Biologic medications are made from living organisms or from their cells, often using biotechnology. They are used to treat diseases and medical conditions including inflammatory arthritis such as rheumatoid arthritis, anemia, diabetes, inflammatory bowel disease, skin conditions such as psoriasis, hormone deficiency and some forms of cancer. Biologic medications are much larger and more complex than chemically produced pharmaceutical drugs.
Biosimilars, or subsequent entry biologics, describe a group of biologic medications that are administered by subcutaneous injection or intravenous infusion and are similar, but not the same, as their originator biologics (also referred to as “brand name” biologics).
Health Canada defines a biosimilar as “a drug demonstrated to be highly similar to a biologic drug that was already authorized for sale (known as the reference biologic drug). Biosimilars are approved based on a thorough comparison to a reference drug and may enter the market after the expiry of reference drug patents and data protection.”
According to Health Canada its authorization of a biosimilar “is not a declaration of equivalence to the reference biologic drug. There are varying definitions of interchangeability. In Canada, the term often refers to the ability for a patient to be changed from one drug to another equivalent drug by a pharmacist, without the intervention of the doctor who wrote the prescription. In Canada, the authority to declare two products interchangeable rests with each province and territory according to its own rules and regulations.”
Health Canada may approve a biosimilar to treat a disease without any clinical trial data to support its use in that disease. Once “biosimilarity” to the originator has been demonstrated, it is no longer a requirement to re-study the biosimilar in all indications previously studied with the originator product. This is called "indication extrapolation." Approval of a biosimilar is not a declaration of bioequivalence with the originator biologic. Post-approval, biosimilars are regulated like any new biologic medicine.
Immunogenicity is the ability to stimulate an immune response in the body of a human or animal. This ability generally protects people against pathogens by recognizing and reacting to foreign proteins. It is a specific concern for biologic medications because they are primarily protein medicines that may be seen as being foreign. An immune response to a biologic medication can range from development of detectable but not clinically significant antibodies to an immune response with significant impact on patient safety. A patient's immune response may also affect a treatment's effectiveness.
Interchangeability is a process that allows a pharmacist to automatically substitute one product for another when it has been deemed interchangeable by a Provincial or Territorial regulatory body. For instance, this is a common practice for drugs that are off patent and have been deemed interchangeable with their generic equivalent.
In the case of a patient not doing well on their current originator biologic or biosimilar of choice, a transition to another originator biologic or biosimilar, or other non-biologic medicine, with a different molecular action is then considered by the patient and their rheumatologist. Transitioning when medically required is important to achieving the best disease control and outcomes.
New starts are patients who have been newly prescribed a biologic medicine. Currently, infliximab (Inflectra) has been approved for patients newly prescribed infliximab (“new starts”) on public drug plans across Canada.
Policy transitions (referred to as non-medical switching) necessitate patients to change their medicine of choice to another, typically less expensive, medicine, not for a medical reason.
Arthritis medication naming system
In light of the recent arrival of new classes of medicines for certain types of inflammatory arthritis, such as biosimilars and Janus kinase (JAK) inhibitors, a new naming system for disease-modifying anti-rheumatic drugs (DMARDs) is being adopted in Europe and North America.
Essentially, there are two categories of medications: a group that treats disease symptoms and a group that treats the underlying disease process.
1. Medications to treat symptoms
- non-steroid anti-inflammatories (NSAIDs)
- pain relievers, like acetaminophen (Tylenol®)
- opioids (narcotics)
Glucocorticoids (GC such as steroids like prednisone): steroids are often used as a “bridging therapy” or to treat life-threatening or organ-threatening complications of rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, systemic lupus erythematosus, and vasculitis.
Non-steroidal anti-inflammatory drugs (NSAIDs such as aspirin, naproxen and celecoxib): these medications help to reduce the inflammation and pain caused by rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and osteoarthritis. Some NSAIDs are available over the counter like ibuprofen (e.g. Motrin or Advil) or naproxen (Aleve) while others require a prescription.
2. Medications to treat the underlying disease
The term “disease-modifying anti-rheumatic drugs” (DMARDs) is used to categorize certain medicines that suppress the disease process that causes the worsening of rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis, among many other types of inflammatory arthritis. They alter the natural course of the disease. DMARDs suppress the inflammation, slow joint damage, decrease autoantibody levels and have positive effects on long-term functional outcome.
DMARDs now come in all “shapes and sizes” and can be taken by pill, self-injection and infusion (IV). Each DMARD works in a unique way and the decision about which one(s) is best for you is perhaps the most important conversation you can have with your rheumatologist.
In the new naming system for disease-modifying anti-rheumatic drugs (DMARDs), there are classifications for:
Synthetic (or chemical) DMARDs are now divided into:
csDMARDs: Conventional synthetic DMARDs include traditional medications such as methotrexate, sulfasalazine, leflunomide, hydroxychloroquine, gold salts and others.
tsDMARDs: Targeted synthetic DMARDs include only those medications that were specifically developed to target a particular molecular structure such as tofacitinib, baricitinib or apremilast, or agents not focused primarily on rheumatic diseases, such as imatinib or ibrutinib.
Biological DMARDs are now divided into:
boDMARDs: Biological original DMARDs include abatacept, adalimumab, anakinra, certolizumab peogl, etanercept, golimumab, infliximab-Remicade, rituximab or tocilizumab
bsDMARDs: SEB or Biosimilar DMARDs include infliximab-Inflectra