Replication-selective oncolytic adenoviruses are being developed for the treatment of
cancer, but the safety and feasibility of repeated adenovirus delivery to
tumors via the bloodstream was unknown, particularly in light of a patient death after hepatic artery infusion of a replication-defective adenovirus vector. We performed a Phase II trial of an oncolytic replication-selective adenovirus (
dl1520, also known as Onyx-015) administered by hepatic artery infusion in patients with gastrointestinal
carcinoma metastatic to the liver (n = 27).
dl1520 was infused into the hepatic artery (2 x 10(12) particles) on days 1 and 8 as a single agent, and thereafter starting on day 22 in combination with i.v.
5-fluorouracil and
leucovorin every 28 days. Repeated viral infusions were feasible, and no deaths occurred on study; reversible grade 3/4
hyperbilirubinemia occurred in 2 patients. Systemic inflammatory
cytokine responses varied greatly between patients and even between cycles within a given patient. Proinflammatory
cytokines [e.g.,
tumor necrosis factor, IFN-gamma, and
interleukin (IL) 6] typically rose within 3 h and were followed at 18 h by a rise in
IL-10. However, in the single patient who suffered a severe but reversible systemic inflammatory response, a unique
cytokine profile was detected: marked acute increases of
IL-6 (20-fold higher than average for all of the patients) and inhibition of
IL-10 production. Delayed secondary peaks of
viremia were reproducibly detected 3-6 days
after treatment, even in the presence of high level
neutralizing antibody titers and
antiviral cytokines. Mathematical modeling was used to calculate the number of virus particles produced and shed into the blood with each replication cycle. The combination of virotherapy and
chemotherapy had antitumoral activity in some
chemotherapy-resistant
colorectal tumors. The
intra-arterial infusion of oncolytic adenoviruses warrants additional study.