Table 1.

TαTs in prostate cancer

TαT	MoA	Half-life	Number of alpha particles emitted	Highlights of ongoing clinical trials or key findings
Radium-223 dichloride	Bone-seeking alpha-emitting radionuclide [8]	11.4 days [15]	4 [15]	The phase III PEACE III trial on the combination of radium-223 and enzalutamide in mCRPC [16]
				The phase III DORA trial on the combination of radium-223 and docetaxel in mCRPC [17]
				Phase I trial on the combination of radium-223 and atezolizumab in mCRPC [18]; phase II trials on pembrolizumab [19] or sipuleucel-T [20] and radium-223 in mCRPC
				Phase Ib trial of radium-223 and niraparib (PARPi) in CRPC [21]; phase I/II trial of radium-223 and olaparib (PARPi) in mCRPC [22]
213Bi-PSMA-617	PSMA-targeting small-molecule ligand conjugated with alpha-emitting radionuclide	45.6 minutes [23]	1 [23]	Molecular imaging and biochemical responses in a patient with mCRPC [24]
225Ac-PSMA-617		10.0 days [25]	4 [25]	Antitumor activity was observed in patients with mCRPC with xerostomia as dosing-limiting factor and reason of treatment discontinuation [26–28]
211At-PSMA-pentanedioic acid		7.2 h [29]	1 [29]	Significant tumor growth delay and improved survival were seen in preclinical prostate cancer xenograft model and mice bearing prostate cancer micrometastases [30]
227Th-PSMA-IgG1	PSMA-targeting mAb conjugated with alpha-emitting radionuclide	18.7 days [31]	5 [31]	Preclinical antitumor activity and safety were observed in models of prostate cancer [32, 33]; phase I trial of 227Th-PSMA immune-conjugate in mCRPC [34]

CRPC, castration-resistant prostate cancer; DSB, double-strand breaks; mAb, monoclonal antibody; mCRPC, metastatic CRPC; MoA, mechanism of action; PARPi, poly (ADP-ribose) polymerase inhibitor; PSA, prostate-specific antigen; PSMA, prostate-specific membrane antigen; TαT, targeted alpha therapy.