A Phase I study of intravenous PI3K inhibitor copanlisib in Japanese patients with advanced or refractory solid tumors

Phase Ib study of the oral PI3Kδ inhibitor linperlisib in patients with advanced solid tumors

BACKGROUND

Patients with advanced solid tumors have a suboptimal prognosis. This study investigated the safety and feasibility of linperlisib, a selective phosphatidylinositol 3-kinase delta isoform (PI3Kδ) inhibitor, for treating patients with advanced solid tumors.

METHODS

In this phase Ib, single-arm, open-label, multi-center clinical trial, patients with histologically confirmed advanced solid tumors from eight centers in China were enrolled to receive oral linperlisib (80 mg/day). The primary endpoint was safety.

RESULTS

Between August 2019 and June 2022, 94 patients were enrolled in the trial and received the study treatment. The most common (≥ 20%) treatment emergent adverse events (TEAEs) of all grades irrespective of causality were increased aspartate aminotransferase (AST) (26.6%), proteinuria (26.6%), decreased appetite (25.5%), increased alanine aminotransferase (ALT) (22.3%), weight loss (21.3%), and anemia (21.3%). The most common grade ≥ 3 TEAEs were diarrhea (4.3%), increased AST (3.2%), increased ALT (3.2%), neutropenia (3.2%), anemia (3.2%), increased blood alkaline phosphatase (3.2%). The objective response rate (ORR) was 1.1% (95% confidence interval [CI] 0.0-5.8), and the disease control rate (DCR) was 37.2% (95% CI 27.5-47.8). As of the data cutoff, the median follow-up time was 4.2 months (95% CI 2.8-6.9). The median progression-free survival (PFS) was 1.85 months (95% CI 1.79-1.88). The median overall survival (OS) was not reached.

CONCLUSION

Linperlisib showed an acceptable safety profile and preliminary clinical benefit in patients with a range of advanced solid tumors. Further studies of linperlisib safety and efficacy are warranted.

What Do German Molecular Tumor Boards Recommend in Patients with PIK3CA-Mutated Tumors? Launch and First Results from the German Transsectoral Molecular Tumor Board Exchange Platform Deutschland

INTRODUCTION

Comprehensive molecular tumor profiling is widely used in the management of patients with cancer. Molecular tumor boards devise treatment strategies based on testing results. In this setting, the Transsectoral Molecular Tumor Board exchange platform Deutschland (TEAM-D) aims to drive peer-to-peer exchange to connect experts in the field.

METHODS

During the first virtual TEAM-D meeting, participants from 16 German universities and 5 nonacademic institutions discussed five cases with PIK3CA hotspot mutations. Furthermore, an illustrative case vignette was presented.

RESULTS

Overall, German caregivers show restraint in administering off-label PIK3CA inhibitor and favor clinical trials in this setting.

CONCLUSION

In the setting of precision oncology, TEAM-D enables virtual case discussion across the different sectors of the German healthcare system. Based on the example of PIK3CA hotspot mutations, TEAM-D demonstrated the value of integrating knowledge from different healthcare professionals.

PI3K/Akt/mTOR Signaling Pathway as a Target for Colorectal Cancer Treatment

In the last decade, pathway-specific targeted therapy has revolutionized colorectal cancer (CRC) treatment strategies. This type of therapy targets a tumor-vulnerable spot formed primarily due to an alteration in an oncogene and/or a tumor suppressor gene. However, tumor heterogeneity in CRC frequently results in treatment resistance, underscoring the need to understand the molecular mechanisms involved in CRC for the development of novel targeted therapies. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of the rapamycin (PI3K/Akt/mTOR) signaling pathway axis is a major pathway altered in CRC. The aberrant activation of this pathway is associated with CRC initiation, progression, and metastasis and is critical for the development of drug resistance in CRC. Several drugs target PI3K/Akt/mTOR in clinical trials, alone or in combination, for the treatment of CRC. This review aims to provide an overview of the role of the PI3K/Akt/mTOR signaling pathway axis in driving CRC, existing PI3K/Akt/mTOR-targeted agents against CRC, their limitations, and future trends.

Copanlisib population pharmacokinetics from phase I-III studies and exposure-response relationships in combination with rituximab

Copanlisib dose selection was established under the maximum tolerated dose paradigm, and no dedicated dose-finding studies have investigated copanlisib dose selection when used in combination with rituximab. In CHRONOS-3, copanlisib plus rituximab demonstrated significantly improved progression-free survival versus placebo plus rituximab in patients with relapsed indolent non-Hodgkin lymphoma (iNHL). We conducted a comprehensive investigation of copanlisib population pharmacokinetics (PopPK) from a pooled analysis of 712 patients across nine copanlisib phase I-III studies and exposure-response (ER) relationships for efficacy and safety from the 1-year follow-up of CHRONOS-3. PopPK analyses examined the impact of demographic, laboratory, and comedication covariates on copanlisib between-patient PK variability. Individual static and time-varying exposure estimates were derived to investigate exposure-efficacy and exposure-safety relationships. Multivariate Cox proportional hazards and logistic regression analyses examined ER relationships with consideration of predefined potentially prognostic demographic-, laboratory-, and/or disease-related baseline covariates. Copanlisib PK were best described by a three-compartment model with first-order elimination. Individual identified covariates had modest effects on copanlisib PK and were generally in line with known copanlisib disposition properties. In CHRONOS-3, ER analyses showed a significant relationship between time-varying exposure estimates and progression-free survival, and no significant exposure-safety relationships. Thus, lower copanlisib doses may result in reduced efficacy but not necessarily improved safety or tolerability. These outcomes substantiate the current intermittent dosing regimen of copanlisib 60 mg on days 1, 8, and 15 of a 28-day cycle and support the observed clinical results of copanlisib in combination with rituximab in the iNHL population.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Safety and antitumor activity of copanlisib in Japanese patients with relapsed/refractory indolent non-Hodgkin lymphoma: a phase Ib/II study

The safety, efficacy, and pharmacokinetics of copanlisib were evaluated in this phase Ib/II study in Japanese patients with relapsed/refractory indolent non-Hodgkin lymphoma (NHL). The primary endpoint was safety at the recommended dose; efficacy endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival. In phase Ib, patients received copanlisib 45 mg intravenously on days 1, 8, and 15 of a 28-day cycle, and when tolerated, consecutive patients received copanlisib 60 mg. As no dose-limiting toxicities occurred at the 45 mg (n = 3) or 60 mg (n = 7) dose in phase Ib, the recommended dose for Japanese patients was determined to be 60 mg, and this dose was used in phase II (n = 15). Although all patients experienced at least one treatment-emergent adverse event (TEAE), with hyperglycemia being the most common AE, no AE-related deaths were reported. The ORR was 68.0% (17/25 patients), median PFS was 302 (95% CI 231-484) days, and the duration of response was 330 (range 65-659) days. The pharmacokinetic properties of copanlisib were similar between Japanese and non-Japanese patients. Overall, copanlisib 60 mg had an acceptable safety profile and showed promising antitumor activity in Japanese patients with relapsed/refractory indolent NHL.

Targeting the PI3K/AKT/mTOR and RAF/MEK/ERK pathways for cancer therapy

The PI3K/AKT/mTOR and RAF/MEK/ERK pathways are commonly activated by mutations and chromosomal translocation in vital targets. The PI3K/AKT/mTOR signaling pathway is dysregulated in nearly all kinds of neoplasms, with the component in this pathway alternations. RAF/MEK/ERK signaling cascades are used to conduct signaling from the cell surface to the nucleus to mediate gene expression, cell cycle processes and apoptosis. RAS, B-Raf, PI3K, and PTEN are frequent upstream alternative sites. These mutations resulted in activated cell growth and downregulated cell apoptosis. The two pathways interact with each other to participate in tumorigenesis. PTEN alterations suppress RAF/MEK/ERK pathway activity via AKT phosphorylation and RAS inhibition. Several inhibitors targeting major components of these two pathways have been supported by the FDA. Dozens of agents in these two pathways have attracted great attention and have been assessed in clinical trials. The combination of small molecular inhibitors with traditional regimens has also been explored. Furthermore, dual inhibitors provide new insight into antitumor activity. This review will further comprehensively describe the genetic alterations in normal patients and tumor patients and discuss the role of targeted inhibitors in malignant neoplasm therapy. We hope this review will promote a comprehensive understanding of the role of the PI3K/AKT/mTOR and RAF/MEK/ERK signaling pathways in facilitating tumors and will help direct drug selection for tumor therapy.

Co-administration of MDR1 and BCRP or EGFR/PI3K inhibitors overcomes lenvatinib resistance in hepatocellular carcinoma

Lenvatinib is the first-line treatment for hepatocellular carcinoma (HCC), the most common type of primary liver cancer; however, some patients become refractory to lenvatinib. The underlying mechanism of lenvatinib resistance (LR) in patients with advanced HCC remains unclear. We focused on exploring the potential mechanism of LR and novel treatments of lenvatinib-resistant HCC. In particular, we established a Huh7 LR cell line and performed in vitro, bioinformatic, and biochemical assays. Additionally, we used a Huh7-LR cell-derived xenograft mouse model to confirm the results in vivo. Following LR induction, multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP) transporters were markedly upregulated, and the epidermal growth factor receptor (EGFR), MEK/ERK, and PI3K/AKT pathways were activated. In vitro, the co-administration of elacridar, a dual MDR1 and BCRP inhibitor, with lenvatinib inhibited proliferation and induced apoptosis of LR cells. These effects might be due to inhibiting cancer stem-like cells (CSCs) properties, by decreasing colony formation and downregulating CD133, EpCAM, SOX-9, and c-Myc expression. Moreover, the co-administration of gefitinib, an EGFR inhibitor, with lenvatinib retarded proliferation and induced apoptosis of LR cells. These similar effects might be caused by the inhibition of EGFR-mediated MEK/ERK and PI3K/AKT pathway activation. In vivo, co-administration of lenvatinib with elacridar or gefitinib suppressed tumour growth and angiogenesis. Therefore, inhibiting MDR1 and BCRP transporters or targeting the EGFR/PI3K pathway might overcome LR in HCC. Notably, lenvatinib should be used to treat HCC after LR induction owing to its role in inhibiting tumour proliferation and angiogenesis. Our findings could help develop novel and effective treatment strategies for HCC.

Prospects of targeting PI3K/AKT/mTOR pathway in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has one of the worst prognoses among all malignancies. PI3K/AKT/mTOR signaling pathway, a main downstream effector of KRAS is involved in the regulation of key hallmarks of cancer. We here report that whole-genome analyses demonstrate the frequent involvement of aberrant activations of PI3K/AKT/mTOR pathway components in PDAC patients and critically evaluate preclinical and clinical evidence on the application of PI3K/AKT/mTOR pathway targeting agents. Combinations of these agents with chemotherapeutics or other targeted therapies, including the modulators of cyclin-dependent kinases, receptor tyrosine kinases and RAF/MEK/ERK pathway are also examined. Although human genetic studies and preclinical pharmacological investigations have provided strong evidence on the role of PI3K/AKT/mTOR pathway in PDAC, clinical studies in general have not been as promising. Patient stratification seems to be the key missing point and with the advent of biomarker-guided clinical trials, targeting PI3K/AKT/mTOR pathway could provide valuable assets for treatment of pancreatic cancer patients.

Tumor Biomarker Testing for Metastatic Colorectal Cancer: a Canadian Consensus Practice Guideline

The systemic therapy management of metastatic colorectal cancer (mCRC) has evolved from primarily cytotoxic chemotherapies to now include targeted agents given alone or in combination with chemotherapy, and immune checkpoint inhibitors. A better understanding of the pathogenesis and molecular drivers of colorectal cancer not only aided the development of novel targeted therapies but led to the discovery of tumor mutations which act as predictive biomarkers for therapeutic response. Mutational status of the KRAS gene became the first genomic biomarker to be established as part of standard of care molecular testing, where KRAS mutations within exons 2, 3, and 4 predict a lack of response to anti- epidermal growth factor receptor therapies. Since then, several other biomarkers have become relevant to inform mCRC treatment; however, there are no published Canadian guidelines which reflect the current standards for biomarker testing. This guideline was developed by a pan-Canadian advisory group to provide contemporary, evidence-based recommendations on the minimum acceptable standards for biomarker testing in mCRC, and to describe additional biomarkers for consideration.

Quantitative systems pharmacology model-based investigation of adverse gastrointestinal events associated with prolonged treatment with PI3-kinase inhibitors

Several PI3K inhibitors are in clinical development for the treatment of various forms of cancers, including pan-PI3K inhibitors targeting all four PI3K isoforms (α, β, γ, and δ), and isoform-selective inhibitors. Diarrhea and immune-mediated colitis are among the adverse events observed with PI3K inhibition which limits the maximal tolerated dose. A quantitative systems pharmacology model was developed to investigate PI3K-inhibitor-induced colitis. The effects of individual PI3K isoforms on relevant cellular pathways were incorporated into a mechanistic representation of mucosal inflammation. A virtual clinical population captures the observed clinical variability in the onset timing and rates of diarrhea and colitis for seven clinically tested PI3K inhibitors. Model-based analysis suggests that colitis development is governed by both the inhibition of PI3Kδ, which drives T cell differentiation and proliferation, and PI3Kα, which regulates epithelial barrier integrity. Specifically, when PI3Kα is inhibited below a given threshold, epithelial barrier dysfunction precipitates an exaggerated T effector response due to PI3Kδ-inhibition, leading to risk of diarrhea and colitis. This synergy explains why the lowest diarrhea and colitis rates are seen with the weakest PI3Kδ inhibition (alpelisib), and higher rates are seen with strong PI3Kδ inhibition if PI3Kα is even mildly inhibited (e.g., idelalisib), whereas strong PI3Kδ inhibition in the absence of PI3Kα inhibition does not result in high colitis rates (umbralisib). Thus, the model-based analysis suggests that PI3Kα and δ inhibition play unique but synergistic roles in driving colitis. Finally, we explore if and how dose-regimen might influence colitis rates for molecules that inhibit both PI3Kα and PI3Kδ.

A phase I pharmacokinetic study of copanlisib in Chinese patients with relapsed indolent non-Hodgkin lymphoma

PURPOSE

Copanlisib, a pan-PI3K inhibitor, has previously shown clinical efficacy and a tolerable safety profile in patients with indolent non-Hodgkin lymphoma. However, the pharmacokinetics, safety, tolerability, and efficacy of copanlisib in Chinese patients have not been reported.

METHODS

This was a single-arm, open-label, phase I study of copanlisib in Chinese patients with relapsed or refractory indolent non-Hodgkin lymphoma (iNHL). Patients received a single intravenous 60 mg infusion of copanlisib over 1 h on days 1, 8, and 15 of a 28-day cycle, with 1 week of rest. Safety was monitored throughout the study, and plasma copanlisib levels were measured for pharmacokinetic analysis. Tumor response was determined by independent central radiologic review.

RESULTS

Sixteen patients were enrolled and 13 were treated with 60 mg of copanlisib for a median of 15.0 weeks. With a C_max of 566 μg/L and a AUC (0-24) of 1880 μg·h/L following single intravenous infusion, the pharmacokinetic parameters of copanlisib were consistent with that in previous studies, and no accumulation in plasma was observed. Treatment-emergent adverse events were reported for all 13 patients, the most common of which were hyperglycemia (100.0%), hypertension (76.9%), decreased neutrophil count (76.9%), and decreased white blood cell count (69.2%). Seven out of 12 evaluated patients achieved partial response, resulting in an overall response rate of 58.3% CONCLUSIONS: Copanlisib was well tolerated in Chinese patients with relapsed or refractory iNHL at the dose of 60 mg and demonstrated encouraging disease control, thus warranting further clinical investigation.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03498430 (April 13, 2018).

Personalizing first-line treatment in advanced colorectal cancer: Present status and future perspectives

BACKGROUND

Colorectal cancer is one of the most frequent neoplasms worldwide, and the majority of patients are diagnosed in advanced stages. Metastatic colorectal cancer (mCRC) harbors several mutations with different prognostic and predictive values; KRAS, NRAS, and BRAF mutations are the best known. Indeed, RAS and BRAF molecular status are associated with a different response to monoclonal antibodies (Anti-epidermal growth factor receptor and anti-vascular endothelial growth factor receptor agents), which are usually added to chemotherapy in first-line, and thus allow to select the optimal therapy for patients with mCRC. Furthermore, sidedness is an important predictive and prognostic factor in mCRC, which is explained by the different molecular profile of left and right-sided tumors. Recently, microsatellite instability-high has emerged as a predictive factor of response and survival from immune checkpoint inhibitors in mCRC. Finally, several other alterations have been described in lower frequencies, such as human epidermal growth factor receptor-2 overexpression/amplification, PIK3CA pathway alterations, phosphatase and tension homolog loss, and hepatocyte growth factor/mesenchymal-epithelial transition factor pathway dysregulation, with several targeted therapies already demonstrating activity or being tested in currently ongoing clinical trials.

AIM

To review the importance of studying the predictive and prognostic roles of the molecular profile of mCRC, the changes occurred in recent years and how they would potentially change in the near future, to guide physicians in treatment decisions.

RELEVANCE FOR PATIENTS

Today, several different therapeutic options can be offered to patients in the first-line setting of mCRC. Therapies at present approved or under investigation in clinical trials will be thoroughly reviewed, with special emphasis on the molecular rationale behind them. Understanding the molecular status, resistance mechanisms and potential new druggable targets may allow physicians to choose the best therapeutic option in the first-line mCRC.

Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer

Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.

PI3K Inhibitors in Cancer: Clinical Implications and Adverse Effects

The phospatidylinositol-3 kinase (PI3K) pathway is a crucial intracellular signaling pathway which is mutated or amplified in a wide variety of cancers including breast, gastric, ovarian, colorectal, prostate, glioblastoma and endometrial cancers. PI3K signaling plays an important role in cancer cell survival, angiogenesis and metastasis, making it a promising therapeutic target. There are several ongoing and completed clinical trials involving PI3K inhibitors (pan, isoform-specific and dual PI3K/mTOR) with the goal to find efficient PI3K inhibitors that could overcome resistance to current therapies. This review focuses on the current landscape of various PI3K inhibitors either as monotherapy or in combination therapies and the treatment outcomes involved in various phases of clinical trials in different cancer types. There is a discussion of the drug-related toxicities, challenges associated with these PI3K inhibitors and the adverse events leading to treatment failure. In addition, novel PI3K drugs that have potential to be translated in the clinic are highlighted.

Cardiovascular toxicity of PI3Kα inhibitors

The phosphoinositide 3-kinases (PI3Ks) are a family of intracellular lipid kinases that phosphorylate the 3'-hydroxyl group of inositol membrane lipids, resulting in the production of phosphatidylinositol 3,4,5-trisphosphate from phosphatidylinositol 4,5-bisphosphate. This results in downstream effects, including cell growth, proliferation, and migration. The heart expresses three PI3K class I enzyme isoforms (α, β, and γ), and these enzymes play a role in cardiac cellular survival, myocardial hypertrophy, myocardial contractility, excitation, and mechanotransduction. The PI3K pathway is associated with various disease processes but is particularly important to human cancers since many gain-of-function mutations in this pathway occur in various cancers. Despite the development, testing, and regulatory approval of PI3K inhibitors in recent years, there are still significant challenges when creating and utilizing these drugs, including concerns of adverse effects on the heart. There is a growing body of evidence from preclinical studies revealing that PI3Ks play a crucial cardioprotective role, and thus inhibition of this pathway could lead to cardiac dysfunction, electrical remodeling, vascular damage, and ultimately, cardiovascular disease. This review will focus on PI3Kα, including the mechanisms underlying the adverse cardiovascular effects resulting from PI3Kα inhibition and the potential clinical implications of treating patients with these drugs, such as increased arrhythmia burden, biventricular cardiac dysfunction, and impaired recovery from cardiotoxicity. Recommendations for future directions for preclinical and clinical work are made, highlighting the possible role of PI3Kα inhibition in the progression of cancer-related cachexia and female sex and pre-existing comorbidities as independent risk factors for cardiac abnormalities after cancer treatment.

Copanlisib in the Treatment of Relapsed Follicular Lymphoma: Utility and Experience from the Clinic

The phosphatidylinositol-3-kinase (PI3K) pathway is ubiquitous to multiple cellular processes and is intricately implicated in lymphomagenesis. The development of PI3K inhibitors has broadened treatment options for relapsed and/or refractory follicular lymphoma (FL) and currently three PI3K inhibitors have been approved in the third-line setting for FL, including idelalisib (oral), duvelisib (oral), and copanlisib (intravenous), with other agents under investigation. In this review, we discuss the clinical advance of copanlisib through preclinical to Phase III trials, its unique cellular targets and side effect profile that have poised it as a safer and equally efficacious option when compared to the older-generation oral PI3Kis, and its utility to the clinician as part of the therapeutic armamentarium for relapsed and/or refractory FL.

Hypertension and QT interval prolongation associated with targeted systemic cancer therapies

Objective

To summarize the proposed mechanisms behind hypertension and QT interval prolongation associated with use of targeted systemic cancer therapies and provide recommendations for monitoring or managing these toxicities.

Summary

The cardiotoxic effects of targeted systemic cancer therapies represents a new paradigm of cancer treatment associated cardiovascular adverse events. National guidelines regarding optimal monitoring and management strategies for hypertension and QT interval prolongation associated with use of these therapies are lacking. While the pathophysiological drivers of hypertension due to targeted systemic cancer therapies differ by class of targeted therapy, general management strategies do not. Routine blood pressure monitoring throughout the duration of therapy is recommended for all agents. Patients who experience hypertension often can be treated with the addition or modification of antihypertensive therapies. Uncontrolled hypertension despite optimal medical management may require dose modifications or discontinuation of the targeted systemic cancer therapy. Electrocardiogram monitoring is recommended for patients who receive targeted therapies that may prolong the QT interval. Minimizing or managing drug interactions with other QT prolonging medications is recommended in addition to ensuring adequate electrolyte supplementation. Dose modifications or discontinuation of the targeted systemic therapy may be necessary for patients who experience QT interval prolongation.

Conclusions

Appropriate cardiovascular monitoring and timely management of treatment-emergent toxicities can optimize therapy for patients receiving targeted systemic cancer therapies associated with a risk of drug-induced hypertension or QT interval prolongation.

PI3Kα in cardioprotection: Cytoskeleton, late Na+ current, and mechanism of arrhythmias

PI 3-kinase α (PI3Kα) is a lipid kinase that converts phosphatidylinositol-4,5-bisphosphate (PIP2) to phosphatidylinositol-3,4,5-triphosphate (PIP3). PI3Kα regulates a variety of cellular processes such as nutrient sensing, cell cycle, migration, and others. Heightened activity of PI3Kα in many types of cancer made it a prime oncology drug target, but also raises concerns of possible adverse effects on the heart. Indeed, recent advances in preclinical models demonstrate an important role of PI3Kα in the control of cytoskeletal integrity, Na⁺ channel activity, cardioprotection, and prevention of arrhythmias.

Cardio-Oncology: Vascular and Metabolic Perspectives: A Scientific Statement From the American Heart Association

Cardio-oncology has organically developed as a new discipline within cardiovascular medicine as a result of the cardiac and vascular adverse sequelae of the major advances in cancer treatment. Patients with cancer and cancer survivors are at increased risk of vascular disease for a number of reasons. First, many new cancer therapies, including several targeted therapies, are associated with vascular and metabolic complications. Second, cancer itself serves as a risk factor for vascular disease, especially by increasing the risk for thromboembolic events. Finally, recent data suggest that common modifiable and genetic risk factors predispose to both malignancies and cardiovascular disease. Vascular complications in patients with cancer represent a new challenge for the clinician and a new frontier for research and investigation. Indeed, vascular sequelae of novel targeted therapies may provide insights into vascular signaling in humans. Clinically, emerging challenges are best addressed by a multidisciplinary approach in which cardiovascular medicine specialists and vascular biologists work closely with oncologists in the care of patients with cancer and cancer survivors. This novel approach realizes the goal of providing superior care through the creation of cardio-oncology consultative services and the training of a new generation of cardiovascular specialists with a broad understanding of cancer treatments.

Targeted therapies for non-HPV-related head and neck cancer: challenges and opportunities in the context of predictive, preventive, and personalized medicine

Head and neck squamous cell carcinoma (HNSCC) develops in the mucosal lining of the upper aerodigestive tract, principally as a result of exposure to carcinogens present in tobacco products and alcohol, with oncogenic papillomaviruses also being recognized as etiological agents in a limited proportion of cases. As such, there is considerable scope for prevention of disease development and progression. However, despite multimodal approaches to treatment, tumor recurrence and metastatic disease are common problems, and clinical outcome is unsatisfactory. As our understanding of the genetics and biochemical aberrations in HNSCC has improved, so the development and use of molecularly targeted drugs to combat the disease have come to the fore. In this article, we review molecular mechanisms that alter signal transduction downstream of the epidermal growth factor receptor (EGFR) as well as those that perturb orderly cell cycle progression, such as p53 mutation, cyclin overexpression, and loss of cyclin-dependent kinase inhibitor function. We outline some of the tactics that have been employed to combat the altered biochemistry. These include blockade of the EGFR using humanized monoclonal antibodies such as cetuximab and small molecule tyrosine kinase inhibitors (TKIs) such as erlotinib/gefitinib and subsequent generations of TKIs, restoration of p53 function using MIRA compounds, and inhibition of cyclin-dependent kinase and aurora kinase activity using drugs such as palbociclib and alisertib. Knowledge of the underlying molecular mechanisms may be utilizable in order to predict disease behavior and tailor therapeutic interventions in a more personalized approach to improve clinical response. Use of liquid biopsy, omics platforms, and salivary diagnostics hold promise in this regard.

The PI3K inhibitor copanlisib synergizes with sorafenib to induce cell death in hepatocellular carcinoma

Sorafenib, a multikinase inhibitor targeting the Ras/Raf/MAPK (mitogen-activated protein kinase) and vascular endothelial growth factor signaling pathways is an established treatment option for patients with advanced-stage hepatocellular carcinoma (HCC); however, despite its clinical benefit, chemoresistance and disease progression eventually occur almost invariably during treatment. Activation of the PI3K/AKT (phosphatidylinositol-3-kinase/serine/threonine kinase) pathway plays a role in the pathogenesis of HCC and may contribute to determine resistance to sorafenib. We thus evaluated in vitro the effects of the combination of sorafenib and copanlisib, a PI3K inhibitor recently approved for clinical use. The effects of copanlisib alone and in combination with sorafenib were assessed in several HCC cell lines by proliferation and colony formation assays, fluorescence-activated cell sorting analyses, and western blot. In addition, sorafenib-resistant cell clones were used. Copanlisib strongly reduced cell viability and colony formation in different native and sorafenib-resistant HCC cell lines by affecting cyclin D1/CDK4/6 signaling and causing cell cycle arrest. Elevation of phosphorylated (p)-AKT was observed upon incubation with sorafenib and was consistently found in six different unstimulated sorafenib-resistant cell clones. Copanlisib counteracted sorafenib-induced phosphorylation of p-AKT and synergistically potentiated its antineoplastic effect. In summary, copanlisib shows potent anticancer activity as a single agent and acts synergistically in combination with sorafenib in human HCC. Combination of sorafenib with copanlisib represents a rational potential therapeutic option for advanced HCC.

Copanlisib: An Intravenous Phosphatidylinositol 3-Kinase (PI3K) Inhibitor for the Treatment of Relapsed Follicular Lymphoma

Objective: To review the mechanism of action, clinical efficacy, safety, dosage, administration, and role of copanlisib in the treatment of relapsed follicular lymphoma (FL). Data Sources: Sources of information were identified through searches of PubMed (August 2014 to January 2019) using the key terms copanlisib, Aliqopa, PI3K inhibitor, and BAY 80-6946. Unpublished abstract information was obtained from the American Society of Clinical Oncology. Study Selection and Data Extraction: Review articles and studies in the English language evaluating the pharmacology, efficacy, and safety of copanlisib were included. Data Synthesis: Copanlisib is the first intravenous phosphatidylinositol 3-kinase (PI3K) inhibitor approved for the treatment of relapsed FL in patients who have received at least 2 prior systemic therapies. The safety and efficacy of copanlisib has been studied in the multicenter, single-arm, phase II CHRONOS-1 study. The results reported for FL patients were an objective response rate of 59%, a complete response of 14%, median duration of response of 22.6 months, and median progression-free survival of 11.2 months. The most common adverse events reported were hyperglycemia and hypertension, which were infusion related and transient. Relevance to Patient Care and Clinical Practice: Copanlisib is unique in that it is a pan-class I PI3K inhibitor with preferential inhibitory activity against the PI3K-α and PI3K-δ isoforms. It has a more favorable safety profile than the other agents in its class with no late-onset toxicities. Conclusions: Copanlisib provides an alternative option for patients with relapsed FL. It is safe and effective and has an acceptable toxicity profile.

Targeting PI3K in cancer: mechanisms and advances in clinical trials

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is one of the most important intracellular pathways, which can be considered as a master regulator for cancer. Enormous efforts have been dedicated to the development of drugs targeting PI3K signaling, many of which are currently employed in clinical trials evaluation, and it is becoming increasingly clear that PI3K inhibitors are effective in inhibiting tumor progression. PI3K inhibitors are subdivided into dual PI3K/mTOR inhibitors, pan-PI3K inhibitors and isoform-specific inhibitors. In this review, we performed a critical review to summarize the role of the PI3K pathway in tumor development, recent PI3K inhibitors development based on clinical trials, and the mechanisms of resistance to PI3K inhibition.

Spotlight on copanlisib and its potential in the treatment of relapsed/refractory follicular lymphoma: evidence to date

The importance of the phosphatidylinositol-3-kinase (PI3K) pathway in cell survival and proliferation has made it an attractive target in cancer therapy. The development of small molecule inhibitors for the PI3K pathway continues to provide treatment alternatives across a range of malignancy types. Several agents, including idelalisib, copanlisib and duvelisib, not only inhibit the PI3K pathway, but also have effects on associated mechanisms including the ATK and mTOR pathways. The advent of PI3K-specific small molecular inhibitors has led to increased efficacy with avoidance of an excessive toxicity profile. Key enzymes of the PI3K pathway exhibit differing expression in tissue types and roles in tumor pathogenesis. Copanlisib (BAY 80-6946) is a pan-specific PI3K small molecule inhibitor for four key isoforms with increased activity against PI3Kα and PI3Kδ, both important in B-cell malignancies. Follicular lymphoma is one of the most common indolent B-cell non-Hodgkin lymphomas worldwide. Follicular lymphoma like other indolent B-cell non-Hodgkin lymphomas is beleaguered by high relapse rates and the need for subsequent therapy options. Based on efficacy and a limited toxicity profile, copanlisib received accelerated US Food and Drug Administration approval for the treatment of adult patients with relapsed follicular lymphoma following two lines of therapy. Here, we review the development of copanlisib and the role of this agent in the treatment of follicular lymphoma.

Cross Talk Networks of Mammalian Target of Rapamycin Signaling With the Ubiquitin Proteasome System and Their Clinical Implications in Multiple Myeloma

Multiple myeloma (MM) is the second most common hematological malignancy and results from the clonal amplification of plasma cells. Despite recent advances in treatment, MM remains incurable with a median survival time of only 5-6years, thus necessitating further insights into MM biology and exploitation of novel therapeutic approaches. Both the ubiquitin proteasome system (UPS) and the PI3K/Akt/mTOR signaling pathways have been implicated in the pathogenesis, and treatment of MM and different lines of evidence suggest a close cross talk between these central cell-regulatory signaling networks. In this review, we outline the interplay between the UPS and mTOR pathways and discuss their implications for the pathophysiology and therapy of MM.

Copanlisib: First Global Approval

Bayer are developing copanlisib (Aliqopa™)-a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor-as a treatment for various haematological and solid malignancies. The US FDA has granted copanlisib accelerated approval for the treatment of adults with relapsed follicular lymphoma who have received at least two prior systemic therapies based on the results of a phase II trial. Phase III trials are underway evaluating copanlisib as treatment for relapsed/refractory diffuse large B-cell lymphoma and in combination with rituximab or rituximab-based chemotherapy or standard immunochemotherapy in patients with relapsed indolent B-cell non-Hodgkin's lymphoma. Phase I/II studies are underway in relapsed or refractory peripheral T-cell or NK/T-cell lymphoma, advanced cholangiocarcinoma, hormone receptor-positive HER2-negative stage I-IV breast cancer, HER2-positive breast cancer and recurrent and/or metastatic head and neck squamous cell carcinomas harbouring a PI3KCA mutation/amplification and/or a PTEN loss. This article summarizes the milestones in the development of copanlisib leading to this first approval for relapsed follicular lymphoma.

Targeting phosphoinositide 3-kinase (PI3K) in head and neck squamous cell carcinoma (HNSCC)

The landscape of head and neck squamous cell carcinoma (HNSCC) has been changing rapidly due to growing proportion of HPV-related disease and development of new therapeutic agents. At the same time, there has been a constant need for individually tailored treatment based on genetic biomarkers in order to optimize patient survival and alleviate treatment-related toxicities. In this regard, aberrations of PI3K pathway have important clinical implications in the treatment of HNSCC. They frequently constitute ‘gain of function’ mutations which trigger oncogenesis, and PI3K mutations can also lead to emergence of drug resistance after treatment with EGFR inhibitors. In this article, we review PI3K pathway as a target of treatment for HNSCC and summarize PI3K/mTOR inhibitors that are currently under clinical trials. In light of recent advancement of immune checkpoint inhibitors, consideration of PI3K inhibitors as potential immune modulators is also suggested.

Phase I study of taselisib in Japanese patients with advanced solid tumors or hormone receptor-positive advanced breast cancer

Taselisib is a potent and selective phosphatidylinositide 3-kinase (PI3K) inhibitor. The present article reports the first study of taselisib administration in Japanese patients. The aim of this 2-stage, phase I, multicenter, open-label, dose-escalation study was to evaluate the safety, pharmacokinetics, and preliminary efficacy of taselisib as monotherapy in Japanese patients with advanced solid tumors (stage 1), and as part of combination therapy in Japanese patients with hormone receptor (HR)-positive locally advanced or recurrent breast cancer (stage 2). In stage 1, oral taselisib tablets 2, 4, and 6 mg/d were given in 28-day cycles. In stage 2, successive cohorts of patients received oral taselisib tablets (2 or 4 mg/d) with i.m. fulvestrant 500 mg. Nine and 6 patients were enrolled in stage 1 and stage 2, respectively. Taselisib was well tolerated. No dose-limiting toxicities were experienced in any cohort of patients and no deaths were observed. The most common treatment-related adverse events in stage 1 and stage 2, respectively, were rash (55.6%, 66.7%), diarrhea (44.4%, 66.7%), and stomatitis (44.4%, 66.7%). Taselisib was rapidly absorbed after dosage; its half-life was 12.9-32.0 hours in stage 1 and 16.1-26.5 hours in stage 2. Two patients achieved partial response (PR), 5 patients had stable disease (SD) and 2 patients had progressive disease (PD) in stage 1, and 1 patient had PR and 3 patients had SD in stage 2. All patients with PR were positive for PIK3CA gene mutations. These preliminary data suggest that taselisib may be effective in patients with PIK3CA-mutated solid tumors or HR-positive advanced breast cancer.

Development of a personalized therapeutic strategy for ERBB-gene-mutated cancers

Background:

The application of genomic technologies to patient tumor samples identified groups of signaling pathways which acquire activating mutations. Some cancers are dependent on these mutations and the aberrant proteins resulting from these mutations can be targeted by novel drugs which can eradicate the cancer.

Methods:

We used www.cbioportal.org to determine the frequency of ERBB mutations in solid tumors. We then determined the sensitivity of a panel of cell lines to clinically available PI3K inhibitors. Using proliferation and apoptosis assays as well as functional interrogation with reverse phase protein arrays we demonstrated the impact of targeting ERBB-mutant cancers with the combination of a PI3K inhibitor and the pan-HER family inhibitor afatinib.

Results:

In over 14,000 patients we found that 12% of their tumors have an ERBB family gene mutation (EGFR, ERBB2, ERBB3 and ERBB4). In cancers not commonly associated with HER family protein overexpression, such as ovarian, endometrial, melanoma and head and neck cancers (n = 2116), we found that ERBB family mutations are enriched, occurring at rates from 14% to 34% and commonly co-occur with PIK3CA mutations. Importantly, we demonstrate that ERBB family mutant cancers are sensitive to treatment with PI3K inhibitors. Finally we show that the combination of afatinib and copanlisib represents a novel therapeutic strategy for patients whose cancers harbor both ERBB family and PIK3CA mutation.

Conclusions:

We demonstrate that ERBB family mutations are common in cancers not associated with overexpression or amplification of HER family proteins. These ERBB family mutant cancers are sensitive to treatment with PI3K inhibitors, and when combined with pan-HER inhibitors have synergistic antiproliferative effects.

SGK1 Is a Critical Component of an AKT-Independent Pathway Essential for PI3K-Mediated Tumor Development and Maintenance

Activation of the PI3K-AKT signaling cascade is a common critical event during malignant transformation. In this study, we used thyroid gland epithelial cells and a series of genetically engineered mouse strains as model systems to demonstrate that, although necessary, AKT activation is not sufficient for PI3K-driven transformation. Instead, transformation requires the activity of the PDK1-regulated AGC family of protein kinases. In particular, SGK1 was found to be essential for proliferation and survival of thyroid cancer cells harboring PI3K-activating mutations. Notably, cotargeting SGK1 and AKT resulted in significantly higher growth suppression than inhibiting either PI3K or AKT alone. Overall, these findings underscore the clinical relevance of AKT-independent pathways in tumors driven by genetic lesions targeting the PI3K cascade. Cancer Res; 77(24); 6914-26. ©2017 AACR.

Novel DNA targeted therapies for head and neck cancers: clinical potential and biomarkers

Head and neck squamous cell carcinoma is the sixth most common cancer worldwide and despite advances in treatment over the last years, there is still a relapse rate of 50%. New therapeutic agents are awaited to increase the survival of patients. DNA repair targeted agents in combination with standard DNA damaging therapies are a recent evolution in cancer treatment. These agents focus on the DNA damage repair pathways in cancer cells, which are often involved in therapeutic resistance. Interesting targets to overcome these cancer defense mechanisms are: PARP, DNA-PK, PI3K, ATM, ATR, CHK1/2, and WEE1 inhibitors. The application of DNA targeted agents in head and neck squamous cell cancer showed promising preclinical results which are translated to multiple ongoing clinical trials, although no FDA approval has emerged yet. Biomarkers are necessary to select the patients that can benefit the most from this treatment, although adequate biomarkers are limited and validation is needed to predict therapeutic response.