Why drug delivery is biotech’s overlooked challenge – and its greatest opportunity

In drug development, the spotlight often shines on the active ingredient: the molecule, the antibody, or the engineered cell that promises to change lives. Yet, too often, the question of how to deliver that therapy safely and effectively is left to the end of the process. For many start-ups under pressure to reach first-in-human trials quickly, delivery considerations feel secondary. The result? Costly delays, failed trials, and therapies that fall short of their potential.

This challenge is magnified with today’s most innovative therapies. Large molecules, peptides, antibodies, and living cells don’t behave like traditional small molecules. They require carriers, stabilisers, or protective “inactive ingredients” to ensure they arrive at the right place, in the right concentration, and for long enough to have an effect. The idea that delivery doesn’t matter – or that “cells will find their way” – is outdated and increasingly costly for patients and the industry.

Several factors explain why delivery lags behind discovery:

• Lack of awareness. Many innovators don’t realise that “inactive ingredients” for complex therapies exist, or that they can be just as critical as the active component. For small molecules, excipients have long extended shelf life, improved tolerability, and enabled oral dosing. The same principles apply to cell and gene therapies.
• Regulatory hesitation. Teams often fear that introducing new materials will complicate their regulatory path. In reality, many polymers with excellent track records are already FDA-approved for use in drugs or medical devices.
• Investor pressure. Early-stage companies are pushed to reach the clinic quickly. Delivery systems that don’t appear “essential” may be sidelined, even if skipping them undermines long-term efficacy.
• The persistence of old dogma. For years, many assumed infused cells would “home” naturally to disease sites. Science has since shown this is rarely true. Most cells given intravenously are filtered out by the lungs, with only a small fraction ever reaching the target tissue. Overdosing has been the workaround, but at the cost of safety, tolerability, and expense.

The cost of getting it wrong

The price of overlooking delivery is staggering. Failed cell therapy trials alone are estimated to cost the industry $15 billion annually. In many cases, the therapy itself is not ineffective – the cells simply don’t persist at the target site long enough to have an impact, or they trigger intolerable off-target effects. Without delivery innovation, promising science is lost.

The next generation of drug delivery focuses on keeping therapies where they’re needed, releasing them gradually, and protecting them during storage and transport.

By holding therapeutic cells, peptides, or antibodies at the disease site and releasing them over days, weeks, or even months, two major barriers are overcome:

1. The “first pass” loss through the lungs is avoided.
2. Doses can be lowered dramatically, reducing toxicity and cost.

A case in point: CAR-T and solid tumours

CAR-T therapies have revolutionised treatment for blood cancers, yet have failed to make the same impact in solid tumours. This isn’t because the T-cells suddenly stop working; it’s because IV delivery doesn’t achieve sustained concentrations of cells in the tumour microenvironment. Moreover, the hostile biology of solid tumours actively works against cell survival.

By embedding CAR-T cells in a protective polymer scaffold infused with survival-promoting factors like interleukins, though, there’s potential to place them directly at or near the tumour. The polymer then releases the cells gradually, maintaining presence at the disease site and shielding them from inhospitable conditions. The result? Improved efficacy, fewer systemic side effects, and renewed hope for patients with solid tumours.

Delivery innovations don’t just improve outcomes – they reshape the entire therapy ecosystem:

• Extended release reduces the need for repeated infusions.
• Durability lowers relapse rates.
• Targeted delivery cuts systemic toxicity.
• Lower doses reduce cost per patient.
• Improved stability means therapies that once required liquid nitrogen can be shipped on dry ice, or even stored at room temperature for weeks. This dramatically improves access, especially for rural or resource-limited clinics.

Looking ahead

Drug delivery is no longer just about convenience. It’s about enabling the therapies of the future to succeed where they would otherwise fail. Over the next decade, excipients and delivery systems for large molecules and living cells will become as central to biotech innovation as they have long been for small molecules.

The industry is at an inflection point. We can continue to see billions lost to failed trials, or we can embrace delivery as the critical bridge between groundbreaking science and real-world patient benefit. Delivery isn’t a side note: it’s the difference between a therapy that works in theory and one that works in patients.

About the author

Dr Lisa Stehno-Bitte is a co-inventor on 33 global patents (issued and pending). She licensed her laboratory patents from the University of Kansas Medical Center and founded the company Likarda. The patents had applications in drug screening for efficacy and toxicity, as well as the ability to transform cell-based therapeutics. Dr Stehno-Bitte has been an invited speaker at scientific and business conferences across the globe and has received numerous awards, including the Jim Baxendale Commercialization Award. Ingram’s Magazine named her one of “50 Kansans You Should Know” and she was awarded the Women in Medicine and Science Sirridge award for female role models. Dr Stehno-Bitte is a Fellow of the American Institute for Medical and Biological Engineering. This year she was named one of the Top 50 Women Leaders of Missouri.