Radiopharmaceutical innovation: Giving cancer drugs second chances and creating new therapeutic possibilities
Radiopharmaceuticals are one of the most exciting frontiers in oncology and targeted therapies today. By combining biologically active molecules with radionuclides, radiopharmaceuticals can deliver highly targeted radiation to tumours. This approach offers an enhanced therapeutic effect with minimal systemic toxicity, addressing one of oncology’s long-standing challenges: how to maximise therapeutic effects on tumours while minimising collateral damage to healthy tissues.
Beyond their clinical promise, radiopharmaceuticals are also opening new strategic opportunities, particularly through repurposing previously shelved or failed oncology molecules. Many compounds that faltered in traditional drug development because of toxicity, or suboptimal pharmacokinetics, or limited efficacy can find a second life as precision delivery vehicles for radionuclides. Molecular recycling could transform the economics and innovation of oncology drug discovery.
Reimagining the role of oncology active pharmaceutical ingredients
Traditional oncology drugs rely on pharmacologic action, such as blocking receptors, inhibiting kinases, or modulating immune pathways, to fight tumours. These approaches often require high systemic doses, leading to toxicity and limited therapeutic windows. Radiopharmaceuticals, by contrast, shift the therapeutic mechanism. Here, a biologic or small molecule will act primarily as a carrier for a radionuclide, homing in specifically on cancer cells while the radioactive payload delivers the cytotoxic effect. This novel class of drugs has seen a surge in funding in recent years.1
As only minute quantities of the molecule are required to achieve therapeutic impact, previous liabilities such as immunogenicity or off-target pharmacology become less of a concern. A compound that was once too toxic to administer systemically may now serve safely and effectively as a delivery vehicle. In this way, radiopharmaceuticals can decouple efficacy from dose, a potentially game-changing concept for oncology drug design.
Repurposing is not limited to failed assets. Molecules with proven tumour-targeting properties, such as antibodies, peptides, or small molecules already used in oncology, can also be transformed into radiopharmaceuticals. By coupling their targeting precision with radionuclide potency, developers can expand portfolio value and accelerate development using known safety and efficacy data.
The dual challenge of combining biology and radiochemistry
Developing radiopharmaceuticals requires mastery across two deeply specialised disciplines: cancer biology and radiochemistry. From the biological perspective, developers must understand receptor expression, tumour microenvironment, and biodistribution patterns to ensure that the targeting molecule reaches and remains in cancer tissue. Meanwhile, the radiochemistry side involves selecting the right radionuclide, attaching it through a stable chelator, and ensuring that the labelling process does not alter the molecule’s affinity or pharmacokinetics.
The conjugation process itself presents unique scientific challenges and each radionuclide has distinct chemical properties. Some require harsh conditions that can denature delicate biomolecules, while others need precise handling to maintain purity and activity. The final product must remain stable throughout storage, handling, and administration, with predictable biodistribution and dosimetry profiles.
Success depends on seamlessly integrating biological insight with radiochemical precision, ensuring the molecule and radionuclide act together, rather than in conflict.
The operational realities of infrastructure and logistics
Even after a viable radiopharmaceutical is designed, operational hurdles remain. Handling radioactive materials requires specialised infrastructure, radiation shielding, and strict safety protocols. Trained radiochemists, nuclear physicists, and radiopharmacists are essential for both regulatory compliance and ensuring scientific quality.
Logistics present another major constraint. Many therapeutic radionuclides have half-lives measured in hours, meaning the window for labelling, delivery, and dosing can be extremely short. If tumour-bearing animal models or clinical patients are not ready at the precise moment the radionuclide arrives, valuable isotopes can decay before use.
This time sensitivity extends to the supply chain. Developers are often drawn to novel or “exotic” radionuclides with promising physical characteristics, only to find that production capacity or regulatory-grade supply is limited. Without a reliable isotope source, even the most promising preclinical programmes can stall before clinical translation.
Mitigating these risks requires early planning. A strong supplier relationship including an integrated coordination with radionuclide production can help with radiolabelling and biological testing.
Regulatory readiness: A growing sophistication
The regulatory landscape for radiopharmaceuticals has evolved rapidly. The US FDA and EMA now have dedicated frameworks for evaluating these therapies, recognising their hybrid nature as both chemical and radioactive entities.
Developers must provide comprehensive data on stability, purity, and radiochemical yield, along with dosimetry and biodistribution studies that quantify both efficacy and safety. Toxicity testing is essential to confirm that radiation exposure to healthy tissues remains within acceptable limits, both for the radioactive component and the conjugated molecule.
While the bar is high, regulators have become more familiar with radiopharmaceuticals through recent approvals. This growing experience, coupled with clearer expectations, means that well-prepared developers can now move faster — provided their data packages are complete and scientifically sound.
Integrating across the development continuum
As radiopharmaceutical development spans biology, chemistry, pharmacology, and regulatory affairs, integration is key. A fragmented approach that outsources different elements to separate vendors can introduce gaps, delays, and costly rework.
An end-to-end development framework brings together:
- Bioconjugation chemistry
- Radiochemistry
- Pharmacokinetics and pharmacodynamics (PK/PD) screening
- Preclinical tumour modelling
- Imaging modalities (PET, SPECT, PET/SPECT-CT, PET-MRI)
- Dosimetry and toxicity testing
This integrated workflow not only accelerates progress, but ensures that early decisions are informed by downstream feasibility and regulatory expectations. Early imaging studies, for example, can reveal whether a compound’s tumour targeting is strong enough to justify further investment. Similarly, dosimetry assessments can help fine-tune isotope selection and dosing strategies before moving into GLP studies.
Strategic collaboration: De-risking through expertise
Radiopharmaceuticals are now moving from niche to mainstream oncology. Advances such as alpha emitters, which deliver intense but localised cell-killing effects, are expanding the therapeutic toolbox. Dual-modality “theranostic” agents, which combine diagnostic imaging and therapeutic functions in a single molecule, are also redefining personalised medicine by allowing clinicians to see and treat tumours simultaneously.
As the field matures, its success will depend not only on technological breakthroughs, but on strategic thinking – recognising when to innovate and when to rely on proven solutions. Repurposing shelved oncology molecules as radiopharmaceutical carriers exemplifies this mindset by turning past challenges into future cures.
For many biotech and pharma companies, radiopharmaceuticals represent unfamiliar territory. Success demands not just infrastructure, but experience navigating the intersection of nuclear science and oncology. Collaboration with specialised partners, including radiopharmaceutical contract research organisations (CROs), can provide access to radiochemistry facilities, preclinical imaging capabilities, and cross-functional expertise.
These partnerships are especially valuable for small or mid-sized innovators aiming to move quickly. Working with experienced CROs allows developers to anticipate supply chain risks, design efficient study sequences, and generate regulatory-ready data packages that stand up to scrutiny. The result is less risk, a smoother path to the clinic and, ultimately, faster delivery to patients.
By embracing cross-disciplinary collaboration and integrated development, the oncology community can accelerate this transformation, bringing the next generation of targeted radiopharmaceuticals from concept to clinic and giving new life to molecules once left behind.
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About the author
Dr Eftychia Koumarianou is the head of the Pharmaco-Imaging and Molecular Radiotherapy (MRT) Department at Oncodesign Services. She brings over 20 years of international experience in nuclear medicine, radiopharmaceutical development, and translational oncology research to her role. Prior to joining Oncodesign Services, she held key roles at ABX-CRO and Advanced Accelerator Applications. Dr Koumarianou holds a PhD from the University of Athens and has conducted postdoctoral research at institutions including Demokritos, Polatom, Duke University, and Duke-NUS Medical School.
