Radioligand therapy

• ClinicalTrials.gov lists 577 ¹ interventional studies of therapeutic radioisotopes; 323 ² are active and 51 ³ are Phase 3.
• 291 ⁴ started between January 2023 and September 2026: 127 ⁵ with a US site and 75 ⁶ with a China site.
• Lutetium-177 agents appear in 222 ⁷ of the new studies and actinium-225 agents in 48 ⁸.
• Prostate cancer is the leading indication, with 145 ⁹ new studies.

Trial starts rose from 36 ¹⁰ in 2020 to 79 ¹¹ in 2025, with the step up coming in 2022 (50 ¹²) and 2023 (67 ¹³), after the FDA approved Pluvicto in March 2022.

The United States is the centre of the field. Studies with a US site went from 17 ¹⁴ in 2020 to 39 ¹⁵ in 2025. China started from a low base, 2 ¹⁶ studies in 2020, and reached 22 ¹⁷ in 2025. Growth there is led by academic nuclear medicine centres, such as Peking Union Medical College Hospital, and by domestic companies building isotope supply.

Lutetium-177, a beta emitter, appears in 222 ⁷ studies started since 2023. PSMA-targeted radioligands appear in 98 ²⁸ and somatostatin-receptor-targeted agents in 45 ²⁹.

Alpha emitters are the main technical shift. They deliver much more energy over a shorter range, which may overcome resistance to beta emitters. Actinium-225 agents appear in 48 ⁸ new studies and lead-212 agents in 11 ³⁰. Radium-223, the first approved alpha therapy, appears in 8 ³¹, a sign that its label-expansion phase is largely over.

New targets are moving in behind PSMA and SSTR: FAP (fibroblast activation protein), GRPR, CA9 in kidney cancer, and HER2. Most are still in Phase 1.

Prostate cancer is listed in 145 ⁹ radioligand studies started since 2023, and neuroendocrine tumours in 49 ³². Breast cancer (25 ³³), lung cancer (25 ³⁴) and kidney cancer (13 ³⁵) are much smaller but are where new-target programmes are heading.

In prostate cancer, the trials are moving earlier in the disease: before chemotherapy, in hormone-sensitive disease, and in oligometastatic disease. Those are larger markets but also need longer and more expensive trials.

• Pluvicto (lutetium Lu 177 vipivotide tetraxetan, PSMA), approved 23 March 2022 (NDA 215833)
• Lutathera (lutetium Lu 177 dotatate, SSTR), 26 January 2018 (NDA 208700)
• Xofigo (radium Ra 223 dichloride), 15 May 2013 (NDA 203971)

Large companies bought their way in. Novartis acquired Advanced Accelerator Applications (Novartis) and Endocyte in 2018. Eli Lilly acquired POINT Biopharma in December 2023, Bristol Myers Squibb completed its RayzeBio acquisition in February 2024 (BMS), and AstraZeneca acquired Fusion Pharmaceuticals in June 2024. AstraZeneca's actinium-225 PSMA agent and Novartis's actinium-225 version of PSMA-617 are now in Phase 3 in prostate cancer.

• Isotope supply is a strategic asset. Actinium-225 and lead-212 are scarce. Companies that control production, generators or manufacturing slots have leverage that a new ligand alone does not.
• New targets beat new PSMA ligands. PSMA already has an approved drug and two alpha-emitter Phase 3 programmes. FAP, CA9, GRPR, DLL3 and other targets have open space, but need proof that tumour uptake is high and kidney and salivary exposure is low.
• Pair diagnostics with therapeutics. A matching imaging agent selects patients and can generate revenue earlier.
• Logistics decide commercial success. Short half-lives mean that site networks, dosimetry and nuclear medicine capacity limit how fast a product can grow. China's expanding nuclear medicine infrastructure is an opportunity for regional players.

Every trial count is the totalCount of one ClinicalTrials.gov API v2 query, retrieved on 26 September 2026. Each numbered citation opens a record whose source link re-runs the query. The track includes interventional studies whose interventions name lutetium-177, actinium-225, lead-212, radium-223, terbium or copper-67, or radioligand therapy. Iodine-131 and imaging-only agents are excluded, but some included studies also use imaging tracers.

Site-country counts overlap and China-only registrations are missing. Isotope and target bars match intervention text and can overlap. Approval dates come from Drugs@FDA. Acquisitions and programme stages are based on company announcements.