Table 1.

Early-phase prostate cancer clinical trials with recently developed adenoviral mutants

Viral mutant	Antitumor mechanisms	Indication and delivery	References
Phase I; Ad5-yCD/mutTK(SR39) rep-hNIS	hNIS enables imaging of tumor to monitor viral spread and efficacy by SPECT and PET; E1B55K-deleted mutant; tumor selective replication and viral lysis	Clinically localized prostate cancer; single intraprostatic injection at multiple sites + intravenous administration of Na99mTcO4	(Feasibility determination of 131I and prodrugs [FC/GCV] administration in future trials)67
Phase I; Ad5-yCD/mutTK(SR39) rep-hIL12	IL-12 alleviates immunosuppression in tumor environment by stimulating innate and adaptive immune responses; CD/TK activates prodrugs (FC/GCV); E1B55K-deleted mutant; tumor selective replication and viral lysis	Locally recurrent prostate cancer; single intraprostatic injection + radiotherapy	NCT02555397 (in progress)58
Phase I; CTL104/GM-CSF (AdNRGM)	NTR activates the prodrug CB1954; GM-CSF activates antitumor immune responses	Locally relapsed PCA; intraprostatic injection + intravenous administration of CB1954	UKCRN study ID: 13599 (in progress)76

Note: Only trials initiated or completed after 2010 are included; for earlier trials, see text with indicated references.

Abbreviations: Ad5, adenovirus serotype 5; yCD, yeast-derived cytosine deaminase; hNIS, human sodium iodide transporter; SPECT, single-photon emission computed tomography; PET, positron emission tomography; FC, fluorocytosine; GCV, ganciclovir; IL, interleukin; CD, cytosine deaminase; TK, thymidine kinase; PCA, prostate cancer antigen; GM-CSF, granulocyte-macrophage colony-stimulating factor; NTR, nitroreductase; NRGM, nitroreductase and GM-CSF.