Cancer Therapy: Clinical Immunogenicity of the Hu14.18-IL2 Immunocytokine Molecule in Adults With Melanoma and Children With Neuroblastoma

Purpose: Immunocytokine (IC) hu14.18-IL2 is a fusion protein of humanized antidisialoganglioside (GD2) antibody (hu14.18) and interleukin (IL)-2. Sixty-one melanoma and neuroblastoma patients received IC in phase I/Ib studies. Patient sera were examined in ELISA to determine if an anti-IC antibody response occurred during treatment. Experimental Design: Serum was assayed for anti-idiotypic antibody (anti-id Ab) based on ability to bridge biotinylated hu14.18 to plate-bound hu14.18 and ability to inhibit binding of hu14.18 to GD2 antigen and/or murine anti-idiotypic antibody. ELISA was also used to detect antibodies to the Fc-IL2 end of hu14.18-IL2. Results: Thirty-two patients (52%) developed an anti-idiotypic antibody response (absorbance, >0.7) in the bridge ELISA. Twelve patients (20%) had an intermediate response, whereas 17 patients (28%) were negative (adsorbance, <0.3). The development of antibody to hu14.18-IL2 detected in the bridge ELISA was not related to the dose of hu14.18IL2. Twenty of 33 adult patients (61%) demonstrated an anti-idiotypic antibody response based on binding inhibition ELISA. The anti-idiotypic response was inversely correlated (P < 0.002) with IC measured during the second course of treatment, indicating that development of anti-idiotypic antibodies interfered with detection of circulating hu14.18-IL2. All patients developed some inhibitory activity in the binding inhibition assay designed to detect antibodies to the Fc-IL2 region of the IC. There was a positive correlation between the peak serum level of IC in course 1 and the anti–Fc-IL2 response. Conclusions: Patients treated with hu14.18-IL2 developed anti-idiotypic antibodies and anti Fc-IL2 antibodies. No association was seen between development of anti-IC antibodies and clinical toxicity. (Clin Cancer Res 2009;15(18):5923–30) In an effort to improve antitumor effects with interleukin 2 (IL-2; ref. 1) or monoclonal antibody (mAb; ref. 2) alone, or combined treatment with the individual components (3–7), an immunocytokine (IC; refs. 8, 9), which contains the tumor reactive 14.18 mAb linked to IL-2 at the carboxy terminus of each IgG1 heavy chain, was created. The proposed mechanism of action is localization to tumor via recognition of tumorassociated GD2 disialoganglioside (10–13). Localization of IC facilitates activation of natural killer cells through Fc and IL-2 receptors (14) and activation of T cells through IL-2 receptors (15). Natural killer cells mediate cytolytic activity via antibodydependent cellular cytotoxicity and non–MHC-restricted cytotoxicity (9). In some preclinical models, tumor antigen–specific T-cell memory is also induced (15, 16). Clinical reports for separate phase I studies treating melanoma (MEL) and neuroblastoma (NBL) patients with this IC were recently published (14, 17). The present study was designed to determine if patients receiving the IC developed an immune response to the IC. We monitored patients for development of antibody to the IC. Adult MEL patients with responding or stable disease were eligible to receive a second course of IC (14). Pediatric NBL patients with stable or responding disease were eligible to receive up to four or six courses of IC, respectively (17). We established ELISAs to detect antibodies specific for the two separate functional ends of the IC. Antibodies against the idiotypic determinant (18) and against the carboxy terminus of the IgG heavy chain where IL-2 is linked (Fc-IL2 end) were detected. These antibodies could potentially interfere with the proposed functions of the IC. An anti-idiotypic antibody might Authors' Affiliations: The University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, Madison, Wisconsin; The EMD-Lexigen Research Center, Billerica, Massachusetts; and EMD Pharmaceuticals, Inc., (now EMD Serono, Inc.), Durham, North Carolina Received 12/19/08; revised 5/26/09; accepted 5/29/09; published OnlineFirst 9/8/09. Grant support: NIH CA32685, CA14520, CA87025, CA81403, RR03186, and a grant from the Midwest Athletes for Childhood Cancer Fund. The pediatric phase I Study (COGADVL0018) was supported by the Children's Oncology Group, and performed by COG phase I institutions. The costs of publication of this article were defrayed in part by the payment of page charges. This articlemust therefore be herebymarked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Note: Stephen D. Gillies is currently employed by Provenance Biopharmaceuticals Corp. Requests for reprints: Jacquelyn A. Hank, University of Wisconsin, K4/454, 600 Highland Avenue, Madison, WI 53792. Phone: 608-263-7262; Fax: 608263-4226. E-mail: [email protected]. F 2009 American Association for Cancer Research. doi:10.1158/1078-0432.CCR-08-2963 5923 Clin Cancer Res 2009;15(18) September 15, 2009 www.aacrjournals.org Research. on April 14, 2017. © 2009 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Published OnlineFirst September 8, 2009; DOI: 10.1158/1078-0432.CCR-08-2963