Acquired resistance to anti-PD1 therapy: checkmate to checkpoint blockade?

Editorial summary Anti-programmed cell death 1 (PD1) immunotherapies are among the most effective anti-cancer immunotherapies available; however, a large number of patients present with or develop resistance to them. Unfortunately, very little is known regarding the mechanisms of resistance to such therapies. A recent study sought to identify mutations associated with resistance to anti-PD1 therapy. Results from this study demonstrated that mutations which affected the sensitivity of tumor cells to T-cell-derived interferons, and mutations limiting tumor-cell antigen presentation, could cause acquired resistance. These findings have significant implications for understanding the mechanisms by which anti-PD1 therapies exert their efficacy, comprehending why and how some patients acquire resistance over time, and ultimately guiding the development of combination therapies designed to overcome, or potentially prevent, the development of acquired immunotherapeutic resistance

From mice to humans: Developments in cancer immunoediting

Cancer immunoediting explains the dual role by which the immune system can both suppress and/or promote tumor growth. Although cancer immunoediting was first demonstrated using mouse models of cancer, strong evidence that it occurs in human cancers is now accumulating. In particular, the importance of CD8+ T cells in cancer immunoediting has been shown, and more broadly in those tumors with an adaptive immune resistance phenotype. This Review describes the characteristics of the adaptive immune resistance tumor microenvironment and discusses data obtained in mouse and human settings. The role of other immune cells and factors influencing the effector function of tumor-specific CD8+ T cells is covered. We also discuss the temporal occurrence of cancer immunoediting in metastases and whether it differs from immunoediting in the primary tumor of origin

PI3K-AKT-mTOR inhibition in cancer immunotherapy, redux

Cancer therapies will increasingly be utilized in combination to treat advanced malignancies so as to increase their long-term efficacy in a greater proportion of patients. In particular, much attention has focused on developing targeted therapies that inhibit the PI3K-AKT-mTOR signaling network which is dysregulated in many cancer types. In addition, there is now a growing appreciation that targeting of these pathways can impact not only on cancer cells, but also host immunity. The clinical success of cancer immunotherapies targeting T-cell immune checkpoint receptors PD-1/PD-L1 has demonstrated the importance of immunoevasion as a hallmark of cancer. In this review, we discuss how PI3K-AKT-mTOR inhibitors target cancer cell biology, attenuate immune cell effector function and modulate the tumor microenvironment. We next discuss how the immunomodulatory potential of these inhibitors can be exploited through rational combinations with immunotherapies and targeted therapies

TIM3+FOXP3+ regulatory T cells are tissue-specific promoters of T-cell dysfunction in cancer

T-cell immunoglobulin mucin 3 (TIM3) is an inhibitory molecule that has emerged as a key regulator of dysfunctional or exhausted CD8+ T cells arising in chronic diseases such as cancer. In addition to exhausted CD8+ T cells, highly suppressive regulatory T cells (Tregs) represent a significant barrier against the induction of antitumor immunity. We have found that the majority of intratumoral FOXP3+ Tregs express TIM3. TIM3+ Tregs co-express PD-1, are highly suppressive and comprise a specialized subset of tissue Tregs that are rarely observed in the peripheral tissues or blood of tumor-bearing mice. The co-blockade of the TIM3 and PD-1 signaling pathways in vivo results in the downregulation of molecules associated with TIM3+ Treg suppressor functions. This suggests that the potent clinical efficacy of co-blocking TIM3 and PD-1 signal transduction cascades likely stems from the reversal of T-cell exhaustion combined with the inhibition of regulatory T-cell function in tumor tissues. Interestingly, we find that TIM3+ Tregs accumulate in the tumor tissue prior to the appearance of exhausted CD8+ T cells, and that the depletion of Tregs at this stage interferes with the development of the exhausted phenotype by CD8+ T cells. Collectively, our data indicate that TIM3 marks highly suppressive tissue-resident Tregs that play an important role in shaping the antitumor immune response in situ, increasing the value of TIM3-targeting therapeutic strategies against cancer

Treatment sequences and prognostic/predictive factors in metastatic pancreatic ductal adenocarcinoma: univariate and multivariate analyses of a real-world study in Europe

BACKGROUND: Real-world data on treatment patterns/outcomes for metastatic pancreatic cancer (mPAC) are limited. This study aims to assess real-world treatment patterns, survival outcomes, and prognostic/predictive factors in patients with mPAC. METHODS: Retrospective, observational, chart-review involving medical oncologists and gastroenterologists from five European countries. Physicians reported information on disease and patient characteristics, diagnosis, and treatment for patients diagnosed with mPAC from January-October 2016. Outcomes included median progression-free survival (mPFS), median overall survival (mOS), and the impact of baseline performance status on survival. Univariate/multivariate regression analyses were undertaken to identify prognostic/predictive factors. RESULTS: Three hundred four physicians and 3432 patients were included. First-line therapies included modified (m)FOLFIRINOX (28.4%), gemcitabine + nab-paclitaxel (28.0%), and gemcitabine monotherapy (23.0%). Frequent second-line therapies were gemcitabine monotherapy (25.0%), fluorouracil (5-FU) + oxaliplatin (21.8%), and gemcitabine + nab-paclitaxel (16.7%). Most frequent first- to second-line treatment sequences were gemcitabine + nab-paclitaxel followed by fluoropyrimidine combinations. Longest unadjusted estimated mOS was observed with (m)FOLFIRINOX followed by gemcitabine-based combinations (19.1 months). Multivariate analysis identified significant prognostic/predictive factors for OS and PFS including performance status and carbohydrate antigen 19-9 (CA 19-9) levels. CONCLUSIONS: Treatment and treatment sequences were generally in accordance with guidelines at the time of the study. Identification of prognostic/predictive factors for survival may help inform the individualised management of mPAC patients in the future

Quantitative aortography for assessment of aortic regurgitation in the era of percutaneous aortic valve replacement

Paravalvular leak (PVL) is a shortcoming that can erode the clinical benefits of transcatheter valve replacement (TAVR) and therefore a readily applicable method (aortography) to quantitate PVL objectively and accurately in the interventional suite is appealing to all operators. The ratio between the areas of the time-density curves in the aorta and left ventricular outflow tract (LVOT-AR) defines the regurgitation fraction (RF). This technique has been validated in a mock circulation; a single injection in diastole was further tested in porcine and ovine models. In the clinical setting, LVOT-AR was compared with trans-thoracic and trans-oesophageal echocardiography and cardiac magnetic resonance imaging. LVOT-AR > 17% discriminates mild from moderate aortic regurgitation on echocardiography and confers a poor prognosis in multiple registries, and justifies balloon post-dilatation. The LVOT-AR differentiates the individual performances of many old and novel devices and is being used in ongoing randomized trials and registries

Quantitative aortography for assessment of aortic regurgitation in the era of percutaneous aortic valve replacement

Paravalvular leak (PVL) is a shortcoming that can erode the clinical benefits of transcatheter valve replacement (TAVR) and therefore a readily applicable method (aortography) to quantitate PVL objectively and accurately in the interventional suite is appealing to all operators. The ratio between the areas of the time-density curves in the aorta and left ventricular outflow tract (LVOT-AR) defines the regurgitation fraction (RF). This technique has been validated in a mock circulation; a single injection in diastole was further tested in porcine and ovine models. In the clinical setting, LVOT-AR was compared with trans-thoracic and trans-oesophageal echocardiography and cardiac magnetic resonance imaging. LVOT-AR &gt; 17% discriminates mild from moderate aortic regurgitation on echocardiography and confers a poor prognosis in multiple registries, and justifies balloon post-dilatation. The LVOT-AR differentiates the individual performances of many old and novel devices and is being used in ongoing randomized trials and registries.</p

Quantitative aortography for assessment of aortic regurgitation in the era of percutaneous aortic valve replacement

Paravalvular leak (PVL) is a shortcoming that can erode the clinical benefits of transcatheter valve replacement (TAVR) and therefore a readily applicable method (aortography) to quantitate PVL objectively and accurately in the interventional suite is appealing to all operators. The ratio between the areas of the time-density curves in the aorta and left ventricular outflow tract (LVOT-AR) defines the regurgitation fraction (RF). This technique has been validated in a mock circulation; a single injection in diastole was further tested in porcine and ovine models. In the clinical setting, LVOT-AR was compared with trans-thoracic and trans-oesophageal echocardiography and cardiac magnetic resonance imaging. LVOT-AR &gt; 17% discriminates mild from moderate aortic regurgitation on echocardiography and confers a poor prognosis in multiple registries, and justifies balloon post-dilatation. The LVOT-AR differentiates the individual performances of many old and novel devices and is being used in ongoing randomized trials and registries.</p