[Immunological tumor therapy]

Targeting Cancer with Genetically Engineered TCR T Cells

The adoptive cell transfer (ACT) of genetically engineered T cell receptor (TCR) T cells is one of the burgeoning fields of immunotherapy, with promising results in current clinical trials. Presently, clinicaltrials.gov has over 200 active trials involving adoptive cell therapy. The ACT of genetically engineered T cells not only allows the ability to select for TCRs with desired properties such as high-affinity receptors and tumor reactivity but to further enhance those receptors allowing for better targeting and killing of cancer cells in patients. Moreover, the addition of genetic material, including cytokines and cytokine receptors, can increase the survival and persistence of the T cell allowing for complete and sustained remission of cancer targets. The potential for improvement in adoptive cell therapy is limitless, with genetic modifications targeting to improve weaknesses of ACT and to thus enhance receptor affinity and functional avidity of the genetically engineered T cells.

Comparative efficacy and safety of first-line treatments for advanced non-small cell lung cancer with immune checkpoint inhibitors: A systematic review and meta-analysis

BACKGROUND

Non-small cell lung cancer (NSCLC) is the predominant type of lung cancer, and most clinically curable patients are diagnosed with locally advanced disease. Although the efficacy of standard platinum-based chemotherapy doublets is relatively limited. The effect of immune checkpoint inhibitors (ICIs) remains controversial, and its role in the first-line treatment of advanced NSCLC is obscure. Thus, we carried out a systematic review and meta-analysis to compare the efficacy and safety of ICIs for advanced NSCLC.

METHODS

The PubMed, Cochrane Central Register Trial, and American Society of Clinical Oncology databases were searched from inception to 30 April 2018. We searched for randomized controlled trials comparing single-agent programmed cell death protein 1/programmed death-ligand 1 inhibitors (nivolumab, pembrolizumab, or atezolizumab) or cytotoxic T-lymphocyte-associated antigen 4 inhibitor (ipilimumab) with chemotherapy in NSCLC patients. Progression-free survival, overall survival, objective response rate, and adverse events were pooled for meta-analysis by Review Manager (RevMan version 5.3) software.

RESULTS

After exclusion of ineligible studies, 12 eligible randomized controlled trials were included. Data showed that ICIs significantly improved progression-free survival (HR 0.66, 95% CI 0.57-0.77, P < 0.00001), overall survival (HR 0.77, 95% CI 0.64-0.91, P = 0.003), and but not objective response rate (RR 1.97, 95% CI 1.25-3.13, P = 0.004) in all unselected NSCLC populations. However, they failed to increase the OS of programmed death-ligand 1 = 1-49% subgroup (HR 0.78, 95% CI 0.51-1.19, P = 0.25) and PFS of programmed death-ligand 1<1% subgroup (HR 0.85; 95%CI 0.70 to 1.03, P=0.09) in ICIs+chemotherapy over chemotherapy. Meanwhile, OS of programmed death-ligand =1-49% subgroup (HR 0.92; 95%CI 0.77 to 1.10, P=0.36) and PFS of programmed death-ligand 1≥50% subgroup (HR 0.76; 95%CI 0.52 to 1.11, P=0.15) showed no significant differences in ICIs over chemotherapy. Furthermore, fewer adverse events were observed in the ICIs groups than control groups.

CONCLUSION

ICIs are overall better tolerated than chemotherapy. Our results provide further evidence supporting the favorable risk/benefit ratio for ICIs.

Effectiveness and safety of PD-1/PD-L1 inhibitors in the treatment of solid tumors: a systematic review and meta-analysis

Background

PD-1/PD-L1 inhibitors have been implicated as potentially effective anti-cancer therapies. Some clinical randomized controlled trials (RCTs) have been completed for a variety of PD-1/PD-L1 inhibitors to treat various malignancies, and more RCTs are still under way. We carried out this systematic meta-analysis to evaluate the efficacy and safety of PD-1/PD-L1 inhibitors in the treatment of solid tumors.

Methods

We searched PubMed, EMBASE, clinical trial registers, conference reports, and related reviews. Eligible RCTs that compared PD-1/PD-L1 inhibitors with other chemotherapy agents or placebo in solid tumor patients were included. For each RCT, progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), stable disease rate (SDR), progressive disease rate (PDR), and adverse events (AEs) were pooled for meta-analysis.

Findings

Based on an analysis of 10 eligible RCTs, PD-1/PD-L1 inhibitors were found to significantly improve PFS (Hazard ratio (HR), 0.65; 95% confidence interval (CI) 0.53 to 0.79, P<0.001), OS (HR, 0.69; 95%CI 0.62 to 0.76, P<0.001), and ORR (Risk Ratio (RR) 292; 95% confidence interval (CI) 2.06 to 4.15, P<0.00001) in all populations, including melanoma and NSCLC subgroups. However, they failed to increase the DCR of cancer patients (RR 1.15; 95%CI 0.91 to 1.45, P=0.25). Furthermore, less AEs were observed in the PD-1/PD-L1 inhibitor groups than the control groups.

Interpretation

PD-1 inhibitors are more effective for improving the PFS, OS, and ORR of cancer patients with little toxicity, despite having little effect on increasing of the DCR.

[Immunotherapy of cancer with checkpoint inhibitors : Not only in malignant melanoma]

The newest weapon in cancer therapy is checkpoint inhibition, which is the result of basic immunology research. The success of this therapy is based on the fact that upon light microscopy, many solid tumors harbor lymphocytic cells infiltrating the tumor (TILs), and in many solid tumors, the presence of these TILs are prognostic. Ipilimumab was the first monoclonal antibody developed against a target present on T cells after becoming activated, CTLA-4. In malignant melanoma, ipilimumab showed its beneficial effect as compared to a placebo peptide. However, the therapy with this antibody harbors significant toxicity. Meanwhile, other targets such as PD-1, also expressed on (late) activated T cells, were identified, and therapies with antibodies inhibiting PD-1/PD-L1 are less toxic. Although these antibodies show response only in a minority of patients, the benefit seems durable in some of these patients. In solid tumors such as melanoma or non-small cell lung cancer (NSCLC), treatment with PD-1 inhibitors has resulted in a significant prolongation of survival, even in first-line treatment. As these drugs have been approved in many indications, it is important to know the drugs and side effects. Resistance towards these drugs are caused by low expression of the natural ligand, PD-L1, in the tumor tissue, as well as acquired loss of signal transduction of interferon-related genes such as JAK1 or JAK2, respectively. Also new in cancer therapy are bispecific T cell engager monoclonal antibodies (BiTEs) such as blinatumomab, and autologous chimeric antigen receptor-modified T cells (CAR-Ts). The later have proven their efficacy mainly in hematological neoplasias such as precursor-B-ALL. The dramatic costs of all these new drugs will have an enormous impact on the health care systems in the near future.

Induced Pluripotent Stem Cell as a New Source for Cancer Immunotherapy

The immune system consists of cells, proteins, and other molecules that beside each other have a protective function for the host against foreign pathogens. One of the most essential features of the immune system is distinguishability between self- and non-self-cells. This function has an important role in limiting development and progression of cancer cells. In this case, the immune system can detect tumor cell as a foreign pathogen; so, it can be effective in elimination of tumors in their early phases of development. This ability of the immune system resulted in the development of a novel therapeutic field for cancer treatment using host immune components which is called cancer immunotherapy. The main purpose of cancer immunotherapy is stimulation of a strong immune response against the tumor cells that can result from expressing either the immune activator cytokines in the tumor area or gene-modified immune cells. Because of the problems of culturing and manipulating immune cells ex vivo, in recent years, embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) have been used as new sources for generation of modified immune stimulatory cells. In this paper, we reviewed some of the progressions in iPSC technology for cancer immunotherapy.