Biosimilars are set to become integral to cancer therapy
A prospective review of the future of oncology and haematology therapeutics concludes emphatically that biosimilars have arrived in this space. The impact of these agents on cancer care will be great – as long as challenges to their uptake can be overcome.
Biological drugs (biologics) are a cornerstone of treatment for advanced solid tumours and haematological malignancies. However, they are structurally complex and expensive to develop and manufacture, and biologic treatment costs remain high. Patent expiration for various anti-cancer biologics has enabled the development of biosimilars – highly similar biologic products that have gained regulatory approval. Biosimilars are subject to abbreviated approval pathways and their lower development cost usually translates to discounted prices once marketed.
The EMA and FDA’s stepwise approach to establish comparability between a candidate biosimilar and its reference product involves a range of analytical, pre-clinical, and clinical studies. These trials determine that the biosimilar pharmacokinetics and efficacy are statistically equivalent (or non-inferior) to the reference product and that there are no differences in safety, pharmacodynamics, and immunogenicity. Regulatory approval of a biosimilar may be granted if the totality of evidence from all these investigations shows no clinically meaningful difference between the biosimilar and the originator. Extrapolation, licensing permission for the additional indications held by the originator biologic, may be considered by regulatory authorities if evidence shows it is scientifically justified. As an example, the anti-CD20 antibody rituximab’s mechanism of action is lysis of B cells expressing this surface protein, therefore the rituximab biosimilar CT-P10 was considered by EMA likely to exert therapeutic effects against other CD20+ cancers and extrapolated approval for these indications accordingly.
To date, biosimilars approved for cancer treatment are generally licensed for all indications held by their originator product. Parallel considerations have also led to broader acceptance that chronic patients may be switched from biologics to biosimilars without affecting treatment outcomes – subject to national and regional regulations on interchangeability. Nonetheless, decisions regarding switching should be led by treating physicians. Further data collection in this area is strongly encouraged.
The availability of new biosimilars offers the potential for direct cost savings as well as stimulating competition among alternative biologic/biosimilar options, pushing down prices and enabling better patient access to these vital treatments. Barriers to the marketing and uptake of biosimilars must be addressed to attain the full benefits of these drugs.
Biosimilars have abbreviated approval pathways leading to lower market costs. Biosimilars approved for cancer treatment are generally licensed for all indications held by their originator product offering the potential for direct cost savings as well as stimulating competition among alternative biologic/biosimilar options. Current barriers to uptake need to be addressed to increase biosimilar market share.