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conferenceseries
.com
Volume 7
Pharmaceutical Regulatory Affairs: Open Access
ISSN: 2167-7689
Pharma Europe 2018
May 07-09, 2018
May 07-09, 2018 | Frankfurt, Germany
15
th
Annual European Pharma Congress
NivolumabradiolabellingwithGa-68:Twodifferent approaches forthe formulationof an immunoPET
tracer to detect PD-1 expressing tumors
S Migliari
1
, A Sammartano
1
, B Pellegrino
1
, D Cavazzini
2
, L Gallani
1
, S Ottonello
2
, G Missale
1
, A Musolino
1
and
L Ruffini
1
1
University Hospital of Parma, Italy
2
University of Parma, Italy
I
n recent years, immunotherapy with drugs that inhibit immune checkpoints has shown clinical efficacy in several different
types of cancer by blocking PD-L1/PD-1 and CTLA-4 checkpoint pathways. Direct imaging of cell surface targets for
immunotherapy using monoclonal antibodies (Mo)Abs labeled with PET and SPECT radioisotopes can visualize drug
distribution and tumor characteristics. The aim of this study was to develop an immunoPET probe labeled with the PET
radioisotope gallium-68 for imaging PD-1 expressing tumors. For noninvasive detection of PD-1, we chose Nivolumab
(Opdivo®; Bristol-Myers Squibb, Princeton, NJ, USA), the first-in-human immunoglobulinG4 (IgG4) PD-1 immune checkpoint
inhibitor antibody. We developed direct (free nivolumab) and indirect (functionalized nivolumab with bifunctional cyclic
chelators, DOTA/NOTA) labeling approach procedure using the PET isotope Ga-68 obtained from a pharmaceutical grade
68Ge/68Ga generator (Eckert & Ziegler, Berlin, Germany). The 68Ge/68Ga generator was eluted with 0.1 M HCl following
the manufacture's protocol. A solution of ultrapure NaOAc 1.25M (Fluka Traceselect, ≥99.99%, metal basis) was added to
nivolumab or DOTA/NOTA-nivolumab protein solution and then the eluate 68GaCl3 (ca. 50-100 MBq) bringing the pH to
5–6. The reaction mix was incubated in a heat block at 37°C for 40 minutes and after that the resulting radiopharmaceutical
was isolated from free Ga-68 by centrifugation. The radiochemical purity percentage of [68Ga]Ga-nivolumab and [68Ga]
Ga-DOTA/NOTA-nivolumab was determined using instant thin layer chromatography (TLC); TLC-SG strips are used as
stationary phase and sodium chloride (0.9%) as mobile phase to separate the radiolabelled (Mo)Abs, which remains at the
bottom, while the free gallium-68 moved to the top. Our results showed that the indirect approach is a site-specific labeling
procedure and these radioimmunoconjugates are more stable than the direct approach. The promising labeling results showed
an efficient procedure to label the antibody with Ga-68 providing the model for the future production of immunoPET imaging
probe.
smigliari@ao.pr.itPharmaceut Reg Affairs 2018, Volume 7
DOI: 10.4172/2167-7689-C1-031