Aptamer Group launches targeted radiopharmaceutical program

Aptamer Group plc has launched a new targeted radiopharmaceutical program in collaboration with Radiopharmium Ltd, a UK-based specialist consultancy in radiopharmaceutical development.

Radiopharmaceuticals deliver a radioactive payload directly to diseased tissue, but a persistent challenge is the degradation of the targeting molecule once it carries a radioactive payload, shortening shelf life, increasing waste, and complicating distribution. The industry standard is to add protective additives such as ascorbic acid to mitigate this degradation.

Optimer platform: A potentially differentiated stability profile

Aptamer has previously developed fully integrated radioligand conjugates incorporating proprietary chemistry, linkers, and chelation systems, and evaluated their stability under clinically relevant conditions using Ga-68 (Gallium-68) and Lu-177 (Lutetium-177), radioactive isotopes widely used in cancer imaging and targeted therapy.

In comparative testing at 24 hours, Lu-177 Optimer^®-based radioligands demonstrated only 8% degradation in the absence of protective additives, compared with 34–83% degradation seen with leading peptide comparators under the same conditions.

The company believes these results may support extended shelf life, reduced waste, and simplified logistics, offering a potentially differentiated profile relative to existing approaches.

Programme development and milestones

Three strategic therapeutic targets, representing high-value clinical conditions, have been identified for Optimer^® radioconjugate development. The programme will progress through in vitro validation before advancing to in vivo studies assessing targeting and therapeutic performance.

Key programme highlights:

• Three therapeutic targets selected across high-value clinical indications
• Optimer^® radioconjugates to be validated in vitro before progressing to in vivo models
• Combined with the existing partnered programme with a top 3 global pharmaceutical company, the pipeline is expected to comprise four radiotherapy assets
• In vivo data targeted for delivery by end of 2026

The program will be led by Dr. Louis Allott, CEO of Radiopharmium Ltd and a member of Aptamer’s Scientific Advisory Board. Dr. Allott is a recognized expert in radiopharmaceutical development, with experience spanning laboratory discovery through to clinical translation. He will take a fractional role as Director of Radioligand Development for Aptamer, overseeing radiochemical conjugation and biological evaluation in established preclinical models.

Dr. Allott said, “I am delighted to be working with Aptamer, a recognized leader in the field of aptamer technology with a strong track record of success. The combination of Aptamer’s innovative Optimer^® platform and Radiopharmium’s expertise in radiopharmaceutical development makes this collaboration well‑positioned to demonstrate the potential of aptamer‑based targeting in next‑generation radiopharmaceuticals.”

Dr. Arron Tolley, Chief Executive Officer of Aptamer Group, added, “We are excited to launch this programme in a high‑growth field where the limitations of existing targeting technologies create a compelling opportunity for our Optimer^® platform.

A key challenge in radiopharmaceuticals is maintaining the stability of the targeting molecule once it is carrying a radioactive payload. Our data indicates that Optimer^®-based radioligands may offer improved stability compared to existing approaches, which could translate into practical advantages in manufacturing, distribution, and clinical use, subject to further validation.

With Louis leading this programme and access to world-class preclinical models through Radiopharmium, we are well-positioned to advance multiple assets towards in vivo validation and further demonstrate the potential of our platform in this rapidly growing therapeutic field.”

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