Immune checkpoint pathways: perspectives on myeloid malignancies

Dermatological adverse events under programmed cell death-1 inhibitors as a prognostic marker in metastatic melanoma

Melanoma is widely treated with programmed cell death-1 (PD-1) inhibitors. As part of their anti-tumor immunity effect, they increase the susceptibility to cutaneous immune-related adverse events (cIRAE) among other autoimmune effects. To characterize the manifestations of cIRAE in melanoma patients treated with PD-1 inhibitors, and evaluate the correlation with tumor response. A retrospective study of 95 metastatic malignant melanoma patients treated with PD-1 inhibitors at the Hadassah Medical Center during 2013-2016. The most common cIRAE was pruritus reported by 39 (41%) patients. All other cIRAE were noted in 34 patients (35.8%), of which the most common cutaneous manifestation was vitiligo, demonstrated in 17 patients (17.9%) followed by various rashes (7.4%, including erythema multiforme, oral lichen planus, photosensitive rash, insect bite-like reaction, and urticaria), psoriasiform rash (3.2%), bullous pemphigoid (3.2%), and eczema (1%). Interestingly, higher response rates to immunotherapy were demonstrated in patients who developed pruritus (85%) and cIRAE (88%), with lower mortality rates in the cIRAE group (38.2%) versus the non-cIRAE group (70.5%, p = 0.002). cIRAE are common among malignant melanoma patients treated with PD-1 inhibitors and may be a marker for favorable prognosis.

PD-1/PD-L1 inhibitors in haematological malignancies: update 2017

The introduction of PD-1/PD-L1 pathway inhibitors is an important landmark in solid oncology with unprecedented practice-changing activity in various types of solid tumours. Among haematological malignancies, PD-1/PD-L1 inhibitors have been successful, so far, only in the treatment of classical Hodgkin lymphoma, which typically exhibits an over-expression of PD-1 ligands (PD-L1, PD-L2) due to alterations in chromosome 9p24.1. Such positive outcomes led to the US Food and Drug Administration approval of nivolumab use in relapsed Hodgkin lymphoma in 2016 as the first haematological indication. Although the results in other lymphoid malignancies have not been so striking, blockade of the PD-1/PD-L1 axis has led to meaningful responses in other lymphoma types such as diffuse large B-cell lymphoma, follicular lymphoma or several T-cell lymphomas. Monotherapy with PD-1/PD-L1 inhibitors in chronic lymphocytic leukaemia and multiple myeloma has been unsatisfactory, suggesting that a combinational approach with other synergistic drugs is needed. In the case of multiple myeloma, immunomodulatory agents together with corticosteroids represent the most promising combinations. Among myeloid malignancies, the anti-PD-1 monoclonal antibodies are examined dominantly in acute myeloid leukaemia and myelodysplastic syndromes in combination with potentially synergistic hypomethylating drugs such as 5-azacitidine, resulting in promising outcomes that warrant further investigation. We have described all available clinical results of PD-1/PD-L1 inhibitors in haematological malignancies and discussed related toxicities, as well as highlighted crucial preclinical studies in this review.

Immune Mechanisms in Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a spectrum of diseases, characterized by debilitating cytopenias and a propensity of developing acute myeloid leukemia. Comprehensive sequencing efforts have revealed a range of mutations characteristic, but not specific, of MDS. Epidemiologically, autoimmune diseases are common in patients with MDS, fueling hypotheses of common etiological mechanisms. Both innate and adaptive immune pathways are overly active in the hematopoietic niche of MDS. Although supportive care, growth factors, and hypomethylating agents are the mainstay of MDS treatment, some patients—especially younger low-risk patients with HLA-DR15 tissue type—demonstrate impressive response rates after immunosuppressive therapy. This is in contrast to higher-risk MDS patients, where several immune activating treatments, such as immune checkpoint inhibitors, are in the pipeline. Thus, the dual role of immune mechanisms in MDS is challenging, and rigorous translational studies are needed to establish the value of immune manipulation as a treatment of MDS.

Current status of ex vivo gene therapy for hematological disorders: a review of clinical trials in Japan around the world

Gene therapies are classified into two major categories, namely, in vivo and ex vivo. Clinical trials of human gene therapy began with the ex vivo techniques. Based on the initial successes of gene-therapy clinical trials, these approaches have spread worldwide. The number of gene therapy trials approved worldwide increased gradually starting in 1989, reaching 116 protocols per year in 1999, and a total of 2210 protocols had been approved by 2015. Accumulating clinical evidence has demonstrated the safety and benefits of several types of gene therapy, with the exception of serious adverse events in several clinical trials. These painful experiences were translated backward to basic science, resulting in the development of several new technologies that have influenced the recent development of ex vivo gene therapy in this field. To date, six gene therapies have been approved in a limited number of countries worldwide. In Japan, clinical trials of gene therapy have developed under the strong influence of trials in the US and Europe. Since the initial stages, 50 clinical trials have been approved by the Japanese government. In this review, the history and current status of clinical trials of ex vivo gene therapy for hematological disorders are introduced and discussed.