Safety of local delivery of low- and intermediate-dose adenovirus gene transfer vectors to individuals with a spectrum of morbid conditions.

To help define the safety profile of the use of adenovirus (Ad) gene transfer vectors in humans, this report summarizes our experience since April 1993 of the local administration of E1(-)/E3(-) Ad vectors to humans using low (<10(9) particle units) or intermediate (10(9)-10(11) particle units) doses. Included in the study are 90 individuals and 12 controls, with diverse comorbid conditions, including cystic fibrosis, colon cancer metastatic to liver, severe coronary artery disease, and peripheral vascular disease, as well as normals. These individuals received 140 different administrations of vector, with up to seven administrations to a single individual. The vectors used include three different transgenes (human cystic fibrosis transmembrane conductance regulator cDNA, E. coli cytosine deaminase gene, and the human vascular endothelial growth factor 121 cDNA) administered by six different routes (nasal epithelium, bronchial epithelium, percutaneous to solid tumor, intradermal, epicardial injection of the myocardium, and skeletal muscle). The total population was followed for 130.4 patient-years. The study assesses adverse events, common laboratory tests, and long-term follow-up, including incidence of death or development of malignancy. The total group incidence of major adverse events linked to an Ad vector was 0.7%. There were no deaths attributable to the Ad vectors per se, and the incidence of malignancy was within that expected for the population. Overall, the observations are consistent with the concept that local administration of low and intermediate doses of Ad vectors appears to be well tolerated.

Analysis of risk factors for local delivery of low- and intermediate-dose adenovirus gene transfer vectors to individuals with a spectrum of comorbid conditions.

In this study we analyze the adverse events and abnormal laboratory parameters following local administration of low (<10(9) particle units) and intermediate (10(9)-10(11) particle units) single and repetitive doses (140 total) of E1(-)E3(-) adenovirus (Ad) gene transfer vectors administered to the respiratory epithelium, solid tumors, skin, myocardium, and skeletal muscle in eight gene transfer trials since April 1993. In the accompanying paper by Harvey et al., (Hum. Gene Ther. 2002; 13:15-63), we conclude that for the total group, no deaths were attributable to the Ad vectors per se, and the incidence of major adverse events likely caused by an Ad vector was 0.7%. The present study analyzes the trials as a group to evaluate risk factors for the adverse events, abnormal values among laboratory parameters, and known deaths. Ten putative risk factors were assessed, including "patient-related" (age, sex, comorbid index and pretherapy anti-Ad antibodies), "vector-related" (dose, route, transgene, and number of vector administrations), and "trial-related" (trial in which the individual was enrolled, and whether surgery was part of the trial). While assessment of each factor individually suggested several possible associations with adverse events, abnormal laboratory parameters, or deaths, multivariate analysis identified only age, comorbid index, and surgery (comorbid index for death; age and surgery for non-death adverse events) as variables significantly associated with increased risk for a major (severity scale 3-4 of 4) adverse event for individuals enrolled in these gene transfer trials. Importantly, multivariate analysis suggested that vector-related parameters, including dose, route, transgene, or number of vector administrations at the doses and routes evaluated in these studies, do not appear to be significant risk factors for a major adverse event. With the caveat that these are phase I, uncontrolled trials, we conclude that (1) there is no definitive risk factor that will clearly predict a major adverse outcome resulting from local administration of low and intermediate doses of Ad gene transfer vectors; and (2) major adverse events in these gene transfer trials are associated primarily with the study population and/or trial procedures, not the Ad vectors themselves. This assessment is consistent with the concept that local administration of low and intermediate doses of Ad gene transfer vectors appears to be well tolerated.