FDA Approves Avonex® Pen™ and Initial Dosing Regimen
Written by Susan Wells Courtney, MSAA Senior Writer
Reviewed by Jack Burks, MD, MSAA Chief Medical Officer
March 7, 2012
Biogen Idec announced last week that the United States Food and Drug Administration (FDA) has approved both a new device (the Avonex Pen) as well as a new dosing regimen for Avonex (interferon beta-1a). These two approvals are aimed at assisting patients who are either taking Avonex presently, or who are just starting Avonex, for the treatment of relapsing forms of multiple sclerosis (MS).
Avonex is taken once per week via intramuscular injections. The full dosage is 30 mcg (micrograms) per week. This drug was originally approved by the FDA in 1996 for relapsing MS and more recently for individuals with clinically isolated syndrome (CIS). Avonex has been shown to reduce the number of relapses and lesions on MRI, as well as slow the progression of physical disability. The drug has been shown to be both safe and effective.
The Avonex Pen
The Avonex Pen is the first intramuscular autoinjector approved for an MS medication. The other self-injected treatments for MS are given via subcutaneous injections, which do not require as deep an injection. Because Avonex is injected intramuscularly, patients may find this type of self-injection to be more difficult, and they may experience increased pain and anxiety as well. The Avonex Pen is designed to be easier to use (than the present Avonex Prefilled Syringe alone), and with its shorter and thinner needle, is designed to reduce both pain and anxiety.
The Avonex Pen incorporates the current Avonex Prefilled Syringe. Its needle is 25 gauge and 5/8ths of an inch in length, making it thinner and 50-percent shorter than the current Avonex syringe. The other features of the Avonex Pen include: a protective injector “shield” to conceal the needle prior to injection; automated insertion of the needle and delivery of the medication; a design that helps to stabilize the device while performing an injection; a safety lock to help prevent an injection error; and a display window to confirm that the full amount of medication has been delivered.
In a Phase IIIb study, 94 percent of patients preferred the Avonex Pen over the Avonex Prefilled Syringe. Both the European Union and Canada approved the Avonex Pen in 2011.
Initial Dosing Regimen
The FDA has also approved a schedule for starting low and gradually increasing the dose of Avonex at the start of therapy. The reason for this change in the initial dosing of Avonex, which introduces the drug gradually (known as titration), is to help reduce the incidence and severity of flu-like symptoms. These can often occur when starting an interferon therapy.
The new dosing regimen is provided on the Avonex label to physicians and patients, and may be facilitated using the Avostartgrip kit. This kit includes a set of three devices that work with the Avonex Prefilled Syringes, each filled with the titrated doses of Avonex. Specifically, 7.5 mcg is given in the first week, 15 mcg is given for week two, and 22.5 mcg is administered for week three. The full dose (of 30 mcg) starts in week four. This titration schedule should only be used by individuals who are just starting Avonex.
An eight-week Phase I study was conducted to test the three-week titration period when starting Avonex. Study results showed that the severity of flu-like symptoms was reduced by 76 percent at four to six hours post-injection, when comparing patients who started on the full dose to patients who worked their way up to the full dose over the course of three weeks. The incidence of flu-like symptoms was also reduced when measured at this same time period.
For More Information
Biogen Idec hopes to have the Avonex Pen and the Avostartgrip kit available to individuals in the United States as soon as possible. For more information, please see Biogen Idec’s press release on these topics. For general information about Avonex, please visit Biogen Idec’s website devoted to Avonex. Readers may also visit MSAA’s “MS Research Update,” published in the Summer/Fall 2011 issue of The Motivator to learn more about Avonex.