title: Phase I study of replication-competent adenovirus-mediated double-suicide gene therapy in combination with conventional-dose three-dimensional conformal radiation therapy for the treatment of newly diagnosed, intermediate- to high-risk prostate cancer.
abstract: The primary study objective was to determine the safety of intraprostatic administration of a replication-competent, oncolytic adenovirus containing a cytosine deaminase (CD)/herpes simplex virus thymidine kinase (HSV-1 TK) fusion gene concomitant with increasing durations of 5-fluorocytosine and valganciclovir prodrug therapy and conventional-dose three-dimensional conformal radiation therapy (3D-CRT) in patients with newly diagnosed, intermediate- to high-risk prostate cancer. Secondary objectives were to determine the persistence of therapeutic transgene expression in the prostate and to examine early posttreatment response. Fifteen patients in five cohorts received a single intraprostatic injection of 10(12) viral particles of the replication-competent Ad5-CD/TKrep adenovirus on day 1. Two days later, patients were administered 5-fluorocytosine and valganciclovir prodrug therapy for 1 (cohorts 1-3), 2 (cohort 4), or 3 (cohort 5) weeks along with 70-74 Gy 3D-CRT. Sextant needle biopsy of the prostate was obtained at 2 (cohort 1), 3 (cohort 2), and 4 (cohort 3) weeks for determination of the persistence of transgene expression. There were no dose-limiting toxicities and no significant treatment-related adverse events. Ninety-four percent of the adverse events observed were mild to moderate and self-limiting. Acute urinary and gastrointestinal toxicities were similar to those expected for conventional-dose 3D-CRT. Therapeutic transgene expression was found to persist in the prostate for up to 3 weeks after the adenovirus injection. As expected for patients receiving definitive radiation therapy, all patients experienced significant declines in prostate-specific antigen (PSA). The mean PSA half-life in patients administered more than 1 week of prodrug therapy was significantly shorter than that of patients receiving prodrugs for only 1 week (0.6 versus 2.0 months; P < 0.02) and markedly shorter than that reported previously for patients treated with conventional-dose 3D-CRT alone (2.4 months). With a median follow-up of only 9 months, 5 of 10 (50%) patients not treated with androgen-deprivation therapy achieved a serum PSA < or = 0.5 ng/ml. The results demonstrate that replication-competent adenovirus-mediated double-suicide gene therapy can be combined safely with conventional-dose 3D-CRT in patients with intermediate- to high-risk prostate cancer. The shorter than expected PSA half-life in patients receiving more than 1 week of prodrug therapy may suggest a possible interaction between the oncolytic adenovirus and/or double-suicide gene therapies and radiation therapy.
authors: Department of Radiation Oncology, Henry Ford Health System, One Ford Place, Detroit, Michigan 48202, USA. sfreyta1@hfhs.org
authors: Svend O
authors: SO
authors: Freytag
authors: Hans
authors: H
authors: Stricker
authors: Jan
authors: J
authors: Pegg
authors: Dell
authors: D
authors: Paielli
authors: Deepak G
authors: DG
authors: Pradhan
authors: James
authors: J
authors: Peabody
authors: Mariza
authors: M
authors: DePeralta-Venturina
authors: Xueqing
authors: X
authors: Xia
authors: Steve
authors: S
authors: Brown
authors: Mei
authors: M
authors: Lu
authors: Jae Ho
authors: JH
authors: Kim
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics / Q000502:physiology; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D043525:Cytosine Deaminase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004279:DNA, Viral / Q000097:blood; D005437:Flucytosine / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D015774:Ganciclovir / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D015870:Gene Expression; D015316:Genetic Therapy / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000628:therapy* / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D019076:Transgenes; D000077562:Valganciclovir; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D011993:Recombinant Fusion Proteins; D005437:Flucytosine; D013937:Thymidine Kinase; D043525:Cytosine Deaminase; D000077562:Valganciclovir; D015774:Ganciclovir