Purpose: The purpose of this study was to assess the feasibility of administering Ad5CMV-p53, an adenoviral vector containing the wild-type p53 gene to patients with advanced malignancies, characterize the pertinent pharmacokinetic parameters, identify evidence of viral uptake in both normal and tumor tissue, and seek evidence of antitumor activity.
Methods: Patients were treated with escalating doses of Ad5CMV-p53 intravenously over 30 minutes on days 1, 2, and 3, every 28 days. The clearance of circulating Ad5CMV-p53 (INGN 201) DNA was characterized in the plasma and paired tumor and skin biopsies were performed in patients treated at the two highest dose levels to assess vector uptake into tissues.
Results: Seventeen patients received 36 courses of Ad5CMV-p53 at doses ranging from 3 x 10(10) to 3 x 10(12) virus particles (vp). Fatigue, nausea, vomiting, and fever were common, but rarely severe. Abnormalities of coagulation parameters, including decreases in fibrinogen and increases in fibrin degradation products at 3 x 10(12)vp, precluded additional dose escalation. Ad5CMV-p53 DNA could be detected in the plasma by polymerase chain reaction assay in the majority of patients at 14 days and 28 days at doses of 3 x 10(10) and higher. Six patients treated at 1 x 10(12)vp and 3 x 10(12)vp dose levels had Ad5CMV-p53 DNA detected within paired tumor tissue collected day 4.
Conclusion: Ad5CMV-p53 can be safely and repetitively administered up to 1 x 10(12)vp intravenously daily for 3 consecutive days. The absence of severe toxicities, the presence of circulating adenovirus 24 hours after administration, and detectable p53 transgene within tumor tissue distant from the site of administration demonstrates that systemic therapy with this adenoviral vector containing p53 is feasible.