P-08.02 Adoptive cell therapy with cytokine-induced killer cells armed with immunotools against HER-2 expressing breast cancer

<h3>Background</h3> Cytokine-induced killer (CIK) cells are heterogeneous population of CD3 and CD56 expressing T lymphocytes, activated and expanded <i>ex vivo</i> from peripheral blood mononuclear cells (PBMCs) or umbilical cord blood. CIK cells are gaining considerable clinical relevance due to the low risk of acute graft-versus-host disease (GvHD) in autologous and allogeneic settings, their feasibility, and limited production costs.^{1 2} In this study, we studied the combination of Trastuzumab (TRS) due to CD16a expression, or Trastuzumab-engineered V90Lec13 or with the bispecific single-chain fragment variable (bsscFv) HER2xCD3. <h3>Materials and Methods</h3> CIK cells were obtained from PBMCs from healthy donors and HER2+ breast cancer patients using a serum-free, GMP-compliant protocol. Effector cell cytotoxicity was evaluated against HER2+ breast cancer cell lines by xCELLigence and the amount of cytokines released was measured with a multiplex assay. To assess <i>in vivo</i> efficacy, NSG mice models with HER2-non amplified (MCF-7 cell line) and HER2-amplified (Patient-derived Xenograft) were treated with CIK cells in combination with isotype control mAb, TRS, TRS V90Lec13 or HER2xCD3. The mice were monitored for tumor growth. <h3>Results</h3> CIK cells expanded from HER2+ patients exhibit similar characteristics to healthy donors, reaching clinically relevant quantities. HER2-amplified cells were susceptible to the combination of CIK cells with the clinically used TRS, while HER2-non amplfied cells were effectively killed by TRS V90Lec13. Furthermore, CIK cells combined with TRS V90Lec13 demonstrated enhanced multiple-killing ability. These combinatory approaches induced a pro-inflammatory cytokine profile without triggering cytokines related to the cytokine release syndrome. <i>In vivo</i> experiments further confirmed that combining CIK cells with TRS in HER2-amplified or TRS V90Lec13 in HER2-non amplified tumors significantly delayed tumor growth. <h3>Conclusions</h3> Taken together, these results highlight the potentiality of using new perspectives for treating HER2+ breast cancer with adoptive cell therapy by combining non-antigen-specific CIK effector cells with clinically approved tumor-antigen-specific antibodies or recombinant molecules.^{3 4} <h3>References</h3> Cappuzzello E, Sommaggio R, Zanovello P, Rosato A. Cytokines for the induction of antitumor effectors: the paradigm of cytokine-induced killer (CIK) cells. <i>Cytokine Growth Factor Rev.</i> 2017 Aug;<b>36</b>:99–105. Palmerini P, Dalla Pietà A, Sommaggio R, Ventura A, Astori G, Chieregato K, Tisi MC, Visco C, Perbellini O, Ruggeri M, Cappuzzello E, Rosato A. A serum-free protocol for the ex vivo expansion of cytokine-induced killer cells using gas-permeable static culture flasks. <i>Cytotherapy</i> 2020 Sep;<b>22</b>(9):511–518. Dalla Pietà A, Cappuzzello E, Palmerini P, Ventura A, Visentin A, Astori G, Chieregato K, Mozzo V, Perbellini O, Tisi MC, Trentin L, Visco C, Ruggeri M, Sommaggio R, Rosato A. Innovative therapeutic strategy for B-cell malignancies that combines obinutuzumab and cytokine-induced killer cells. <i>J Immunother Cancer</i> 2021 Jul;<b>9</b>(7):e002475. Sommaggio R, Cappuzzello E, Dalla Pietà A, Tosi A, Palmerini P, Carpanese D, Nicolè L, Rosato A. Adoptive cell therapy of triple negative breast cancer with redirected cytokine-induced killer cells. <i>Oncoimmunology</i> 2020 Jun 11;<b>9</b>(1):1777046. N.T. Hieu: None. E. Cappuzzello: None. E. Vigolo: None. G. D’Accardio: None. P. Palmerini: None. G. Griguolo: None. M. Peipp: None. R. Sommaggio: None. A. Rosato: None.