The Role of KIR and FcR Genotype in the Efficacy of mAb and IL2 Immunotherapy

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DESCRIPTION (provided by applicant): Killer Immunoglobulin-like Receptors (KIR) recognize specific KIR ligands (KIR-L) encoded by HLA alleles, and regulate activation and function of human natural killer (NK) cells. The interactions between KIR receptors on donor NK cells and KIR ligands on recipient tissues can influence anti-tumor efficacy of allogeneic hematopoietic stem cell transplantation (HSCT). In autologous HSCT, an autologous KIR/KIR-L "mismatch" relationship between an individual's inherited arrays of KIR alleles and KIR-ligands can augment anti-tumor effects. We thus hypothesized that favorable KIR/KIR-L genotypic relationships (i.e.: KIR/KIR-L mismatch) could augment the efficacy of NK mediated immunotherapy. We found, in a small Phase II immunotherapy trial for neuroblastoma, that patients were more likely to benefit from NK-targeted immunotherapy if they were KIR/KIR-L mismatched. To extend and confirm this result our team is proposing confirmatory KIR/KIR-L analyses in 3 separate large (multi-institution cooperative group) clinical trials, each using a different form of immunotherapy known to activate or involve NK cells. For each of these trials we will determine whether KIR/KIR-L status is associated with clinical response. These analyses will explore 3 separate algorithms for characterizing KIR/KIR-L relationships, and use several distinct measures of clinical effect/response to evaluate possible associations. In addition, other studies have shown that the presence of high affinity Fc Receptor (FcR) alleles is associated with clinical benefit in the use of tumor-reactive monoclonal antibody (mAb), likely via antibody dependent cell-mediated cytotoxicity (ADCC). We will obtain genotype data for patients from these 3 trials for their FcR alleles, as we hypothesize that the efficacy of mAb treatment may be influenced by the potential interaction of both FcR and KIR/KIR-L genotype. Finally, we hypothesize that: a) some of the clinical anti-tumor efficacy of single agent IL2 might be NK mediated; and b) a component of the IL2 induced antitumor effect may be due to ADCC activity facilitated by putative endogenous antitumor antibody. These IL2 induced mechanisms should also be reflected by favorable KIR/KIR-L and FcR genotype. These hypotheses will be tested by determining KIR/KIR-L and FcR genotypes, correlating genotypes with clinical outcome data, and assessing whether favorable genotypes are predictive of response. If this genotyping proves to be predictive of beneficial clinical effect, KIR, KIR-L and FcR genotyping can be used as an eligibility-screening test to: 1) improve the efficacy of these immunotherapy regimens, and 2) identify alternative/additional treatments for those individuals with unfavorable genotypes. Overall Hypothesis: We hypothesize that KIR/KIR-L data, independently and combined with FcR genotype data, can identify patients more likely to respond to: a) single agent mAb therapy for lymphoma, b) single agent IL2 treatment for renal cell carcinoma (RCC), and c) mAb + cytokine (IL2 + GM-CSF) therapy for neuroblastoma (NBL). PUBLIC HEALTH RELEVANCE:: Cancer immunotherapies, using tumor reactive monoclonal antibodies, IL2 and their combination have shown clinical activity and efficacy, and have been approved as the standard of care in several clinical settings, including: 1) the use of the rituximab monoclonal antibody for treatment of certain lymphomas, 2) the use of IL2 for metastatic renal cell carcinoma, and 3) the combination of ch14.18 monoclonal antibody with IL2 and GM-CSF for patients with high-risk neuroblastoma in remission. Despite antitumor effects for some patients in these 3 settings, many patients that receive these treatments experience immune-mediated toxicities but do not show clinical benefit. We hypothesize that a patient's ability to benefit from these treatments should be predictable, at least in part, based o the inheritance of certain genes (KIR, KIR-Ligand, and FcR) that are known to influence the functional capabilities of immune cells involved in monoclonal antibody and IL2 responses. We will test this hypothesis in each of these 3 settings, using data from large cooperative group clinical trials. If the data validate this hypothesis, in any one of these clinical settings, it wold enable this genotyping to be used in the future to determine which patients are most likely to benefit from this treatment, thereby increasing the clinical efficacy of that approach.