Anti-ALK Antibodies in Patients with ALK-Positive Malignancies Not Expressing NPM-ALK

ALKing the flames of lung cancer immunosensitivity

Immune checkpoint inhibitors (ICIs) are utilised in treating non-small cell lung cancer (NSCLC) by enhancing the immune response against cancer cells. However, they are not effective against cancers with certain genetic alterations. A recent study by Mota et al. focussed on understanding why ALK+ NSCLC cancers are immune cold and making them more receptive to ICIs using a vaccine-based approach. The study highlighted cell-specific differences in the presentation of immunogenic peptides and the location of tumours as factors in the poor immune response. Vaccines based on ALK peptides improved immune response, and when combined with ICIs, this led to a striking improvement in survival in a mouse model of ALK+ NSCLC.

Narrative review: immunotherapy in anaplastic lymphoma kinase (ALK)+ lung cancer-current status and future directions

Background and Objective

Patients with metastatic anaplastic lymphoma kinase (ALK)+ non-small cell lung cancer (NSCLC) often experience years of disease control on targeted therapies but the disease eventually develops resistance and progresses. Multiple clinical trial efforts to incorporate PD-1/PD-L1 immunotherapy into the treatment paradigm for ALK+ NSCLC have resulted in significant toxicities without clear improvement in patient outcomes. Observations from clinical trials, translational studies, and preclinical models suggest the immune system interacts with ALK+ NSCLC and this interaction is heightened with the initiation of targeted therapy. The objective of this review is to summarize knowledge to date about current and potential immunotherapy approaches for patients with ALK+ NSCLC.

Methods

To identify the relevant literature and clinical trials the databases PubMed.gov and ClinicalTrials.gov were queried with keywords "ALK" and "lung cancer". PubMed search was further refined with terms such as "immunotherapy", "tumor microenvironment or TME", "PD-1", and "T cells". The search for clinical trials was limited to interventional studies.

Key Content and Findings

In this review, the current status of PD-1/PD-L1 immunotherapy for ALK+ NSCLC is updated and alternative immunotherapy approaches are highlighted in the context of available patient level and translational data on the ALK+ NSCLC tumor microenvironment (TME). An increase in CD8+ T cells within the ALK+ NSCLC TME has been observed with targeted therapy initiation across multiple studies. Therapies to augment this including tumor infiltrating lymphocyte (TIL) therapy, modified cytokines, and oncolytic viruses are reviewed. Furthermore, the contribution of innate immune cells in TKI mediated tumor cell clearance is discussed as a future target for novel immunotherapy approaches that promote cancer cell phagocytosis.

Conclusions

Immune modulating strategies derived from current and evolving knowledge of the ALK+ NSCLC TME may have a role in ALK+ NSCLC beyond PD-1/PD-L1 based immunotherapy.

Current status and challenges of immunotherapy in ALK rearranged NSCLC

Rearrangements of the anaplastic lymphoma kinase (ALK) gene account for 5-6% in non-small cell lung cancer (NSCLC). ALK rearranged NSCLC is sensitive to ALK tyrosine kinase inhibitors (TKIs) but prone to drug resistance. Meanwhile, ALK rearranged NSCLC has poor response to single immunotherapy. Here we mainly describe the immune escape mechanisms of ALK mutated NSCLC and the role of related biomarkers. Additionally, we collate and evaluate preclinical and clinical studies of novel immune combination regimens, and describe the prospects and perspectives for the in vivo application of novel immune technologies in patients with ALK rearranged NSCLC.

Clinical Significance of Antinucleolar Antibodies: Biomarkers for Autoimmune Diseases, Malignancies, and others

Nucleolar staining is one of the standard patterns in immunofluorescence antinuclear antibodies (ANA), seen in 5-9% of ANA in various conditions. Antinucleolar antibodies (ANoA) are classified into 3 patterns in the International Consensus on ANA Patterns (ICAP) classification; AC-8 homogeneous pattern, AC-9 clumpy pattern, and AC-10 punctate pattern. Specificities known to show AC-8 include anti-Th/To, -PM-Scl, -nucleophosmin/B23, -nucleolin/C23, -No55, and others. AC-9 is seen by anti-fibrillarin/U3RNP and AC-10 by anti-RNA polymerase I and hUBF/NOR-90. ANoA has been classically known to be associated with scleroderma (SSc) and the characterization of nucleolar antigens identified several autoantigens recognized by SSc autoantibodies. The clinical association of anti-Th/To, PM-Scl, fibrillarin/U3RNP, and RNA polymerase I with SSc or SSc-overlap syndrome is well established, and commercial assays are developed. Anti-hUBF/NOR90, nucleophosmin/B23, and nucleolin/C23 are known for decades and reported in systemic autoimmune rheumatic diseases (SARDs), malignancies, graft versus host disease (GVHD), and others; however, their clinical significance remains to be established.

Anaplastic lymphoma kinase-special immunity and immunotherapy

Alterations in the anaplastic lymphoma kinase (ALK) gene play a key role in the development of various human tumors, and targeted therapy has transformed the treatment paradigm for these oncogene-driven tumors. However, primary or acquired resistance remains a challenge. ALK gene variants (such as gene rearrangements and mutations) also play a key role in the tumor immune microenvironment. Immunotherapy targeting the ALK gene has potential clinical applications. Here, we review the results of recent studies on the immunological relevance of ALK-altered tumors, which provides important insights into the development of tumor immunotherapies targeting this large class of tumors.

Emerging Roles of ALK in Immunity and Insights for Immunotherapy

Anaplastic lymphoma kinase (ALK) is mostly known for its oncogenic role in several human cancers. Recent evidences clearly indicate new roles of ALK and its genetic aberrations (e.g. gene rearrangements and mutations) in immune evasion, innate and cell-mediated immunity. New ALK-related immunotherapy approaches are demonstrating both preclinical and clinical promises. Here, we provide a timely review on the most updated laboratory and patient-related findings on ALK and immunity, which would grant us important insights for the development of novel ALK immunotherapies for ALK-altered cancers.

Benefit of crizotinib in a lung cancer patient with discordant ALK testing results

Crizotinib is a first line treatment for patients with non-small cell lung cancer (NSCLC) harboring translocations in anaplastic lymphoma kinase (ALK). The current gold standard for determining ALK status is fluorescence in-situ hybridisation (FISH), but immunohistochemistry (IHC) is becoming increasingly popular due to lower cost. There are currently few reports on clinical outcomes with crizotinib therapy in patients who have tested negative by FISH and positive by IHC. A 53 year old lifelong non-smoking, physically active male with newly diagnosed Stage IV NSCLC presented with shortness of breath on exertion one month prior to referral. Staging CT scan failed to show a discreet lung lesion, but the left lower lobe was collapsed due to pleural effusion. Pleural fluid showed adenocarcinoma and IHC was positive for an ALK mutation, while FISH was negative. Pre-treatment PET-CT showed hypermetabolic, enlarged lymph nodes in the mediastinum and retroperitoneum. Partially due to patient concerns about cytotoxic chemotherapy toxicity, crizotinib therapy was instituted. Repeat CT conducted two months after crizotinib initiation showed a decrease in lymphadenopathy at all sites compared to the PET-CT. Furthermore, the patient showed clinical improvement, with less drainage through his PleurX catheter and stability of his excellent performance status. After 12 months on crizotinib CT showed ongoing improvement in lymphadenopathy. His bloodwork has been stable, and he denies significant drug toxicity. This case illustrates a sustained response to crizotinib therapy in a patient with an ALK translocation identified by IHC, but with negative FISH testing. The literature suggests that the population with these discordant results could be up to 19% of ALK positive NSCLC. Patients in this subgroup who are receiving crizotinib should be identified and outcome data pooled. However, in the interim, oncologists may wish to consider targeted therapy for these discordant patients.

Epitope mapping of anti-ALK antibodies in children with anaplastic large cell lymphoma

Patients with Nucleophosmin (NPM)-Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) mount ALK autoantibodies. The titer of these autoantibodies inversely correlates with the risk of relapse. The epitopes recognized by these autoantibodies in NPM-ALK might be associated with different ALK-antibody levels. We used overlapping peptide microarray technology to analyze epitope-binding to NPM-ALK by plasma or serum from 129 ALK-positive ALCL patients and 21 controls. Antibodies present in sera from ALCL patients bound to epitopes mainly in the C-terminal region of the ALK portion of NPM-ALK (amino acid positions 469-496, 561-588, 617-644). Patients with higher ALK antibody titers detected the epitope 561-588 more frequently as well as three further epitopes at the N-terminus of the kinase domain compared to patients with intermediate and low titers. These results identify new potential target epitopes for immunotherapy in ALK-positive ALCL. The methodology can be adapted for more reproducible analyses of tumor antigen detection.

Immune Response against ALK in Children with ALK-Positive Anaplastic Large Cell Lymphoma

Patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) mount a humoral and cellular immune response against ALK. More than 90% of children and adolescents with ALK-positive ALCL have detectable anti-ALK antibodies in serum or plasma, and the antibody titer inversely correlates with the risk of relapse. ALK-specific CD8 and CD4 T cell responses have been described in patients with ALK-positive ALCL. Vaccination with ALK DNA led to protection against lymphoma growth in a murine model. Collectively, these data suggest that the ALK-specific immune response is involved in the control of the disease. The characteristics of the humoral and cellular immune response against ALK as well as tumor immune escape mechanisms have been increasingly investigated. However, tumor and host factors contributing to the individual immune response against ALK are still largely unknown. Depending on the individual strength of the immune response and its determinants, individualized immunological approaches might be appropriate for the consolidation of ALCL patients. Strategies such as ALK vaccination could be effective for those with a pre-existing anti-tumor immunity, while an allogeneic blood stem cell transplantation or check-point inhibition could be effective for others.

Epitope mapping of spontaneous autoantibodies to anaplastic lymphoma kinase (ALK) in non-small cell lung cancer

The anaplastic lymphoma kinase (ALK) is recognized by the immune system as a tumor antigen, and preclinical evidence suggests that ALK-rearranged NSCLCs can also be successfully targeted immunologically using vaccine-based approaches. In contrast to ALK-rearranged lymphomas, the frequency and clinical significance of spontaneous ALK immune responses in patients with ALK-rearranged NSCLCs are largely unknown. We developed an enzyme-linked immunosorbent assay (ELISA) to measure anti-ALK antibody levels and mapped specific peptide epitope sequences within the ALK cytoplasmic domain in patients with non-small cell lung cancer. The ELISA method showed good correlation with ALK antibody titers measured with a standard immunocytochemical approach. Strong anti-ALK antibody responses were detected in 9 of 53 (17.0%) ALK-positive NSCLC patients and in 0 of 38 (0%) ALK-negative NSCLC patients (P<0.01), and the mean antibody levels were significantly higher in ALK-positive than in ALK-negative NSCLC patients (P=0.02). Across individual patients, autoantibodies recognized different epitopes in the ALK cytoplasmic domain, most of which clustered outside the tyrosine kinase domain. Whether the presence of high ALK autoantibody levels confers a more favorable prognosis in this patient population warrants further investigation.