibody (NAb) during the first 6 months of interferon β ;treatment as response indicators in multiple sclerosis (MS). Methods: Patients with relapsing-remitting MS were followed during the first 2 years of treatment. Neurological assessments were performed every 3 months or when a relapse was suspected. MRI scans performed at baseline and at 3, 4, 5 and 6 months after the start of treatment were assessed centrally for disease activity: new T2 or gadolinium enhancing T1 lesions. NAb were assessed using the MxA protein assay; positivity was defined as two consecutive titres ≥20 NU/ml. We evaluated the predictivity of an active scan, NAb positivity, or both, during the first 6 months of treatment, on the occurrence of clinical disease activity in the following 18 months. Results: 147 patients were assessed at 16 centres. Predictivity parameters (with confidence intervals) were as follows: active scan, sensitivity (SN) 52% (34-69%), specificity (SP) 80% (65-91%), negative predictive value (NPV) 73% (58-77%), positive predictive value (PPV) 62% (42-79%), p = 0.002; NAb positivity, SN 71% (45-88%), SP 66% (55-76%), NPV 92% (82-97%), PPV 29% (16-45%), p = 0.01; active scan and NAb positivity, SN 71% (38-91%), SP 86% (73-94%), NPV 94% (86-98%), PPV 50% (29-70%), p = 0.0003. Conclusions: MRI activity and NAb occurrence during the first 6 months of interferon β treatment were reliable predictors of long term clinical response, particularly when combined. Patients with negative predictors showed a less than 10% risk of developing clinical activity. Patients with positive predictors showed a 50% risk of further clinical activity. These patients need to be followed carefully with further MRI and NAb tests