Plegridy™ (PEGylated interferon beta-1a)
FDA-Approved Medications: Administered by Self-Injection
- Administered by subcutaneous injection once every two weeks at a dose of 125 mcg (micrograms)
- Plegridy is approved for relapsing forms of MS
PEGylation is a chemical modification that has been performed on the interferon beta-1a molecule that allows it to be given subcutaneously (under the skin) every two or four weeks, in contrast to the more frequent injections utilized by the currently approved forms of interferon. The goal is to reduce the number of injections, while maintaining the positive effect of the drug. Studies have tested this experimental therapy for safety and effectiveness. Approved by the FDA in the fall of 2014, this formulation of interferon gives patients the option of using a single-dose auto-injector with a prefilled syringe less frequently than the other self-injected DMTs.
The Phase III clinical trial (ADVANCE) enrolled patients with relapsing-remitting MS (RRMS) to determine the safety and efficacy of Plegridy as compared to placebo. Results were presented in 20138 from the first year of this Phase III study, where 1,512 patients were randomized to one of three groups: one group receiving placebo; a second group receiving Plegridy given by subcutaneous injection once every two weeks; and a third group receiving Plegridy by subcutaneous injection once every four weeks.
Plegridy dosed every two weeks significantly reduced MS disease activity versus placebo. Relapses were reduced by 36 percent, and new brain lesions by 67 percent, compared to placebo at one year. Disability outcomes were also positive in this one-year trial. In total, the proportion of disease activity-free patients over one year was significantly higher in the two treatment groups compared to placebo.
The overall incidence of serious adverse events (SAE) and adverse events (AE) was similar among the Plegridy and placebo groups. The most common serious adverse event was infection, which was balanced across all treatment groups (less than or equal to 1 percent per group). The most commonly reported adverse events with Plegridy treatment were redness at the injection site and influenza-like illness. Flu-like illness was reported in 47 percent of both treatment groups compared to 13 percent in the placebo group. These safety data are consistent with the established safety profile of interferon beta-1a therapies for MS.
After the first year, study participants who were taking the placebo were re-randomized to one of the two treatment groups (taking the active drug either once every two weeks or once every four weeks), and continued on their new treatment for the remainder of the second year in the study. Results of the second year of the ADVANCE study9 were presented at the 2014 meeting of the American Academy of Neurology. Plegridy given every other week significantly reduced the risk of 12-week confirmed disability progression by 38 percent versus placebo, and significantly reduced the annualized relapse rate by 36 percent. Participants in the ADVANCE study were given the option to enroll in the ATTAIN open-label (no longer blinded) extension study. Participants will be followed for up to four years in this second study.
In a subgroup of ADVANCE participants, up to 120 were enrolled in a sub-study that involves optical coherence tomography (OCT). This is a rapid, noninvasive, office-based imaging technique that allows objective evaluation of the thickness of the retinal axon (the nerve behind the eye) and nerve layers that atrophy (shrinking due to nerve cell death) in MS.
Preliminary evidence from other studies supports the use of OCT as an objective tool to monitor the effectiveness of a therapy as it is a direct way of visualizing loss of nervous system tissue, and it is expected that OCT may be used as an outcome measure in other future trials.