FDA has finally issued draft guidance documents for biosimilars. However, the guidelines still do not address the issue of interchangeability of originator drugs and biosimilars.
In the US, the Biologics Price Competition and Innovation Act gives FDA the authority to designate a biosimilar as interchangeable with its reference product. This means that the biosimilar may be substituted for the originator product by the pharmacist without reference to the prescribing physician [1].
FDA has made it clear that it will use a step-wise process to approval of biosimilars. Drugmakers will first have to establish ‘similarity’, followed by ‘biosimilarity’, and then finally developers can decide whether to pursue ‘interchangeability’ or not [2]. This approach, however, has raised questions as to what would happen if a product was deemed not interchangeable [3].
It was hoped that with the publishing of biosimilars guidance this issue would be ironed out, however, this appears not to be the case. In fact, FDA has stated that ‘at this time, it would be difficult as a scientific matter for a prospective biosimilar applicant to establish interchangeability in an original 351(k) application’ due to the ‘sequential nature of that assessment’, adding that ‘FDA is continuing to consider the type of information sufficient to enable FDA to determine that a biological product is interchangeable with the reference product.’
It appears that separate clinical trials will be required to prove interchangeability, involving switching the originator (reference) drug and the biosimilar back and forth, more than once. Such studies would ensure that switching between products does not affect the safety or efficacy of the product.
Some believe that without automatic substitution, use of biosimilars could be limited and that a biosimilar product for which comparability is demonstrated should be interchangeable with its comparator, as is the case for conventional generics [4]. Automatic substitution would enable biosimilars to be adopted much more rapidly, thus increasing access for patients to these often life-changing medicines and reducing healthcare costs for both patients and governments.
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Editor’s Comment
The question is how high will the bar be set for biosimilars? Of course patient safety is paramount, but the requirements should not be set so high as to discourage competition which will drive down prices and increase patient access to affordable medicines.
Please feel free to share your thoughts via email or in the comments section below. What are your views on interchangeability of biosimilars? Should biosimilars that are approved as ‘comparable’ be automatically designated as interchangeable in the US?
Related article
US guidelines for biosimilars
References
1. GaBI Online - Generics and Biosimilars Initiative. Interchangeability of biosimilars in the US [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2012 Feb 17]. Available from: www.gabionline.net/Biosimilars/News/Interchangeability-of-biosimilars-in-the-US
2. GaBI Online - Generics and Biosimilars Initiative. FDA and biosimilars: update on key themes [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2012 Feb 17]. Available from: www.gabionline.net/Biosimilars/General/FDA-and-biosimilars-update-on-key-themes
3. GaBI Online - Generics and Biosimilars Initiative. FDA gives some insight into biosimilar pathway [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2012 Feb 17]. Available from: www.gabionline.net/Biosimilars/News/FDA-gives-some-insight-into-biosimilar-pathway
4. GaBI Online - Generics and Biosimilars Initiative. Interchangeability or substitution of biosimilars [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2012 Feb 17]. Available from: www.gabionline.net/Biosimilars/Research/Interchangeability-or-substitution-of-biosimilars
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