Opportunities, Issues, and Challenges for Biosimilars in Oncology


Key Points

  • Biosimilars may reduce cost and improve access to treatment.
  • A number of challenges face the integration of biosimilars into clinical practice.

In an article in The New England Journal of Medicine, Lyman et al reviewed opportunities, issues, and challenges posed by the advent of biosimilar medications, focusing on biosimilars in cancer treatment. Although these agents could help to meet the health-care goals of high quality care with cost containment, there are challenges facing their adoption and use in clinical practice.

Potential Benefits

Biosimilars are biologic agents that are highly similar but not identical to approved reference biologic agents. Regulatory approval of these agents requires absence of meaningful differences in efficacy, safety, and purity compared with reference agents. Pricing of biosimilars can be lower than reference agents, because their development is not associated with some of the costs incurred by pharmaceutical companies in the development of reference agents.

Thus far, three biosimilars have been approved in oncology settings: the myeloid growth factor filgrastim-sndz (Zarxio) as a biosimilar to filgrastim (Neupogen), bevacizumab-awwb as a biosimilar to bevacizumab (Avastin), and trastuzumab-dkst as biosimilar to trastuzumab (Herceptin). As related by the authors, once filgrastim-sndz became available, it gained 24% of the market within 4 months at a price that was 15% lower at launch than that of filgrastim; currently, a 300-μg vial of filgrastim costs $377.80 and a 300-μg vial of filgrastim-sndz costs $330.79, with the cost of a 480-μg vial being $601.60 and $526.78.

Overall, biologic oncology products expected to lose patent protection by 2020 account for more than $20 billion in annual spending worldwide; cost-savings could be substantial if biosimilars take over substantial market share for these agents. As noted by the authors, a recent RAND Corporation analysis estimates that the availability of biosimilars could reduce direct spending by $54 billion between 2017 and 2026. However, as stated by the authors, “Challenges remain concerning the acceptance of biosimilars by physicians and patients in the United States. Their overall effect on health-care costs will be heavily influenced by provider, payer, and patient understanding of their safety and efficacy.”

Issues and Challenges   

Approval Process: In contrast to the regulatory process for biologic agents, with approval depending most heavily on demonstration of safety and efficacy in clinical trials, regulatory review of biosimilars focuses on molecular characterization and preclinical studies and pharmacokinetic and pharmacodynamic studies to establish biosimilarity, with additional studies assessing immunogenicity and other potential toxicities; clinical trials are performed if uncertainty remains regarding safety and efficacy of the biosimilar. As noted by the authors, often 50% or more of the data in applications for approval of biosimilar agents concern manufacturing processes. Further, the regulatory approval process for biosimilars does not require the performance of clinical trials across all approved indications of the reference drug; with approval, a biosimilar drug may have labeling that is identical to that of the reference product across multiple indications. Thus, as noted by the authors, clinician appraisal of and confidence in biosimilars will initially depend less on large clinical trials than on preclinical and pharmacologic data establishing bioequivalence and on their own clinical experience. In the absence of data from large clinical trial programs, there is also uncertainty regarding how biosimilars can be integrated into evidence-based clinical practice guidelines.

Interchangeability and Substitution: The advent of biosimilars also comes with new concepts in use and labeling, including substitution and interchangeability. An “interchangeable” biosimilar is one that is expected to produce the same clinical outcomes and no greater safety concerns as the reference drug upon substitution at any point in treatment. No biosimilar has been approved as interchangeable thus far in the US. Such a designation could affect substitution, which is regulated at the state level; state-specific laws could allow pharmacists to substitute an interchangeable biosimilar for a reference product without consulting prescribers, as is often done with generic drugs. As noted by the authors, “As individual states work to regulate the use of biosimilars, oncologists and patients must be aware of regulations, authorities, and responsibilities that may affect their treatment choices.”

Reliance on Postmarketing Reporting: As stated by the authors, “minor modifications in manufacturing, processing, and packaging may result in lot-to-lot differences in both biosimilars and originator products, which could potentially lead to a small but real risk of differences in immunogenicity and adverse event profiles appearing over time.” In the absence of data from clinical trials, both the FDA and clinicians will have to rely on postmarketing surveillance to confirm the safety, as well as efficacy, of biosimilars. However, as noted by the authors, many clinicians feel that the process of postmarketing reporting is cumbersome and do not participate in the current reporting system due to time and resource constraints.

Cost and Reimbursement: According to the authors, the Centers for Medicare and Medicaid Services has determined that all newly approved biosimilars that have a common reference product will be coded separately and reimbursed at the current rate of the average sales price plus 6% of the average sales price of the originator reference product minus any mandated sequester adjustment. Medicaid categorizes biosimilars as “single source,” resulting in different reimbursement rates for each biosimilar. However, under Medicare Part D, biosimilars are exempt from the Medicare Coverage Gap Discount Program—which requires manufacturers to provide a 50% discount on brand-name drugs and brand-name biologic drugs. As stated by the authors, “As a result of this coverage gap, seniors and persons with disabilities will pay higher out-of-pocket costs for biosimilars than for competing reference biologic drugs. To close this gap, a legislative solution will be necessary to modify the definition of “applicable drugs” to include biosimilars.” In the absence of such a solution, the potential cost savings arising from use of biosimilars could be lost.

In concluding their The New England Journal of Medicine article, Lyman et al state, “… [T]he potential for biosimilars to mitigate rising health-care costs while improving access to highly effective therapies provides a true opportunity to reduce disparities in access to care and limit the financial burden of new treatments for cancer and other major illnesses. It is essential that professional organizations provide educational programs about biosimilars to inform the medical community of the opportunities and the challenges that these new agents provide for our patients now and in the years to come.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.