DuoHexaBody-CD37 induces direct cytotoxic signaling in diffuse large B-cell lymphoma

Joint Public Reviews:

In this study, the authors suggest that DuoHexaBody-CD37, a biparatopic CD37-targeting antibody, can induce direct cytotoxicity in diffuse large B-cell lymphoma (DLBCL) cells through antibody clustering and SHP-1 activation, independent of complement. They further propose that DuoHexaBody-CD37 inhibits cytokine-mediated pro-survival signalling, suggesting a broader role for CD37-directed therapy in disrupting tumour supportive signalling networks.

A strength of the study is the systematic in vitro characterisation of signalling responses to DuoHexaBody-CD37 across both malignant and normal B-cells. The inclusion of phosphoproteomic profiling and mutant constructs provides mechanistic detail, and the findings may be of interest to researchers working on antibody therapeutics in lymphoma.

However, the evidence supporting key mechanistic processes - particularly the role of SHP-1 in mediating cytotoxicity and the requirement for Fc receptor crosslinking - is incomplete and would benefit from further functional validation. While CD37 has been explored previously as a therapeutic target, this study does add mechanistic insight into direct cytotoxicity and cytokine modulation. Nevertheless, the exclusive reliance on in vitro systems makes the translational relevance unclear.

Overall, the study provides valuable insight into CD37-mediated signalling in lymphoma cells, but the evidence remains incomplete to support broader conclusions about therapeutic impact.

Author response:

The evidence supporting this mechanism is incomplete, with additional work needed to clarify SHP-1's role, the contribution of Fc receptor crosslinking, and the biological relevance across normal and malignant B cells.

We will address these points by:

- including SHP-1 inhibitors in the DuoHexaBody-CD37 cytotoxicity experiments to address the role of SHP-1

- investigating which Fc receptors are involved in the crosslinking using FcR blocking antibodies and/or use purified fixed effector cells that express different Fc receptors in the DuoHexaBody-CD37 cytotoxicity experiments

- study the effect of DuoHexaBody-CD37 on normal B cells

As the findings are based primarily on in vitro models, further validation would be required to support broader translational conclusions.

We would like to refer to previous studies that showed potent cytotoxicity of DuoHexaBody-CD37 in vivo, including xenograft and PDX lymphoma models supporting broader translational conclusions:

Oostindie et al. Blood Cancer Journal (2020) 10:30 https://doi.org/10.1038/s41408-020-0292-7