Phase I safety, pharmacokinetic, and pharmacodynamic study of SAR245408 (XL147), an oral pan-class I PI3K inhibitor, in patients with advanced solid tumors

Targeting the RAS upstream and downstream signaling pathway for cancer treatment

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

Medication-Induced Hyperglycemia and Diabetes Mellitus: A Review of Current Literature and Practical Management Strategies

With the increasing global incidence of diabetes mellitus, physicians may encounter more patients with acute and chronic complications of medication-induced hyperglycemia and diabetes. Moreover, medication-induced diabetes may be an important contributing factor to the high rates of diabetes, and recognizing its impact and risk is a critical step in curtailing its effect on the global population. It has long been recognized that multiple classes of medications are associated with hyperglycemia through various mechanisms, and the ability to foresee this and implement adequate management strategies are important. Moreover, different antihyperglycemic medications are better suited to combat the hyperglycemia encountered with different classes of medications, so it is critical that physicians can recognize which agents should be used, and which medications to avoid in certain types of medication-induced hyperglycemia. In this review, we will discuss the evidence behind the main classes of medications that cause hyperglycemia, their mechanism of action, specific agents that are associated with worsened glycemic control, and, most importantly, management strategies that are tailored to each specific class.

Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions

The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.

Current perspectives of KRAS in non-small cell lung cancer

NSCLC has a diverse genomic background with mutations in key proto-oncogenic drivers including Kirsten rat sarcoma (KRAS) and epidermal growth factor receptor (EGFR). Roughly 40% of adenocarcinoma harbor Kras activating mutations regardless of smoking history. Most KRAS mutations are located at G12, which include G12C (roughly 40%), G12V (roughly 20%), and G12D (roughly 15%). KRAS mutated NSCLC have higher tumor mutational burden and some have increased PD-1 expression, which has resulted in better responses to immunotherapy than other oncogenes. While initial treatment for metastatic NSCLC still relies on chemo-immunotherapy, directly targeting KRAS has proven to be efficacious in treating patients with KRAS mutated metastatic NSCLC. To date, two G12C inhibitors have been FDA-approved, namely sotorasib and adagrasib. In this review, we summarize the different drug combinations used to target KRAS G12c, upcoming G12D inhibitors and novel therapies targeting KRAS.

Emerging Therapies in Kirsten Rat Sarcoma Virus (+) Non-Small-Cell Lung Cancer

Kirsten rat sarcoma virus (KRAS) is the most frequently found oncogene in human cancers, including non-small-cell lung cancer (NSCLC). For many years, KRAS was considered "undruggable" due to its structure and difficult targeting. However, the discovery of the switch II region in the KRAS-G12C-mutated protein has changed the therapeutic landscape with the design and development of novel direct KRAS-G12C inhibitors. Sotorasib and adagrasib are FDA-approved targeted agents for pre-treated patients with KRAS-G12C-mutated NSCLC. Despite promising results, the efficacy of these novel inhibitors is limited by mechanisms of resistance. Ongoing studies are evaluating combination strategies for overcoming resistance. In this review, we summarize the biology of the KRAS protein and the characteristics of KRAS mutations. We then present current and emerging therapeutic approaches for targeting KRAS mutation subtypes intending to provide individualized treatment for lung cancer harboring this challenging driver mutation.

Inhibitors of phosphoinositide 3-kinase (PI3K) and phosphoinositide 3-kinase-related protein kinase family (PIKK)

Phosphoinositide 3-kinases (PI3K) and phosphoinositide 3-kinase-related protein kinases (PIKK) are two structurally related families of kinases that play vital roles in cell growth and DNA damage repair. Dysfunction of PIKK members and aberrant stimulation of the PI3K/AKT/mTOR signalling pathway are linked to a plethora of diseases including cancer. In recent decades, numerous inhibitors related to the PI3K/AKT/mTOR signalling have made great strides in cancer treatment, like copanlisib and sirolimus. Notably, most of the PIKK inhibitors (such as VX-970 and M3814) related to DNA damage response have also shown good efficacy in clinical trials. However, these drugs still require a suitable combination therapy to overcome drug resistance or improve antitumor activity. Based on the aforementioned facts, we summarised the efficacy of PIKK, PI3K, and AKT inhibitors in the therapy of human malignancies and the resistance mechanisms of targeted therapy, in order to provide deeper insights into cancer treatment.

Design and Synthesis of 1,3,5-Triazines or Pyrimidines Containing Dithiocarbamate Moiety as PI3Kα Selective Inhibitors

Recent studies have shown that phosphoinositide 3-kinase (PI3K) plays a vital role in cell division, and it has become a therapeutic target for many cancers. In this paper, some new 1,3,5-triazine or pyrimidine skeleton derivatives containing dithiocarbamate were designed and synthesized based on the reasonable drug design strategy from the previously effective compound 2-(difluoromethyl)-1-[4,6-di(4-morpholinyl)-1,3,5-triazin-2-yl]-1H-benzimidazole (ZSTK-474), in order to get effective selective PI3Kα inhibitors that have not been reported in the literature. In addition, the inhibitory activities of these compounds on PI3Kα and two tumor cell lines in vitro (HCT-116, U87-MG) were evaluated. The representative compound 13 showed a half-maximal inhibitory concentration (IC50) value of 1.2 nM for PI3Kα and an exciting kinase selectivity. Compound 13 displayed strong efficacy in HCT-116 and U87-MG cell lines with IC50 values of 0.83 and 1.25 μM, respectively. In addition, compound 13 induced obvious tumor regression in the U87-MG cell line xenografts mouse model, with no obvious signs of toxicity after intraperitoneal injection at a dose of 40 mg/kg. Compound 13 can be an effective selective inhibitor of PI3Kα, and it provides patients with an opportunity to avoid the side effects related to the wider inhibition of the class I PI3K family.

Pomegranate-specific natural compounds as onco-preventive and onco-therapeutic compounds: Comparison with conventional drugs acting on the same molecular mechanisms

Pomegranate, scientifically known as Punica granatum, has been a traditional medicinal remedy since ancient times. Research findings have shown that using pomegranate extracts can positively affect a variety of signaling pathways, including those involved in angiogenesis, inflammation, hyperproliferation, cellular transformation, the beginning stages of tumorigenesis, and lastly, a reduction in the final stages of metastasis and tumorigenesis. This is due to the fact that pomegranate extracts are rich in polyphenols, which are known to inhibit the activity of certain signaling pathways. In the United States, cancer is the second biggest cause of death after heart disease. The number of fatalities caused by cancer in the United States escalates yearly. Altering one's diet, getting involved in regular physical activity, and sustaining a healthy body weight are three easy steps an individual may follow to lower their cancer risk. Simply garnishing one's diet with vegetables and fruits has the potential to avert at least 20% of all cancer diagnoses and around 200,000 deaths caused by cancer each year. Vegetables, fruits, and other dietary constituents, such as minerals and phytochemicals, are currently being researched for their potential to prevent cancer. It is being done because they are safe, have minimal toxicity, possess antioxidant properties, and are universally accepted as dietary supplements. Ancient civilizations used the fruit of pomegranate (Punica granatum L.) to prevent and cure a number of diseases. The anti-tumorigenic, anti-inflammatory and anti-proliferative qualities of pomegranate have been shown in studies with the fruit, juice, extract, and oil of the pomegranate. Pomegranate has the capacity to affect several signaling pathways, which implies that it may have the potential to be employed not only as a chemopreventive agent but also as a chemotherapeutic drug. This article elaborates on some recent preclinical and clinical research which shows that pomegranate seems to have a role in the prevention and treatment of a number of cancers, including but not limited to breast, bladder, skin, prostate, colon, and lung cancer, among others.

Driver mutation characteristics of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) in advanced non-small cell lung cancer

OBJECTIVES

The identification and targeting of actionable genomic alterations (AGA) have revolutionized the treatment of cancer in general and mostly for non-small cell lung cancer (NSCLC). We investigated whether in NSCLC patients PIK3CA mutations are actionable.

MATERIALS AND METHODS

Chart review was performed of advanced NSCLC patients. PIK3CA mutated patients were analyzed as two groups: Group A: without any non-PIK3CA established AGA; Group B: with coexisting AGA. Group A was compared to a cohort of non-PIK3CA patients (group C), using t-test and chi-square. To evaluate the impact of PIK3CA mutation on outcome, we compared Group A survival to age/sex/histology matched cohort of non-PIK3CA mutated patients (group D) by Kaplan-Meier method. A patient with a PIK3CA mutation was treated with a PI3Ka-isoform selective inhibitor BYL719 (Alpelisib).

RESULTS

Of a cohort of 1377 patients, 57 are PIK3CA mutated (4.1%). Group A: n-22, group B: n-35. Group A median age is 76 years, 16 (72.7%) men, 10 (45.5%) squamous, 4 (18.2%) never smokers. Two never-smoker female adenocarcinoma patients had solitary PIK3CA mutation. One of them was treated with a PI3Ka-isoform selective inhibitor BYL719 (Alpelisib), with rapid clinical and partial radiological improvement. Group B, compared with Group A, included younger patients (p = 0.030), more females (p = 0.028) and more adenocarcinoma cases (p < 0.001). Compared to group C, group A patients were older (p = 0.030) and had more squamous histology (p = 0.011).

CONCLUSION

In a small minority of NSCLC patients with PIK3CA mutation there are no additional AGA. PIK3CA mutations may be actionable in these cases.

Small molecule inhibitors targeting the cancers

Compared with traditional therapies, targeted therapy has merits in selectivity, efficacy, and tolerability. Small molecule inhibitors are one of the primary targeted therapies for cancer. Due to their advantages in a wide range of targets, convenient medication, and the ability to penetrate into the central nervous system, many efforts have been devoted to developing more small molecule inhibitors. To date, 88 small molecule inhibitors have been approved by the United States Food and Drug Administration to treat cancers. Despite remarkable progress, small molecule inhibitors in cancer treatment still face many obstacles, such as low response rate, short duration of response, toxicity, biomarkers, and resistance. To better promote the development of small molecule inhibitors targeting cancers, we comprehensively reviewed small molecule inhibitors involved in all the approved agents and pivotal drug candidates in clinical trials arranged by the signaling pathways and the classification of small molecule inhibitors. We discussed lessons learned from the development of these agents, the proper strategies to overcome resistance arising from different mechanisms, and combination therapies concerned with small molecule inhibitors. Through our review, we hoped to provide insights and perspectives for the research and development of small molecule inhibitors in cancer treatment.

The Role of Genomics and Proteomics in Lung Cancer Early Detection and Treatment

Lung cancer is the leading cause of cancer-related death worldwide, with non-small-cell lung cancer (NSCLC) being the primary type. Unfortunately, it is often diagnosed at advanced stages, when therapy leaves patients with a dismal prognosis. Despite the advances in genomics and proteomics in the past decade, leading to progress in developing tools for early diagnosis, targeted therapies have shown promising results; however, the 5-year survival of NSCLC patients is only about 15%. Low-dose computed tomography or chest X-ray are the main types of screening tools. Lung cancer patients without specific, actionable mutations are currently treated with conventional therapies, such as platinum-based chemotherapy; however, resistances and relapses often occur in these patients. More noninvasive, inexpensive, and safer diagnostic methods based on novel biomarkers for NSCLC are of paramount importance. In the current review, we summarize genomic and proteomic biomarkers utilized for the early detection and treatment of NSCLC. We further discuss future opportunities to improve biomarkers for early detection and the effective treatment of NSCLC.

Treating non-small cell lung cancer by targeting the PI3K signaling pathway

ABSTRACT

The phosphosphatidylinositol-3-kinase (PI3K) signaling pathway is one of the most important intracellular signal transduction pathways affecting cell functions, such as apoptosis, translation, metabolism, and angiogenesis. Lung cancer is a malignant tumor with the highest morbidity and mortality rates in the world. It can be divided into two groups, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). NSCLC accounts for >85% of all lung cancers. There are currently many clinical treatment options for NSCLC; however, traditional methods such as surgery, chemotherapy, and radiotherapy have not been able to provide patients with good survival benefits. The emergence of molecular target therapy has improved the survival and prognosis of patients with NSCLC. In recent years, there have been an increasing number of studies on NSCLC and PI3K signaling pathways. Inhibitors of various parts of the PI3K pathway have appeared in various phases of clinical trials with NSCLC as an indication. This article focuses on the role of the PI3K signaling pathway in the occurrence and development of NSCLC and summarizes the current clinical research progress and possible development strategies.

The treatment of advanced non-small cell lung cancer harboring KRAS mutation: a new class of drugs for an old target-a narrative review

Background and Objective

The genetic nature of cancer provides the rationale to support the need for molecular diagnosis and patient selection for individualised antineoplastic treatments that are the best in both tolerability and efficacy for each cancer patient, including non-small cell lung cancer (NSCLC) patients. Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations represent the prevalent oncogenic driver in NSCLC, being detected in roughly one-third of cases and KRAS G12C is the most frequent mutation found in approximately 13% of patients.

Methods

This paper gives an overview of the numerous scientific efforts in recent decades aimed at KRAS inhibition.

Key Content and Findings

Sotorasib is the first approved KRAS G12C inhibitor that has been shown to provide a durable clinical benefit in patients with pre-treated NSCLC with KRAS G12C mutation. Together with the development of new targeted drugs, the development of strategies to control resistance mechanisms is one of the major drivers of research that is exploring the use of KRAS inhibitors not only alone, but also in combination with other targeted therapies, chemotherapy and immunotherapy.

Conclusions

This review will describe the major therapeutic developments in KRAS mutation-dependent NSCLC and will analyse future perspectives to maximise benefits for this group of patients.

The PI3K/Akt/mTOR pathway in lung cancer; oncogenic alterations, therapeutic opportunities, challenges, and a glance at the application of nanoparticles

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Lung cancer is the most common and deadliest human malignancies.

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The alterations of PI3K/Akt/mTOR pathway are related to lung cancer progression.

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PI3K axis regulates proliferation, apoptosis, metastasis, and EMT of lung cancer.

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Agents inhibiting components of PI3K axis diminish lung tumor growth and invasion.

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Low efficacy and off-target toxicity could be improved by nanoparticle application.

Lung cancer is the leading cause of cancer-related mortality worldwide. Although the PI3K/Akt/mTOR signaling pathway has recently been considered as one of the most altered molecular pathways in this malignancy, few articles reviewed the task. In this review, we aim to summarize the original data obtained from international research laboratories on the oncogenic alterations in each component of the PI3K/Akt/mTOR pathway in lung cancer. This review also responds to questions on how aberrant activation in this axis contributes to uncontrolled growth, drug resistance, sustained angiogenesis, as well as tissue invasion and metastatic spread. Besides, we provide a special focus on pharmacologic inhibitors of the PI3K/Akt/mTOR axis, either as monotherapy or in a combined-modal strategy, in the context of lung cancer. Despite promising outcomes achieved by using these agents, however, the presence of drug resistance as well as treatment-related adverse events is the other side of the coin. The last section allocates a general overview of the challenges associated with the inhibitors of the PI3K pathway in lung cancer patients. Finally, we comment on the future research aspects, especially in which nano-based drug delivery strategies might increase the efficacy of the therapy in this malignancy.

Resistance to anti-EGFR therapies in metastatic colorectal cancer: underlying mechanisms and reversal strategies

Cetuximab and panitumumab are monoclonal antibodies (mAbs) against epidermal growth factor receptor (EGFR) that are effective agents for metastatic colorectal cancer (mCRC). Cetuximab can prolong survival by 8.2 months in RAS wild-type (WT) mCRC patients. Unfortunately, resistance to targeted therapy impairs clinical use and efficiency. The mechanisms of resistance refer to intrinsic and extrinsic alterations of tumours. Multiple therapeutic strategies have been investigated extensively to overcome resistance to anti-EGFR mAbs. The intrinsic mechanisms include EGFR ligand overexpression, EGFR alteration, RAS/RAF/PI3K gene mutations, ERBB2/MET/IGF-1R activation, metabolic remodelling, microsatellite instability and autophagy. For intrinsic mechanisms, therapies mainly cover the following: new EGFR-targeted inhibitors, a combination of multitargeted inhibitors, and metabolic regulators. In addition, new cytotoxic drugs and small molecule compounds increase the efficiency of cetuximab. Extrinsic alterations mainly disrupt the tumour microenvironment, specifically immune cells, cancer-associated fibroblasts (CAFs) and angiogenesis. The directions include the modification or activation of immune cells and suppression of CAFs and anti-VEGFR agents. In this review, we focus on the mechanisms of resistance to anti-EGFR monoclonal antibodies (anti-EGFR mAbs) and discuss diverse approaches to reverse resistance to this therapy in hopes of identifying more mCRC treatment possibilities.

Pancreatic cancer intrinsic PI3Kα activity accelerates metastasis and rewires macrophage component

Pancreatic ductal adenocarcinoma (PDAC) patients frequently suffer from undetected micro-metastatic disease. This clinical situation would greatly benefit from additional investigation. Therefore, we set out to identify key signalling events that drive metastatic evolution from the pancreas. We searched for a gene signature that discriminate localised PDAC from confirmed metastatic PDAC and devised a preclinical protocol using circulating cell-free DNA (cfDNA) as an early biomarker of micro-metastatic disease to validate the identification of key signalling events. An unbiased approach identified, amongst actionable markers of disease progression, the PI3K pathway and a distinctive PI3Kα activation signature as predictive of PDAC aggressiveness and prognosis. Pharmacological or tumour-restricted genetic PI3Kα-selective inhibition prevented macro-metastatic evolution by hindering tumoural cell migratory behaviour independently of genetic alterations. We found that PI3Kα inhibition altered the quantity and the species composition of the produced lipid second messenger PIP3 , with a selective decrease of C36:2 PI-3,4,5-P3 . Tumoural PI3Kα inactivation prevented the accumulation of pro-tumoural CD206-positive macrophages in the tumour-adjacent tissue. Tumour cell-intrinsic PI3Kα promotes pro-metastatic features that could be pharmacologically targeted to delay macro-metastatic evolution.

Phosphatidylinositol 3-kinase (PI3K) inhibitors: a recent update on inhibitor design and clinical trials (2016-2020)

Introduction: The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway plays a central role in regulating cell growth and proliferation and thus has been considered as effective anticancer drug targets. Many PI3K inhibitors have been developed and progressed to various stages of clinical trials, and some have been approved as anticancer treatment. In this review, we discuss the drug design and clinical development of PI3K inhibitors over the past 4 years. We review the selectivity and potency of 47 PI3K inhibitors. Structural determinants for increasing selectivity toward PI3K subtype-selectivity or mutant selectivity are discussed. Future research direction and current clinical development in combination therapy of inhibitors involved in PI3Ks are also discussed.Area covered: This review covers clinical trial reports and patent literature on PI3K inhibitors and their selectivity published between 2016 and 2020.Expert opinion: To PI3Kα mutants (E542K, E545K, and H1047R), it is highly desirable to design and develop mutant-specific PI3K inhibitors. It is also necessary to develop subtype-selective PI3Kα inhibitors to minimize toxicity. To reduce drug resistance and to improve efficacy, future studies should include combination therapy of PI3K inhibitors with existing anticancer drugs from different pathways.

Current State of Breast Cancer Diagnosis, Treatment, and Theranostics

Breast cancer is one of the leading causes of cancer-related morbidity and mortality in women worldwide. Early diagnosis and effective treatment of all types of cancers are crucial for a positive prognosis. Patients with small tumor sizes at the time of their diagnosis have a significantly higher survival rate and a significantly reduced probability of the cancer being fatal. Therefore, many novel technologies are being developed for early detection of primary tumors, as well as distant metastases and recurrent disease, for effective breast cancer management. Theranostics has emerged as a new paradigm for the simultaneous diagnosis, imaging, and treatment of cancers. It has the potential to provide timely and improved patient care via personalized therapy. In nanotheranostics, cell-specific targeting moieties, imaging agents, and therapeutic agents can be embedded within a single formulation for effective treatment. In this review, we will highlight the different diagnosis techniques and treatment strategies for breast cancer management and explore recent advances in breast cancer theranostics. Our main focus will be to summarize recent trends and technologies in breast cancer diagnosis and treatment as reported in recent research papers and patents and discuss future perspectives for effective breast cancer therapy.

KRAS-Mutant Non-Small Cell Lung Cancer: An Emerging Promisingly Treatable Subgroup

Lung cancer, the leading cause of cancer-related deaths worldwide, can be classified into small cell lung cancer and non-small cell lung cancer (NSCLC). NSCLC is the most common histological type, accounting for 85% of all lung cancers. Kirsten rat sarcoma viral oncogene (KRAS) mutations, common in NSCLC, are associated with poor prognosis, likely due to poor responses to most systemic therapies and lack of targeted drugs. The latest published clinical trial data on new small-molecule KRAS G12C inhibitors, AMG510 and MRTX849, indicate that these molecules may potentially help treat KRAS-mutant NSCLC. Simultaneously, within the immuno-therapeutic process, immune efficacy has been observed in those patients who have KRAS mutations. In this article, the pathogenesis, treatment status, progress of immunotherapy, and targeted therapy of KRAS-mutant NSCLC are reviewed.

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.

Novel Emerging Molecular Targets in Non-Small Cell Lung Cancer

In the scenario of systemic treatment for advanced non-small cell lung cancer (NSCLC) patients, one of the most relevant breakthroughs is represented by targeted therapies. Throughout the last years, inhibitors of the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-Ros oncogene 1 (ROS1), and V-raf murine sarcoma viral oncogene homolog B (BRAF) have been approved and are currently used in clinical practice. However, other promising molecular drivers are rapidly emerging as therapeutic targets. This review aims to cover the molecular alterations with a potential clinical impact in NSCLC, including amplifications or mutations of the mesenchymal–epithelial transition factor (MET), fusions of rearranged during transfection (RET), rearrangements of the neurotrophic tyrosine kinase (NTRK) genes, mutations of the Kirsten rat sarcoma viral oncogene (KRAS) and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA), as well as amplifications or mutations of human epidermal growth factor receptor 2 (HER2). Additionally, we summarized the current status of targeted agents under investigation for such alterations. This revision of the current literature on emerging molecular targets is needed as the evolving knowledge on novel actionable oncogenic drivers and targeted agents is expected to increase the proportion of patients who will benefit from tailored therapeutic approaches.

IQGAP3 Overexpression Correlates With Poor Prognosis and Radiation Therapy Resistance in Breast Cancer

Background: IQ motif-containing GTPase activating protein 3 (IQGAP3), the latest identified member of the IQGAP family, may act as a crucial factor in cancer development and progression; however, its clinical value in breast cancer remains unestablished. We explored the correlation between IQGAP3 expression profile and the clinicopathological features in breast cancer.

Methods: IQGAP3 mRNA and protein levels were detected in breast cancer cell lines and tumor tissues by real-time PCR and western blotting and compared to the normal control groups. Protein expression of IQGAP3 was also evaluated immunohistochemically in archived paraffin-embedded specimens from 257 breast cancer patients, and the associations between IQGAP3 expression level, clinical characteristics, and prognosis were analyzed. We assessed the relationship between IQGAP3 expression and sensitivity to radiation therapy which was determined by subgroup analysis.

Results: IQGAP3 was significantly upregulated in breast cancer cell lines and human tumor tissues at both the mRNA and protein level compared to controls. Additionally, high levels of IQGAP3 expression were detected in 110/257 (42.8%) of archived paraffin-embedded breast cancer specimens. High IQGAP3 expression level was significantly related to clinical stage (p = 0.001), T category (p = 0.002), N category (p = 0.001), locoregional recurrence (p = 0.002), distant metastasis (p = 0.001), and vital status (p = 0.001). Univariate and multivariate statistical analysis showed that IQGAP3 expression was an independent prognostic factor among all 257 breast cancer patients in our cohort (p = 0.003, p = 0.001). Subgroup analysis revealed IQGAP3 expression correlated with radioresistance and was also an independent predictor of radiotherapy outcome.

Conclusion: Our findings suggest that high IQGAP3 expression predicts poor prognosis and radioresistance in breast cancer. Therefore, IQGAP3 may be a reliable prognostic biomarker in breast cancer and could be used to identify patients who may benefit from radiotherapy.

Structure-Based Drug Design and Synthesis of PI3Kα-Selective Inhibitor (PF-06843195)

The phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway is a frequently dysregulated pathway in human cancer, and PI3Kα is one of the most frequently mutated kinases in human cancer. A PI3Kα-selective inhibitor may provide the opportunity to spare patients the side effects associated with broader inhibition of the class I PI3K family. Here, we describe our efforts to discover a PI3Kα-selective inhibitor by applying structure-based drug design (SBDD) and computational analysis. A novel series of compounds, exemplified by 2,2-difluoroethyl (3S)-3-{[2'-amino-5-fluoro-2-(morpholin-4-yl)-4,5'-bipyrimidin-6-yl]amino}-3-(hydroxymethyl)pyrrolidine-1-carboxylate (1) (PF-06843195), with high PI3Kα potency and unique PI3K isoform and mTOR selectivity were discovered. We describe here the details of the design and synthesis program that lead to the discovery of 1.

Novel N-(aryl/heteroaryl)-2-chlorobenzenesulfonamide derivatives: Synthesis and anticancer activity evaluation

A new series of N-(aryl/heteroaryl)-2-chlorobenzenesulfonamide derivatives 4-21 have been synthesized, and evaluated at the National Cancer Institute (USA) for their in vitro activities against a panel of 60 different human cancer cell lines. Among them, compounds 16, 20 and 21 exhibited remarkable cytotoxic activity against numerous human cancer cell lines. We found that sulfonamide derivative 21 appeared to be more selective than compounds 16 and 20. In comparison to compounds 16 and 20 it showed higher cytotoxic activity against A549 non-small cell lung adenocarcinoma and HCT-116 colon carcinoma cells and was less toxic to HEK-293 human embryonic kidney cells and HaCaT immortalized human keratinocytes. Treatment of A549 and HCT-116 cells with compound 21 resulted in the G0/G1-cell cycle arrest with a concomitant increase in p53 and p21 protein levels. Moreover, compound 21 led to ATP depletion and disruption of the mitochondrial membrane potential in both studied cell lines. Our results suggest that 2,4-dichloro-N-(quinolin-8-yl and/or 1H-indazol-7-yl)benzenesulfonamides serve as novel promising anticancer agents.

Targeting the PI3K/Akt/mTOR pathway in estrogen-receptor positive HER2 negative advanced breast cancer

Recently many therapeutic classes have emerged in advanced hormone receptor-positive breast cancer, which is the leading cause of cancer death in women. In absence of visceral crisis, treatment relies on endocrine therapy combined with cyclin dependent kinase 4 and 6 inhibitor. Many mechanisms lead to resistance to endocrine therapy, including the activation of intracellular signaling pathways critical for cell survival. Approximately 70% of breast tumors harbor an alteration in the phosphoinositide 3 kinase (PI3K)/Akt pathway, leading to its hyper activation. This pathway is involved in the regulation of growth, proliferation and cell survival as well as in angiogenesis and is consequently a major target in the oncogenesis. An aberrant PIK3CA mutation is a common phenomenon in breast cancer and found in approximately 40% of patients with advanced hormone receptor-positive breast cancer. For the moment, the only positive trials showing a progression free survival benefit in this population are BOLERO-2 (2012), SOLAR-1 (2019), which tested everolimus, a mammalian target of rapamycin inhibitor, and alpelisib, a PI3K inhibitor, and led to their marketing authorization. However, many other inhibitors of this pathway are promising; nevertheless their development is actually limited by toxicity, mainly cutaneous (rash), digestive (diarrhea) and endocrine (diabetes).

PI3K-targeting strategy using alpelisib to enhance the antitumor effect of paclitaxel in human gastric cancer

PIK3CA mutations are frequently observed in various human cancers including gastric cancer (GC). This study was conducted to investigate the anti-tumor effects of alpelisib, a PI3K p110α-specific inhibitor, using preclinical models of GC. In addition, the combined effects of alpelisib and paclitaxel on GC were evaluated. Among the SNU1, SNU16, SNU484, SNU601, SNU638, SNU668, AGS, and MKN1 GC cells, three PIK3CA-mutant cells were predominantly sensitive to alpelisib. Alpelisib monotherapy decreased AKT and S6K1 phosphorylation and induced G₀/G₁ phase arrest regardless of PIK3CA mutational status. The alpelisib and paclitaxel combination demonstrated synergistic anti-proliferative effects, preferentially on PIK3CA-mutant cells, resulting in increased DNA damage response and apoptosis. In addition, alpelisib and paclitaxel combination potentiated anti-migratory activity in PIK3CA-mutant cells. Alpelisib partially reversed epithelial–mesenchymal transition markers in PIK3CA-mutant cells. In a xenograft model of MKN1 cells, the alpelisib and paclitaxel combination significantly enhanced anti-tumor activity by decreasing Ki-67 expression and increasing apoptosis. Moreover, this combination tended to prolong the survival of tumor-bearing mice. Our data suggest promising anti-tumor efficacy of alpelisib alone or in combination with paclitaxel in PIK3CA-mutant GC cells.

Novel PI3K/Akt/mTOR pathway inhibitors plus radiotherapy: Strategy for non-small cell lung cancer with mutant RAS gene

Non-small cell lung cancer (NSCLC) with RAS -mutant gene has been the most difficult obstacle to overcome. Over 25% of muted lung adenocarcinomas have RAS mutation. The prognosis of NSCLC patients with RAS-mutant genes is always poor because there is no effective drug to suppress RAS-mutant genes. NSCLC patients with RAS-mutant usually develop resistance to radiotherapy and chemotherapy, which in some cases leads to a 5-10% survival rate for non-small cell lung cancer (NSCLC). As little clinical symptom of NSCLC was presented at its early stages, thus it always brings in disappointing treatment outcome. Currently, NSCLC presents the highest morbidity and mortality all over the world. The combination of PI3K/AKT/mTOR pathway inhibitors with radiotherapy is a novel strategy to improve radiosensitivity and therapeutic outcome of NSCLC with a RAS-mutant gene. There have been many preclinical studies and clinical trials on the effect of PI3K/AKT/mTOR pathway inhibitors combined with radiotherapy in NSCLC with a RAS-mutant gene have been reported in the past years. This review provides current knowledge of the combination of PI3K/Akt/mTOR pathway inhibitors with radiotherapy, which prove to be a significant improvement for the treatment of NSCLC patients with RAS mutations and will benefit NSCLC patients with RAS mutations.

Buparlisib in combination with tamoxifen in pretreated patients with hormone receptor-positive, HER2-negative advanced breast cancer molecularly stratified for PIK3CA mutations and loss of PTEN expression

The PIKTAM study evaluated the efficacy and safety of the PI3K inhibitor buparlisib in combination with tamoxifen in hormone receptor-positive (HR⁺ ), HER2-negative advanced breast cancer patients after failure of prior endocrine therapy. In this open-label, single-arm phase II trial, 25 patients were enrolled in 11 sites in Germany. Patients were stratified according to PIK3CA mutation status (tissue and cfDNA from serum samples) and/or loss of PTEN expression. Patients received buparlisib (100 mg) and tamoxifen (20 mg) once daily on a continuous schedule (28-day cycle) until progression or unacceptable toxicity. Primary endpoint was overall 6-month progression-free survival (PFS) rate. Key secondary endpoints included the 6-month PFS rate in subpopulations, PFS, overall survival, overall response rate (ORR), disease control rate (DCR), and safety. Overall, the 6-month PFS rate was 33.3% (n/N = 7/21, one-sided 95% CI 16.8-100) and median PFS was 6.1 (CI 2.6-10.6) months. The ORR and DCR were 12.5% and 44%. The PIK3CA-mutated subgroup consistently showed the highest 6-month PFS rate (62.5%, n/N = 5/8), median PFS (8.7 months), ORR (40%), and DCR (80%). No new safety signals emerged. Most common adverse events were gastrointestinal disorders (56%), psychiatric/mood disorders (48%), skin rash/hypersensitivity (44%), cardiovascular (40%), and hepatic (32%) events. The trial was prematurely terminated due to the substantially altered risk-benefit profile of buparlisib. Nevertheless, PIK3CA mutations emerged as a clinically feasible and useful biomarker for combined PI3K inhibition and endocrine therapy in patients with HR⁺ breast cancer. Further biomarker-stratified studies with isoform-specific PI3K inhibitors are warranted. EudraCT No: 2014-000599-24.

Targeting the PI3K/Akt/mTOR pathway in non-small cell lung cancer (NSCLC)

The traditional classification of lung cancer into small cell lung cancer and non-small cell lung cancer (NSCLC) has been transformed with the increased understanding of the molecular alterations and genomic biomarkers that drive the development of lung cancer. Increased activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway leads to numerous hallmarks of cancer and this pathway represents an attractive target for novel anticancer therapies. In NSCLC, the PI3K/Akt/mTOR pathway has been heavily implicated in both tumorigenesis and the progression of disease. A number of specific inhibitors of PI3K, Akt and mTOR are currently under development and in various stages of preclinical investigation and in early phase clinical trials for NSCLC. Early evidence has yielded disappointing results. Clinical trials, however, have been performed on predominantly molecularly unselected populations, and patient enrichment strategies using high-precision predictive biomarkers in future trials will increase the likelihood of success. A greater understanding of the underlying molecular biology including epigenetic alterations is also crucial to allow for the detection of appropriate biomarkers and guide combination approaches.

Targeting PIK3CA Alterations in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor-2-Negative Advanced Breast Cancer: New Therapeutic Approaches and Practical Considerations

The phosphatidylinositol-3-kinase (PI3K) pathway is frequently dysregulated in human breast cancer. Approximately 30% of all patients with breast cancer will carry mutations of the PIK3CA gene, which encodes the PI3K catalytic subunit isoform p110α. Mutations in PIK3CA have been associated with resistance to endocrine therapy, HER2-directed therapy, and cytotoxic therapy. Early trials of pan-PI3K inhibitors showed little treatment benefit as monotherapy owing to disease resistance arising through enhanced estrogen receptor pathway signaling. Combining PI3K inhibition with endocrine therapy can help overcome resistance. Clinical trials of pan-PI3K inhibitors combined with endocrine therapy demonstrated modest clinical benefits but challenging toxicity profiles, facilitating the development of more selective PI3K-targeting agents. More recent trials of isoform-specific PI3K inhibitors in patients with PIK3CA mutations have shown promising clinical efficacy with a predictable, manageable safety profile. In the present review, we discuss the clinical relevance of mutations of PIK3CA and their potential use as a biomarker to guide treatment choices in patients with HR⁺ HER2^- advanced breast cancer.

Prediction of active human dose: learnings from 20 years of Merck KGaA experience, illustrated by case studies

High-quality dose predictions based on a good understanding of target engagement is one of the main translational goals in drug development. Here, we systematically evaluate active human dose predictions for 15 Merck KGaA/EMD Serono assets spanning several modalities and therapeutic areas. Using case studies, we illustrate the value of adhering to the translational best practices of having an exposure-response relationship in an appropriate animal model; having validated, translatable pharmacodynamic (PD) biomarkers measurable in Phase I populations in the right tissue; having a deeper understanding of biology; and capturing uncertainties in predictions. Given the gap in publications on the subject, we believe that the learnings from this unique diverse data set, which are generic to the industry, will trigger actions to improve future predictions.

Molecular basis for class side effects associated with PI3K/AKT/mTOR pathway inhibitors

Introduction: The phosphatidylinositide 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway has emerged as an important target in cancer therapy. Numerous PI3K/AKT/mTOR pathway inhibitors are extensively studied; some are used clinically, but most of these drugs are undergoing clinical trials. Potential adverse effects, such as severe hepatotoxicity and pneumonitis, have largely restricted the application and clinical significance of these inhibitors. A summary of mechanisms underlying the adverse effects is not only significant for the development of novel PI3K/AKT/mTOR inhibitors but also beneficial for the optimal use of existing drugs. Areas covered: We report a profile of the adverse effects, which we consider the class effects of PI3K/AKT/mTOR inhibitors. This review also discusses potential molecular toxicological mechanisms of these agents, which might drive future drug discovery. Expert opinion: Severe toxicities associated with PI3K/AKT/mTOR inhibitors hinder their approval and limit long-term clinical application of these drugs. A better understanding regarding PI3K/AKT/mTOR inhibitor-induced toxicities is needed. However, the mechanisms underlying these toxicities remain unclear. Future research should focus on developing strategies to reduce toxicities of approved inhibitors as well as accelerating new drug development. This review will be useful to clinical, pharmaceutical, and toxicological researchers.

For Better or Worse: The Potential for Dose Limiting the On-Target Toxicity of PI 3-Kinase Inhibitors

The hyper-activation of the phosphoinositide (PI) 3-kinase signaling pathway is a hallmark of many cancers and overgrowth syndromes, and as a result, there has been intense interest in the development of drugs that target the various isoforms of PI 3-kinase. Given the key role PI 3-kinases play in many normal cell functions, there is significant potential for the disruption of essential cellular functions by PI 3-kinase inhibitors in normal tissues; so-called on-target drug toxicity. It is, therefore, no surprise that progress within the clinical development of PI 3-kinase inhibitors as single-agent anti-cancer therapies has been slowed by the difficulty of identifying a therapeutic window. The aim of this review is to place the cellular, tissue and whole-body effects of PI 3-kinase inhibition in the context of understanding the potential for dose limiting on-target toxicities and to introduce possible strategies to overcome these.

Safety and Tolerability of Phosphatidylinositol-3-Kinase (PI3K) Inhibitors in Oncology

Activation of phosphatidylinositol-3-kinase (PI3K) and downstream signalling by AKT/mammalian target of rapamycin (mTOR) modulates cellular processes such as increased cell growth, cell proliferation and increased cell migration as well as deregulated apoptosis and oncogenesis. The PI3K/AKT/mTOR pathway (particularly Class I PI3K isoforms) is frequently activated in a variety of solid tumours and haematological malignancies, making PI3K an attractive therapeutic target in oncology. Inhibitors of PI3K also have the potential to restore sensitivity to other modalities of treatments when administered as part of combination regimens. Although many PI3K inhibitors have reached different stages of clinical development, only two (idelalisib and copanlisib) have been currently approved for use in the treatment of B cell lymphoma and leukaemias. While these two agents are effective clinically, their use is associated with a number of serious class-related as well as drug-specific adverse effects. Some of these are immune-mediated and include cutaneous reactions, severe diarrhoea with or without colitis, hepatotoxicity and pneumonitis. They also induce various metabolic abnormalities such as hyperglycaemia and hypertriglyceridaemia. Not surprisingly, therefore, many new PI3K inhibitors with a varying degree of target selectivity have been synthesised in expectations of improved safety and efficacy, and are currently under clinical investigations for use in a variety of solid tumours as well as haematological malignancies. However, evidence from early clinical trials, reviewed herein, suggests that these newer agents are also associated not only with class-related but also other serious and unexpected adverse effects. Their risk/benefit evaluations have resulted in a number of them being discontinued from further development. Cumulative experience with the use of PI3K inhibitors under development suggests that, compared with their use as monotherapy, combining them with other anticancer therapies may be a more effective strategy in improving current standard-of-care and clinical outcomes in cancers beyond haematological cancers. For example, combination of alpelisib with fulvestrant has recently demonstrated unexpectedly superior efficacy compared to fulvestrant alone. Furthermore, the immunomodulatory activity of PI3Kδ and PI3Kγ inhibitors also provides unexpected opportunities for their use in cancer immunotherapy, as is currently being tested in several clinical trials.

Dual Inhibitors-Loaded Nanotherapeutics that Target Kinase Signaling Pathways Synergize with Immune Checkpoint Inhibitor

Introduction

Immune checkpoint inhibitors that boost cytotoxic T cell-based immune responses have emerged as one of the most promising approaches in cancer treatment. However, it is increasingly being realized that T cell activation needs to be rationally combined with molecularly targeted therapeutics for a maximal anti-tumor outcome. Currently, two oncogenic drivers, MAPK and PI3K-mTOR have emerged as the two main molecular targets for combining with immunotherapy. However, there are major challenges in enabling such combinations: first, such combinations can result in high rates of toxicity. Second, while, these molecular targets could be driving tumor progression, they are essential for activation of the immune cells. So, the kinase inhibitors and immunotherapy can antagonize each other.

Objectives

We rationalized that the synergistic combination of kinase inhibitors and immunotherapy could be enabled by dual inhibitors-loaded supramolecular nanotherapeutics (DiLN) that can co-deliver PI3K- and MAPK-inhibitors to the cancer cells and activate immune response by T cell-modulating immunotherapy, resulting in greater anti-tumor efficacy while minimizing toxicity.

Methods

We engineered DiLNs by designing the amphiphilic building blocks (both drugs and co-lipids) that enables supramolecular nanoassembly. DiLNs were tested for their physiochemical properties including size, morphology, stability and drug release kinetics profiles. The efficacy of DiLNs was tested in drug-resistant cells such as BRAF^V600E melanoma (D4M), Clear cell ovarian carcinoma (TOV21G) cells. The tumor inhibition efficiency of DiLNs in combination with immune checkpoint inhibitor antibody was studied in syngeneic D4M animal model.

Results

DiLNs were stable for over a month and released the drugs in a sustained manner. In vitro cytotoxicity studies in D4M and TOV21G cells showed that DiLNs were significantly more effective than free drugs. In vivo studies showed that the combination of DiLNs with anti PD-L1 antibody resulted in superior antitumor effect and survival.

Conclusion

This study shows that the rational combination of DiLNs that target multiple oncogenic signaling pathways with immune checkpoint inhibitors could emerge as an effective strategy to improve immunotherapeutic response against drug resistant tumors.

The relation between PI3K/AKT signalling pathway and cancer

Phosphatidylinositol 3-kinases (PI3Ks) are crucial coordinators of intracellular signalling in response to the extracellular stimulators. Hyperactivation of PI3K signalling cascades is one among the most ordinary events in human cancers. Focusing on the PI3K pathway remains both a chance and a challenge for cancer therapy. The high recurrence of phosphoinositide 3-kinase (PI3K) pathway adjustments in cancer has led to a surge in the progression of PI3K inhibitors. Recent developments incorporate a re-assessment of the oncogenic mechanisms behind PI3K pathway modifications. Receptor tyrosine kinases upstream of PI3K, the p110a catalytic fractional unit of PI3K, the downstream kinase, AKT, and therefore the negative regulator, PTEN, are all often altered in cancer. In this review, we consider about the phosphoinositide 3-kinases family and mechanisms of PI3K-Akt stimulation in cancer.

RASpecting the oncogene: New pathways to therapeutic advances

RAS is the most commonly mutated driver of tumorigenesis, seen in about 30% of all cancer cases. There is a subset of tumors termed RAS-driven cancers in which RAS mutation or overactivation is evident, including as much as 95% in pancreatic and 50% in colon cancer. RAS is a family of small membrane bound GTPases that act as a signaling node to control both normal and cancer biology. Since the discovery of RAS' overall prominence in many tumor types and specifically in RAS-dependent cancers, it has been an obvious therapeutic target for drug development. However, RAS has proved a very elusive target, and after a few prominent RAS targeted drugs failed in clinical trials after decades of research, RAS was termed "undruggable" and research in this field was greatly hampered. An increase in knowledge about basic RAS biology has led to a resurgence in the generation of novel therapeutics targeting RAS signaling utilizing various and distinct approaches. These new drugs target RAS activation directly, block downstream signaling effectors and inhibit proper post-translational processing and trafficking/recycling of RAS. This review will cover how these new drugs were developed and how they have fared in preclinical and early phase clinical trials.

New Insights into the Role of Exercise in Inhibiting mTOR Signaling in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) does not express estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 and is characterized by its aggressive nature, lack of targets for targeted therapies, and early peak of recurrence. Due to these specific characteristics, chemotherapy does not usually yield substantial improvements and new target therapies and alternative strategies are needed. The beneficial responses of TNBC survivors to regular exercise, including a reduction in the rate of tumor growth, are becoming increasingly apparent. Physiological adaptations to exercise occur in skeletal muscle but have an impact on the entire body through systemic control of energy homeostasis and metabolism, which in turn influence the TNBC tumor microenvironment. Gaining insights into the causal mechanisms of the therapeutic cancer control properties of regular exercise is important to improve the prescription and implementation of exercise and training in TNBC survivors. Here, we provide new evidence of the effects of exercise on TNBC prevention, control, and outcomes, based on the inhibition of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (PKB also known as Akt)/mammalian target of rapamycin (mTOR) (PI3K-Akt-mTOR) signaling. These findings have wide-ranging clinical implications for cancer treatment, including recurrence and case management.

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.

A phase I, open-label, two-stage study to investigate the safety, tolerability, pharmacokinetics, and pharmacodynamics of the oral AKT inhibitor GSK2141795 in patients with solid tumors

Background We sought to determine the recommended phase II dose (RP2D) and schedule of GSK2141795, an oral pan-AKT kinase inhibitor. Patients and Methods Patients with solid tumors were enrolled in the dose-escalation phase. Pharmacokinetic (PK) analysis after a single dose (Cycle 0) informed dose escalation using accelerated dose titration. Once one grade 2 toxicity or dose-limiting toxicity was observed in Cycle 1, the accelerated dose titration was terminated and a 3 + 3 dose escalation was started. Continuous daily dosing was evaluated along with two intermittent regimens (7 days on/7 days off and 3 times per week). In the expansion phase at RP2D, patients with endometrial or prostate cancer, as well as those with select tumor types with a PIK3CA mutation, AKT mutation or PTEN loss, were enrolled. Patients were evaluated for adverse events (AEs), PK parameters, blood glucose and insulin levels, and tumor response. Results The RP2D of GSK2141795 for once-daily dosing is 75 mg. The most common (>10%) treatment-related AEs included diarrhea, fatigue, vomiting, and decreased appetite. Most AEs were low grade. The frequency of hyperglycemia increased with dose; however, at the RP2D, grade 3 hyperglycemia was only reported in 4% of patients and no grade 4 events were observed. PK characteristics were favorable, with a prolonged half-life and low peak-to-trough ratio. There were two partial responses at the RP2D in patients with either a PIK3CA mutation or PTEN loss. Conclusion GSK2141795 was safe and well-tolerated, with clinical activity seen as monotherapy at the RP2D of 75 mg daily. NCT00920257.

Phase I Trial of a Tablet Formulation of Pilaralisib, a Pan-Class I PI3K Inhibitor, in Patients with Advanced Solid Tumors

Lessons Learned.

A phase I study of the pan‐class I phosphoinositide 3‐kinase inhibitor pilaralisib (in capsule formulation) in advanced solid tumors established the maximum tolerated dose as 600 mg once daily.

The current study investigated pilaralisib in tablet formulation.

Pilaralisib tablets were associated with a favorable safety profile and preliminary antitumor activity.

Based on pharmacokinetic data, the recommended phase II dose of pilaralisib tablets was established as 400 mg once daily.

Background.

A phase I trial of pilaralisib, an oral pan‐class I phosphoinositide 3‐kinase (PI3K) inhibitor, established the maximum tolerated dose (MTD) of the capsule formulation in patients with advanced solid tumors as 600 mg once daily. This phase I study investigated pilaralisib in tablet formulation.

Materials and Methods.

Patients with advanced solid tumors received pilaralisib tablets (100–600 mg once daily). Primary endpoints were MTD and safety; secondary and exploratory endpoints included pharmacokinetics (PK), pharmacodynamics, and efficacy.

Results.

Twenty‐two patients were enrolled. No dose‐limiting toxicities (DLTs) were reported. The most common treatment‐related adverse events were diarrhea (40.9%), fatigue (40.9%), decreased appetite (22.7%), and hyperglycemia (22.7%). Pilaralisib plasma exposure did not appear to increase dose‐proportionally. Steady‐state exposure was higher with pilaralisib tablet formulation at 400 mg than with pilaralisib capsule formulation at 400 or 600 mg (mean area under the curve [AUC_0–24] 2,820,000 ng × h/mL vs. 2,653,000 and 1,930,000 ng × h/mL, respectively). Of 18 evaluable patients, 2 (11.1%) had a partial response (PR).

Conclusion.

Pilaralisib tablets were associated with a favorable safety profile and preliminary antitumor activity. MTD was not determined. The recommended phase II dose for pilaralisib tablets, based on PK data, was 400 mg once daily.

Targeting the PI3K pathway in cancer: are we making headway?

The PI3K-AKT-mTOR pathway is one of the most frequently dysregulated pathways in cancer and, consequently, more than 40 compounds that target key components of this signalling network have been tested in clinical trials involving patients with a range of different cancers. The clinical development of many of these agents, however, has not advanced to late-phase randomized trials, and the antitumour activity of those that have been evaluated in comparative prospective studies has typically been limited, or toxicities were found to be prohibitive. Nevertheless, the mTOR inhibitors temsirolimus and everolimus and the PI3K inhibitors idelalisib and copanlisib have been approved by the FDA for clinical use in the treatment of a number of different cancers. Novel compounds with greater potency and selectivity, as well as improved therapeutic indices owing to reduced risks of toxicity, are clearly required. In addition, biomarkers that are predictive of a response, such as PIK3CA mutations for inhibitors of the PI3K catalytic subunit α isoform, must be identified and analytically and clinically validated. Finally, considering that oncogenic activation of the PI3K-AKT-mTOR pathway often occurs alongside pro-tumorigenic aberrations in other signalling networks, rational combinations are also needed to optimize the effectiveness of treatment. Herein, we review the current experience with anticancer therapies that target the PI3K-AKT-mTOR pathway.

Phosphatidylinositol 3-Kinase α-Selective Inhibition With Alpelisib (BYL719) in PIK3CA-Altered Solid Tumors: Results From the First-in-Human Study

Purpose We report the first-in-human phase Ia study to our knowledge ( ClinicalTrials.gov identifier: NCT01219699) identifying the maximum tolerated dose and assessing safety and preliminary efficacy of single-agent alpelisib (BYL719), an oral phosphatidylinositol 3-kinase α (PI3Kα)-selective inhibitor. Patients and Methods In the dose-escalation phase, patients with PIK3CA-altered advanced solid tumors received once-daily or twice-daily oral alpelisib on a continuous schedule. In the dose-expansion phase, patients with PIK3CA-altered solid tumors and PIK3CA-wild-type, estrogen receptor-positive/human epidermal growth factor receptor 2-negative breast cancer received alpelisib 400 mg once daily. Results One hundred thirty-four patients received treatment. Alpelisib maximum tolerated doses were established as 400 mg once daily and 150 mg twice daily. Nine patients (13.2%) in the dose-escalation phase had dose-limiting toxicities of hyperglycemia (n = 6), nausea (n = 2), and both hyperglycemia and hypophosphatemia (n = 1). Frequent all-grade, treatment-related adverse events included hyperglycemia (51.5%), nausea (50.0%), decreased appetite (41.8%), diarrhea (40.3%), and vomiting (31.3%). Alpelisib was rapidly absorbed; half-life was 7.6 hours at 400 mg once daily with minimal accumulation. Objective tumor responses were observed at doses ≥ 270 mg once daily; overall response rate was 6.0% (n = 8; one patient with endometrial cancer had a complete response, and seven patients with cervical, breast, endometrial, colon, and rectal cancers had partial responses). Stable disease was achieved in 70 (52.2%) patients and was maintained > 24 weeks in 13 (9.7%) patients; disease control rate (complete and partial responses and stable disease) was 58.2%. In patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative breast cancer, median progression-free survival was 5.5 months. Frequently mutated genes (≥ 10% tumors) included TP53 (51.3%), APC (23.7%), KRAS (22.4%), ARID1A (13.2%), and FBXW7 (10.5%). Conclusion Alpelisib demonstrated a tolerable safety profile and encouraging preliminary activity in patients with PIK3CA-altered solid tumors, supporting the rationale for selective PI3Kα inhibition in combination with other agents for the treatment of PIK3CA-mutant tumors.

A PI3K p110α-selective inhibitor enhances the efficacy of anti-HER2/neu antibody therapy against breast cancer in mice

Combination therapies with phosphoinositide 3-kinase (PI3K) inhibitors and trastuzumab (anti-human epidermal growth factor receptor [HER]2/neu antibody) are effective against HER2+ breast cancer. Isoform-selective PI3K inhibitors elicit anti-tumor immune responses that are distinct from those induced by inhibitors of class I PI3K isoforms (pan-PI3K inhibitors). The present study investigated the therapeutic effect and potential for stimulating anti-tumor immunity of combined therapy with an anti-HER2/neu antibody and pan-PI3K inhibitor (GDC-0941) or a PI3K p110α isoform-selective inhibitor (A66) in mouse models of breast cancer. The anti-neu antibody inhibited tumor growth and enhanced anti-tumor immunity in HER2/neu+ breast cancer TUBO models, whereas GDC-0941 or A66 alone did not. Anti-neu antibody and PI3K inhibitor synergistically promoted anti-tumor immunity by increasing functional T cell production. In the presence of the anti-neu antibody, A66 was more effective than GDC-0941 at increasing the fraction of CD4⁺, CD8⁺, and IFN-γ⁺CD8⁺ T cells in the tumor-infiltrating lymphocyte population. Detection of IFN-γ levels by enzyme-linked immunospot assay showed that the numbers of tumor-specific T cells against neu and non-neu tumor antigens were increased by combined PI3K inhibitor plus anti-neu antibody treatment, with A66 exhibiting more potent effects than GDC-0941. In a TUBO (neu+) and TUBO-P2J (neu-) mixed tumor model representing immunohistochemistry 2+ tumors, A66 suppressed tumor growth and prolonged survival to a greater extent than GDC-0941 when combined with anti-neu antibody. These results demonstrate that a PI3K p110α-isoform-selective inhibitor is an effective adjunct to trastuzumab in the treatment of HER2-positive breast cancer.

PI3K inhibition to overcome endocrine resistance in breast cancer

INTRODUCTION

Activation of the phosphatidylinositol-3 kinase (PI3K) pathway is a critical step in oncogenesis and plays a role in the development of treatment resistance for both estrogen receptor (ER) positive and human epidermal growth factor receptor 2 (HER2) positive breast cancers. Hence, there have been efforts to therapeutically inhibit this pathway.

AREAS COVERED

Several inhibitors of PI3K are now progressing through clinical trials with varying degrees of efficacy and toxicity to date. Numerous unresolved questions remain concerning the optimal isoform selectivity of PI3K inhibitors and use of predictive biomarkers. This review examines the most important PI3K inhibitors in ER positive breast cancer to date, with a particular focus on their role in overcoming endocrine therapy resistance and the possible use of PIK3CA mutations as a predictive biomarker.

EXPERT OPINION

We discuss some of the emerging challenges and questions encountered during the development of PI3K inhibitors from preclinical to phase III studies, including other novel biomarkers and future combinations to overcome endocrine resistance.

First-in-human phase I study of copanlisib (BAY 80-6946), an intravenous pan-class I phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors and non-Hodgkin's lymphomas

BACKGROUND

To evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of copanlisib, a phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors or non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Phase I dose-escalation study including patients with advanced solid tumors or NHL, and a cohort of patients with type 2 diabetes mellitus. Patients received three weekly intravenous infusions of copanlisib per 28-day cycle over the dose range 0.1-1.2 mg/kg. Plasma copanlisib levels were analyzed for pharmacokinetics. Biomarker analysis included PIK3CA, KRAS, BRAF, and PTEN mutational status and PTEN immunohistochemistry. Whole-body [(18)F]-fluorodeoxyglucose positron emission tomography ((18)FDG-PET) was carried out at baseline and following the first dose to assess early pharmacodynamic effects. Plasma glucose and insulin levels were evaluated serially.

RESULTS

Fifty-seven patients received treatment. The MTD was 0.8 mg/kg copanlisib. The most frequent treatment-related adverse events were nausea and transient hyperglycemia. Copanlisib exposure was dose-proportional with no accumulation; peak exposure positively correlated with transient hyperglycemia post-infusion. Sixteen of 20 patients treated at the MTD had reduced (18)FDG-PET uptake; 7 (33%) had a reduction >25%. One patient achieved a complete response (CR; endometrial carcinoma exhibiting both PIK3CA and PTEN mutations and complete PTEN loss) and two had a partial response (PR; both metastatic breast cancer). Among the nine NHL patients, all six with follicular lymphoma (FL) responded (one CR and five PRs) and one patient with diffuse large B-cell lymphoma had a PR by investigator assessment; two patients with FL who achieved CR (per post hoc independent radiologic review) were on treatment >3 years.

CONCLUSION

Copanlisib, dosed intermittently on days 1, 8, and 15 of a 28-day cycle, was well tolerated and the MTD was determined to be 0.8 mg/kg. Copanlisib exhibited dose-proportional pharmacokinetics and promising anti-tumor activity, particularly in patients with NHL.

CLINICALTRIALSGOV

NCT00962611; https://clinicaltrials.gov/ct2/show/NCT00962611.