CAR T-Cell Therapy for Multiple Myeloma: A Clinical Practice-Oriented Review.

The emergence of chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematologic malignancies, including multiple myeloma (MM). Two BCMA-directed CAR T-cell products - idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel) - have received US Food and Drug Administration (FDA) approval for patients with relapsed/refractory MM who underwent four or more prior lines of therapy (including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody). Despite producing unprecedented response rates in an otherwise difficult to treat patient population, CAR T-cell therapies are commonly associated with immune-related adverse events (e.g., cytokine release syndrome and neurotoxicity), cytopenias, and infections. Moreover, many patients continue to exhibit relapse post-treatment, with resistance mechanisms yet to be fully understood. Ongoing basic, translational, and clinical research efforts are poised to generate deeper insights into the optimal utilization of these therapies, improve their efficacy, minimize associated toxicity, and identify new target antigens in patients with MM.

Targeting mTOR signaling overcomes acquired resistance to combined BRAF and MEK inhibition in BRAF-mutant melanoma.

Targeting MAPK pathway using a combination of BRAF and MEK inhibitors is an efficient strategy to treat melanoma harboring BRAF-mutation. The development of acquired resistance is inevitable due to the signaling pathway rewiring. Combining western blotting, immunohistochemistry, and reverse phase protein array (RPPA), we aim to understanding the role of the mTORC1 signaling pathway, a center node of intracellular signaling network, in mediating drug resistance of BRAF-mutant melanoma to the combination of BRAF inhibitor (BRAFi) and MEK inhibitor (MEKi) therapy. The mTORC1 signaling pathway is initially suppressed by BRAFi and MEKi combination in melanoma but rebounds overtime after tumors acquire resistance to the combination therapy (CR) as assayed in cultured cells and PDX models. In vitro experiments showed that a subset of CR melanoma cells was sensitive to mTORC1 inhibition. The mTOR inhibitors, rapamycin and NVP-BEZ235, induced cell cycle arrest and apoptosis in CR cell lines. As a proof-of-principle, we demonstrated that rapamycin and NVP-BEZ235 treatment reduced tumor growth in CR xenograft models. Mechanistically, AKT or ERK contributes to the activation of mTORC1 in CR cells, depending on PTEN status of these cells. Our study reveals that mTOR activation is essential for drug resistance of melanoma to MAPK inhibitors, and provides insight into the rewiring of the signaling networks in CR melanoma.

A Critical Role for Fas-Mediated Off-Target Tumor Killing in T-cell Immunotherapy.

T cell-based therapies have induced cancer remissions, though most tumors ultimately progress, reflecting inherent or acquired resistance including antigen escape. Better understanding of how T cells eliminate tumors will help decipher resistance mechanisms. We used a CRISPR/Cas9 screen and identified a necessary role for Fas-FasL in antigen-specific T-cell killing. We also found that Fas-FasL mediated off-target "bystander" killing of antigen-negative tumor cells. This localized bystander cytotoxicity enhanced clearance of antigen-heterogeneous tumors in vivo, a finding that has not been shown previously. Fas-mediated on-target and bystander killing was reproduced in chimeric antigen receptor (CAR-T) and bispecific antibody T-cell models and was augmented by inhibiting regulators of Fas signaling. Tumoral FAS expression alone predicted survival of CAR-T-treated patients in a large clinical trial (NCT02348216). These data suggest strategies to prevent immune escape by targeting both the antigen expression of most tumor cells and the geography of antigen-loss variants. SIGNIFICANCE: This study demonstrates the first report of in vivo Fas-dependent bystander killing of antigen-negative tumors by T cells, a phenomenon that may be contributing to the high response rates of antigen-directed immunotherapies despite tumoral heterogeneity. Small molecules that target the Fas pathway may potentiate this mechanism to prevent cancer relapse.This article is highlighted in the In This Issue feature, p. 521.

Google search histories of patients presenting to an emergency department: an observational study.

OBJECTIVE: To test patients' willingness to share and link their prior Google search histories with data from their electronic medical record (EMR), and to explore associations between search histories and clinical conditions. DESIGN: Cross-sectional study of emergency department (ED) patients from 2016 to 2017. SETTING: Academic medical centre ED. PARTICIPANTS: A total of 703 patients were approached; 334 of a volunteer sample of 411 (81%) reported having a Google account; 165 of those (49%) consented to share their Google search histories and EMR data; 119 (72%) were able to do so. 16 (13%) of those 119 patients had no data and were not included in the final count. Patients under the age of 18 or with a triage level of 1 were considered ineligible and were not approached. MAIN OUTCOME MEASURES: Health relatedness of searches in the remote past and within 7 days of the ED visit, and associations between patients' clinical and demographic characteristics and their internet search volume and search content. RESULTS: The 103 participants yielded 591 421 unique search queries; 37 469 (6%) were health related. In the 7 days prior to an ED visit, the percentage of health-related searches was 15%. During that time, 56% of patients searched for symptoms, 53% for information about a hospital and 23% about the treatment or management of a disease. 53% of participants who used Google in the week leading up to their ED visit searched for content directly related to their chief complaint. CONCLUSIONS: Patients were willing to allow researchers simultaneous access to their Google search histories and their EMR data. The change in volume and content of search activity prior to an ED visit suggests opportunities to anticipate and improve health care utilisation in advance of ED visits.

Author Correction: PAK signalling drives acquired drug resistance to MAPK inhibitors in BRAF-mutant melanomas.

In this Letter, two relevant references were omitted; see the accompanying Amendment for details. The original Letter has not been corrected.

Induction of Telomere Dysfunction Prolongs Disease Control of Therapy-Resistant Melanoma.

Purpose: Telomerase promoter mutations are highly prevalent in human tumors including melanoma. A subset of patients with metastatic melanoma often fail multiple therapies, and there is an unmet and urgent need to prolong disease control for those patients.Experimental Design: Numerous preclinical therapy-resistant models of human and mouse melanoma were used to test the efficacy of a telomerase-directed nucleoside, 6-thio-2'-deoxyguanosine (6-thio-dG). Integrated transcriptomics and proteomics approaches were used to identify genes and proteins that were significantly downregulated by 6-thio-dG.Results: We demonstrated the superior efficacy of 6-thio-dG both in vitro and in vivo that results in telomere dysfunction, leading to apoptosis and cell death in various preclinical models of therapy-resistant melanoma cells. 6-thio-dG concomitantly induces telomere dysfunction and inhibits the expression level of AXL.Conclusions: In summary, this study shows that indirectly targeting aberrant telomerase in melanoma cells with 6-thio-dG is a viable therapeutic approach in prolonging disease control and overcoming therapy resistance. Clin Cancer Res; 24(19); 4771-84. ©2018 AACR See related commentary by Teh and Aplin, p. 4629.

PAK signalling drives acquired drug resistance to MAPK inhibitors in BRAF-mutant melanomas.

Targeted BRAF inhibition (BRAFi) and combined BRAF and MEK inhibition (BRAFi and MEKi) therapies have markedly improved the clinical outcomes of patients with metastatic melanoma. Unfortunately, the efficacy of these treatments is often countered by the acquisition of drug resistance. Here we investigated the molecular mechanisms that underlie acquired resistance to BRAFi and to the combined therapy. Consistent with previous studies, we show that resistance to BRAFi is mediated by ERK pathway reactivation. Resistance to the combined therapy, however, is mediated by mechanisms independent of reactivation of ERK in many resistant cell lines and clinical samples. p21-activated kinases (PAKs) become activated in cells with acquired drug resistance and have a pivotal role in mediating resistance. Our screening, using a reverse-phase protein array, revealed distinct mechanisms by which PAKs mediate resistance to BRAFi and the combined therapy. In BRAFi-resistant cells, PAKs phosphorylate CRAF and MEK to reactivate ERK. In cells that are resistant to the combined therapy, PAKs regulate JNK and ß-catenin phosphorylation and mTOR pathway activation, and inhibit apoptosis, thereby bypassing ERK. Together, our results provide insights into the molecular mechanisms underlying acquired drug resistance to current targeted therapies, and may help to direct novel drug development efforts to overcome acquired drug resistance.

Enhancing CD8+ T Cell Fatty Acid Catabolism within a Metabolically Challenging Tumor Microenvironment Increases the Efficacy of Melanoma Immunotherapy.

How tumor-infiltrating T lymphocytes (TILs) adapt to the metabolic constrains within the tumor microenvironment (TME) and to what degree this affects their ability to combat tumor progression remain poorly understood. Using mouse melanoma models, we report that CD8+ TILs enhance peroxisome proliferator-activated receptor (PPAR)-α signaling and catabolism of fatty acids (FAs) when simultaneously subjected to hypoglycemia and hypoxia. This metabolic switch partially preserves CD8+ TILs' effector functions, although co-inhibitor expression increases during tumor progression regardless of CD8+ TILs' antigen specificity. Further promoting FA catabolism improves the CD8+ TILs' ability to slow tumor progression. PD-1 blockade delays tumor growth without changing TIL metabolism or functions. It synergizes with metabolic reprogramming of T cells to achieve superior antitumor efficacy and even complete cures.

Successful use of talc sclerodesis to control a persistent high-output groin seroma following endovascular abdominal aortic aneurysm repair.

Groin wound lymphatic complications after vascular procedures are accompanied by increased risk of infection, prolonged hospital stay, and greater patient morbidity. High-output groin seromas can be difficult to manage and refractory to established interventions. Although subcutaneous talc has been used to prevent seroma accumulation in other high-risk surgical fields, such as after axillary lymph node dissection, it has not been described in the context of vascular surgery. This article presents the first reported case of a persistent high-output groin seroma after endovascular abdominal aortic aneurysm repair managed successfully with intraoperative application of sterile talc.

Spontaneous upper limb monoplegia secondary to probable cerebral amyloid angiopathy.

Cerebral amyloid angiopathy is a clinicopathological disorder characterised by vascular amyloid deposition initially in leptomeningeal and neocortical vessels, and later affecting cortical and subcortical regions. The presence of amyloid within the walls of these vessels leads to a propensity for primary intracerebral haemorrhage. We report the unusual case of a 77-year-old female who presented to our emergency department with sudden onset isolated hypoaesthesia and right upper limb monoplegia. A CT scan demonstrated a peripheral acute haematoma involving the left perirolandic cortices. Subsequent magnetic resonance imaging demonstrated previous superficial haemorrhagic events. One week following discharge the patient re-attended with multiple short-lived episodes of aphasia and jerking of the right upper limb. Further imaging demonstrated oedematous changes around the previous haemorrhagic insult. Cerebral amyloid angiopathy is an overlooked cause of intracerebral haemorrhage; the isolated nature of the neurological deficit in this case illustrates the many guises in which it can present.

Call for consistent coding in diabetes mellitus using the Royal College of General Practitioners and NHS pragmatic classification of diabetes.

BACKGROUND: The prevalence of diabetes is increasing with growing levels of obesity and an aging population. New practical guidelines for diabetes provide an applicable classification. Inconsistent coding of diabetes hampers the use of computerised disease registers for quality improvement, and limits the monitoring of disease trends. OBJECTIVE: To develop a consensus set of codes that should be used when recording diabetes diagnostic data. METHODS: The consensus approach was hierarchical, with a preference for diagnostic/disorder codes, to define each type of diabetes and non-diabetic hyperglycaemia, which were listed as being completely, partially or not readily mapped to available codes. The practical classification divides diabetes into type 1 (T1DM), type 2 (T2DM), genetic, other, unclassified and non-diabetic fasting hyperglycaemia. We mapped the classification to Read version 2, Clinical Terms version 3 and SNOMED CT. RESULTS: T1DM and T2DM were completely mapped to appropriate codes. However, in other areas only partial mapping is possible. Genetics is a fastmoving field and there were considerable gaps in the available labels for genetic conditions; what the classification calls 'other' the coding system labels 'secondary' diabetes. The biggest gap was the lack of a code for diabetes where the type of diabetes was uncertain. Notwithstanding these limitations we were able to develop a consensus list. CONCLUSIONS: It is a challenge to develop codes that readily map to contemporary clinical concepts. However, clinicians should adopt the standard recommended codes; and audit the quality of their existing records.