The effect of interferon beta-1b on size of short-lived enhancing lesions in patients with multiple sclerosis

Abstract

Background Contrast enhancing lesions (CELs) in MRI represent inflammatory events in multiple sclerosis (MS). IFN-β-1b decreases the formation of CELs. However, the ability of IFN-β-1b to reduce the size of CELs arising during therapy has not been extensively investigated. Methods Thirty patients with relapsing-remitting (RR) MS were followed for a 3-month pre-therapy phase then for a 6-month therapy phase during which treatment with IFN-β-1b at a dosage of 250 μg subcutaneously injected every other day was employed. Each patient underwent monthly clinical and MRI examinations. For all patients, CELs were identified on postcontrast T1-weighted MRIs. CEL number, size, and volume were computed using Medx software. Results The average number and total lesion volume of CELs visible during the therapy phase were significantly lower than the number and total lesion volume of CELs observed in the pre-therapy phase. However, there was no significant reduction between pre-therapy and therapy phases in the mean size of individual lesions arising during the respective phases. Conclusions Since size of CELs has been related to severity of tissue damage, the lack of size decrease during therapy suggested a limited therapeutic effect of IFN-β-1b if a blood–brain barrier breakdown has occurred.

Population‐Based Pharmacokinetic and Exposure‐Efficacy Analyses of Peginterferon Beta‐1a in Patients With Relapsing Multiple Sclerosis

“…The AUC was derived from individual posterior Bayes estimates of CL using a sequential analysis approach . The monthly cumulative AUC was selected to represent exposure because interferon reduced acute inflammation as early as within a month of treatment initiation, and acute inflammation was associated with relapses . Therefore, reduction of ARR is considered a cumulative effect of peginterferon beta‐1a, and the exposure was represented by AUC.…”

A Population Approach to Characterize Interferon Beta‐1b Effect on Contrast Enhancing Lesions in Patients With Relapsing Remitting Multiple Sclerosis

“…Because the conversion of CELs into black holes is an indirect sign of more aggressive pathology, it was concluded that IFNβ‐1b was not able to affect the severity of CELs once these were formed. In a larger cohort of 30 patients with RRMS treated with IFNβ‐1b at the same dosage and regimen, it was found that although the count of CELs was dramatically reduced during treatment, the average size of each CEL was not affected . The results of the current analysis provide an additional demonstration that IFNβ‐1b, on a population level, may affect the count of CELs, but once a CEL is formed the medication is not effective in promoting lesion resolution.…”

Application of Interferon Beta-1b in Multiple Sclerosis

“…A relatively large study performed in the NINDS group during a short-term (six-month) time window, has shown that the effect of IFNβ-1b in reducing the likelihood of CEL formation is not paralleled by its ability to reduce the size of CELs once formed. 47 IFNβ-1b reduced the number of CELs by 76.4 % over 18 months of therapy. This decrease however, was statistically greater for small lesions enhancing only once during therapy (82.3 %) than for larger ones enhancing multiple times (57.4 %).…”