Repurposing of biologics: Has the time come for a systematic approach?

<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto" id="d15945285e89">Most drug repurposing projects consider the use of a small molecule drug as a starting point. However, the developmental, regulatory and commercial landscape for repurposing of biologics is quite different. Biologic drugs made up 16 of the 50 new drugs (32%) approved by FDA in 2024. The economics of pharmaceutical development favour biologics over small molecules, and that proportion is increasing. At the same time, the biosimilar pathway is becoming better understood and more reliable, meaning that for most successful marketed products, biosimilars are likely to also be made available after branded products lose their exclusivity period. <p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d15945285e91">However, unlike small molecule generics, biosimilars are not always interchangeable. The extent to which off-label prescriptions can be substituted at the pharmacy level depends on regulatory status, jurisdiction and whether on- or off-label. In the US, so-called “switching” clinical studies are mandated whereas this is normally not required in Europe. Biosimilars, by virtue of their lower price, may enable greater access to certain patients with certain indications that are denied access to branded alternatives. It is possible that a biosimilar is considered ‘value for money’ when the reference product is not. <p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d15945285e93">This indication-specific landscape for similar biologic products is further complicated if the biosimilar is patented for a new indication that lies outside the label of the reference product or its extrapolated uses. <p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d15945285e95">A simpler category of repurposeable biologic developments derives from those products which have been abandoned for lack of efficacy, or from re-formulation of an existing marketed biologic for a different tissue bed (e.g. intravitreal or oral rather than i.v. or s.c.). Various examples aredescribed to illustrate these strategies.