Biosimilars in oncology in the US

As part of the Affordable Care Act of 2010, the Biologics Price Competition and Innovation Act of 2009 (BPCI Act) allows for an abbreviated license pathway for the approval of biosimilars in the US. In light of continuing increases in healthcare costs, particularly for cancer drugs, use of biosimilars is increasingly being considered as a strategy for containing the cost of cancer care, according to Dr Gary Lyman of the Fred Hutchinson Cancer Research Center and University of Washington, Seattle, WA, USA [1, 2].

As of October 2017, the US Food and Drug Administration (FDA) has approved six biosimilars in the US [3]. One of those biosimilars is Zarxio (filgrastim-sndz). This biosimilar was approved by FDA in March 2015 to be used as supportive care in patients receiving cancer chemotherapy to reduce the risk of febrile neutropenia [4].

Filgrastim-sndz demonstrated identical protein structure, mass, size, charge and hydrophobicity to the originator product, while pharmacokinetic and pharmacodynamic modelling confirmed that the mechanism of action occurs through the binding of the granulocyte colony-stimulating factor (G-CSF) receptor as with the originator. Clinical data leading to the approval of filgrastim-sndz were predominately based on information gathered from healthy volunteers and data in patients with cancer in the context of the prevention of chemotherapy-induced neutropenia. Once granted approval for this indication as a biosimilar, FDA approved the agent for all indications of the originator filgrastim. Clinical practice guidelines now consider this biosimilar and other approved forms of G-CSF as therapeutic options for patients receiving cancer chemotherapy.

FDA published draft guidance on the interchangeability of biosimilars with their reference products in January 2017 [5]. However, to date, no biosimilars are as yet approved as interchangeable and concerns have been raised regarding extrapolation, as well as interchangeabilty, switching and provider notification [6-8].

In order to dispel any reservations about biosimilars it is important that professional bodies get behind biosimilars when it comes to issuing policy statements and guidelines.

In 2015, the American Society of Clinical Oncology (ASCO) issued a policy brief on biosimilars to provide guidance to its members and to policymakers on the evolving regulatory landscape of biosimilars. The policy brief highlighted the following principles, among others:

Biosimilar clinical trials should demonstrate efficacy and safety, including lack of immunogenicity.
FDA should establish a transparent regulatory pathway for approval of biosimilars.
Physician choice between biologicals in the best interest of patients should not be restricted.
Approved biosimilars should be subject to careful post-market safety surveillance.
Interchangeability should be established by clinical trials that are adequately designed and performed to support substitution.
Congress should ensure adequate FDA funding to meet new demands.

However, continuing confusion around the appropriate regulation and role of biosimilars in oncology practice have led ASCO to set up a Working Group to evaluate the evidence and develop a formal ASCO Policy Statement on Biosimilars in Oncology.

According to Dr Lyman, ‘biosimilars will have an important role in future cancer care and scientific innovation’. However, he cautions that ‘although many biosimilars in oncology will be available in the next several years, their use and impact on patient care and healthcare costs will depend largely on patient and provider acceptance based on an adequate understanding of the safety and efficacy of these agents in cancer care’.

Conflict of interest
The author of the research papers [1, 2] reported conflicts of interest, including being an advisor/consultant for Halozyme, G1 Therapeutics and Coherus Biosciences and having received research funding from Amgen. For full details of the author’s conflict of interest, see the research papers [1, 2].

Editor’s comment
Readers interested to learn more about biosimilars in oncology are invited to visit www.gabi-journal.net to view the following manuscript published in GaBI Journal:

Oncologists urged to embrace biosimilars to help control spiralling costs of cancer care

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Biosimilars in oncology in Europe

Opportunities and challenges for biosimilars in oncology

References
1. Lyman GH. Emerging opportunities and challenges of biosimilars in oncology practice. J Oncol Pract. 2017;13(9_suppl):7s-9s.
2. Lyman GH. Biosimilars in the changing cancer care landscape. ASCO Daily News. 3 June 2017.
3. GaBI Online - Generics and Biosimilars Initiative. Biosimilars approved in the US [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Oct 24]. Available from: www.gabionline.net/Biosimilars/General/Biosimilars-approved-in-the-US
4. GaBI Online - Generics and Biosimilars Initiative. FDA approves its first biosimilar [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Oct 24]. Available from: www.gabionline.net/Biosimilars/News/FDA-approves-its-first-biosimilar
5. GaBI Online - Generics and Biosimilars Initiative. FDA issues draft guidance on biosimilar interchangeability [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Nov 24]. Available from: www.gabionline.net/Guidelines/FDA-issues-draft-guidance-on-biosimilar-interchangeability
6. GaBI Online - Generics and Biosimilars Initiative. Comments on extrapolation in FDA’s interchangeability guidance from big pharma [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Nov 24]. Available from: www.gabionline.net/Guidelines/Comments-on-extrapolation-in-FDA-s-interchangeability-guidance-from-big-pharma
7. GaBI Online - Generics and Biosimilars Initiative. Physicians' concerns on FDA’s interchangeability guidance [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Nov 24]. Available from: www.gabionline.net/Guidelines/Physicians-concerns-on-FDA-s-interchangeability-guidance
8. GaBI Online - Generics and Biosimilars Initiative. Comments on switching in FDA’s interchangeability guidance from big pharma [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Nov 24]. Available from: www.gabionline.net/Guidelines/Comments-on-switching-in-FDA-s-interchangeability-guidance-from-big-pharma

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