The number of investigational biosimilars continues to grow, but their successful integration into routine cancer care will hinge on greater awareness and education, said Nancy Nixon, MD, a medical oncologist at The University of Calgary.
“For patients, it's important to ask your healthcare provider if you have questions and [need] guidance on understanding the differences [between biosimilars and biologics]. For physicians, it’s the same,” said Nixon, lead author of a retrospective study on the evolution of biosimilars in oncology. “If you have questions, there are different venues for education. It's important to feel comfortable with what you're using. The more we educate ourselves, the more comfortable we'll become.”
In December 2017, MYL-1401O (Ogivri; trastuzumab-dkst) became the first FDA-approved biosimilar for trastuzumab (Herceptin) with indications in HER2-positive breast cancer and metastatic gastric or gastroesophageal junction adenocarcinoma. Biosimilars offer the potential to reduce the cost of cancer care; however the retrospective study revealed that complexities in manufacturing, assessment, price, and clinical utility will pose significant hurdles in the process.
In an interview with OncLive
, Nixon discussed the retrospective study of the evolution of biosimilars in oncology, with a focus on trastuzumab and the path toward the integration of biosimilars into cancer care.
OncLive: Could you provide a summary of the study?
: It is a review study looking at the introduction of biosimilar agents from a global perspective. We looked at unique challenges in anticipation of trastuzumab becoming a biosimilar in the near future. We currently use the trastuzumab biologic to treat [patients with] breast cancer as well as other HER2-positive malignancies.
What considerations should be made if these agents are introduced into routine cancer care?
We looked at differences between biosimilar agents and generic molecules. As a result of the complexities in manufacturing with biologic drugs, it's not possible to make an identical generic alternative. Instead, there are biosimilar agents, which are similar to but not identical to the reference biologic drug. Because of these differences, there are various considerations to make when considering interchanging one drug for the other. [There are] differences in automatic substitution [for biosimilars and biologics]. Thus far, there has been success with these agents. Nonetheless, there are new considerations with monoclonal antibodies in particular because of the size and complexity of their nature. Moreover, it will affect potentially curative situations.
How does a biosimilar demonstrate similarity to that of a biologic?
Typically, Health Canada requires strong pharmacodynamic and pharmacokinetic data to support that the 2 agents are similar. Then, there are expectations of clinical similarity with regard to safety and toxicity. They don't necessarily have clinical studies in all of the indications for which the agent could be used. For example, the drug may be approved for treating patients with inflammatory arthritis based on a study done in inflammatory bowel disease. Compared with a [biologic], the extent of clinical testing [for a biosimilar] is less.
What are the biggest hurdles in bringing biosimilars to the forefront of oncology?
The biggest hurdle will be education for physicians and patients in terms of understanding how to integrate these agents into our current practice. Careful pharmacovigilance in terms of post-marketing surveillance will be important for us to gather real-world data to support that these agents are, in fact, similar to their reference drug and increase our comfort in using them.
Would you be comfortable prescribing a biosimilar? How can physicians increase their comfort level?
In general, yes, I would be comfortable prescribing a biosimilar. I would need to see the data on which that approval was based. Because of the way our health system works here in Canada, I don’t think we’ll end up being given the choice of a biosimilar versus a reference drug. Instead, [the decision will rest on] what the government will fund—what the cheaper drug will be. In order to gain that confidence in using them, we need to educate ourselves and look for the data that drove the approval. Additionally, try to be vigilant in collecting real-world outcomes to further support their use.
Do biosimilars have a benefit beyond lower costs?
Lower cost would be the driving factor. Certainly, increased access is an important aspect as well. In terms of global access, it's important that drugs are more cost effective so that we can fund a greater number of agents for various indications.
How can other countries build on the European success with biosimilars?
The advantage is that we get to build on their real-world data that show similar efficacy and good outcomes with these agents. The advantage here in Canada is increased comfort with their experiences and learning from the challenges that [Europe] had.
You cited education as an important factor in integrating biosimilars into cancer care. Will marketing carry any weight in this integration?
Education is going to be a key part of marketing for these agents. With education, you'll see greater comfort and greater acceptance from physicians and patients. That will be an important tool in a successful marketing approach.
Are there any misconceptions about biosimilars you would like to address?
There are concerns about the integration of these agents. In particular, [there are concerns with] switching from a reference drug to a biosimilar. Additionally, there are concerns about efficacy and toxicity. Most of the real-world data that we have from the drugs so far, especially with the European experience, suggest that they are safe and effective. Switching from the reference drug to the biosimilar doesn't necessarily affect outcomes or toxicity. Being aware of that data is important in increasing comfort and acceptance of these new agents.
Nixon N, Hannouf M, Verma S. The evolution of biosimilars in oncology, with a focus on trastuzumab. Curr Oncol. 2018;25(suppl 1). doi: 10.3747/co.25.3942.