Abstract Book 2010 - CIMT Annual Meeting

008 Schroeder | Therapeutic vaccination
In vitro characterization of an irradiated gene-transfer medicinal
product consisting of a prostate cancer derived cell line
constitutively secreting interleukin-2 and interferon-gamma
Petra Schroeder 1 , Carsten Lindemann 1 , Uwe Irmer 1 , Henning Weigt 2 , Bernd Eisele 2 , Klaus Kuehlcke 1
1 EUFETS GmbH, Vollmersbachstraße 66, 55743 Idar-Oberstein, Germany
2 Vakzine Projekt Management GmbH, Mellendorfer Straße 9, 30625 Hannover, Germany
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In a first in man Phase I/II study, a prostate cancer
cell line constitutively secreting the pro-inflammatory
cytokines interferon-gamma (IFN-γ) and interleukin-2
(IL-2) has shown anti-tumor response
(median PSA doubling time prolonged from 63 days
to 114 days, p = 0.0035; Brill et al., J Gene Med
2007 and Hum Gene Ther 2009). Further drug development
requires thorough characterization of
the tumour vaccine. We designed a non-clinical
program regarding aspects of safety, stability and
the proof of principle of the tumour vaccine adopting
an in vitro approach based on human cells
to rectify the limitations of homologous animal
models. A clinical scale manufacturing process
including centralized irradiation was developed
in parallel. Considering safety and stability of the
tumour vaccine we tested the viability, colony formation,
phenotype (surface marker expression of
the prostate specific antigens PSA, PSMA, EpCAM),
the release and bioactivity of IL-2 and IFN-γ, vector
integrity and the release of replication competent
retrovirus besides the generic tests stipulated for
such products. The absence of tumourigenicity,
e.g. outgrowth of potentially remaining replication
competent cells, of the finally irradiated cells was
controlled by the assessment of proliferating cells
in long term cultures and proliferation assays. In
order to show the induction of an immunological
reaction which is considered as a prerequisite to
induce an anti-tumour response we evaluated the
allogenic response towards the irradiated cells,
analysed the deposition of complement and the
uptake of cellular particles by phagocytes. The stability
and safety as well as the functionality and biologic
activity of the cellular product could be reliably
demonstrated. Results of phenotyping, colony
formation, bioassays and the proof of principle will
be presented.