Where have all the inhaled biologics gone ?

Jeremy G Clarke¹

¹GSK, Priory Street, Ware, Hertfordshire, SG12 0DJ, UK

Summary

The regulatory approval of Humulin (recombinant human insulin) in 1982 heralded the arrival of medicines derived from biotechnology.  In the years that have followed, the proportion of biologics-based New Molecular Entities (NMEs) has continued to grow, recent CDER Approvals Reports indicating that Biologics Licence Applications (BLAs) now account for some 30-40% of FDA approvals^[1,2].  In the field of respiratory medicine, subcutaneous injection of monoclonal antibodies targeting immune and inflammatory pathways^[3] now offer treatment options for severe allergic asthma.

Recognition of the limitations of parenteral administration has driven significant efforts to develop non-invasive delivery approaches for biotherapeutics, including oral, dermal, nasal and pulmonary administration routes^[4,5].  However the formidable challenges to realise safe, stable, efficacious and cost-effective products is evidenced by the continued predominance of subcutaneous and intravenous injection for delivery of biologics.

A historical review (1995) of the potential for pulmonary delivery of biologics described the evaluation of a broad diversity of molecules^[6], but, despite considerable activity in the scientific community, over 20 years later dornase alfa and insulin remain the only two regulatory approved inhaled biologics – where have all the inhaled biologics gone ?

In this paper, the challenges to realising an inhaled biologic will be discussed (exemplified by the dornase alfa and insulin case studies), advances in other non-parenteral delivery approaches briefly reviewed and finally some areas where pulmonary delivery continues to shows promise will be highlighted.