ErbB small molecule tyrosine kinase inhibitor (TKI) induced diarrhoea: Chloride secretion as a mechanistic hypothesis

Safety of current treatments for advanced cholangiocarcinoma

INTRODUCTION

Biliary tract cancer (BTC) originates from the biliary epithelium of the small ducts within the liver (intrahepatic cholangiocarcinoma, IHCC), the main ducts of the hilum (extrahepatic cholangiocarcinoma, EHCC), or in the gallbladder (gallbladder cancer, GC). Due to presentation with nonspecific symptoms as well as absence of screening, most patients present with advanced disease and unfavorable prognosis.

AREAS COVERED

The ABC-02 trial established the current first-line chemotherapy with gemcitabine/platinum for advanced BTC in 2010. Since then, multiple therapies have become available exploring different targetable alterations, emphasizing the importance of molecular profiling in all patients with BTC as well as understanding the distinct toxicity profile associated with these therapies. Besides chemotherapy, immunotherapy as well as targeted therapies for FGFR2, IDH1 and HER2 will be discussed in this manuscript. We performed a non-systematic review, largely based on high-quality articles on the topic of interest with no predefined protocol.

EXPERT OPINION

The primary objective of this manuscript is to conduct a thorough review of diverse aspects related to the safety of systemic treatment in BTC. As the benefit of these therapies depends on compliance and/or tolerance, the authors aim to discuss different toxicity profiles and to provide insights into strategies for overcoming them.

Disruption of serotonin homeostasis in intestinal organoids provides insights into drug-induced gastrointestinal toxicity

Drug-induced gastrointestinal toxicity is a frequent clinical adverse event that needs to be carefully monitored and managed to ensure patient compliance. While preclinical assessment of drug-induced gastrointestinal toxicity mostly relies on animal experimentation, intestinal organoids have gained increasing attention to identify gastrointestinal toxicants in vitro. Nonetheless, current in vitro protocols primarily assess structural alterations induced by drugs, whereas gastrointestinal adverse events can often stem from functional disturbances. Disruption of serotonin signaling in the gastrointestinal tract is associated with impaired motility, as well as nausea and vomiting. We aimed to investigate alterations of serotonin homeostasis in organoids derived from the canine small intestine as a driver of drug-induced gastrointestinal toxicity. Treatment of the organoids with a compound (NVS-1) inducing acute gastrointestinal toxicity in dogs as well as with three tyrosine kinase inhibitors with known preclinical and clinical gastrointestinal adverse effects (afatinib, crizotinib and vandetanib) led to increased supernatant serotonin levels. Mechanistic assays showed that, while NVS-1 and afatinib stimulate serotonin release, crizotinib and vandetanib inhibit serotonin re-uptake via direct inhibition of the serotonin re-uptake transporter. Using a data mining approach, we further suggest that inhibition of serotonin re-uptake could contribute to gastrointestinal toxicity observed with multiple marketed drugs. In conclusion, we present the implementation of a novel in vitro gastrointestinal toxicity endpoint that could complement current methods and serve as a mechanistic and predictive/screening tool for drug-induced gastrointestinal toxicity.

Unraveling the future: Innovative design strategies and emerging challenges in HER2-targeted tyrosine kinase inhibitors for cancer therapy

Human epidermal growth factor receptor 2 (HER2) is a transmembrane receptor-like protein with tyrosine kinase activity that plays a vital role in processes such as cell proliferation, differentiation, and angiogenesis. The degree of malignancy of different cancers, notably breast cancer, is strongly associated with HER2 amplification, overexpression, and mutation. Currently, widely used clinical HER2 tyrosine kinase inhibitors (TKIs), such as lapatinib and neratinib, have several drawbacks, including susceptibility to drug resistance caused by HER2 mutations and adverse effects from insufficient HER2 selectivity. To address these issues, it is essential to create innovative HER2 TKIs with enhanced safety, effectiveness against mutations, and high selectivity. Typically, SPH5030 has advanced to phase I clinical trials for its strong suppression of four HER2 mutations. This review discusses the latest research progress in HER2 TKIs, with a focus on the structural optimization process and structure-activity relationship analysis. In particular, this study highlights promising design strategies to address these challenges, providing insightful information and inspiration for future development in this field.

Efficacy and Safety of Neoadjuvant Pyrotinib for Human Epidermal Receptor 2-Positive Breast Cancer: A Meta-Analysis

Neoadjuvant pyrotinib shows the potential to improve treatment response in human epidermal receptor 2 (HER2)-positive breast cancer patients, but relevant meta-analyses are scarce. This meta-analysis intended to explore the efficacy and safety of neoadjuvant pyrotinib for HER2-positive breast cancer patients. Studies comparing the efficacy and safety between HER2-positive breast cancer patients receiving pyrotinib-containing neoadjuvant treatment (pyrotinib group) and those receiving other neoadjuvant treatments (control group), were searched in EMBASE, Web of Science, Cochrane, PubMed, China National Knowledge Infrastructure, Wanfang, and SinoMed until December 2023. Six randomized controlled trials (RCTs) and 4 cohort studies were included. The pyrotinib group and control group contained 540 and 684 patients, respectively. Pathological complete response (pCR) was higher in the pyrotinib group than in the control group [relative risk (RR)=1.93; 95% confidence interval (CI) = 1.63-2.29; P < 0.001]. Similar results were discovered in subgroup analyses of RCTs (RR = 1.89; 95% CI = 1.49-2.40; P < 0.001) and cohort studies (RR = 1.98; 95% CI = 1.55-2.53; P < 0.001). The objective response rate (ORR) was also higher in the pyrotinib group than in the control group (RR = 1.14; 95% CI = 1.07-1.21; P < 0.001). Regarding adverse events, only the incidence of diarrhea was increased in the pyrotinib group versus the control group (RR = 1.97; 95% CI = 1.31-2.96; P = 0.001), while others were not different, including nausea and vomiting, leukopenia, thrombocytopenia, hand-foot syndrome, and alopecia (all P > 0.05). No publication bias existed, and sensitivity analysis suggested the satisfactory robustness of this meta-analysis. In conclusion, compared with other neoadjuvant treatments, pyrotinib-containing neoadjuvant treatment achieves a better treatment response with a good safety profile in HER2-positive breast cancer patients.

Underlying mechanisms and management strategies for regorafenib-induced toxicity in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) accounts for 85% of liver cancer cases and is the third leading cause of cancer death. Regorafenib is a multi-target inhibitor that dramatically prolongs progression-free survival in HCC patients who have failed sorafenib therapy. However, one of the primary factors limiting regorafenib's clinical utilization is toxicity. Using Clinical Trials.gov and PubMed, we gathered clinical data on regorafenib and conducted a extensive analysis of the medication's adverse reactions and mechanisms. Next, we suggested suitable management techniques to improve regorafenib's effectiveness.

AREAS COVERED

We have reviewed the mechanisms by which regorafenib-induced toxicity occurs and general management strategies through clinical trials of regorafenib. Furthermore, by examining the literature on regorafenib and other tyrosine kinase inhibition, we summarized the mechanics of the onset of regorafenib toxicity and mechanism-based intervention strategies by reviewing the literature related to regorafenib and other tyrosine kinase inhibition.

EXPERT OPINION

One of the primary factors restricting regorafenib's clinical utilization and combination therapy is its toxicity reactions. To optimize regorafenib treatment regimens, it is especially important to further understand the specific toxicity mechanisms of regorafenib as a multi-kinase inhibitor.

ERBB2 Targeting Reveals a Significant Suppression of Tumorigenesis in Murine Endometrial Cancer with Pten Mutation

Endometrial cancer is the most common gynecologic malignancy. PTEN is a negative regulator of PI3K signaling and is deficient in > 50% of primary human endometrial cancer. Amplification of ERBB2 promotes tumorigenesis and pathogenesis of several human cancers. However, the effect of ERBB2 targeting has not been studied in endometrial cancer with PTEN mutations. The murine model Pgrcre/+Erbb2f/fPtenf/f (Erbb2d/d Ptend/d) was developed to evaluate the effect of ERBB2 targeted therapy in endometrial cancer with PTEN deficiency. Histopathological and molecular analysis was performed for Ptend/d and Erbb2d/dPtend/d mice. Histopathological analysis revealed that Erbb2d/dPtend/d mice significantly reduced development and progression of endometrial cancer compared to Ptend/d mice. Furthermore, percentage of proliferative cells in Erbb2d/dPtend/d mice revealed anti-tumorigenic effect of Erbb2 ablation compared to Ptend/d mice. Our results demonstrate that Erbb2 ablation reveals a significant suppression of tumorigenesis on endometrial cancer of Ptend/d mice. Our results suggest that Erbb2 functions as an oncogene in endometrial cancer of Ptend/d mice implying that Erbb2 targeting can be used as an effective therapeutic approach for treatment of endometrial cancer with PTEN deficiency to hinder cancer development.

Safety and efficacy of pyrotinib for HER‑2‑positive breast cancer in the neoadjuvant setting: A systematic review and meta‑analysis

As a novel tyrosine kinase inhibitor (TKI), pyrotinib can irreversibly block dual pan-ErbB receptors and has been used in the treatment of advanced or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, there are limited data on the use of pyrotinib in early breast cancer. Therefore, the present meta-analysis was conducted to evaluate the safety and efficacy of pyrotinib in the neoadjuvant setting for patients with early-stage or locally advanced HER2-positive breast cancer. Online databases (Pubmed, Web of Science, Embase and Cochrane Library) were comprehensively searched for eligible prospective clinical trials on August 17, 2023. The primary endpoint was the treatment-related adverse events (TRAEs), and the secondary endpoint was pathological complete response (pCR) rate. In total, seven trials with a total enrolment of 407 patients were included. A total of seven studies evaluated pyrotinib in combination with trastuzumab and chemotherapy in the neoadjuvant setting. The median age ranged from 47-50 years. The most common TRAEs were diarrhea [98% of patients; 95% confidence interval (CI): 92-100%], followed by anemia (71%; 95% CI: 55-89%), vomiting (69%; 95% CI: 55-82%), and leucopenia (66%; 95% CI: 35-91%). No treatment-related deaths occurred. The pooled pCR rate was 57% (95% CI: 47-68%). It was concluded that pyrotinib-containing neoadjuvant therapy could be an effective treatment strategy in patients with early-stage or locally advanced HER2-positive breast cancer; however, the management of adverse events should be a key consideration. The management of adverse events should be paid great attention to, during pyrotinib therapy, although pyrotinib-contained neoadjuvant therapy could be an effective treatment for patients with early-stage or locally advanced HER2-positive breast cancer. Head-to-head randomized clinical trials are warranted to further confirm the benefits and risks associated with pyrotinib therapy in patients with breast cancer.

Mechanism and treatment of diarrhea associated with tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKIs) have become first-line drugs for cancer treatment. However, their clinical use is seriously hindered since many patients experience diarrhea after receiving TKIs. The mechanisms of TKI-associated diarrhea remain unclear. Most existing therapies are symptomatic treatments based on experience and their effects are unsatisfactory. Therefore, clarification of the mechanisms underlying diarrhea is critical to develop effective anti-diarrhea drugs. This article summarizes several potential mechanisms of TKI-associated diarrhea and reviews current treatment progress.

Management and Mechanisms of Diarrhea Induced by Tyrosine Kinase Inhibitors in Human Epidermal Growth Factor Receptor-2-Positive Breast Cancer

Breast cancer has the highest incidence among female malignancies, significantly impacting women's health. Recently, numerous HER2-targeted therapies have achieved excellent clinical outcomes. Currently, anti-HER2 drugs are divided into three main categories: monoclonal antibodies, small-molecule tyrosine kinase inhibitors, and antibody-coupled drugs (ADCs). The main toxic side effects of small molecule TKI-based therapy are diarrhea, hand-foot syndrome, rash, nausea, and vomiting. Diarrhea is a potential predictor of tumor response, affecting up to 95% of cancer patients treated with TKIs. Severe gastrointestinal toxicity can result in the need for dose reductions and treatment interruptions. This not only compromises the efficacy of TKIs but also deteriorates human nutrition and quality of life. The majority of individuals develop diarrhea within 7 days of starting treatment, with approximately 30% developing grade 3 or higher diarrhea within 2-3 days of starting treatment. The severity of diarrhea typically correlates with the dosage of most TKIs. Current prevention and management strategies are primarily empirical, focusing on symptom alleviation rather than addressing the toxicological mechanisms underlying TKI-induced diarrhea. Consequently, anti-diarrheal drugs are often less effective in managing this condition in cancer patients receiving TKIs. Moreover, our understanding of the toxicological mechanisms responsible for such diarrhea remains limited, underscoring the urgent need to identify these mechanisms in order to develop effective anti-diarrheal medications tailored to this specific context. This review aims to elucidate management approaches and mechanisms for diarrhea induced by TKIs during HER2-positive breast cance.

Multicenter phase I dose escalation and expansion study of pyrotinib in combination with camrelizumab and chemotherapy as first-line treatment for HER2-positive advanced gastric and gastroesophageal junction adenocarcinoma

Background

Pembrolizumab plus trastuzumab and chemotherapy showed remarkable efficacy as first-line therapy for advanced HER2-positive gastric cancer. Pyrotinib is an irreversible pan-HER inhibitor. This single-arm, open-label phase 1 dose-escalation (1a) and expansion (1b) study investigated camrelizumab, an anti-PD-1 antibody, plus pyrotinib and chemotherapy as first-line treatment for advanced HER2-positive gastric and gastroesophageal junction (G/GEJ) adenocarcinoma.

Methods

Between June 2020 and June 2022, 41 patients with previously untreated HER2-positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma were enrolled. In phase 1a, patients underwent a 3 + 3 escalating dose design, receiving oral pyrotinib (240 mg, 320 mg, or 400 mg daily), intravenous camrelizumab (200 mg), and CapeOX (oxaliplatin 130 mg/m2 on day 1 and capecitabine 1000 mg/m2 twice daily for two weeks) every 3 weeks until progression, intolerable toxicity or consent withdrawal. The recommended phase 2 dose (RP2D) of pyrotinib was determined and used in the phase 1b. The primary endpoints were the safety, maximum tolerated dose (MTD), RP2D, and confirmed objective response rate (ORR). This trial was registered with chictr.org, number ChiCTR2000029717.

Findings

Among 41 patients, 10 were in phase 1a (3 at 240 mg, 3 at 400 mg, and 4 at 320 mg due to one patient withdrawing consent), and 31 were in phase 1b. In phase 1a, the MTD of pyrotinib was 320 mg daily due to dose-limiting toxicities (diarrhea [n = 3] and vomiting [n = 1]) observed at 400 mg. Based on all available data, the RP2D of pyrotinib was set at 320 mg. Among 41 patients, 20 patients (48.8%) developed grade ≥3 treatment-emergent adverse events (TEAEs), and four patients (9.8%) had any grade serious adverse events. No deaths occurred due to TEAEs. Among 27 patients who received the RP2D of pyrotinib and had a post-baseline tumor assessment, two patients (7.4%) achieved a confirmed complete response, and 19 patients (70.4%) achieved a confirmed partial response, resulting in a confirmed ORR of 77.8% (95% CI: 57.7-91.4).

Interpretation

Pyrotinib plus camrelizumab and chemotherapy showed promising efficacy in the first-line treatment of advanced HER2-positive G/GEJ cancer. The safety profile was consistent with known toxicities of the agents, and no new or unexpected safety signals were identified.

Funding

This study was funded by the Beijing Xisike Clinical Oncology Research Foundation (Y-HR2019-0377).

Management of diarrhea induced by EGFR-TKIs in advanced lung adenocarcinoma

The identification of Epidermal Growth Factor Receptor (EGFR) mutations in lung adenocarcinoma has facilitated the development of personalized medicine based on oncogenic drivers. EGFR-Tyrosine Kinase Inhibitors (TKIs) are part of the targeted therapy; they impede the phosphorylation of the intracellular tyrosine kinase component of EGFR and consequently block signal transduction pathways. These drugs inhibit the proliferation and survival of tumor cells, leading to long-term progression-free survival and overall survival. Diarrhea is one of the most frequent adverse events associated with EGFR-TKIs, affecting at least 18% of patients and reaching up to 95% in some cases. Diarrhea should be managed carefully given its association with important complications, treatment interruptions, and dose reductions. Moreover, nutritional status and quality of life (QoL) can deteriorate due to severe diarrhea. Changes in diet, such as increment of fiber, supplementation with glutamine, and use of probiotics, may contribute to a decrease in the incidence of diarrhea. Improving the control of diarrhea can provide a significant benefit to the QoL of patients.

Gene Reprogramming Armed Macrophage Membrane-Camouflaged Nanoplatform Enhances Bionic Targeted Drug Delivery to Solid Tumor for Synergistic Therapy

Efficient drug delivery to solid tumors remains a challenge. HER2-positive (HER2⁺) tumors are an aggressive cancer subtype with a resistance to therapy, high risk of relapse, and poor prognosis. Although nanomedicine technology shows obvious advantages in tumor treatment, its potential clinical translation is still impeded by the unsatisfactory delivery and therapeutic efficacy. In this study, a gene reprogramming macrophage membrane-encapsulated drug-loading nanoplatform was developed for HER2⁺ cancer therapy based on the co-assembly of poly (lactic-co-glycolic acid) (PLGA) nanoparticles and engineered modified macrophage membranes. In this nanoplatform, near-infrared (NIR) fluorescent dye ICG or chemotherapeutic drug doxorubicin (DOX) was loaded into the PLGA cores, and an anti-HER2 affibody was stably expressed on the membrane of macrophages. In comparison to the nanoparticles with conventional macrophage membrane coating, the ICG/DOX@AMNP nanoparticles armed with anti-HER2 affibody showed excellent HER2-targeting ability both in vitro and in vivo. Small animal imaging studies confirmed the improved pharmacokinetics of drug delivery and specific distribution of the ICG/DOX@AMNPs in HER2⁺ tumors. Mechanistically, compared with DOX@NPs or DOX@MNPs nanoparticles, DOX@AMNPs exhibited synergistic inhibition of HER2⁺ cancer cells or mice tumor growth by inducing apoptosis and blocking the PI3K/AKT signaling pathway. Altogether, this study proposes a promising biomimetic nanoplatform for the efficient targeted delivery of chemotherapeutic agents to HER2⁺ tumors, demonstrating its great potential for solid tumor therapy.

Differences in the Intestinal Microbiome Associated with Diarrhea during Lenvatinib Treatment for Hepatocellular Carcinoma

INTRODUCTION

Lenvatinib has been widely used for the treatment of advanced hepatocellular carcinoma (HCC). Some adverse events, including diarrhea, have been reported for lenvatinib. Diarrhea may be associated with the changes in the intestinal microbiome; however, the underlying mechanism has not been elucidated.

AIM

In this study, we aimed to investigate the relationship between the intestinal microbiome and diarrhea caused by lenvatinib via analysis of fecal samples collected before treatment.

METHODS

A total of 21 patients with advanced HCC who were treated with lenvatinib were enrolled. Fecal samples were collected from patients. The patients were divided into diarrhea (n = 8) and nondiarrhea groups (n = 12). We compared the characteristics of patients, incidence of adverse events, composition of the intestinal microbiome, and enrichment of functional pathways between both groups using QIIME2 and PICRUSt2.

RESULTS

The median age of the two groups was 73 years. The nondiarrhea group comprised a relatively higher number of male patients than the diarrhea group; however, there were no significant differences in patient characteristics between both groups. The proportion of the microbiome was similar, and alpha and beta diversities were not significantly different between both groups. The relative abundance of order Bacteroidales, including Parabacteroides and Prevotella, was higher in the diarrhea group than in the nondiarrhea group. PICRUSt2 analysis showed some metabolic pathways, including butanoate (butyrate) metabolism, were enriched in the nondiarrhea group when compared with those in the diarrhea group.

CONCLUSION

Differences in the intestinal microbiomes and their functions may influence the incidence of diarrhea during lenvatinib treatment.

Gastrointestinal injury induced by immunomodulators: A review article

An increasing number of immunomodulators, either anti-inflammatory or immunity-enhancing, have brought about a revolutionary effect in the management of a variety of autoimmune disorders and malignancies. However, their ability to cause gastrointestinal (GI) injury and induce GI symptoms has been increasingly and unexpectedly recognized. GI injury associated with immunomodulators may demonstrate various histologic and endoscopic patterns. Optimal diagnosis and treatment require a multidisciplinary approach. This review aims to provide an overview of the literature on its pathogenesis, the clinical, endoscopic, and histologic features, and suggested approaches to manage these newly recognized immunomodulator-induced GI adverse effects (AEs). We also reviewed current biomarkers predictive of GI toxicity and potential risk factors to identify susceptible patients. In addition, these immune-mediated AEs were compared with inflammatory bowel disease, a well-documented form of inflammation-driven GI injury. We hope this review will raise awareness and vigilance among clinicians of these entities to increase early diagnosis and rapid referral to specialist care.

Nuclear Receptor and Stress Response Pathways Associated with Antineoplastic Agent-Induced Diarrhea

In severe cases, antineoplastic agent-induced diarrhea may be life-threatening; therefore, it is necessary to determine the mechanism of toxicity and identify the optimal management. The mechanism of antineoplastic agent-induced diarrhea is still unclear but is often considered to be multifactorial. The aim of this study was to determine the molecular initiating event (MIE), which is the initial interaction between molecules and biomolecules or biosystems, and to evaluate the MIE specific to antineoplastic agents that induce diarrhea. We detected diarrhea-inducing drug signals based on adjusted odds ratios using the Food and Drug Administration Adverse Event Reporting System. We then used the quantitative structure-activity relationship platform of Toxicity Predictor to identify potential MIEs that are specific to diarrhea-inducing antineoplastic agents. We found that progesterone receptor antagonists were potential MIEs associated with diarrhea. The findings of this study may help improve the prediction and management of antineoplastic agent-induced diarrhea.

Targeted therapy for breast cancer: An overview of drug classes and outcomes

The last 25 years have seen significant growth in new therapeutic options for breast cancer, termed targeted therapies based on their ability to block specific pathways known to drive breast tumor growth and survival. Introduction of these drugs has been made possible through advances in the understanding of breast cancer biology. While the promise of targeted therapy for breast cancer has been clear for some time, the experience of the clinical use of multiple drugs and drug classes allows us to now present a summary and perspective as to the success and impact of this endeavor. Here we will review breast cancer targeted therapeutics in clinical use. We will provide the rationale for their indications and summarize clinical data in patients with different breast cancer subtypes, their impact on breast cancer progression and survival and their major adverse effects. The focus of this review will be on the development that has occurred within classes of targeted therapies and subsequent impact on breast cancer patient outcomes. We will conclude with a perspective on the role of targeted therapy in breast cancer treatment and highlight future areas of development.

Antibiotic treatment targeting gram negative bacteria prevents neratinib-induced diarrhea in rats

Background

Neratinib is a pan-ErbB tyrosine kinase inhibitor used for extended adjuvant treatment of HER2-positive breast cancer. Diarrhea is the main adverse event associated with neratinib treatment. We aimed here to determine whether antibiotic-induced gut microbial shifts altered development of neratinib-induced diarrhea.

Methods

Female Albino Wistar rats (total n = 44) were given antibiotics (vancomycin, neomycin, or a cocktail of vancomycin, neomycin and ampicillin) in drinking water for four weeks, and then treated daily with neratinib (50 mg/kg) for 28 days. Diarrhea, along with markers of gastrointestinal damage and microbial alterations were measured by histopathology and 16S sequencing, respectively.

Results

Rats treated with vancomycin or neomycin had significantly lower levels of diarrhea than rats treated with neratinib alone. In the distal ileum, neratinib was associated with a statistically significant increase in histological damage in all treatment groups expect the antibiotic cocktail. Key features included villous blunting and fusion and some inflammatory infiltrate. Differences in microbial composition at necropsy in vehicle control, neratinib and neratinib + neomycin groups, were characterized by a neratinib-induced increase in gram-negative bacteria that was reversed by neomycin. Neomycin shifted bacterial composition so that Blautia become the dominant genus.

Conclusions

Narrow spectrum antibiotics reduced neratinib-induced diarrhea. This suggests that the microbiome may play a key role in the development and prolongation of diarrhea following neratinib treatment, although further research is required to understand the key bacteria and mechanisms by which they reduce diarrhea, as well as how this may impact presentation of diarrhea in clinical cohorts.

Three Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer: Similarities and Differences

Osimertinib, almonertinib and furmonertinib are third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) approved for non-small cell lung cancer (NSCLC) patients with EGFR T790M mutation. This article reviews research advances in pharmacokinetics, pharmacodynamics, treatment-related adverse events, and other aspects related to the three EGFR-TKIs were systematically reviewed in order to provide references for clinical drug selection. There are differences in dosing schedule and incidence of adverse events among three drugs. Optimization of third-generation EGFR-TKIs options for individuals may produce the maximal benefits to NSCLC patients with EGFR T790M mutation.

Renal Safety Profile of EGFR Targeted Therapies: A Study from VigiBase® the WHO Global Database of Individual Case Safety Reports

Kidney EGFR expression together with reported cases of glomerular diseases in the context of anti-EGFR drug administration raise concerns about the renal safety profile of these drugs. This issue is addressed in a case/non-case study carried out on VigiBase®, the WHO global database of individual case safety reports (ICRS). Disproportionality analysis of renal adverse effects related to the selected anti-EGFR drugs, erlotinib, gefitinib, afatinib, osimertinib, cetuximab and panitumumab, was assessed using the reporting odds ratio (ROR). Nine hundred and eighty-nine ICRSs were included. A signal of disproportionate reporting (SDR) was found for afatinib (ROR = 2.70; 95% CI [2.22-3.29]) and erlotinib (ROR = 1.73; 95% CI [1.46-2.04]) with acute kidney injury, and for afatinib (ROR = 2.41; 95% CI [1.78-3.27]), cetuximab (ROR = 1.42; 95% CI [1.14-1.78]) and erlotinib (ROR = 2.23; 95% CI [1.80-2.77]) with renal failure. The preferred term "diarrhoea" was frequently reported in the included cases. An SDR was found for erlotinib with haemolytic and uremic syndrome (ROR = 4.01; 95% CI [1.80-8.94]) and thrombotic microangiopathy (ROR = 4.94; 95% CI [2.80-8.72]). No SDR was seen for glomerular or tubule-interstitial diseases. This study showed that the anti-EGFR drug renal toxicity is mainly related to renal failure in the context of digestive toxicity.

Diarrhea Induced by Small Molecule Tyrosine Kinase Inhibitors Compared With Chemotherapy: Potential Role of the Microbiome

Small molecule receptor tyrosine kinase inhibitors (SM-TKIs) are among a group of targeted cancer therapies, intended to be more specific to cancer cells compared with treatments, such as chemotherapy, hence reducing adverse events. Unfortunately, many patients report high levels of diarrhea, the pathogenesis of which remains under investigation. In this article, we compare the current state of knowledge of the pathogenesis of chemotherapy-induced diarrhea (CID) in comparison to SM-TKI–induced diarrhea, and investigate how a similar research approach in both areas may be beneficial. To this end, we review evidence that both treatment modalities may interact with the gut microbiome, and as such the microbiome should be investigated for its ability to reduce the risk of diarrhea.

Calcium-activated chloride channel is involved in the onset of diarrhea triggered by EGFR tyrosine kinase inhibitor treatment in rats

EGFR tyrosine kinase inhibitors (TKIs) are mainly used to treat non-small cell lung cancer; however, adverse effects such as severe diarrhea represent a major obstacle towards the continuation of EGFR-TKIs therapy. Chloride channels, which control the fluid flow in the intestinal lumen, are proposed as an important target to remediate EGFR-TKIs-induced diarrhea, but the mechanism remains unclear. The aim of this study was to clarify the mechanism underlying EGFR-TKIs-induced diarrhea with a particular focus on the role of intestinal chloride channels. Here, we show that osimertinib-treated rats exhibit diarrhea and an increase in fecal water content without showing any severe histopathological changes. This diarrhea was attenuated by intraperitoneal treatment with the calcium-activated chloride channel (CaCC) inhibitor CaCCinh-A01. These findings were confirmed in afatinib-treated rats with diarrhea. Moreover, treatment with the Japanese traditional herbal medicine, hangeshashinto (HST), decreased fecal water content and improved fecal appearance in rats treated with EGFR-TKIs. HST inhibited the ionomycin-induced CaCC activation in HEK293 cells in patch-clamp current experiments and its active ingredients were identified. In conclusion, secretory diarrhea induced by treatment with EGFR-TKIs might be partially mediated by the activation of CaCC. Therefore, blocking the CaCC could be a potential new treatment for EGFR-TKI-induced diarrhea.

Potentiation of calcium-activated chloride secretion and barrier dysfunction may underlie EGF receptor tyrosine kinase inhibitor-induced diarrhea

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFr TKIs) are first‐line therapies for various cancers, and cause dose‐limiting severe diarrhea in many patients. We hypothesized that diarrhea caused by EGFr TKIs might reflect actions on epithelial transport, barrier function, or both, which we tested using cell cultures including murine and human enteroid‐derived monolayers (EDMs), analyzed using electrophysiological and other relevant methods. EGFr TKIs (such as afatinib, erlotinib, and osimertinib) reversed the acute inhibitory effect of EGF on chloride secretion induced by carbachol (CCh) across T84 human colonic epithelial cells, which correlated with the diarrhea‐inducing effect of each agent clinically. EGFr TKIs also reduced transepithelial electrical resistance (TEER), whereas co‐treatment with CCh delayed the decrease in TEER compared with that of cells co‐treated with EGF. Furthermore, afatinib and erlotinib prevented EGF‐ or CCh‐induced EGFr phosphorylation. EGFr TKIs also suppressed phosphorylation of extracellular signal‐regulated kinase (Erk)1/2 in response to EGF, whereas they had weaker effects on CCh‐induced Erk1/2 phosphorylation. In human EDMs, EGF potentiated ion transport induced by CCh, whereas afatinib reversed this effect. The ability of EGFr TKIs to reverse the effects of EGF on calcium‐dependent chloride secretion could contribute to the diarrheal side effects of these agents, and their disruption of epithelial barrier dysfunction is likely also pathophysiologically significant. CCh‐activated Erk1/2 phosphorylation was relatively insensitive to EGFr TKIs and delayed the deleterious effects of EGFr TKIs on barrier function. These findings confirm and extend those of other authors, and may be relevant to designing strategies to overcome the diarrheal side effects of EGFr TKIs.

Pancreatic Insufficiency in Patients Under Sorafenib Treatment for Hepatocellular Carcinoma

GOALS

To describe the occurrence of malabsorption (MA) in hepatocellular carcinoma (HCC) patients under sorafenib, the potential relationship with pancreatic insufficiency (PI), and the role of pancreatic enzymes supplementation.

BACKGROUND

With the increasing options of second-line systemic therapies for HCC, the recognition of drug intolerance using practical tools is crucial. It has been proposed that a MA syndrome could be due to sorafenib-induced pancreatic dysfunction.

STUDY

All sorafenib-treated patients with suspicion of MA (defined as decreased stool consistency lasting >4 wk or presenting ≥10% body weight loss without HCC progression) were prospectively evaluated by serum markers, endoscopy, and imaging techniques.

RESULTS

We evaluated 81 sorafenib-treated patients and 21 developed MA suspicion (85.7% male, 81.5% Child-Pugh A, 52.4% BCLC-B, and 47.6% BCLC-C) within a median 5.9 months after starting sorafenib. The median treatment duration, follow-up, and overall survival after MA suspicion were 5.9, 20.3, and 20.3 months, respectively. Nine of them (42.9%) presented hyperparathyroidism secondary to vitamin D deficiency and 8 with PI. A gradual decrease in pancreatic volume of up to 19% was observed among patients with PI. Six of the 8 patients with PI received pancreatic enzymes, with complete recovery from MA symptoms and stabilization of pancreatic volume.

CONCLUSIONS

We validated the association between MA and PI in 10% of sorafenib-treated patients. Pancreatic enzymes supplementation successfully led to symptomatic recovery. Awareness of this adverse event can help in the management of sorafenib irrespective of cancer type and likely, of other tyrosine kinase inhibitors for HCC patients.

Neoadjuvant docetaxel with or without carboplatin plus dual HER2 blockade for HER2-positive breast cancer: a retrospective multi-center Chinese study

Background

This study aimed to compare the real-world efficacy and safety of the TCbHP regimen (docetaxel, carboplatin, trastuzumab and pertuzumab) and the THP regimen (docetaxel, trastuzumab and pertuzumab) as neoadjuvant therapy for Chinese patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

Methods

We compared efficacy and safety outcomes from 72 Chinese patients with HER2-positive breast cancer who underwent neoadjuvant dual HER2 blockade plus TCb or T chemotherapy and surgery between March 2019 and June 2020.

Results

All 72 patients were women (32-76 years old) and the overall pathological complete response (pCR) rate was 70.8% (51/72). The pCR rates were 76.1% (35/46) for the TCbHP regimen and 61.5% (16/26) for the THP regimen (P=0.28). Univariate analyses revealed that pCR was associated with clinical T classification (P=0.024), AJCC stage (P=0.042), estrogen receptor (ER) status (P=0.002), progesterone receptor (PR) status (P=0.035), Ki-67 index (P<0.001), and immunohistochemical HER2 status (P<0.001). Multivariate analyses revealed that pCR was independently predicted by ER status (OR: 0.227, 95% CI: 0.053-0.852; P=0.032) and immunohistochemical HER2 status (OR: 43.673, 95% CI: 6.801-875.86; P<0.001). The common adverse events for both regimens included neutropenia, anemia, thrombocytopenia, nausea, and diarrhea. Relative to the THP group, the TCbHP group had higher frequencies of grade 3-4 thrombocytopenia (17% vs. 0%, P=0.044) and grade 3-4 diarrhea (15% vs. 0%, P=0.044). Both regimens had very good cardiac safety.

Conclusions

These results suggest that both TCbHP and THP regimens may be useful neoadjuvant treatments for high-risk early or locally advanced HER2-positive breast cancer. Both regimens had generally good safety outcomes, although clinicians should be aware of the risks of grade 3-4 thrombocytopenia and diarrhea during TCbHP treatment. Elderly patients who require neoadjuvant therapy may benefit from 6 cycles of THP treatment, based on its good efficacy and mild adverse events.

Potential Successes and Challenges of Targeted Cancer Therapies

The concept and realization of targeted anticancer therapy (TAT) have existed for at least two decades and continue to expand rapidly. It has become clear that there is no "magic bullet" to cure cancer and that even TATs are unlikely to be successful as single agents, necessitating combination with chemotherapy, radiotherapy, or even other targeting agents. The other promise that has not been fulfilled by TAT is that of reduced toxicity. It was thought that by targeting receptors on or within cells, rather than particular phases of the cell cycle, TATs would not be toxic. However, it turns out that the targets also exist on or within normal cells and that there is even cross-reactivity between receptors on nontarget tissues. All of this results in toxicity, the mechanism of which are the same as the mechanism of action of the drugs, making toxicity reduction or prevention very difficult. This leads to new toxicities with new targeted treatments. Nevertheless, all of the above should not detract from the obvious successes of targeted agents, which have turned several acutely fatal cancers into chronic diseases and rendered some hitherto untreatable cancers into treatable diseases.

Pathophysiology of neratinib-induced diarrhea in male and female rats: microbial alterations a potential determinant

BACKGROUND

Neratinib is a potent irreversible pan-ErbB tyrosine kinase inhibitor, approved by the FDA for extended adjuvant treatment of HER2-positive breast cancer. Diarrhea is the most frequently observed adverse event with tyrosine kinase inhibitor therapy. In this study, we developed a reproducible model for neratinib-induced diarrhea in male and female rats.

METHODS

At first, male rats were treated with neratinib at 15, 30 or 50 mg/kg or vehicle control via oral gavage for 28 days (total n = 12). Secondly, we compared outcomes of male (n = 7) and female (n = 8) rats, treated with 50 mg/kg neratinib.

RESULTS

Rats treated with a 50 mg/kg daily dose of neratinib had a reproducible and clinically relevant level of diarrhea and therefore was confirmed as an appropriate dose. Male rats treated with neratinib had significant changes to their gut microbiome. This included neratinib-induced increases in Ruminococcaceae (P = 0.0023) and Oscillospira (P = 0.026), and decreases in Blautia (P = 0.0002). On average, female rats experienced more significant neratinib-induced diarrhea (mean grade 1.526) compared with male rats (mean grade 1.182) (P < 0.0001). Neratinib caused a reduction in percentage weight gain after 28 days of treatment in females (P = 0.0018) compared with vehicle controls. Females and males both showed instances of villus atrophy and fusion, most severely in the distal ileum. Serum neratinib concentration was higher in female rats compared to male rats (P = 0.043).

CONCLUSIONS

A reproducible diarrhea model was developed in both female and male rats, which indicated that diarrhea pathogenesis is multifactorial, including anatomical disruption particularly evident in the distal ileum, and alterations in microbial composition.

A case of torsades de pointes induced by the third-generation EGFR-TKI, osimertinib combined with moxifloxacin

Background

Torsade de pointes (TdP) is a malignant arrhythmia that can be induced by QT internal prolongation due to a variety of factors. Here we report an elderly patient with advanced non-small cell lung cancer (NSCLC) had sudden TdP during hospitalization, which was caused by multiple factors such as osimertinib, moxifloxacin and patient self-factors.

Case presentation

An 85-year-old man with advanced NSCLC with brain andbone metastasis was initially treated with gefitinib targeted therapy. After 4 months treatment, the patient developed drug resistance and a second genetic testing revealed that the T790M mutation was positive. And the patient was then changed to targeted therapy with osimertinib, followed by adverse reactions of varying severity such as diarrhea, electrolyte imbalance, decreased cardiac function, leukopenia, and prolonged QTc interval. Six months after the administration of osimertinib, the patient was admitted to the hospital, chest CT showed the lesion progressed again, and during which hospital-acquired infection occurred. After concomitant use of moxifloxacin, the patient had sudden TdP, and finally died of this cardiac event.

Conclusions

It is suggested that clinicians need to identify patients with high risk factors of TdP, and consider comprehensively in concomitant medication to avoid such events to the greatest extent.

Safety of EGFR-TKIs for EGFR mutation-positive non-small cell lung cancer

Introduction: Lung cancer is the most prevalent malignant tumors worldwide. Over the past decade, the emergence of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has ushered in a new era of lung cancer treatment. Therefore, clinical trials investigating the efficacy and safety of these drugs are important.Areas covered: This review provides an overview on the safety of three classes of EGFR-TKIs and discusses the adverse events (AEs) and reactions reported in the literature.Expert opinion: EGFR-TKIs significantly improve progression-free survival and overall survival in non-small cell lung cancer (NSCLC) patients with an activating mutation of EGFR. However, EGFR-TKIs also block the EGFR-regulating pathways in the skin and gastrointestinal tract and cause AEs, including diarrhea, liver toxicity, skin disease, stomatitis, interstitial lung disease, and ocular toxicity, which have detrimental effects on quality of life and drug compliance. Clinicians should understand how to prevent and control these adverse reactions, which can often be achieved by dose reduction, discontinuation of treatment, or switching to another drug.

Combination Compositions Composed of l-Glutamine and Si-Jun-Zi-Tang Might Be a Preferable Choice for 5-Fluorouracil-Induced Intestinal Mucositis: An Exploration in a Mouse Model

Intestinal mucositis is a common toxicity of many anti-neoplastic therapies that negatively influences health, the quality of life, economic outcomes, and even the success of cancer treatment. Unfortunately, there is presently no optimal medicine that is able to effectively manage this condition. l-glutamine is one of the most frequently used agent in practice among the limited treatment choices due to its safety and inexpensiveness despite there being a lack of evidence. Previous studies indicated that l-glutamine may alleviate mucositis and mucosal atrophy but failed to improve patients' macroscopic conditions, such as the occurrence of diarrhea. A compound glutamine capsule (G-SJZ), composed of l-glutamine and the traditional Chinese herbal formula Si-Jun-Zi-Tang, has been used in China for 23 years to treat many types of gastrointestinal diseases, including gastrointestinal reactions induced by radiotherapy and chemotherapy. However, the exact effect of G-SJZ on intestinal mucositis is unclear, and moreover, whether l-glutamine combined with Si-Jun-Zi-Tang is more effective than l-glutamine alone have not been studied. In the current study, we explored the effects of G-SJZ and l-glutamine in a mouse model of intestinal mucositis induced by 5-fluorouracil (5-Fu). The results revealed that pretreatment with G-SJZ ameliorated the physical manifestations of weight loss and the severity of diarrhea following continuous 5-Fu injections in mice. Likewise, the histopathological damage and the destruction of villus and crypt structures in the intestinal mucosa as well as the increase in circulating intestinal injury markers caused by 5-Fu were reversed with G-SJZ pretreatment. Furthermore, the protective effect of G-SJZ was accompanied by modulations in the immunohistochemical expression of tight junction proteins. Interestingly, although treatment with a dose of l-glutamine alone that was equivalent to the dose in G-SJZ also showed a protective effect, it did not appear to be as strong as treatment with G-SJZ. Si-Jun-Zi-Tang in G-SJZ may compensate for the deficiencies of l-glutamine in this model which seems not to be related to the regulation of tight junction proteins. Our study is the first to suggest that the combined use of l-glutamine and Si-Jun-Zi-Tang might be more effective than l-glutamine alone despite exact mechanism still needs further study. Because of the limited number of therapeutic agents, G-SJZ is likely to be a preferable choice for intestinal mucositis.

A Citrulline-Based Translational Population System Toxicology Model for Gastrointestinal-Related Adverse Events Associated With Anticancer Treatments

Gastrointestinal (GI)-related adverse events (AEs) are commonly observed in the clinic during cancer treatments. Citrulline is a potentially translatable biomarker of GI AEs. In this study, irinotecan-induced citrulline changes were studied for a range of doses and schedules in rats. A translational system toxicology model for GI AEs using citrulline was then developed based on new experimental data and parameters from a literature intestinal cell dynamic model. With the addition of feedback-development and tolerance-development mechanisms, the model well captured the plasma citrulline profiles after irinotecan treatment in rats. Subsequently, the model was translated to humans and predicted the observed GI AE dynamics in humans including dose-scheduling effect using the cytotoxic and feedback parameters estimated in rats with slight calibrations. This translational toxicology model could be used for other antineoplastic drugs to simulate various clinical dosing scenarios before human studies and mitigate potential GI AEs.

Pertuzumab in the treatment of HER2-positive breast cancer: an evidence-based review of its safety, efficacy, and place in therapy

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is a distinct subset of breast cancer that results from overexpression of HER2 protein. Pertuzumab-a recombinant humanized monoclonal antibody that binds to the extracellular dimerization domain II of HER2-was recently approved for adjuvant therapy and neoadjuvant therapy of HER2-positive early breast cancer. As pertuzumab and trastuzumab bind to different domains of the extracellular dimerization domain of HER2, a combination therapy of pertuzumab and trastuzumab is beneficial for the treatment of metastatic cancer, advanced local cancer, or early cancer by dual HER2 blockage. Many clinical trials have been performed using pertuzumab for breast cancer patients; these include the CLEOPATRA trial for palliative therapy, the APHINITY trial for adjuvant therapy, and the NeoSphere and the TRYPHAENA trials for neoadjuvant therapy. These trials revealed pertuzumab to be a safe and effective drug regardless of the patient age and hormone receptor status. Notably, pertuzumab use was associated with severe cardiac toxicity in some cases; however, the risk of pertuzumab-induced cardiac dysfunction was low. The most common adverse effect associated with pertuzumab-use was diarrhea, but most cases were not severe. Several different chemotherapeutic agents have been investigated to determine optimal chemotherapeutic combinations for dual HER2 blockage. Some exploratory analyses indicate that pertuzumab treatment offered little benefit to patients with node-negative and small primary tumors; pertuzumab treatment was also found not be cost-effective. Further research will reveal the appropriate usage of pertuzumab for treating a subset of eligible patients.

Safety and Tolerability of Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors in Oncology

Tyrosine kinase inhibitors (TKIs) that target epidermal growth factor receptor (EGFR) have dramatically improved progression-free survival in non-small-cell lung cancer (NSCLC) patients who carry sensitizing EGFR-activating mutations and in patients with breast and pancreatic cancers. However, EGFR-TKIs are associated with significant and disabling undesirable effects that adversely impact on quality of life and compliance. These effects include dermatological reactions, diarrhoea, hepatotoxicity, stomatitis, interstitial lung disease and ocular toxicity. Each individual EGFR-TKI is also associated with additional adverse effect(s) that are not shared widely by the other members of its class. Often, these effects call for dose reduction, treatment discontinuation or pharmacotherapeutic intervention. Since dermatological effects result from on-target effects on wild-type EGFR, rash is often considered to be a biomarker of efficacy. A number of studies have reported better outcomes in patients with skin reactions compared with those without. This has led to a 'dosing-to-rash' strategy to optimize therapeutic outcomes. Although conceptually attractive, there is currently insufficient evidence-based support for this strategy. While skin reactions following EGFR-TKIs are believed to result from an effect on wild-type EGFR, their efficacy is related to effects on mutant variants of EGFR. It is noteworthy that newer EGFR-TKIs that spare wild-type EGFR are associated with fewer dermatological reactions. Furthermore, secondary mutations such as T790M in exon 20 often lead to development of resistance to the clinical activity and efficacy of first- and second-generation EGFR-TKIs. This has stimulated the search for later-generations of EGFR-TKIs with the ability to overcome this resistance and with greater target selectivity to spare wild-type EGFR in expectations of an improved safety profile. However, available data reviewed herein indicate that not only are these newer agents associated with the aforementioned adverse effects typical of earlier agents, but they are also susceptible to resistance due to tertiary mutations, most frequently C797S. At least three later-generation EGFR-TKIs, canertinib, naquotinib and rociletinib, have been discontinued from further development in NSCLC following concerns about their safety and risk/benefit.

Pertuzumab in HER2-positive early breast cancer: current use and perspectives

Although the prognosis of HER2-positive breast cancer patients has dramatically improved with modern chemotherapy and the monoclonal antibody trastuzumab, up to 31% of them will experience a recurrence in the long term. After the unprecedented benefit in overall survival with the addition of the second monoclonal antibody pertuzumab for patients with metastatic disease, the drug was tested with various degrees of success in the preoperative and postoperative settings. In this review, we will focus on the pharmacologic aspects of the drug, including mechanism of action and toxicities, and discuss clinical data regarding its use in advanced and early stage HER2-positive breast cancer, placing in perspective the pros and cons regarding other available drugs and biomarkers.

Intestinal epithelial potassium channels and CFTR chloride channels activated in ErbB tyrosine kinase inhibitor diarrhea

Diarrhea is a major side effect of ErbB receptor tyrosine kinase inhibitors (TKIs) in cancer chemotherapy. Here, we show that the primary mechanism of ErbB TKI diarrhea is activation of basolateral membrane potassium (K+) channels and apical membrane chloride (Cl-) channels in intestinal epithelia and demonstrate the efficacy of channel blockers in a rat model of TKI diarrhea. Short-circuit current in colonic epithelial cells showed that the TKIs gefitinib, lapatinib, and afatinib do not affect basal secretion but amplify carbachol-stimulated secretion by 2- to 3-fold. Mechanistic studies with the second-generation TKI afatinib showed that the amplifying effect on Cl- secretion was Ca2+ and cAMP independent, was blocked by CF transmembrane conductance regulator (CFTR) and K+ channel inhibitors, and involved EGFR binding and ERK signaling. Afatinib-amplified activation of basolateral K+ and apical Cl- channels was demonstrated by selective membrane permeabilization, ion substitution, and channel inhibitors. Rats that were administered afatinib orally at 60 mg/kg/day developed diarrhea with increased stool water from approximately 60% to greater than 80%, which was reduced by up to 75% by the K+ channel inhibitors clotrimazole or senicapoc or the CFTR inhibitor (R)-BPO-27. These results indicate a mechanism for TKI diarrhea involving K+ and Cl- channel activation and support the therapeutic efficacy of channel inhibitors.

Varlitinib Downregulates HER/ERK Signaling and Induces Apoptosis in Triple Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is a complex disease associated with the aggressive phenotype and poor prognosis. TNBC harbors heterogeneous molecular subtypes with no approved specific targeted therapy. It has been reported that HER receptors are overexpressed in breast cancer including TNBC. In this study, we evaluated the efficacy of varlitinib, a reversible small molecule pan-HER inhibitor in TNBC. Our results showed that varlitinib reduced cell viability and induced cell apoptosis in most TNBC cell lines but not in MDA-MB-231 cells. MEK and ERK inhibition overcame resistance to varlitinib in MDA-MB-231 cells. Varlitinib inhibited HER signaling which led to inhibition of migration, invasion and mammosphere formation of TNBC cells as well as significant suppression of tumor growth of MDA-MB-468 xenograft mouse model. In summary, these results suggest that HER signaling plays an important role in TNBC progression and that pan-HER inhibition is potentially an effective treatment for TNBC patients.

Phase Ib study evaluating safety and clinical activity of the anti-HER3 antibody lumretuzumab combined with the anti-HER2 antibody pertuzumab and paclitaxel in HER3-positive, HER2-low metastatic breast cancer

Purpose To investigate the safety and clinical activity of comprehensive human epidermal growth factor receptor (HER) family receptor inhibition using lumretuzumab (anti-HER3) and pertuzumab (anti-HER2) in combination with paclitaxel in patients with metastatic breast cancer (MBC). Methods This phase Ib study enrolled 35 MBC patients (first line or higher) with HER3-positive and HER2-low (immunohistochemistry 1+ to 2+ and in-situ hybridization negative) tumors. Patients received lumretuzumab (1000 mg in Cohort 1; 500 mg in Cohorts 2 and 3) plus pertuzumab (840 mg loading dose [LD] followed by 420 mg in Cohorts 1 and 2; 420 mg without LD in Cohort 3) every 3 weeks, plus paclitaxel (80 mg/m2 weekly in all cohorts). Patients in Cohort 3 received prophylactic loperamide treatment. Results Diarrhea grade 3 was a dose-limiting toxicity of Cohort 1 defining the maximum tolerated dose of lumretuzumab when given in combination with pertuzumab and paclitaxel at 500 mg every three weeks. Grade 3 diarrhea decreased from 50% (Cohort 2) to 30.8% (Cohort 3) with prophylactic loperamide administration and omission of the pertuzumab LD, nonetheless, all patients still experienced diarrhea. In first-line MBC patients, the objective response rate in Cohorts 2 and 3 was 55% and 38.5%, respectively. No relationship between HER2 and HER3 expression or somatic mutations and clinical response was observed. Conclusions Combination treatment with lumretuzumab, pertuzumab and paclitaxel was associated with a high incidence of diarrhea. Despite the efforts to alter dosing, the therapeutic window remained too narrow to warrant further clinical development.

TRIAL REGISTRATION

on ClinicalTrials.gov with the identifier NCT01918254 first registered on 3rd July 2013.

Phase Ib Study of Lumretuzumab Plus Cetuximab or Erlotinib in Solid Tumor Patients and Evaluation of HER3 and Heregulin as Potential Biomarkers of Clinical Activity

Purpose: This study investigated the safety, clinical activity, and target-associated biomarkers of lumretuzumab, a humanized, glycoengineered, anti-HER3 monoclonal antibody (mAb), in combination with the EGFR-blocking agents erlotinib or cetuximab in patients with advanced HER3-positive carcinomas.Experimental Design: The study included two parts: dose escalation and dose extension phases with lumretuzumab in combination with either cetuximab or erlotinib, respectively. In both parts, patients received lumretuzumab doses from 400 to 2,000 mg plus cetuximab or erlotinib according to standard posology, respectively. The effect of HRG mRNA and HER3 mRNA and protein expression were investigated in a dedicated extension cohort of squamous non-small cell lung cancer (sqNSCLC) patients treated with lumretuzumab and erlotinib.Results: Altogether, 120 patients were treated. One dose-limiting toxicity (DLT) in the cetuximab part and two DLTs in the erlotinib part were reported. The most frequent adverse events were gastrointestinal and skin toxicities, which were manageable. The objective response rate (ORR) was 6.1% in the cetuximab part and 4.2% in the erlotinib part. In the sqNSCLC extension cohort of the erlotinib part, higher tumor HRG and HER3 mRNA levels were associated with a numerically higher disease control rate but not ORR.Conclusions: The toxicity profile of lumretuzumab in combination with cetuximab and erlotinib was manageable, but only modest clinical activity was observed across tumor types. In the sqNSCLC cohort, there was no evidence of meaningful clinical benefit despite enriching for tumors with higher HRG mRNA expression levels. Clin Cancer Res; 23(18); 5406-15. ©2017 AACR.

Incidence and management of diarrhea in patients with HER2-positive breast cancer treated with pertuzumab

Background

Pertuzumab disrupts heterodimerization between human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR), HER3, and HER4. Thus, pertuzumab could result in adverse events similar to those observed with EGFR antagonists, such as diarrhea. We report the incidence and severity of diarrhea observed with pertuzumab in the CLEOPATRA, NeoSphere, and TRYPHAENA studies.

Patients and methods

Patients (n = 1443) had metastatic [CLEOPATRA (n = 804)] or early-stage breast cancer [NeoSphere (n = 416) and TRYPHAENA (n = 223)]. The incidence and severity of diarrhea were analyzed by treatment received. The incidence of febrile neutropenia concurrent with diarrhea and the effect of pre-existing gastrointestinal comorbidities were also evaluated. Subgroup analyses were carried out using CLEOPATRA data.

Results

The incidence of all-grade diarrhea across studies was generally greater for pertuzumab-based treatment, ranging from 28% to 72% (grade 1, 21%-54%; grade 2, 8%-37%; grade 3, 0%-12%; grade 4, 0%). Incidence was highest during the first pertuzumab-containing cycle, decreasing with subsequent cycles. Dose delays or discontinuations due to diarrhea were infrequent, ranging from 0% to 8%. Among pertuzumab-treated patients with diarrhea, 47%-67% received pharmacological intervention, most commonly with loperamide. Overlap between diarrhea and febrile neutropenia was uncommon, ranging from 0% to 11%. No relationship was observed between pre-existing gastrointestinal comorbidities and diarrhea. In CLEOPATRA, patients ≥65 years treated with pertuzumab had a higher incidence of grade 3 diarrhea than patients <65 years (19% versus 8%). All-grade diarrhea occurred at greater frequency among pertuzumab-treated Asian versus white patients with metastatic breast cancer (74% versus 63%); the corresponding rates in the control arm were 53% and 45%, respectively.

Conclusions

In both the metastatic and early-stage breast cancer settings, diarrhea was common but manageable for all pertuzumab-containing regimens. Diarrheal episodes were mainly low grade and occurred most often during the first treatment cycle. Diarrheal-related drug delays or discontinuations were uncommon.

ClinicalTrials.gov identifiers

NCT00567190 (CLEOPATRA), NCT00545688 (NeoSphere), NCT00976989 (TRYPHAENA).

Dacomitinib-induced diarrhoea is associated with altered gastrointestinal permeability and disruption in ileal histology in rats

Dacomitinib-an irreversible pan-ErbB tyrosine kinase inhibitor (TKI)-causes diarrhoea in 75% of patients. Dacomitinib-induced diarrhoea has not previously been investigated and the mechanisms remain poorly understood. The present study aimed to develop an in-vitro and in-vivo model of dacomitinib-induced diarrhoea to investigate underlying mechanisms. T84 cells were treated with 1-4 μM dacomitinib and resistance and viability were measured using transepithelial electrical resistance (TEER) and XTT assays. Rats were treated with 7.5 mg/kg dacomitinib daily via oral gavage for 7 or 21 days (n = 6/group). Weights, and diarrhoea incidence were recorded daily. Rats were administered FITC-dextran 2 hr before cull, and serum levels of FITC-dextran were measured and serum biochemistry analysis was conducted. Detailed histopathological analysis was conducted throughout the gastrointestinal tract. Gastrointestinal expression of ErbB1, ErbB2 and ErbB4 was analysed using RT-PCR. The ileum and the colon were analysed using multiplex for expression of various cytokines. T84 cells treated with dacomitinib showed no alteration in TEER or cell viability. Rats treated with dacomitinib developed severe diarrhoea, and had significantly lower weight gain. Further, dacomitinib treatment led to severe histopathological injury localised to the ileum. This damage coincided with increased levels of MCP1 in the ileum, and preferential expression of ErbB1 in this region compared to all other regions. This study showed dacomitinib induces severe ileal damage accompanied by increased MCP1 expression, and gastrointestinal permeability in rats. The histological changes were most pronounced in the ileum, which was also the region with the highest relative expression of ErbB1.

HALT-D: A Phase II Evaluation of Crofelemer for the Prevention and Prophylaxis of Diarrhea in Patients With Breast Cancer on Pertuzumab-Based Regimens

Approximately 40% to 80% of patients receiving pertuzumab-directed therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer will develop chemotherapy-induced diarrhea (CID). Loperamide and octreotide are frequently used to treat CID after diarrhea occurs, but neither is used prophylactically or targets the underlying mechanism. Previous studies suggest blocking epidermal growth factor receptor may cause excess chloride secretion, resulting in diarrhea. Crofelemer is derived from the red latex of the Croton lechleri tree, blocks gastrointestinal cystic fibrosis transmembrane regulator and calcium-activated chloride channels, and is U.S. Food and Drug Administration approved for relief of diarrhea in HIV/AIDS patients on anti-retroviral therapy. Crofelemer is not systemically absorbed, has relatively few side effects, and presents a targeted approach at preventing CID in patients receiving pertuzumab-based therapy. HALT-D (DiarrHeA Prevention and ProphyLaxis with Crofelemer in HER2-Positive Breast Cancer Patients Receiving Trastuzumab, Pertuzumab, and Docetaxel or Paclitaxel with or without Carboplatin, NCT02910219) is a phase II, randomized, open-label trial that aims to recruit 46 patients from 3 MedStar sites. Adults with HER2-positive breast cancer being treated with trastuzumab, pertuzumab, and docetaxel or paclitaxel (THP) or trastuzumab, pertuzumab, docetaxel, and carboplatin (TCHP) will be randomized to receive crofelemer or no medication for diarrhea prophylaxis. The primary endpoint is incidence of all grade diarrhea for ≥ 2 consecutive days during cycles 1 to 2 of THP or TCHP. Secondary endpoints include overall incidence, duration, and severity of diarrhea; time to onset of diarrhea; use of other anti-diarrheal medications; stool frequency and consistency; and quality of life. HALT-D will provide important information about the feasibility and tolerability of crofelemer in preventing diarrhea for patients receiving THP or TCHP.

Neratinib in HER-2-positive breast cancer: results to date and clinical usefulness

The management of HER-2-positive breast cancer has improved significantly with the use of targeted agents to the HER-2 signaling pathway. Despite the improved survival achieved with the use of trastuzumab and chemotherapy in both the adjuvant and metastatic setting, patients may still recur or progress; whilst preclinical data demonstrate that these cancer cells remain addicted to the HER-2 oncogene. Neratinib, an oral small molecule tyrosine-kinase inhibitor has efficacy in the metastatic and adjuvant setting of patients who have previously received trastuzumab-based treatment. Diarrhea, being a class effect of tyrosine-kinase inhibitor, is the most common side effect seen following neratinib administration, but recent data suggests that a prophylactic loperamide regimen can reduce the incidence of grade 3 diarrhea. Phase I through to III clinical trials of neratinib will be reviewed, with discussion of the postulated mechanism underlying diarrheal events and its management.