Background: Carbonic anhydrase IX (CAIX) is an attractive target for the development of a RCC specific vaccine. We developed a fusion gene construct, GM-CSF + CAIX, transduced by a replication deficient adenovirus into autologous dendritic cells (DC) that are injected in patients with mRCC. This is a ph1 study of cancer vaccine against CAIX gene expressed on RCC tumors.
Methods: A recombinant adenovirus encoding the GMCSF-CAIX fusion gene (AdGMCAIX) was produced per GMP in collaboration with the NCI RAID program. The final product is produced in an in-house GMP cell processing facility using DCs cultured ex vivo from patients’ PBMC’s and engineered with AdGMCAIX prior to intradermal injection. The transduced DCs are expected to stimulate an antigen specific immune response against CAIX expressing RCC, leading to a potential anti-tumor effect. Dose escalation in 3 dose cohorts (5 X 106, 15 X 106, and 50 X 106 cells/administration) follows the std 3+3 ph1 design with an expansion cohort. DC-AdGMCAIX is given intradermally Q 2 weeks X 3 doses. The primary aim is safety of DC-AdGMCAIX injections. Secondary aims are to evaluate immune responses & the antitumor effects per RECIST 1.1. Pts with clear cell mRCC with ECOG 0-1 & measurable disease & adequate organ function were enrolled.
Results: Six pts with clear cell mRCC are enrolled. Four pts received all 3 planned vaccine doses and the fifth pt only the 1st dose. No SAE’s were seen to date. One pt had chills that lasted several minutes and transient Gr1 leucopenia. One pt has worsening of pre-existing proteinuria, though unclear if related to the vaccine. One pt has PD & the other two have SD on D85 scans. Tumor bx shows intra-tumoral infiltration by T cells.
Conclusions: These early data show that autologous DC transduced by Ad-GMCAIX vector can be safely given to mRCC patients without any acute SAE’s noted at the doses tested so far. The study will complete its 3rd cohort & expansion cohort enrollment. This data support the further development of Ad-GMCAIX vaccine strategies either alone or in combination with approved therapies. Funding: Supported by NCI RAID Initiative NSC 740833 and Kite Pharma.