A phase I trial of cabozantinib and gemcitabine in advanced pancreatic cancer

Hallmarks of pancreatic cancer: spotlight on TAM receptors

Pancreatic ductal adenocarcinoma (PDAC) represents the most prevalent type of pancreatic cancer and ranks among the most aggressive tumours, with a 5-year survival rate of less than 11%. Projections indicate that by 2030, it will become the second leading cause of cancer-related deaths. PDAC presents distinctive hallmarks contributing to its dismal prognosis: (i) late diagnosis, (ii) heterogenous and complex mutational landscape, (iii) high metastatic potential, (iv) dense fibrotic stroma, (v) immunosuppressive microenvironment, and (vi) high resistance to therapy. Mounting evidence has shown a role for TAM (Tyro3, AXL, MerTK) family of tyrosine kinase receptors in PDAC initiation and progression. This review aims to describe the impact of TAM receptors on the defining hallmarks of PDAC and discuss potential future directions using these proteins as novel biomarkers for early diagnosis and targets for precision therapy in PDAC, an urgent unmet clinical need.

A Phase 1 Study of Cabozantinib and Trifluridine/Tipiracil in Metastatic Colorectal Adenocarcinoma

INTRODUCTION

This study determined the safety and recommended phase 2 dose (RP2D) of the multikinase inhibitor cabozantinib in combination with trifluridine/tipiracil (FTD/TPI) in refractory metastatic colorectal carcinoma (mCRC).

PATIENTS AND METHODS

Single institution investigator-initiated phase 1 study using 3+3 design. Eligible mCRC patients had received prior standard regimens. Cabozantinib was given orally (p.o.) at 20 mg (dose level [DL] 0) or 40 mg (DL 1) daily on days 1-28, and FTD/TPI p.o. at 35 mg/m2 on days 1-5 and 8-12 every 28 days. Prophylactic growth-factor support was allowed.

RESULTS

Fifteen patients were enrolled. Median age 56 years (31-80), male (12/15), ECOG 0/1 = 9/6. Three patients were treated at DL 0 and another nine were treated at DL 1, none exhibiting a DLT. Most common any grade (G) treatment related adverse events (TRAE) were diarrhea (50%), nausea (42%), neutropenia (42%), fatigue (33%), and rash (25%). G3-4 TRAE were neutropenia (25%) and thrombocytopenia, hypokalemia, and weight loss (each 8%). No serious TRAE or G5 were reported. The RP2D was determined to be DL 1. Median PFS was 3.8 months (95% CI 1.9-6.8) and disease control rate was 86.7%.

CONCLUSION

The combination of cabozantinib and FTD/TPI is feasible and tolerable at standard doses with the use of growth factors and showed encouraging clinical activity in refractory mCRC.

CLINICALTRIALS

GOV: NCT04868773.

Phase 1 study of cabozantinib in combination with topotecan-cyclophosphamide for patients with relapsed Ewing sarcoma or osteosarcoma

PURPOSE

Phase 1 study assessing the safety and toxicity of cabozantinib in combination with topotecan and cyclophosphamide for relapsed osteosarcoma and Ewing sarcoma.

METHODS

Oral cabozantinib (25 mg/m2 ) was administered daily for 21 (dose level 1) or 14 (dose level -1B) days. Topotecan (0.75 mg/m2 ) and cyclophosphamide (250 mg/m2 ) were administered intravenously (IV) on days 1-5. A modified 3+3 design based upon first cycle dose-limiting toxicities (DLT) was used for dose escalation.

RESULTS

Twelve patients with a median age of 15 (12.9-33.2) years were enrolled (seven with Ewing sarcoma; five with osteosarcoma); all were evaluable for toxicity. At dose level 1, three of six patients developed first cycle DLT: grade 3 epistaxis, grade 3 transaminitis, and prolonged grade 2 thrombocytopenia. Six patients were enrolled on dose level -1B (interrupted cabozantinib, given days 8-21), with one first cycle DLT (grade 3 pneumothorax) observed. Of the 10 response evaluable patients, one had partial response (Ewing sarcoma), seven had stable disease, and two had progressive disease.

CONCLUSIONS

The recommended phase 2 doses and schedules for this combination are topotecan 0.75 mg/m2 IV days 1-5, cyclophosphamide 250 mg/m2 IV days 1-5, and cabozantinib 25 mg/m2 days 8-21. Non-concomitant administration of cabozantinib with cytotoxic therapy in this population has acceptable toxicity, while allowing for potential disease control.

Second-line treatment options for patients with metastatic pancreatic ductal adenocarcinoma: A systematic literature review

INTRODUCTION

The aim of this review was to characterize the second- and later-line (≥2L) treatment landscape for patients with metastatic pancreatic ductal adenocarcinoma (mPDAC).

METHODS

This systematic literature review (PROSPERO: CRD42021279753) involved searches of MEDLINE® and Embase to identify results from prospective studies of ≥2L treatment options for metastatic pancreatic cancer published from 2016 to 2021. Publications were screened according to predetermined eligibility criteria; population-level data were extracted using standardized data fields. Publication quality was assessed according to Grading of Recommendations Assessment, Development and Evaluation (GRADE). The data were analyzed descriptively, grouped by drug class.

RESULTS

Sixty publications were identified, including 23 relating to comparative trials. GRADE assessment found that, of these 23 trials, 83% reported high or moderate-quality evidence. Of the publications relating to comparative trials, nine (three trials) reported favorable results: the pivotal phase 3 NAPOLI-1 trial for liposomal irinotecan; a phase 3 trial of non-liposomal irinotecan within the FOLFIRINOX regimen; and a phase 2 trial of eryaspase plus chemotherapy.

CONCLUSIONS

The level of unmet need for ≥2L treatment options for mPDAC remains high. Irinotecan-based regimens currently offer the greatest promise. Investigations into paradigm-changing agents and combination approaches continue.

Discovery of anticancer agents with c-Met inhibitory potential by virtual and experimental screening of a chemical library

c-Met receptor tyrosine kinase has recently emerged as an important target with therapeutic implications in pancreatic cancer. In this study, we carried out a docking virtual screening on an in-house library of 441 synthesized compounds and selected the compounds with the best interactions with the c-Met protein to be subjected to experimental tests. Ten compounds belonging to 3 different classes of chemical structures were selected for this purpose and their antiproliferative effects were studied against 4 pancreatic ductal adenocarcinoma (PDAC) cell lines including AsPC-1, Suit-2, Panc-1 and Mia-Paca-2 cells, primary PDAC cells and also c-Met amplified EBC-1 cell line by sulforhodamine-B assay. Apoptosis induction was examined by Hoechst 33258 staining and annexin V-FITC/propidium iodide flow cytometric assay. The best compound was also assayed in three-dimensional cultures of AsPC-1 cells and its c-Met inhibitory potential was studied by immunoblotting and a homogenous time resolved fluorescence (HTRF) assay. The compound with a phenanthrotriazine hydrazinyl scaffold bearing nitrophenyl pendant (PhTH) was the most active derivative, with IC50 values in the range of 5-8 μM. This compound exerted antiproliferative effect against AsPC-1 cells also in the presence of hepatocyte growth factor (HGF). PhTH induced apoptosis, dose-dependently inhibited spheroid growth, inhibited c-Met activity in cell-free HTRF assay and also inhibited the phosphorylation of c-Met and its downstream effector ERK1/2 in AsPC-1 cells. Molecular docking and dynamics simulation and MM-PBSA analysis confirmed close interactions of PhTH with c-Met kinase domain. Some of the tested compounds in this study seem to be potential c-Met inhibitors with promising activities against PDAC cells.

Emerging kinase inhibitors for the treatment of pancreatic ductal adenocarcinoma

INTRODUCTION

Pancreatic cancer is one of the deadliest solid organ cancers. In the absence of specific warning symptoms pancreatic cancer is diagnosed notoriously late. Current systemic chemotherapy regimens extend survival by a mere few months. With the advances in genetic, proteomic, and immunological profiling there is strong rationale to test kinase inhibitors to improve outcome.

AREAS COVERED

This review article provides a comprehensive summary of approved treatments and past, present, and future developments of kinase inhibitors in pancreatic cancer. Emerging roles of protein kinase inhibitors are discussed in the context of the unique stroma, the lack of high-prevalence therapeutic targets and rapid emergence of acquired resistance, novel immuno-oncology kinase targets, and recent medicinal chemistry advances.

EXPERT OPINION

Due to the to-date frequent failure of protein kinase inhibitors indiscriminately administered to unselected pancreatic cancer patients, there is a shift toward the development of these agents in molecularly defined subgroups which are more likely to respond. The development of accurate biomarkers to select patients who are the best candidates based on a detailed understanding of mechanism of action, pro-survival roles, and mediation of resistance of targeted kinases will be critical for the future development of protein kinase inhibitors in this disease.

Cabozantinib combination therapy for the treatment of solid tumors: a systematic review

Background

Cabozantinib monotherapy is approved for the treatment of several types of solid tumors. Investigation into the use of cabozantinib combined with other therapies is increasing. To understand the evidence in this area, we performed a systematic review of cabozantinib combination therapy for the treatment of solid tumors in adults.

Methods

This study was designed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses, and the protocol was registered with PROSPERO (CRD42020144680). On 9 October 2020, we searched for clinical trials and observational studies of cabozantinib as part of a combination therapy for solid tumors using Embase, MEDLINE, and Cochrane databases, and by screening relevant congress abstracts. Eligible studies reported clinical or safety outcomes, or biomarker data. Randomized and observational studies with a sample size of fewer than 25 and studies of cabozantinib monotherapy were excluded. For each study, quality was assessed using National Institute for Health and Care Excellence methodology, and the study characteristics were described qualitatively. This study was funded by Ipsen.

Results

Of 2421 citations identified, 32 articles were included (6 with results from randomized studies, 24 with results from non-randomized phase I or II studies, and 2 with results from both). The most commonly studied tumor types were metastatic urothelial carcinoma/genitourinary tumors and castration-resistant prostate cancer (CRPC). Findings from randomized studies suggested that cabozantinib combined with other therapies may lead to better progression-free survival than some current standards of care in renal cell carcinoma, CRPC, and non-small-cell lung cancer. The most common adverse events were hypertension, diarrhea, and fatigue.

Conclusion

This review demonstrates the promising efficacy outcomes of cabozantinib combined with other therapies, and a safety profile similar to cabozantinib alone. However, the findings are limited by the fact that most of the identified studies were reported as congress abstracts only. More evidence from randomized trials is needed to explore cabozantinib as a combination therapy further.

Patient-Derived Upper Tract Urothelial Carcinoma Organoids as a Platform for Drug Screening

Upper tract urothelial carcinomas (UTUCs) are rare entities that are usually diagnosed at advanced stages. Research on UTUC pathobiology and clinical management has been hampered by the lack of models accurately reflecting disease nature and diversity. In this study, a modified organoid culture system is used to generate a library of 25 patient-derived UTUC organoid lines retaining the histological architectures, marker gene expressions, genomic landscapes, and gene expression profiles of their parental tumors. The study demonstrates that the responses of UTUC organoids to anticancer drugs can be identified and the model supports the exploration of novel treatment strategies. This work proposes a modified protocol for generating patient-derived UTUC organoid lines that may help elucidate UTUC pathophysiology and assess the responses of these diseases to various drug therapies in personalized medicine.

Targeting the Stroma in the Management of Pancreatic Cancer

Pancreatic cancer (PC) presents extremely aggressive tumours and is associated with poor survival. This is attributed to the unique features of the tumour microenvironment (TME), which is known to create a dense stromal formation and poorly immunogenic condition. In particular, the TME of PC, including the stromal cells and extracellular matrix, plays an essential role in the progression and chemoresistance of PC. Consequently, several promising agents that target key components of the stroma have already been developed and are currently in multiple stages of clinical trials. Therefore, the authors review the latest available evidence on novel stroma-targeting approaches, highlighting the potential impact of the stroma as a key component of the TME in PC.

The State-of-the-Art of Phase II/III Clinical Trials for Targeted Pancreatic Cancer Therapies

Pancreatic cancer is a devastating disease with very poor prognosis. Currently, surgery followed by adjuvant chemotherapy represents the only curative option which, unfortunately, is only available for a small group of patients. The majority of pancreatic cancer cases are diagnosed at advanced or metastatic stage when surgical resection is not possible and treatment options are limited. Thus, novel and more effective therapeutic strategies are urgently needed. Molecular profiling together with targeted therapies against key hallmarks of pancreatic cancer appear as a promising approach that could overcome the limitations of conventional chemo- and radio-therapy. In this review, we focus on the latest personalised and multimodal targeted therapies currently undergoing phase II or III clinical trials. We discuss the most promising findings of agents targeting surface receptors, angiogenesis, DNA damage and cell cycle arrest, key signalling pathways, immunotherapies, and the tumour microenvironment.

HGF/c-Met Axis: The Advanced Development in Digestive System Cancer

Numerous studies have indicated that abnormal activation of the HGF/c-Met signaling pathway can lead to cell proliferation, invasiveness, and metastasis of cancers of the digestive system. Moreover, overexpression of c-Met has been implicated in poor prognosis of patients with these forms of cancer, suggesting the possibility for HGF/c-Met axis as a potential therapeutic target. Despite the large number of clinical and preclinical trials worldwide, no significant positive success in the use of anti-HGF/c-Met treatments on cancers of the digestive system has been achieved. In this review, we summarize advanced development of clinical research on HGF/c-Met antibody and small-molecule c-Met inhibitors of cancers of the digestive system and provide a possible direction for future research.

Targeting TAM to Tame Pancreatic Cancer

Pancreatic cancer is expected to become the second leading cause of cancer-related death within the next few years. Current therapeutic strategies have limited effectiveness and therefore there is an urgency to develop novel effective therapies. The receptor tyrosine kinase subfamily TAM (Tyro3, Axl, MerTK) is directly implicated in the pathogenesis of the metastatic, chemoresistant, and immunosuppressive phenotype in pancreatic cancer. TAM inhibitors are promising investigational therapies for pancreatic cancer due to their potential to target multiple aspects of pancreatic cancer biology. Specifically, recent mechanistic investigations and therapeutic combinations in the preclinical setting suggest that TAM inhibition with chemotherapy, targeted therapy, and immunotherapy should be evaluated clinically.

Practicalities in running early-phase trials using the time-to-event continual reassessment method (TiTE-CRM) for interventions with long toxicity periods using two radiotherapy oncology trials as examples

BACKGROUND

Awareness of model-based designs for dose-finding studies such as the Continual Reassessment Method (CRM) is now becoming more commonplace amongst clinicians, statisticians and trial management staff. In some settings toxicities can occur a long time after treatment has finished, resulting in extremely long, interrupted, CRM design trials. The Time-to-Event CRM (TiTE-CRM), a modification to the original CRM, accounts for the timing of late-onset toxicities and results in shorter trial duration. In this article, we discuss how to design and deliver a trial using this method, from the grant application stage through to dissemination, using two radiotherapy trials as examples.

METHODS

The TiTE-CRM encapsulates the dose-toxicity relationship with a statistical model. The model incorporates observed toxicities and uses a weight to account for the proportion of completed follow-up of participants without toxicity. This model uses all available data to determine the next participant's dose and subsequently declare the maximum tolerated dose. We focus on two trials designed by the authors to illustrate practical issues when designing, setting up, and running such studies.

RESULTS

In setting up a TiTE-CRM trial, model parameters need to be defined and the time element involved might cause complications, therefore looking at operating characteristics through simulations is essential. At the grant application stage, we suggest resources to fund statisticians' time before funding is awarded and make recommendations for the level of detail to include in funding applications. While running the trial, close contact of all involved staff is required as a dose decision is made each time a participant is recruited. We suggest ways of capturing data in a timely manner and give example code in R for design and delivery of the trial. Finally, we touch upon dissemination issues while the trial is running and upon completion.

CONCLUSION

Model-based designs can be complex. We hope this paper will help clinical trial teams to demystify the conduct of TiTE-CRM trials and be a starting point for using this methodology in practice.

Cabozantinib Inhibits Photodynamic Therapy-Induced Auto- and Paracrine MET Signaling in Heterotypic Pancreatic Microtumors

Extensive desmoplasia is a hallmark of pancreatic ductal adenocarcinoma (PDAC), which frequently associates with treatment resistance. Recent findings indicate that a combination of photodynamic therapy and the multi-kinase inhibitor cabozantinib achieved local tumor control and a significant decrease in tumor metastases in preclinical PDAC models, but the underlying therapeutic mechanisms remain unclear. This study elucidates the molecular basis of this multi-agent regimen, focusing on the role of MET signaling. Since MET activation stems from its interaction with hepatocyte growth factor (HGF), which is typically secreted by fibroblasts, we developed heterotypic PDAC microtumor models that recapitulate these interactions. In these models, MET signaling can be constitutively activated through paracrine and autocrine mechanisms. Photodynamic therapy caused significant elevations in HGF secretion by fibroblasts, suggesting it plays a complex role in the modulation of the paracrine HGF–MET signaling cascade in desmoplastic tumors. Blocking MET phosphorylation with adjuvant cabozantinib caused a significant improvement in photodynamic therapy efficacy, most notably by elevating spheroid necrosis at low radiant exposures. These findings highlight that adjuvant photodynamic therapy can augment chemotherapy efficacies, and potentially achieve improved management of desmoplastic PDAC in a more tolerable manner.

Targeted Dual Intervention-Oriented Drug-Encapsulated (DIODE) Nanoformulations for Improved Treatment of Pancreatic Cancer

Despite recent advancements, effective treatment for pancreatic ductal adenocarcinoma (PDAC) has remained elusive. The overall survival rate in PDAC patients has been dismally low due to resistance to standard therapies. In fact, the failure of monotherapies to provide long-term survival benefits in patients led to ascension of several combination therapies for PDAC treatment. However, these combination therapies provided modest survival improvements while increasing treatment-related adverse side effects. Hence, recent developments in drug delivery methods hold the potential for enhancing therapeutic benefits by offering cocktail drug loading and minimizing chemotherapy-associated side effects. Nanoformulations-aided deliveries of anticancer agents have been a success in recent years. Yet, improving the tumor-targeted delivery of drugs to PDAC remains a major hurdle. In the present paper, we developed several new tumor-targeted dual intervention-oriented drug-encapsulated (DIODE) liposomes. We successfully formulated liposomes loaded with gemcitabine (G), paclitaxel (P), erlotinib (E), XL-184 (c-Met inhibitor, X), and their combinations (GP, GE, and GX) and evaluated their in vitro and in vivo efficacies. Our novel DIODE liposomal formulations improved median survival in comparison with gemcitabine-loaded liposomes or vehicle. Our findings are suggestive of the importance of the targeted delivery for combination therapies in improving pancreatic cancer treatment.

ImmunoPET Predicts Response to Met-targeted Radioligand Therapy in Models of Pancreatic Cancer Resistant to Met Kinase Inhibitors

Background: Pancreatic ductal adenocarcinoma (PDAC) has limited standard of care therapeutic options. While initially received with enthusiasm, results from targeted therapy with small molecule tyrosine kinases inhibitors (TKIs) have been mixed, in part due to poor patient selection and compensatory changes in signaling networks upon blockade of one or more kinase of tumors. Here, we demonstrate that in PDACs otherwise resistant to rational kinase inhibition, Met-directed immuno-positron emission tomography (immunoPET) can identify targets for cell-signaling independent targeted radioligand therapy (RLT). In this study, we use Met-directed immunoPET and RLT in models of human pancreatic cancer that are resistant to Met- and MEK-selective TKIs, despite over-expression of Met and KRAS-pathway activation. Methods: We assessed cell membrane Met levels in human patient samples and pancreatic ductal adenocarcinoma (PDAC) cell lines (BxPC3, Capan2, Suit2, and MIA PaCa-2) using immunofluorescence, flow cytometry and cell-surface biotinylation assays. To determine whether Met expression levels correlate with sensitivity to Met inhibition by tyrosine kinase inhibitors (TKIs), we performed cell viability studies. A Met-directed imaging agent was engineered by labeling Met-specific onartuzumab with zirconium-89 (Zr-89) and its in vivo performance was evaluated in subcutaneous and orthotopic PDAC xenograft models. To assess whether the immunoPET agent would predict for targeted RLT response, onartuzumab was then labeled with lutetium (Lu-177) as the therapeutic radionuclide to generate our [¹⁷⁷Lu]Lu-DTPA-onartuzumab RLT agent. [¹⁷⁷Lu]Lu-DTPA-onartuzumab was administered at 9.25MBq (250μCi)/20μg in three fractions separated by three days in mice subcutaneously engrafted with BxPC3 (high cell-membrane Met) or MIA PaCa-2 (low cell-membrane Met). Primary endpoints were tumor response and overall survival. Results: Flow cytometry and cell-surface biotinylation studies showed that cell-membrane Met was significantly more abundant in BxPC3, Capan2, and Suit2 when compared with MIA PaCa-2 pancreatic tumor cells. Crizotinib and cabozantinib, TKIs with known activity against Met and other kinases, decreased PDAC cell line viability in vitro. The TKI with the lowest IC₅₀ for Met, capmatinib, had no activity in PDAC lines. No additive effect was detected on cell viability when Met-inhibition was combined with MEK1/2 inhibition. We observed selective tumor uptake of [⁸⁹Zr]Zr-DFO-onartuzumab in mice subcutaneously and orthotopically engrafted with PDAC lines containing high cell-surface levels of Met (BxPC3, Capan2, Suit2), but not in mice engrafted with low cell-surface levels of Met (MIA PaCa-2). Significant tumor growth delay and overall survival benefit were observed in both BxPC3 and MIA PaCa-2 engrafted animals treated with RLT when compared to controls, however, the benefit was more pronounced and more durable in the BxPC3 engrafted animals treated with [¹⁷⁷Lu]Lu-DTPA-onartuzumab RLT. Conclusions: Our findings demonstrate that while over-expression of Met is not predictive of Met-directed TKI response, immunoPET can detect Met over-expression in vivo and predicts for therapeutic response to Met-selective RLT. This phenomenon can be exploited for other Met-overexpressing tumor types specifically, and to any differentially overexpressed surface molecule more broadly.

Proteogenomic Network Analysis of Context-Specific KRAS Signaling in Mouse-to-Human Cross-Species Translation

The highest frequencies of KRAS mutations occur in colorectal carcinoma (CRC) and pancreatic ductal adenocarcinoma (PDAC). The ability to target downstream pathways mediating KRAS oncogenicity is limited by an incomplete understanding of the contextual cues modulating the signaling output of activated K-RAS. We performed mass spectrometry on mouse tissues expressing wild-type or mutant Kras to determine how tissue context and genetic background modulate oncogenic signaling. Mutant Kras dramatically altered the proteomes and phosphoproteomes of preneoplastic and neoplastic colons and pancreases in a context-specific manner. We developed an approach to statistically humanize the mouse networks with data from human cancer and identified genes within the humanized CRC and PDAC networks synthetically lethal with mutant KRAS. Our studies demonstrate the context-dependent plasticity of oncogenic signaling, identify non-canonical mediators of KRAS oncogenicity within the KRAS-regulated signaling network, and demonstrate how statistical integration of mouse and human datasets can reveal cross-species therapeutic insights.

Dose Optimization for Anticancer Drug Combinations: Maximizing Therapeutic Index via Clinical Exposure-Toxicity/Preclinical Exposure-Efficacy Modeling

PURPOSE

Recommended phase II dose (RP2D) determination for combination therapy regimens is a constrained optimization problem of maximizing antitumor activity within the constraint of clinical tolerability to provide a wide therapeutic index. A methodology for addressing this problem was developed and tested using clinical and preclinical data from combinations of the investigational drugs TAK-117, a PI3Kα inhibitor, and TAK-228, a TORC1/2 dual inhibitor.

EXPERIMENTAL DESIGN

Utilizing free fraction-corrected average concentrations, [Formula: see text] and [Formula: see text], which are the primary pharmacokinetic predictors of single-agent preclinical antitumor activity, a preclinical exposure-efficacy surface was characterized, allowing for nonlinear interactions between growth rate inhibition of the agents on a MDA-MB-361 cell line xenograft model. Logistic regression was used to generate an exposure-effect surface for [Formula: see text] and [Formula: see text] versus clinical toxicity outcomes [experiencing a dose-limiting toxicity (DLT)] in single-agent and combination dose-escalation studies. A maximum tolerated exposure curve was defined at which DLT probability was 25%; predicted antitumor activity along this curve was used to determine optimal RP2D.

RESULTS

The toxicity constraint curve determined from early clinical data predicted that any clinically tolerable combination was unlikely to result in greater antitumor activity than either single-agent TAK-117 or TAK-228 administered at their respective MTDs. Similar results were obtained with 10 other cell lines, with one agent or the other predicted to outperform the combination.

CONCLUSIONS

This methodology represents a general, principled way of evaluating and selecting optimal RP2D combinations in oncology. The methodology will be retested upon availability of clinical data from TAK-117/TAK-228 combination phase II studies.See related commentary by Mayawala et al., p. 6564.

Cabozantinib induces PUMA-dependent apoptosis in colon cancer cells via AKT/GSK-3β/NF-κB signaling pathway

Cabozantinib is a multi-kinase inhibitor targeting MET, AXL, and VEGFR2, and has been approved for use in multiple malignancies. The means by which Cabozantinib acts to target colorectal cancer (CRC) cells remains poorly understood, and we sought to investigate how this drug disrupts cell growth in CRC cells and how it interacts to enhance the efficacy of other chemotherapeutic agents. In this study, we found that Cabozantinib activated a p65-dependent signaling pathway in response to both inhibition of AKT and activation of glycogen synthase kinase 3β (GSK3β), leading to upregulation of PUMA in CRC cells regardless of p53 activity. PUMA upregulation facilitates CRC apoptosis in response to Cabozantinib, which also acts synergistically with the chemotherapeutic agents Cetuximab and 5-FU to induce robust apoptosis in a PUMA-dependent manner. Eliminating PUMA expression ablated this apoptosis induced by Cabozantinib in xenograft mouse model. Our findings revealed that Cabozantinib acts to drive CRC cells apoptosis via a PUMA-dependent mechanism, thus identifying PUMA expression as a potential predictor of Cabozantinib efficacy and a potential novel therapeutic target.

Clinical Trials Targeting the Stroma in Pancreatic Cancer: A Systematic Review and Meta-Analysis

The tumor microenvironment plays an important role in the initiation and progression of pancreatic adenocarcinoma (PDAC). In this systematic review, we provide an overview of clinical trials with stroma-targeting agents. We systematically searched MEDLINE/PubMed and the EMBASE database, using the PRISMA guidelines, for eligible clinical trials. In total, 2330 records were screened, from which we have included 106 articles. A meta-analysis could be performed on 51 articles which describe the targeting of the vascular endothelial growth factor (VEGF) pathway, and three articles which describe the targeting of hyaluronic acid. Anti-VEGF therapies did not show an increase in median overall survival (OS) with combined hazard ratios (HRs) of 1.01 (95% confidence interval (CI) 0.90-1.13). Treatment with hyaluronidase PEGPH20 showed promising results, but, thus far, only in combination with gemcitabine and nab-paclitaxel in selected patients with hyaluronic acid (HA)high tumors: An increase in median progression free survival (PFS) of 2.9 months, as well as a HR of 0.51 (95% CI 0.26-1.00). In conclusion, we found that anti-angiogenic therapies did not show an increased benefit in median OS or PFS in contrast to promising results with anti-hyaluronic acid treatment in combination with gemcitabine and nab-paclitaxel. The PEGPH20 clinical trials used patient selection to determine eligibility based on tumor biology, which underlines the importance to personalize treatment for pancreatic cancer patients.

Management of Adverse Events Associated with Cabozantinib Therapy in Renal Cell Carcinoma

Cabozantinib was recently approved for the treatment of advanced renal cell carcinoma (RCC) after treatment with vascular endothelial growth factor (VEGF)-targeted therapy. Cabozantinib is a multikinase inhibitor targeting VEGF receptor (VEGFR) 2, mesenchymal-epithelial transition receptor, and "anexelekto" receptor tyrosine kinase. A 60-mg daily dose led to improved overall survival and progression-free survival (PFS) versus everolimus in advanced RCC patients as a second- or later-line treatment in the METEOR trial. Improved PFS with cabozantinib versus sunitinib has also been demonstrated in the first-line setting in CABOSUN. However, cabozantinib, like other VEGFR inhibitors, is associated with toxicity that may affect the patient's quality of life. The most frequent adverse events (AEs) are diarrhea, fatigue, hypertension, hand-foot syndrome, weight loss, nausea, and stomatitis. This article summarizes the safety profile of cabozantinib in RCC patients and offers guidance for the management of these AEs. We discuss the underlying mechanisms of these AEs and, based on our experiences with cabozantinib and other multikinase inhibitors, we present approaches to manage toxicity. Prophylactic and therapeutic solutions are available to help with the management of toxicity associated with cabozantinib, and adequate interventions can ensure optimum adherence and maximize patient outcomes.

IMPLICATIONS FOR PRACTICE

Cabozantinib leads to improved survival outcomes in renal cell carcinoma patients compared with everolimus. However, management of the adverse event profile is crucial to achieve optimum adherence and outcomes with the use of cabozantinib. This review aims to provide appropriate guidance that will minimize the impact of adverse events and help to maximize the utility of this agent in patients with advanced renal cell carcinoma.

Pancreatic Cancer: Molecular Characterization, Clonal Evolution and Cancer Stem Cells

Pancreatic Ductal Adenocarcinoma (PDAC) is the fourth most common cause of cancer-related death and is the most lethal of common malignancies with a five-year survival rate of <10%. PDAC arises from different types of non-invasive precursor lesions: intraductal papillary mucinous neoplasms, mucinous cystic neoplasms and pancreatic intraepithelial neoplasia. The genetic landscape of PDAC is characterized by the presence of four frequently-mutated genes: KRAS, CDKN2A, TP53 and SMAD4. The development of mouse models of PDAC has greatly contributed to the understanding of the molecular and cellular mechanisms through which driver genes contribute to pancreatic cancer development. Particularly, oncogenic KRAS-driven genetically-engineered mouse models that phenotypically and genetically recapitulate human pancreatic cancer have clarified the mechanisms through which various mutated genes act in neoplasia induction and progression and have led to identifying the possible cellular origin of these neoplasias. Patient-derived xenografts are increasingly used for preclinical studies and for the development of personalized medicine strategies. The studies of the purification and characterization of pancreatic cancer stem cells have suggested that a minority cell population is responsible for initiation and maintenance of pancreatic adenocarcinomas. The study of these cells could contribute to the identification and clinical development of more efficacious drug treatments.

Pharmacotherapeutic Management of Pancreatic Ductal Adenocarcinoma: Current and Emerging Concepts

Pancreatic ductal adenocarcinoma is a devastating malignancy, which is the result of late diagnosis, aggressive disease, and a lack of effective treatment options. Thus, pancreatic ductal adenocarcinoma is projected to become the second leading cause of cancer-related death by 2030. This review summarizes recent developments of oncological therapy in the palliative setting of metastatic pancreatic ductal adenocarcinoma. It further compiles novel targets and therapeutic approaches as well as promising treatment combinations, which are presently in preclinical evaluation, covering several aspects of the hallmarks of cancer. Finally, challenges to the implementation of an individualized therapy approach in the context of precision medicine are discussed.