REG - Aptamer Group PLC - Launch of targeted radiopharmaceutical programme

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RNS Number : 0352X  Aptamer Group PLC  18 March 2026

 

18 March 2026

Aptamer Group plc

("Aptamer", the "Company" or the "Group")

 

Launch of targeted radiopharmaceutical programme

Optimer® radiopharmaceutical programme initiated with Radiopharmium Ltd

Three therapeutic targets selected across high‑value clinical indications

Pipeline planned for four radiotherapy assets with in vivo data expected by
end of 2026

 

Aptamer Group plc (AIM: APTA), the developer of next‑generation synthetic
binders for the life sciences industry, is pleased to announce the launch of a
new programme to develop targeted radiopharmaceuticals, in collaboration with
Radiopharmium Ltd, a UK-based consultancy providing specialist expertise,
contacts and access to facilities in radiopharmaceutical development, from
early research to manufacturing.

 

Building a proprietary radiopharmaceutical pipeline

In parallel to the project with a top 3 pharma partner developing radioligand
delivery vehicles (RNS dated 8 October 2025), Aptamer has identified three
strategic therapeutic targets, representing high‑value clinical conditions,
for which Optimer® radioconjugates will be developed. The targeted
radiopharmaceuticals market is valued at approximately US$7.5 billion in 2025
and is a high‑growth high priority sector, with current targeting
technologies presenting well-recognised limitations.

 

Radiopharmaceuticals deliver a radioactive payload directly to diseased
tissue, but the payload can degrade the delivery molecule over time,
shortening shelf life, increasing waste, and complicating distribution. The
industry standard is to add protective additives, such as ascorbic acid. Based
on recent studies, Aptamer believes that the properties of its Optimer®
platform, including enhanced tissue penetration, reduced immunogenicity, and
ease of chemical optimisation, position it well to address these limitations
and potentially provide differentiated therapeutic candidates.

 

Demonstrating differentiated radioligand stability

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

 

In comparative testing at 24 hours, Lu-177 Optimer®-based radioligands were
stable in the presence of ascorbic acid, a known antioxidant, showing only 8%
degradation in its absence. This compares with 34-83% degradation of leading
peptide comparators under the same conditions, in the absence of ascorbic
acid.

The observed improvement in intrinsic stability, both with and without
protective additives, may support extended shelf life, reduced waste, and
simplified handling and logistics. This offers a potentially differentiated
profile for Optimer®-radioligands relative to
existing approaches and may support ongoing and future collaborations in
radioligand imaging and therapy.

Programme development and milestones

Optimers will be developed to targets initially and validated through in vitro
laboratory-based experiments. They will then be optimised and prepared for
radiopharmaceutical incorporation before further in vitro and in vivo studies
to assess targeting and therapeutic performance.

 

Combined with the Company's existing partnered radiotherapy development
programme with a top‑3 global pharmaceutical company, this new initiative is
expected to expand Aptamer's radiotherapy pipeline to four assets, with in
vivo data targeted for delivery by the end of 2026.

 

World‑class expertise and preclinical access

The programme will be overseen by Dr Louis Allott, a member of Aptamer's
Scientific Advisory Board and a recognised expert in the development and
production of radiopharmaceuticals, with direct experience spanning laboratory
discovery through to clinical translation.

 

Through his consultancy, Radiopharmium Ltd, Dr Allott will take a fractional
role as Director of Radioligand Development for Aptamer, overseeing the
radiochemical conjugation of Optimer® binders and their biological evaluation
in established preclinical models. This work will involve the design,
synthesis, and evaluation of radiolabelled Optimer®‑based ligands in
validated animal models to assess safety, targeting performance, and
therapeutic potential prior to clinical trials.

 

Dr Arron Tolley, Chief Executive Officer of Aptamer Group, commented:

"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."

 

Dr Louis Allott, Chief Executive Officer of Radiopharmium Ltd, commented:

"I am delighted to be working with Aptamer, a recognised 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."

 

- Ends -

 

For further information, please contact:

 

 Aptamer Group plc                                               +44 (0) 1904 217 404 

 Dr Arron Tolley, Chief Executive Officer
 SPARK Advisory Partners Limited - Nominated Adviser             +44 (0) 20 3368 3550 

 Andrew Emmott / Dillon Wall
 Turner Pope Investments (TPI) Limited - Broker                  +44 (0) 20 3657 0050 

 Andrew Thacker / Guy McDougall
 Northstar Communications Limited - Investor Relations           +44 (0) 113 730 3896

 Sarah Hollins

 

About Aptamer Group

 

Aptamer Group is a leading developer of next-generation synthetic binders
delivering innovation to the life sciences industry. The Group develops
Optimer® binders, advanced molecules that work like antibodies by attaching
to specific targets in the body. These binders are used in medicine,
diagnostic tests, and research tools, offering benefits like high stability,
reliable performance, and lower costs compared to traditional antibodies.

 

Aptamer operates a fee-for-service business in the US$210 billion market for
antibody alternatives, working with all top 10 global pharmaceutical
companies. It is also building valuable Optimer® assets with partners, aiming
for future licensing revenue.

 

Founded in 2008, the Group listed on the London Stock Exchange AIM market in
December 2021 and is headquartered in York, UK.

 

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