As biosimilar drugs are making their ways into the market, I wonder why there is little emphasis on how to deal with these prescription orders in the community.  Previously known as subsequent entry biologics (SEBs) in Canada, a biosimilar is a new, highly similar version of a biologic drug.

This is analogous to a “generic” equivalent to a brand name medication. The main difference is that biologics are never exactly identical, given its complex manufacturing process. Instead of a brand name medication, a biosimilar is compared to a reference biologic drug.  For example, one of the biosimilar drugs is filgrastim (Grastofil). It was made to mimic the original filgastim (Neupogen). While Grastofil was made to compare itself to Neupogen in terms of its biochemical structure, pharmacokinetic and pharmacodynamic characteristics, there is no requirement to have data support its use for a specific indication or patient population (e.g.  cancer patients recieving myelosuppressive therapy or patient with Acute Myeloid Leukemia).

Another example is etanercept (Enbrel) which is the first biologic introduced in the Canadian Market. Recently two biosimilar drugs have emerged:  etanercept (Erelzi) and etanercept (Brenzys).  Another example is insulin glargine (Lantus) as it also has a biosimilar drug known as insulin glargine (Basaglar).

I sometimes wonder if the pharmaceutical industry is trying to confuse clinicians intentionally with all the biosimilar drugs introduced into the market without some formal education  or warning?

So why waste time on biosimilar drugs?

Well they are usually cheaper without the same prescribing restrictions?  For instance, Grastofil was recently added to the ODB formulary as a general benefit with a cheaper pricing as compared to Neupogen which continues to be under Limited Use Criteria. The biosimilar drug for etanercept (Brenzys) is also added to the ODB formulary with lower cost compared to etanercept (Enbrel).  And soon, insulin glargine (Basaglar) will added to the ODB formulary for coverage and is cheaper than insulin glargine (Lantus).

So it appears that the greatest benefits is the improved accessibility with reduced costs to the patients and payers.

However, I have yet to see a good communication to advise clinicians how to safely prescribe biosimilar drugs.  There are safety concerns given they have the same chemical / generic names.  Biosimilar drugs are not considered interchangable in Ontario. As such, it must be clear whether a physician intends to prescribe the original biologic or the biosimilar(s) that have been made available.  In some cases, they may want to switch to the  biosimilar to save costs. Indeed, there is so much potential for errors or confusion.

So far, here are my humble thoughts:

  • Prescribing by the brand name (e.g. Lantus or Basaglar) whenever possible
  • If intend to switch to a biosimilar drug, make it clear on the prescription (e.g. Discontinue Enbrel and Start Brenzys)
  • Communicate with patient about the similarities and differences betwen the original biologic and biosimilar
  • Document clearly in chart for rationale for switching

Do you have any experience with biosimilar drugs you like to share? Here’s a link to a documents developed by CADTH which I have found useful to review.

Thank you for reading and have a wonderful Monday!