Safety profile of therapeutic pox virus-based vaccines for cancer

Abstract

2513 Background: The eradication of smallpox is, in part, attributed to the effectiveness of vaccination with poxvirus vaccines. Recombinant poxviruses have now been developed as core components of therapeutic tumor vaccines. To date >700 patients received a variety of anti-tumor poxvirus vaccines in clinical trials. A major objective of these early trials was a safety assessment and this study summarizes the safety profile of the Poxvirus Tumor Vaccine Initiative. Methods: The OBA, local IRB and biosafety committees approved all trials. Case report forms or medical records for all patients treated on recombinant poxvirus clinical trials through the NCI or Therion Biologics Corporation between 1991 and 2003 were reviewed. Results: There were 707 patients treated in 29 clinical trials for a variety of tumors.. Vaccines consisted of vaccinia virus, fowlpox virus and ALVAC at doses between 106 – 109 pfu. Vaccines targeted CEA, PSA, MUC-1, gp100, MART-1, and tyrosinase. Second generation vaccines included B7.1 or TRICOM (B7.1, ICAM-1, and LFA-3) and some patients received GM-CSF and/or IL-2. Vaccines were administered through i.d., s.c., i.m., i.t., and i.v. routes. There were no deaths attributed to vaccination in the 707 evaluable patients and therapy was generally well tolerated. The most common adverse events reported were cutaneous reactions associated with local administration of the vaccines. In addition, mild systemic symptoms, such as fatigue, low grade fever, and malaise, were observed. There were 7 cases of serious events (SAEs) attributed to the vaccine following intravenous administration: 5 hypotension, 1 rash, and 1 fever/chills. Conclusions: Therapeutic vaccination with pox virus-based vectors has been tested in clinical trials including >700 patients over the past 10 years. The vaccines are well tolerated at a broad range of doses, routes of administration, tumor types, and regimens with only 7 SAEs after intravenous administration. These data demonstrate the safety profile of recombinant poxvirus vaccines and support the development of randomized trials evaluating clinical effectiveness for poxvirus vaccines in patients with cancer. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Therion Biologics Corp. Novartis Oncology; Therion Biologics Corp. Therion Biologics Corp.