August 17, 2015

Health Canada approves Plegridy™ for the management of relapsing-remitting MS


Health Canada recently approved Plegridy™ (peginterferon beta-1a) as a disease-modifying therapy for adults with relapsing-remitting multiple sclerosis (RRMS), to reduce frequency of relapses and slow the progression of disability. The approval followed the completion of pivotal phase III clinical trial ADVANCE and results obtained from phase III extension trial ATTAIN.

Plegridy™ is part of a class of interferon drugs that have been used to treat relapsing forms of multiple sclerosis since the mid nineteen-nineties.  Plegridy™ is similar to MS drug Avonex® (interferon beta-1a), but is a new molecular entity resulting from a pegylation process. This process involves the addition of a polyethylene glycol molecule, which prolongs the effect of the drug in the body. This means that Plegridy™ can be taken less frequently. 

Clinical trial results - efficacy

Health Canada’s approval was primarily based on data from the ADVANCE trial, which included just over 1,500 MS patients. The patients were randomly selected to receive either Plegridy™ (taken at a dose of 125µg via under-the-skin injection once every two or four weeks) or placebo (a mock drug).

Data from the first year showed that Plegridy™, dosed once every two weeks, significantly reduced annualized relapse rate (ARR) by 36% compared to placebo. Treatment with Plegridy™ also significantly reduced the risk of further disability arising from relapses – as measured by the Expanded Disability Status Scale (EDSS) – by 38%, and the number of new or active lesions observed on MRI, compared to placebo. In year two of the ADVANCE trial, all patients received Plegridy™ (placebo patients were randomized to PLEGRIDY™ every two or four weeks). Results after two years were consistent with what was observed after one year.

A 2-year extension trial called ATTAIN was conducted to evaluate the long-term safety and efficacy of Plegridy™. The trial included 1,468 MS patients who continued to take Plegridy™ for up to a total of three years. Results of the trial showed that treatment with Plegridy™ at a dose of 125µg via under-the-skin injection once every two weeks maintained positive efficacy on outcomes including ARR, the proportion of patients who experienced a relapse, the proportion of patients with 24-week confirmed disability progression, and MRI measures over a three year period.

Clinical trial results – safety and tolerability

Plegridy™ is shown to be well tolerated. Adverse effects reported from clinical trials were similar to those resulting from injection of interferon beta-1a, such as redness at the injection site and flu-like symptoms. The most common serious adverse effect reported was infection. The safety and tolerability of Plegridy™ observed in all patients enrolled in the ATTAIN study were in line with the profile demonstrated in the ADVANCE study.


The approval of Plegridy™ provides another option for people with MS who are seeking treatment. Having a range of treatment options available enables individuals to select a regimen that accommodates their needs and lifestyles. Selecting an MS therapy should be done in consultation with a health care team. The MS Society of Canada will provide updates on availability and public coverage of Plegridy™ as they become available.

Full drug information will be available on the MS Society website shortly


Calabresi PA et al. Pegylated interferon beta-1a for relapsing-remitting multiple sclerosis (ADVANCE): a randomised, phase 3, double-blind study. The Lancet. 2014; 13: 657-665.

Arnold DL et al. Effect of peginterferon beta-1a on MRI measures and achieving no evidence of disease activity: results from a randomized controlled trial in relapsing-remitting multiple sclerosis. BMC Neurology. 2014; 14: 240.