Active Specific Intranodal Immunotherapy of Recombinant Vaccinia Virus in Locally Advanced to Metastatic Melanoma

Overview

The purpose of this study is to assess intranodal immunotherapy in locally advanced to metastatic melanoma patients (American Joint Committee on Cancer \[AJCC\] stages IIb to IV). For this, the investigators capitalize on their previous melanoma clinical trial (published by Zajac P et al in Human Gene Ther 2003) and take advantage of a proprietary recombinant vaccinia virus (replication inactivated) expressing 5 minigenes: 3 melanoma associated antigens and 2 costimulatory molecules. Immunization with the recombinant vaccinia virus is followed by 3 boosts with soluble, synthetic melanoma associated antigens. The patients are immunized intranodally (groin lymph node) under ultrasonographic guidance in an outpatient clinic. The protocol foresees 2 cycles of immunotherapy for alternate weeks and lasts 15 weeks.

The investigators have conducted a phase I/II clinical trial based on the intradermal administration to stage III/IV melanoma patients of a recombinant vaccinia virus encoding tumor associated antigens and costimulatory epitopes for the priming of immune responses, followed by boosts with corresponding synthetic peptides (Zajac P et al in Human Gene Ther 2003). Specific cytotoxic T cells could be induced in a majority of patients following priming, but sustained responsiveness could not be maintained by peptide boosting on a long term basis. Emerging evidence supports the notion that expansion of specific T cells requires trafficking of antigen presenting cells loaded with specific determinants to lymphatic nodes, as induced, among others, by pro-inflammatory stimuli. Therefore, we now adopt the intranodal injection of the immunogenic formulations. As for the former melanoma active specific immunotherapy trial, GM-CSF is used as a supporting cytokine. The epitopes considered are expressed, either all or some of them, in over 90% of the melanomas in Western countries; namely, we immunize with Mart-1/Melan-A epitope 27-35, Gp-100 epitope 280-288 and tyrosinase epitope 1-9. As a consequence, HLA-A2 positivity is mandatory for inclusion in the trial. The 2 costimulatory molecules expressed by cells infected with our replication-incompetent recombinant vaccinia virus are B7.1 (CD80) and B7.2 (CD86).