Targeting B-cell malignancies with the beta-emitting anti-CD37 radioimmunoconjugate 177Lu-NNV003

Abstract

Purpose The aim of this study was to explore the β-emitting lutetium-177 labelled anti-CD37 antibody NNV003 ( 177 Lu-NNV003, Humalutin®) for the treatment of non-Hodgkin’s lymphoma in in vitro studies and in animal models. Methods Cytotoxicity of 177 Lu-NNV003 was measured in REC-1 (mantle cell lymphoma) and DOHH-2 (diffuse large B cell lymphoma) cell lines. Biodistribution was studied in mice bearing subcutaneous DOHH-2 or MEC-2 (chronic lymphocytic leukaemia) xenografts. The therapeutic effect of a single injection of 177 Lu-NNV003 was measured in mice intravenously or subcutaneously injected with REC-1 cells. Haematological and histopathological assessments were used to evaluate the toxic effect of 177 Lu-NNV003. The immunotherapeutic effect of NNV003 was assessed by measuring binding to Fcγ receptors, activation of ADCC and ADCP. NNV003’s immunogenicity potential was assessed using in silico immunogenicity prediction tools. Results 177 Lu-NNV003 showed an activity dependent antiproliferative effect in all cell lines. Maximum tumour uptake in vivo was 45% of injected activity/g in MEC-2 tumours and 15% injected activity/g in DOHH-2 tumours. In mice injected intravenously with REC-1 cells, 177 Lu-NNV003 (50–100 MBq/kg) improved survival compared to control groups ( p < 0.02). In mice with subcutaneous REC-1 xenografts, 500 MBq/kg 177 Lu-NNV003 extended survival compared to the control treatments ( p < 0.005). Transient haematological toxicity was observed in all mice treated with radioactivity. NNV003 induced ADCC and ADCP and was predicted to have a lower immunogenicity potential than its murine counterpart. Conclusion 177 Lu-NNV003 had a significant anti-tumour effect and a favourable toxicity profile. These results warrant further clinical testing in patients with CD37-expressing B cell malignancies. Electronic supplementary material The online version of this article (10.1007/s00259-019-04417-1) contains supplementary material, which is available to authorized users.

Targeted alpha therapy for chronic lymphocytic leukaemia and non-Hodgkin’s lymphoma with the anti-CD37 radioimmunoconjugate 212Pb-NNV003

“…injected with MEC-2 cells were often euthanised due to weight loss after massive infiltration in several critical organs, while mice injected with Daudi cells were euthanised due to hind leg paralysis caused by localised infiltration of the bone marrow. Moreover, CB17 SCID mice have functional natural killer cells, whereas R2G2 do not, and the chimeric antibody NNV003 could induce some immunotherapeutic effect in this strain [8]. Accordingly, in a separate therapy study with Daudi-bearing CB17 SCID ( S4 Fig) we observed that 5 μg NNV003 had a similar anti-tumour effect as 185 kBq 212 Pb-NNV003, while 100 μg NNV003 had no effect in the MEC-2 model.…”

“…This suboptimal binding was due to radiation induced oxidation of the antibody after labelling and not the conjugation method. The addition of ascorbic acid during labelling restored the binding of 212 Pb-NNV003 to the cells to approximately 80%, which is normally obtained with NNV003 labelled with lutetium-177 [8].…”

“…Specific activities (SA) used: 37 MBq/mg (biodistribution and acute toxicity studies), 370 MBq/mg (cytotoxicity assay) and 3.7-370 MBq/mg (therapy studies). The immunoreactivity (IRF) of 212 Pb-NNV003 was measured as previously described [8].…”

“…We have conjugated the IgG1 chimeric antibody NNV003 with the chelator TCMC and labelled it with the alpha-particle generating radionuclide 212 Pb ( 212 Pb-NNV003). NNV003 binds with high affinity to CD37 and has been shown to internalise in some cell lines and induce antibody-dependent cellular phagocytosis and antibody-dependent cellular cytotoxicity [8]. CD37 is a glycosylated transmembrane protein, which has emerged as a therapeutic target in the recent years.…”

The therapeutic effectiveness of 177Lu-lilotomab in B-cell non-Hodgkin lymphoma involves modulation of G2/M cell cycle arrest

“…Nevertheless, our results indicate that Ramos and DOHH2 cells exposed to 177 Lu-lilotomab generate DAMPs that can further stimulate the immune system. In a clinical setting, the immunological response could be enhanced by using the chimeric version of lilotomab that can activate ADCC [47].…”