Targeted therapy-induced diarrhea: A review of the literature

Targeted RT study: results on early toxicity of targeted therapies and radiotherapy

PURPOSE/OBJECTIVE

Currently, there are few prospective data on the tolerability of combining targeted therapies (TT) with radiation therapy (RT). The objective of this prospective study was to assess the feasibility and toxicity of pairing RT with concurrent TT in cancer patients. The aim was to enhance the existing evidence base for the simultaneous administration of targeted substances together with radiotherapy.

METHODS

Prospective study enrollment was conducted at a single institution between March 1, 2020, and December 31, 2021, for all patients diagnosed with histologically confirmed cancer who underwent external beam radiotherapy in combination with targeted therapy. The study, known as the "targeted RT study," was registered in the German Clinical Trials Register under DRKS00026193. Systematic documentation of the toxicity profiles of different targeted therapies was performed, and the assessment of acute toxicity followed the guidelines of the National Cancer Institute Common Terminology Criteria for Adverse Events Version v5.0.

RESULTS

A total of 334 patients underwent 683 radiation therapy series. During the course of RT, 51 different TT substances were concurrently administered. External beam radiotherapy was employed for various anatomical sites. The combination of RT and concurrent TT administration was generally well tolerated, with no instances of severe acute toxicity observed. The most commonly reported toxicity was fatigue, ranging from mild to moderate Common Terminology Criteria for Adverse Events (CTCAE) °I-°III. Other frequently observed toxicities included dermatitis, dyspnea, dysphagia, and dry cough. No toxicity greater than moderate severity was recorded at any point. In only 32 patients (4.7% of evaluated RT series), the concurrent substance administration was discontinued due to side effects. However, these side effects did not exceed mild severity according to CTCAE, suggesting that discontinuation was a precautionary measure. Only one patient receiving Imatinib treatment experienced a severe CTCAE °III side effect, leading to discontinuation of the concurrent substance due to the sudden occurrence of melaena during RT.

CONCLUSION

In conclusion, the current study did not demonstrate a significant increase or additional toxicity when combining radiotherapy and concurrent targeted therapy. However, additional research is required to explore the specific toxicity profiles of the various substances that can be utilized in this context.

TRIAL REGISTRATION NUMBER

DRKS00026193. Date of registration 12/27/2022 (retrospectively registered).

Reaffirming Adverse Events Related to Lung Cancer Survivors' Target Therapies and Their Apparent Effects on Fear of Cancer Progression, Anxiety, and Depression

BACKGROUND

Most advanced non-small-cell lung cancer (NSCLC) patients received targeted therapies of epidermal growth factor receptor tyrosine kinase inhibitors. However, few studies reported the relationships between adverse events (AEs) and psychological distress.

OBJECTIVES

The aims of this study were to (1) examine the differences in the incidence of AEs, fear of progression (FoP), anxiety, and depression among 3 generations of epidermal growth factor receptor tyrosine kinase inhibitors (first, gefitinib and erlotinib; second, afatinib; third, osimertinib) and (2) examine the difference in levels of FoP, anxiety, and depression between the presence and absence of AEs in NSCLC patients.

METHODS

This study used a cross-sectional study design. Patients with NSCLC (N = 120) were recruited from a medical center in northern Taiwan. Adverse events, FoP, anxiety, and depression were assessed by questionnaires.

RESULTS

The incidence rates of photosensitivity, mouth and throat sores, and diarrhea were significantly high in the gefitinib, erlotinib, and afatinib groups, respectively. A lesser proportion of patients experienced AEs in the osimertinib group, compared with those in the gefitinib and erlotinib, and afatinib groups. The incidence rates of FoP, anxiety, and depression were 13.8% to 26.0%, 24.1% to 40.4%, and 17.6% to 40.0%, respectively. Patients with photosensitivity, paronychia, and alopecia had significantly higher levels of FoP, anxiety, and depression.

CONCLUSION

This study confirmed the priorities of care among 3 generations of epidermal growth factor receptor tyrosine kinase inhibitors in NSCLC patients, using both the Common Terminology Criteria for Adverse Events (CTCAE 4.03) and PRO-CTCAE 1.0. Photosensitivity, paronychia, and alopecia were associated with higher levels of FoP, anxiety, and depression. Therefore, these AEs require further management.

IMPLICATIONS FOR PRACTICE

Our study suggests a follow-up to address AEs and psychological distress.

Cancer management from a chronic gastrointestinal function perspective

Bowel dysfunction in cancer is a significant and challenging issue for both clinicians and patients. As cancer survival improves, the impact of gastrointestinal symptoms on quality of life is of ever-increasing relevance. This review aims to provide an overview of the common gastrointestinal complaints seen in cancer sufferers and discuss the principles of management and up to date treatment options available.

Decisional conflict and its determinants among patients with cancer undergoing immunotherapy combined with chemotherapy or targeted therapy: a cross-sectional study

Decisional conflict might occur during shared decision-making (SDM) because immunotherapy is a rather novel treatment option for patients with cancer. To explore the prevalence and severity of physical and psychological symptoms and the effort invested in SDM in relation to decisional conflict among patients with cancer undergoing immunotherapy combined with chemotherapy or targeted therapy. This was a cross-sectional survey study. The SURE version of the Decisional Conflict Scale was used to screen cancer patients' decisional conflict status. Demographic or clinical characteristics, physical symptoms and psychological distress; efforts invested in the SDM process were also assessed as potential factors related to decisional conflict. One hundred seventeen patients surveyed, the prevalence of fatigue (79.5%), sleep disturbance (78.6%), poor appetite (67.5%), and pain (58.1%) symptoms were high and the severity was at moderate levels. The prevalence of pruritus (40.2%), rash (34.2%), dry skin (41.9%), and diarrhea (17.1%) symptoms were low and the severity was at mild levels. 65.8% of patients reported uncertainty, with mild to moderate levels. Furthermore, 97.4% of the patients made some effort in SDM, and the effort level was moderate (mean: 5.56 ± 2.02). 64.1% of patients were certain that immunotherapy was the best option. Age, uncertainty, and effort in the SDM process were major factors related to decisional conflict. We observed that older patients (age: ≥ 65) and those with higher uncertainty levels and less effort in SDM reported higher levels of decisional conflict. Future studies should explore older patients' decisional related needs of immunotherapy. Interventions should be designed to reduce the uncertainty experienced by patients with cancer and enhance their understanding of immunotherapy to enable them to take more effort in the SDM process.

Chitosan Oligosaccharide Promotes Junction Barrier through Modulation of PI3K/AKT and ERK Signaling Intricate Interplay in T84 Cells

Chitosan oligosaccharide (COS) is a breakdown product of chitin, a polymer of N-acetyl-D-glucosamine. COS promotes barrier function in intestinal epithelial cells. However, the exact mechanism of COS-induced barrier function remains unknown. This study was aimed to explore the intricate signaling cascades in the junction barrier induced by COS (100 μg/mL) in human intestinal epithelial cells (T84 cells). COS (100 μg/mL) promoted tight junction assembly and increased transepithelial electrical resistance (TEER). COS inhibited FITC-dextran flux in T84 cell monolayers at 2 h, 4 h, 6 h and 24 h post treatment. In addition, the effect of COS on TEER and FITC-dextran flux was abrogated by pre-incubation of wortmannin (2 μM), an AKT (protein kinase B) inhibitor, at 2 h and 4 h post treatment, indicating that COS-induced tight junction integrity was mediated at least in part by AKT activation. COS-induced TEER was amplified at 24 h and 48 h post treatment by pre-incubation with SC79 (2.5 μM), an AKT activator. Moreover, COS induced inhibition of extracellular signal-regulated kinase (ERK) in T84 cells. Wortmannin and SC79 pre-incubation promoted ERK activation and ERK inhibition, respectively, suggesting that COS-induced ERK inhibition was mediated by AKT. Collectively, this study reveals that COS promotes junction barrier integrity via regulating PI3K/AKT and ERK signaling intricate interplay in T84 cell monolayers. COS may be beneficial in promoting junction barrier in intestinal disorders.

HALT-D: a randomized open-label phase II study of crofelemer for the prevention of chemotherapy-induced diarrhea in patients with HER2-positive breast cancer receiving trastuzumab, pertuzumab, and a taxane

PURPOSE

To assess whether crofelemer would prevent chemotherapy-induced diarrhea (CID) diarrhea in patients with HER2-positive, any-stage breast cancer receiving trastuzumab (H), pertuzumab (P), and a taxane (T; docetaxel or paclitaxel), with/without carboplatin (C; always combined with docetaxel rather than paclitaxel).

METHODS

Patients scheduled to receive ≥ 3 consecutive TCHP/THP cycles were randomized to crofelemer 125 mg orally twice daily during chemotherapy cycles 1 and 2 or no scheduled prophylactic medication (control). All received standard breakthrough antidiarrheal medication (BTAD) as needed. The primary endpoint was incidence of any-grade CID for ≥ 2 consecutive days. Secondary endpoints were incidence of all-grade and grade 3/4 CID by cycle/stratum; time to onset and duration of CID; stool consistency; use of BTAD; and quality of life (Functional Assessment of Chronic Illness Therapy for Patients With Diarrhea [FACIT-D] score).

RESULTS

Fifty-one patients were randomized to crofelemer (n = 26) or control (n = 25). There was no statistically significant difference between arms for the primary endpoint; however, incidence of grade ≥ 2 CID was reduced with crofelemer vs control (19.2% vs 24.0% in cycle 1; 8.0% vs 39.1%, in cycle 2). Patients receiving crofelemer were 1.8 times more likely to see their diarrhea resolved and had less frequent watery diarrhea.

CONCLUSION

Despite the choice of primary endpoint being insensitive, crofelemer reduced the incidence and severity of CID in patients with HER2-positive breast cancer receiving P-based therapy. These data are supportive of further testing of crofelemer in CID.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02910219, prospectively registered September 21, 2016.

Chitosan Oligosaccharide Prevents Afatinib-Induced Barrier Disruption and Chloride Secretion through Modulation of AMPK, PI3K/AKT, and ERK Signaling in T84 Cells

Diarrhea is an important adverse effect of epidermal growth factor receptor-tyrosine kinase inhibitors, especially afatinib. Novel antidiarrheal agents are needed to reduce epidermal growth factor receptor-tyrosine kinase inhibitor-associated diarrhea to improve the quality of life and treatment outcome in cancer patients. This study aimed to investigate the anti-diarrheal activity of chitosan oligosaccharide against afatinib-induced barrier disruption and chloride secretion in human intestinal epithelial cells (T84 cells). Chitosan oligosaccharide (100 μg/mL) prevented afatinib-induced barrier disruption determined by changes in transepithelial electrical resistance and FITC-dextran flux in the T84 cell monolayers. In addition, chitosan oligosaccharide prevented afatinib-induced potentiation of cAMP-induced chloride secretion measured by short-circuit current analyses in the T84 cell monolayers. Chitosan oligosaccharide induced the activation of AMPK, a positive regulator of epithelial tight junction and a negative regulator of cAMP-induced chloride secretion. Moreover, chitosan oligosaccharide partially reversed afatinib-induced AKT inhibition without affecting afatinib-induced ERK inhibition via AMPK-independent mechanisms. Collectively, this study reveals that chitosan oligosaccharide prevents the afatinib-induced diarrheal activities in T84 cells via both AMPK-dependent and AMPK-independent mechanisms. Chitosan oligosaccharide represents a promising natural polymer-derived compound for further development of treatment for afatinib-associated diarrheas.

A Review of Potential Role of Capsule Endoscopy in the Work-Up for Chemotherapy-Induced Diarrhea

Chemotherapy-induced diarrhea (CID) is a common, severe side effect of chemotherapy, immunotherapy, and targeted therapy. Because patients are more prone to continuing chemotherapy if they do not suffer from CID, appropriate diagnosis and monitoring of this disease are essential. However, suitable monitoring methods are yet to be developed. To date, several studies have shown that small-bowel capsule endoscopy (SBCE) is useful in visualizing the entire small intestinal mucosa and detecting small intestinal abnormalities, including bleeding, malignant tumors, and mucosal injury, associated with the use of nonsteroidal anti-inflammatory drugs and low-dose aspirin. Currently, limited studies have evaluated the small intestinal mucosa using SBCE in patients receiving fluoropyrimidine-based chemotherapy or immune checkpoint inhibitors. These studies have reported that small intestinal mucosal injury is common in patients with severe fluoropyrimidine-induced diarrhea. SBCE might be a useful screening method for the early detection of enterocolitis induced by immune checkpoint inhibitors. SBCE may be a powerful tool for the diagnosis and monitoring of CID, and understanding its indication, contraindication, and capsule-retention risk for each patient is important for clinicians.

A Phase I Study of Alpelisib in Combination with Trastuzumab and LJM716 in Patients with PIK3CA-Mutated HER2-Positive Metastatic Breast Cancer

PURPOSE

Activating mutations in PIK3CA promote resistance to HER2-targeted therapy in breast cancer; however, inhibition of PI3K alone leads to escape via feedback upregulation of HER3. Combined inhibition of HER2, HER3, and PI3K overcomes this mechanism preclinically.

PATIENTS AND METHODS

This phase I study investigated the MTD of alpelisib given in combination with trastuzumab and LJM716 (a HER3-targeted antibody) in patients with PIK3CA-mutant HER2-positive (HER2+) metastatic breast cancer (MBC) using the continual reassessment method. Secondary analyses included efficacy and exploratory correlative studies.

RESULTS

Ten patients were treated initially with daily alpelisib (arm A). Grade ≥3 adverse events seen in ≥2 patients included diarrhea (n = 6), hypokalemia (n = 3), abnormal liver enzymes (n = 3), hyperglycemia (n = 2), mucositis (n = 2), and elevated lipase (n = 2). The MTD of alpelisib in arm A was 250 mg daily. This prompted the opening of arm B in which 11 patients received intermittently dosed alpelisib. Grade ≥3 adverse events seen in ≥2 patients included diarrhea (n = 5), hypokalemia (n = 3), and hypomagnesemia (n = 2). The MTD of alpelisib in arm B was 350 mg given 4 days on, 3 days off. Among 17 patients assessed, 1 had a partial response, 14 had stable disease, and 2 had disease progression at best response. Five patients had stable disease for >30 weeks. mRNA profiling of pre- and on-treatment tissue demonstrated PIK3CA target engagement by alpelisib via induction of downstream signaling and feedback pathways.

CONCLUSIONS

Combination treatment with alpelisib, trastuzumab, and LJM716 was limited by gastrointestinal toxicity. Further efforts are warranted to target the PI3K pathway in HER2+ MBC.

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.

TLR4 deficiency upregulates TLR9 expression and enhances irinotecan-related intestinal mucositis and late-onset diarrhoea

BACKGROUND AND PURPOSE

Severe diarrhoea, a common gastrointestinal manifestation of anticancer treatment with irinotecan, might involve single nucleotide polymorphisms (SNPs) of toll-like receptors (TLRs), described as critical bacterial sensors in the gut. Here, colorectal cancer patients carrying missense TLR4 A896G (rs4986790) or C1,196T (rs4986791) SNPs and Tlr4 knockout (Tlr4-/-) mice were given irinotecan to investigate the severity of the induced diarrhoea.

EXPERIMENTAL APPROACH

Forty-six patients treated with irinotecan-based regimens had diarrhoea severity analysed according to TLR4 genotypes. In the experimental setting, wild-type (WT) or Tlr4-/- mice were given irinotecan (45 or 75 mg·kg^-1 , i.p.) or saline (3 ml·kg^-1 ). Diarrhoea severity was evaluated by measuring intestinal injury and inflammatory markers expression after animals were killed.

KEY RESULTS

All patients with TLR4 SNPs chemotherapy-treated presented diarrhoea, whereas gastrointestinal toxicity was observed in 50% of the wild homozygous individuals. Mice injected with irinotecan presented systemic bacterial translocation and increased TLR4 immunostaining in the intestine. In line with the clinical findings, Tlr4 gene deficiency enhanced irinotecan-related diarrhoea and TLR9 expression in mice. An increased myeloperoxidase activity and Il-18 expression along with IL-10 decreased production in Tlr4-/- mice also indicated an intensified intestinal damage and inflammatory response.

CONCLUSION AND IMPLICATIONS

TLR4 deficiency upregulates TLR9 expression and enhances intestinal damage and the severity of late-onset diarrhoea during irinotecan-based treatment. Identifying patients genetically predisposed to chemotherapy-associated diarrhoea is a strategy toward precision medicine.

Antidiarrheal, Antimicrobial, and Antioxidant Properties of the Aqueous Extract of Tunisian Persimmon (Diospyros kaki Thunb.) Fruits

Medicinal plants were used to prevent and treat numerous gastrointestinal disorders owing, in part, to their antioxidant capacity. The protective effects of Diospyros kaki fruit aqueous extract (DKFAE) against castor oil (CO)-induced diarrhea was studied. The in vitro antioxidant and antibacterial properties were investigated using colorimetric and biochemical analyses. In vivo, 60 male rats were divided into 6 groups of 10 animals each (n = 10): control (C), CO, CO+various doses of DKFAE (100, 200, and 400 mg/kg, b.w., p.o.), and CO+loperamide (LOP, 10 mg/kg, b.w., p.o.).The DKFAE was rich in tannins and showed interesting antioxidant and antibacterial activities. The liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis resulted in the identification of 16 phenolic compounds, among which quinic acid was the main one. The in vivo study showed that diarrhea was accompanied by an oxidative stress status as measured by an increase of lipid peroxidation, a decrease of glutathione and thiol group levels, as well as antioxidant enzyme activity depletion, such as glutathione peroxidase, superoxide dismutase, and catalase. The DKFAE administration significantly decreased the gastrointestinal transit in a dose-dependent manner. Besides, DKFAE protected against CO-induced diarrhea and intestinal fluid accumulation. Interestingly, DKFAE pretreatment counteracted all the oxidative stress status deregulation induced by CO intoxication. D. kaki fruit could be suggested for its strong protective effect against CO-induced acute diarrhea, which could be explained, in part, to its antimicrobial and antioxidant properties.

Assessment of diarrhea as side effect of oral targeted antineoplastic agents in clinical practice

BACKGROUND

Diarrhea is one of the most frequent class adverse events associated with targeted oral antineoplastic agents (OAAs). Our objective was to analyze the incidence, characteristics, and severity of diarrhea in cancer patients in clinical practice.

METHODS

An observational, longitudinal, and prospective study of cancer outpatients treated with targeted OAAs was carried out in a tertiary hospital. Targed OAAs analyzed were anaplastic lymphoma kinase inhibitors, BCR-ABL inhibitors, cyclin-dependent kinase inhibitors, epidermal growth factor receptor inhibitors, mTOR inhibitors, poly (ADP-ribose) polymerase inhibitors, and vascular endothelial growth factor receptor inhibitors. Patients were given a data collection form to record daily the number, severity (CTCAE version 5.0), and characteristics of stools during the first 30 days of treatment with OAAs. Multivariate analysis was performed to identify risk factors associated with the incidence of diarrhea.

RESULTS

We analyzed 240 patients, of whom 28.7% experienced diarrhea (25.4% grades 1-2 and 3.3% grades 3-4). Patients treated with EGFR and VEGFR inhibitors had a higher incidence of diarrhea. The multivariate analysis revealed that taking the OAA with food was associated with a lower risk of diarrhea (OR = 0.404 [0.205-0.956], p = 0.038).

CONCLUSIONS

More than a third of patients in treatment with OAAs presented diarrhea (any grade), and 22.1% of stools were semi-liquid/liquid. In multivariate analysis, taking the OAA on an empty stomach was associated with a statistically significant increase in the incidence of diarrhea.

Chronic diarrhoea in an oncology patient - Clinical assessment and decision making

Cancer survival is improving rapidly due to advances in treatments that will often involve radiotherapy, chemotherapy and novel biological agents in addition to surgery. This comes at the price of living with chronic symptoms, of which diarrhoea is particularly common. There is good evidence that for many patients these symptoms become part of everyday life, their "normality" is adjusted and symptoms are tolerated even when limiting activities severely. Clinicians often fail to appreciate the impact of these problems, as the focus of follow up tends to be on cancer recurrence. However, the rapid identification of patients in significant trouble can lead to earlier diagnosis of treatable pathologies and improvement of patients' symptoms. The aim of this review is to highlight the mechanisms which cause oncology patients to develop diarrhoea and highlight useful investigational and treatment strategies.

An overview of acute gastrointestinal side effects of systemic anti-cancer therapy and their management

Treatment-related acute gastrointestinal toxicities are a common and often debilitating hurdle encountered in the treatment of cancer patients. While the introduction of targeted therapies such as tyrosine kinase inhibitors has led to improvements in survival outcomes, their use has also been complicated by a high frequency of clinically important adverse effects. Gastrointestinal toxicities such as nausea, vomiting, diarrhoea and hepatotoxicity represent potentially serious adverse events that may necessitate dose reductions, treatment interruptions and cessation of treatment. An improved knowledge of the incidence, pathophysiology, management and prophylaxis of these toxicities is crucial in order to reduce patient morbidity and mortality. In this review, we discuss the main gastrointestinal toxicities associated with chemotherapy and targeted therapies in oncology, outlining their incidence, pathophysiology and expert management guidelines.

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.

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.

Targeted Therapies: Immunologic Effects and Potential Applications Outside of Cancer

Two pharmacologic approaches that are currently at the forefront of treating advanced cancer are those that center on disrupting critical growth/survival signaling pathways within tumor cells (commonly referred to as "targeted therapies") and those that center on enhancing the capacity of a patient's immune system to mount an antitumor response (immunotherapy). Maximizing responses to both of these approaches requires an understanding of the oncogenic events present in a given patient's tumor and the nature of the tumor-immune microenvironment. Although these 2 modalities were developed and initially used independently, combination regimens are now being tested in clinical trials, underscoring the need to understand how targeted therapies influence immunologic events. Translational studies and preclinical models have demonstrated that targeted therapies can influence immune cell trafficking, the production of and response to chemokines and cytokines, antigen presentation, and other processes relevant to antitumor immunity and immune homeostasis. Moreover, because these and other effects of targeted therapies occur in nonmalignant cells, targeted therapies are being evaluated for use in applications outside of oncology.

Rifaximin for Pertuzumab-Related GI Toxicities

Pertuzumab is a monoclonal antibody against HER2. Diarrhea and abdominal pain are common adverse events of pertuzumab-based therapy, occurring in almost 70% of patients. The incidence of gastrointestinal toxicities intensifies when pertuzumab is given in combination with chemotherapy. Rifaximin, a non-absorbable oral antibiotic, may provide symptomatic relief in patients with refractory gastrointestinal toxicities from pertuzumab-based therapy beyond standard routine antidiarrheal medications. We present a case of HER2-related therapy-induced diarrhea and abdominal pain managed successfully with Rifaximin.

Spectrum of Drug-induced Chronic Diarrhea

The evaluation of a patient with chronic diarrhea can be quite frustrating, as it is expensive and involves multiple diagnostic studies. Moreover, identification of a drug as a cause of chronic diarrhea is a challenge in patients taking multiple medications. The disease may either be associated with intestinal mucosal changes, mimicking diseases such as celiac disease, or purely functional, with no histopathologic change. Drug-induced diarrhea may or may not be associated with malabsorption of nutrients, and a clinical improvement may occur within days of discontinuation of the drug, or may take longer when associated with mucosal injury. Diarrhea in diabetics, often attributed to poor management and lack of control, may be due to oral hypoglycaemic agents. Chemotherapy can result in diffuse or segmental colitis, whereas olmesartan and a few other medications infrequently induce a disease that mimics celiac disease, but is not associated with gluten intolerance. In short, increased awareness of a drug, as a cause for diarrhea and a clear understanding of the clinical manifestations will help clinicians to solve this challenging problem. This article aims to review drug-induced diarrhea to (a) understand known pathophysiological mechanisms; (b) assess the risk associated with frequently prescribed medications, and discuss the pathogenesis; and

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.

Electroacupuncture for patients with diarrhea-predominant irritable bowel syndrome or functional diarrhea: A randomized controlled trial

Diarrhea-predominant irritable bowel syndrome (IBS-D) and functional diarrhea (FD) are highly prevalent, and the effectiveness of acupuncture for managing IBS-D and FD is still unknown.The aim of this study was to compare the effectiveness of electroacupuncture with loperamide.It was a prospective, randomized, parallel group controlled trial.A total of 448 participants were randomly assigned to He electroacupuncture group (n = 113), Shu-Mu electroacupuncture group (n = 111), He-Shu-Mu electroacupuncture group (n = 112), or loperamide group (n = 112). Participants in the 3 acupuncture groups received 16 sessions of electroacupuncture during a 4-week treatment phase, whereas participants in the loperamide group received oral loperamide 2 mg thrice daily. The primary outcome was the change from baseline in stool frequency at the end of the 4-weeks treatment. The secondary outcomes were the Bristol scale, the MOS 36-item short form health survey (SF-36), the weekly average number of days with normal defecations and the proportion of adverse events.Stool frequency was significantly reduced at the end of the 4-week treatment in the 4 groups (mean change from baseline, 5.35 times/week). No significant difference was found between the 3 electroacupuncture groups and the loperamide group in the primary outcome (He vs. loperamide group [mean difference 0.6, 95% CI, -1.2 to 2.4]; Shu-Mu vs. loperamide group [0.4, 95% CI, -1.4 to 2.3]; He-Shu-Mu vs. loperamide group [0.0, 95% CI, -1.8 to 1.8]). Both electroacupuncture and loperamide significantly improved the mean score of Bristol scale and increased the weekly average number of days with normal defecations and the mean scores of SF-36; they were equivalent in these outcomes. However, the participants in electroacupuncture groups did not report fewer adverse events than those in the loperamide group. Similar results were found in a subgroup analysis of separating patients with IBS-D and FD patients.Electroacupuncture is equivalent to loperamide for reducing stool frequency in IBS-D and FD patients. Further studies on cost effectiveness of acupuncture are warranted.

Pertuzumab for the treatment of breast cancer: a safety review

INTRODUCTION

Approximately twenty to thirty percent of newly diagnosed breast cancers are human epidermal growth factor receptor 2 (HER2) positive. The use of trastuzumab, and more recently pertuzumab, has significantly improved the progression free survival (PFS) and overall survival (OS) in this patient population. However, pertuzumab has side effects that can impact treatment tolerability and quality of life.

AREAS COVERED

This review describes the safety and tolerability of pertuzumab, a monoclonal antibody targeted at HER2 approved by the United States Food and Drug Administration (FDA) for use in the neoadjuvant and first line metastatic settings.

EXPERT OPINION

The combination of trastuzumab, pertuzumab, and chemotherapy is approved in the neoadjuvant and first line metastatic settings and should be strongly considered by providers. Further studies are needed to look at side effect prevention, novel pertuzumab containing regimens, and re-treating patients with pertuzumab.

Nintedanib in advanced NSCLC: management of adverse events

Nintedanib plus docetaxel is approved in the EU for the treatment of patients with locally advanced, metastatic or locally recurrent NSCLC of adenocarcinoma histology after first-line chemotherapy. Nintedanib in combination with docetaxel has a manageable safety profile in adenocarcinoma NSCLC patients. The most frequent adverse events (AEs) associated with nintedanib are gastrointestinal events and elevations in liver enzymes. Most AEs can be managed effectively with supportive treatment or a dose reduction and do not require permanent discontinuation. This article aims to provide practical guidance on management of AEs and how patients should be assessed for AEs prior to initiation and regularly monitored throughout treatment. Patients and their carers can play an important role in recognizing and managing AEs and should be given the relevant information, skills and confidence to achieve this.

Safe handling of oral antineoplastic medications: Focus on targeted therapeutics in the home setting

Introduction With the growing number of oral targeted therapies being approved for use in cancer therapy, the potential for long-term administration of these drugs to cancer patients is expanding. The use of these drugs in the home setting has the potential to expose family members and caregivers to them either through direct contact with the drugs or indirectly by exposure to the parent compounds and/or their active metabolites in contaminated patients' waste. Methods A systematic literature review was performed and the known adverse health effect of 32 oral targeted therapeutics is summarized. In particular, the carcinogenicity, genotoxicity, and embryo-fetal toxicity, along with the route of excretion were evaluated. Results Carcinogenicity testing has not been performed on most of the oral targeted therapeutics and the genotoxicity data are mixed. However, the majority of these drugs exhibit adverse reproductive effects, some of which are severe. Currently, available data does not permit the possibility of a health hazard from inappropriate handling of drugs and contaminated patients waste to be ignored, especially in a long-term home setting. Further research is needed to understand these issues. Conclusions With the expanding use of targeted therapies in the home setting, family members and caregivers, especially those of reproductive risk age, are, potentially at risk. Overall basic education and related precautions should be taken to protect family members and caregivers from indirect or direct exposure from these drugs. Further investigations and discussion on this subject are warranted.

Antidiarrhoeal, antimicrobial and antioxidant effects of myrtle berries (Myrtus communis L.) seeds extract

OBJECTIVES

The present study was carried out to determine the antidiarrheal effects of myrtle (Myrtus communis L.) berries seeds aqueous extract (MBSAE) from Tunisia as well as the involvement of its antimicrobial and antioxidant properties in such protection.

METHODS

Adult male wistar rats were used and divided into six groups of ten each: control, Castor oil, Castor oil + Loperamide and Castor oil + various doses of MBSAE. Animals were per orally (p.o.) pre-treated with MBSAE for one hour and intoxicated by castor oil acute oral administration.

KEY FINDINGS

Our results demonstrated that the MBSAE is rich in total and condensed tannins and exhibited a broad spectrum of antibacterial activity. In vivo, we found that MBSAE administration induced a significant dose-dependent protection against diarrhoea and intestinal fluid accumulation. Castor oil-induced intestinal hypersecretion was accompanied by an oxidative stress status in the intestine. More importantly, we showed that acute diarrhoea was accompanied by an increase in intestinal mucosa hydrogen peroxide (H2 O2 ), calcium and free iron levels while MBSAE pre-treatment reversed all castor oil-induced intracellular mediators disturbances.

CONCLUSIONS

We suggest that MBSAE had a potent protective effects against castor oil-induced acute diarrhoea due in part to its antioxidant and antimicrobial properties.

Secretory diarrhoea: mechanisms and emerging therapies

Diarrhoeal disease remains a major health burden worldwide. Secretory diarrhoeas are caused by certain bacterial and viral infections, inflammatory processes, drugs and genetic disorders. Fluid secretion across the intestinal epithelium in secretory diarrhoeas involves multiple ion and solute transporters, as well as activation of cyclic nucleotide and Ca(2+) signalling pathways. In many secretory diarrhoeas, activation of Cl(-) channels in the apical membrane of enterocytes, including the cystic fibrosis transmembrane conductance regulator and Ca(2+)-activated Cl(-) channels, increases fluid secretion, while inhibition of Na(+) transport reduces fluid absorption. Current treatment of diarrhoea includes replacement of fluid and electrolyte losses using oral rehydration solutions, and drugs targeting intestinal motility or fluid secretion. Therapeutics in the development pipeline target intestinal ion channels and transporters, regulatory proteins and cell surface receptors. This Review describes pathogenic mechanisms of secretory diarrhoea, current and emerging therapeutics, and the challenges in developing antidiarrhoeal therapeutics.

Personalized targeted therapy for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma continues to heavily burden clinicians worldwide. Researchers have discovered the genomic landscape of esophageal squamous cell carcinoma, which holds promise for an era of personalized oncology care. One of the most pressing problems facing this issue is to improve the understanding of the newly available genomic data, and identify the driver-gene mutations, pathways, and networks. The emergence of a legion of novel targeted agents has generated much hope and hype regarding more potent treatment regimens, but the accuracy of drug selection is still arguable. Other problems, such as cancer heterogeneity, drug resistance, exceptional responders, and side effects, have to be surmounted. Evolving topics in personalized oncology, such as interpretation of genomics data, issues in targeted therapy, research approaches for targeted therapy, and future perspectives, will be discussed in this editorial.