Subcutaneous vs Intramuscular Injections

Question:
Why did Biogen make Plegridy a subcutaneous shot instead of an IM one like Avonex? I'm switching from Tecfidera (which I took from 5/2014 to 5/2015) to Plegridy on June 12 because of my persistent low lymphocyte count, and I'm feeling very nervous about the possibility of injection-site reactions. I took Avonex for over 14 years (2000 to 2014), and never had an injection-site reaction. My neurologist didn't want me to go back on Avonex because I had 2 flare-ups within a 6-month period of time right before I switched to Tecfidera (however, from July of 1992 until October of 2013, I was relapse-free). I really wish Plegridy was an IM shot!

Answer:
My understanding is that Biogen elected to administer Plegridy subcutaneously based on market research suggesting that patients preferred subcutaneous injection. I personally disagree with this assessment. My experience has always been that patients prefer subcutaneous over intramuscular interferon shots only until they have experienced both forms of injection. With experience most patients learn that intramuscular injections are not as painful and do not create pain skin reactions as often. We are almost pre-programmed to think that a larger needle injected slightly deeper is more painful when this is not at all the case with interferons.

Whether Plegridy is the best choice for you now is a different question altogether. If you had two relapses on interferon beta 1a (Avonex) within 6 months of starting tecfidera, why would pegylated interferon beta 1a produce a better response? They bind to the same receptor and have the same mechanism of action. There is certainly no evidence that Plegridy is superior to Avonex. If would seem to me that you and your physician should be considering a non interferon choice at this point in time. After all, there are a lot of treatment choices available today.

Discuss this further with your MS specialist and good luck with whatever decisions you make together.

Revere (Rip) Kinkel MD
Director of the Multiple Sclerosis Program
Professor of Clinical Neurosciences
University of California San Diego