Phase II Study of Activated Charcoal to Prevent Irinotecan-Induced Diarrhea

Mechanisms and emerging strategies for irinotecan-induced diarrhea

Irinotecan (also known as CPT-11) is a topoisomerase I inhibitor first approved for clinical use as an anticancer agent in 1996. Over the past more than two decades, it has been widely used for combination regimens to treat various malignancies, especially in gastrointestinal and lung cancers. However, severe dose-limiting toxicities, especially gastrointestinal toxicity such as late-onset diarrhea, were frequently observed in irinotecan-based therapy, thus largely limiting the clinical application of this agent. Current knowledge regarding the pathogenesis of irinotecan-induced diarrhea is characterized by the complicated metabolism of irinotecan to its active metabolite SN-38 and inactive metabolite SN-38G. A series of enzymes and transporters were involved in these metabolic processes, including UGT1A1 and CYP3A4. Genetic polymorphisms of these metabolizing enzymes were significantly associated with the occurrence of irinotecan-induced diarrhea. Recent discoveries and progress made on the detailed mechanisms enable the identification of potential biomarkers for predicting diarrhea and as such guiding the proper patient selection with a better range of tolerant dosages. In this review, we introduce the metabolic process of irinotecan and describe the pathogenic mechanisms underlying irinotecan-induced diarrhea. Based on the mechanisms, we further outline the potential biomarkers for predicting the severity of diarrhea. Finally, based on the current experimental evidence in preclinical and clinical studies, we discuss and prospect the current and emerging strategies for the prevention of irinotecan-induced diarrhea.

Non-pharmacological interventions for chemotherapy-induced diarrhoea and constipation management: A scoping review

PURPOSE

Chemotherapy-induced diarrhoea (CID) and constipation (CIC) are among the most common and severe gastrointestinal symptoms related to chemotherapy. This review aimed to identify and describe the evidence for non-pharmacological interventions for the management of CID and CIC.

METHODS

The scoping review was based on the Joanna Briggs Institute methodology and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Evidence from five databases were included: CINAHL, MEDLINE, Embase, PubMed, and APA PsycInfo. Data were systematically identified, screened, extracted and synthesised narratively to describe the evidence for non-pharmacological interventions and their effects on CID and CIC.

RESULTS

We included 33 studies, of which 18 investigated non-pharmacological interventions for CID management, six for CIC management, and nine for both CID and CIC management. Interventions were categorized into five groups, including (1) digital health interventions, (2) physical therapies, (3) diet and nutrition therapies, (4) education, and (5) multimodal. Diet and nutrition therapies were the most common to report potential effectiveness for CID and CIC outcomes. Most of the interventions were implemented in hospitals under the supervision of healthcare professionals and were investigated in randomised control trials.

CONCLUSIONS

The characteristics of non-pharmacological interventions were diverse, and the outcomes were inconsistent among the same type of interventions. Diet and nutritional interventions show promise but further research is needed to better understand their role and to contribute to the evidence base. Nurses are well placed to assess and monitor for CIC and CID, and also deliver effective non-pharmacological interventions.

Prophylactic Oral Application of Activated Charcoal Mitigates Acute Campylobacteriosis in Human Gut Microbiota-Associated IL-10-/- Mice

The incidence of human Campylobacter jejuni infections is increasing worldwide. It is highly desirable to prevent campylobacteriosis in individuals at risk for severe disease with antibiotics-independent non-toxic compounds. Activated charcoal (AC) has long been used as an anti-diarrheal remedy. Here, we tested the disease-mitigating effects of oral AC versus placebo in human gut microbiota-associated (hma) IL-10-/- mice starting a week prior to C. jejuni infection. On day 6 post-infection, the gastrointestinal C. jejuni loads were comparable in both infected cohorts, whereas campylobacteriosis symptoms such as wasting and bloody diarrhea were mitigated upon AC prophylaxis. Furthermore, AC application resulted in less pronounced C. jejuni-induced colonic epithelial cell apoptosis and in dampened innate and adaptive immune cell responses in the colon that were accompanied by basal concentrations of pro-inflammatory mediators including IL-6, TNF-α, IFN-γ, and nitric oxide measured in colonic explants from AC treated mice on day 6 post-infection. Furthermore, C. jejuni infection resulted in distinct fecal microbiota shift towards higher enterobacterial numbers and lower loads of obligate anaerobic species in hma mice that were AC-independent. In conclusion, our pre-clinical placebo-controlled intervention study provides evidence that prophylactic oral AC application mitigates acute murine campylobacteriosis.

Mechanisms underlying dose-limiting toxicities of conventional chemotherapeutic agents

Dose-limiting toxicities (DLTs) are severe adverse effects that define the maximum tolerated dose of a cancer drug. In addition to the specific mechanisms of each drug, common contributing factors include inflammation, apoptosis, ion imbalances, and tissue-specific enzyme deficiencies. Among various DLTs are bleomycin-induced pulmonary fibrosis, doxorubicin-induced cardiomyopathy, cisplatin-induced nephrotoxicity, methotrexate-induced hepatotoxicity, vincristine-induced neurotoxicity, paclitaxel-induced peripheral neuropathy, and irinotecan, which elicits severe diarrhea. Currently, specific treatments beyond dose reduction are lacking for most toxicities. Further research on cellular and molecular pathways is imperative to improve their management. This review synthesizes preclinical and clinical data on the pharmacological mechanisms underlying DLTs and explores possible treatment approaches. A comprehensive perspective reveals knowledge gaps and emphasizes the need for future studies to develop more targeted strategies for mitigating these dose-dependent adverse effects. This could allow the safer administration of fully efficacious doses to maximize patient survival.

Efficiency of Protective Interventions on Irinotecan-Induced Diarrhea: A Systematic Review and Meta-Analysis

BACKGROUND

Irinotecan is widely used in the treatment of various solid tumors, but the adverse effects from it, especially diarrhea, limit its use. Several clinical trials of prophylactic treatment of irinotecan-induced diarrhea (IID) have been ongoing, and some of the data are controversial. This encouraged us to conduct a meta-analysis of the effects of interventions on preventing IID.

METHOD

This systematic review was conducted based on the PRISMA statement. We performed literature searches from PubMed, Web of Science, Embase, and Cochrane Library. The number registered in PROSPERO is CRD42022368633. After searching 1034 articles in the database and references, 8 studies were included in this meta-analysis.

RESULT

The RR of high-grade diarrhea and all-grade diarrhea were 0.31 (I2 = 51%, 95% CI: 0.14-0.69; P = .004) and .76 (I2 = 65%, 95% CI: 0.62-0.93; P < .008) respectively, thus the use of intervention measures for preventing IID is effective, and the risk reduction of high-grade diarrhea was more significant. Subgroup analysis revealed that the monotherapy group (RR: 0.48, 95% CI: 0.21-1.13, I2 = 0%) and combination therapy group (RR: 0.14, 95% CI: 0.06-0.32, I2 = 0%) in the risk of high-grade diarrhea had no significant heterogeneity within the groups, and traditional herbal medicines (Kampo medicine Hangeshashin-to, PHY906 and hot ironing with Moxa Salt Packet on Tianshu and Shangjuxu) were effective preventive measures (RR:0.20, 95% CI: 0.07-0.60, I2 = 0%). The Jadad scores for traditional herbal medicines studies were 3, and the follow-up duration was only 2 to 6 weeks.

CONCLUSION

This systematic review and meta-analysis suggest that preventive treatments significantly reduced the risk of high-grade and all-grade diarrhea, confirming the efficacy in the incidence and severity of IID, among which traditional herbal medicines (baicalin-containing) provided a protective effect in reducing the severity of IID. However, the traditional herbal medicines studies were of low quality. Combined irinotecan therapy can obtain better preventive effects than monotherapy of IID. These would be helpful for the prevention of IID in clinical practice.

Randomized double-blind, placebo-controlled multicenter phase III study of prevention of irinotecan-induced diarrhea by a probiotic mixture containing Bifidobacterium BB-12®Lactobacillus rhamnosus LGG® in colorectal cancer patients

Background

The incidence of irinotecan-induced diarrhea varies between 60-90%, by which the incidence of severe diarrhea is 20-40%. The objective of this phase III trial was to determine the effectiveness of the probiotic mixture containing Bifidobacterium, BB-12® and Lactobacillus rhamnosus, LGG® in the prophylaxis of irinotecan-induced diarrhea in metastatic colorectal cancer patients due to a reduction in the activity of intestinal beta-D-glucuronidase.

Methods

From March 2016 to May 2022, a total of 242 patients with colorectal cancer starting a new line of irinotecan-based therapy were registered to the study in 11 cancer centers in Slovakia. Patients were randomized in a ratio 1:1 to probiotic formula vs. placebo that was administered for 6 weeks. Each capsule of Probio-Tec® BG-Vcap-6.5 contained 2.7x109 colony-forming units (CFU) of 2 lyophilized probiotic strains Bifidobacterium, BB-12® (50%) and Lactobacillus rhamnosus GG, LGG® (50%).

Results

Administration of probiotics compared to placebo was not associated with a significant reduction of grade 3/4 diarrhea (placebo arm 11.8% vs. probiotic arm 7.9%, p=0.38). Neither the overall incidence of diarrhea (46.2% vs. 41.2%, p=0.51) nor the incidence of enterocolitis (3.4% vs. 0.9%, p=0.37) was different in the placebo vs. probiotic arm. Subgroup analysis revealed that patients with colostomy had higher incidence of any diarrhea and grade 3/4 diarrhea in the placebo arm compared to the probiotic arm (48.5% vs. 22.2%, p=0.06 and 15.2% vs. 0%, p=0.06, respectively). Moreover, patients on probiotic arm had significantly better diarrhea-free survival (HR = 0.41, 95%CI 0.18 - 0.95, p=0.05) and needed less loperamide (p=0.01) compared to patients on placebo arm. We did not observe any infection caused by probiotic strains used in this study.

Conclusion

This study failed to achieve its primary endpoint, and results suggest a lack of benefit of administered probiotic formula for the prevention of irinotecan-induced diarrhea. However, subgroup analysis suggests a possible benefit in patients with colostomy.

Oral Supramolecular Adsorbent for Preventing Chemo-Induced Gastrointestinal Mucositis and Microbial Dysbiosis and for Enhancing Chemoimmunotherapy

The addition of immune checkpoint blockade (ICB) to cytotoxic chemotherapy has emerged as the first-line treatment for multiple cancers. Paradoxically, cytotoxic chemotherapy may limit the therapeutic potential of ICB by significantly impairing the largest immune organ, the gastrointestinal (GI) tract, and driving gut microbial dysbiosis. Here, an orally administered polymeric adsorbent containing a supramolecular motif (named SPORA-SN9) is reported, which can selectively remove chemotherapeutics from the GI tract, thereby preventing chemotherapy-induced GI mucositis and microbial dysbiosis and providing better chemoimmunotherapy synergy. By theoretical design and experimental screening of the molecular recognition motifs, SPORA-SN9 exhibits superior complexation capacity for doxorubicin and irinotecan and high selectivity over a range of commonly used combinational medications. In mouse models of chemotherapy-induced GI mucositis, SPORA-SN9 protects the integrity of the GI tissues and the homeostasis of the gut microbiota. Finally, the addition of SPORA-SN9 enhances the efficacy of chemoimmunotherapy in tumor-bearing mice. SPORA-SN9 offers a translational approach for supramolecular chemistry to modulate complex biosystems by selectively removing target substrates from the GI tract.

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.

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.

Understanding chemotherapy-induced intestinal mucositis and strategies to improve gut resilience

Intestinal mucositis remains one of the most debilitating side effects related to chemotherapy. The onset and persistence of mucositis is an intricate physiological process involving cross-communication between the specific chemotherapeutic drug, the immune system, and gut microbes that results in a loss of mucosal integrity leading to gut-barrier dysfunction. Intestinal mucositis has a severe impact on a patient's quality of life and negatively influences the outcome of treatment. Most importantly, intestinal mucositis is a major contributor to the decreased survival rates and early onset of death associated with certain chemotherapy treatments. Understanding the pathophysiology and symptomology of intestinal mucositis is important in reducing the negative consequences of this condition. Prophylaxis, early diagnosis, and proper symptom management are essential to improved survival outcomes in patients with cancer. This review focuses on the pathobiology of intestinal mucositis that accompanies chemotherapy treatments. In addition, we will discuss the therapeutic potential of select strategies that have shown promise in mitigating chemotherapies' off-target effects without hampering their anticancer efficacy.NEW & NOTEWORTHY Intestinal mucositis, or damage to the intestinal mucosa, is a common side effect of chemotherapy. In this review, we describe the pathobiology of intestinal mucositis that is associated with chemotherapy treatments. In addition, we discuss the efficacy of several potential therapeutic strategies that have shown some potential in alleviating chemotherapies' off-target effects.

Potential role of drug metabolizing enzymes in chemotherapy-induced gastrointestinal toxicity and hepatotoxicity

INTRODUCTION

Toxicity of chemotherapy drugs is the leading cause of poor therapeutic outcome in many cancer patients. Gastrointestinal (GI) toxicity and hepatotoxicity are among the most common side effects of current chemotherapies. Emerging studies indicate that many chemotherapy-induced toxicities are driven by drug metabolism, but very few reviews summarize the role of drug metabolism in chemotherapy-induced GI toxicity and hepatotoxicity. In this review, we highlighted the importance of drug metabolizing enzymes (DMEs) in chemotherapy toxicity.

AREAS COVERED

Our review demonstrated that altered activity of DMEs play important role in chemotherapy-induced GI toxicity and hepatotoxicity. Besides direct changes in catalytic activities, the transcription of DMEs is also affected by inflammation, cell-signaling pathways, and/or by drugs in cancer patients due to the disease etiology.

EXPERT OPINION

More studies should focus on how DMEs are altered during chemotherapy treatment, and how such changes affect the metabolism of chemotherapy drug itself. This mutual interaction between chemotherapies and DMEs can lead to excessive exposure of parent drug or toxic metabolites which ultimately cause GI adverse effect.

Individualization of Irinotecan Treatment: A Review of Pharmacokinetics, Pharmacodynamics, and Pharmacogenetics

Since its clinical introduction in 1998, the topoisomerase I inhibitor irinotecan has been widely used in the treatment of solid tumors, including colorectal, pancreatic, and lung cancer. Irinotecan therapy is characterized by several dose-limiting toxicities and large interindividual pharmacokinetic variability. Irinotecan has a highly complex metabolism, including hydrolyzation by carboxylesterases to its active metabolite SN-38, which is 100- to 1000-fold more active compared with irinotecan itself. Several phase I and II enzymes, including cytochrome P450 (CYP) 3A4 and uridine diphosphate glucuronosyltransferase (UGT) 1A, are involved in the formation of inactive metabolites, making its metabolism prone to environmental and genetic influences. Genetic variants in the DNA of these enzymes and transporters could predict a part of the drug-related toxicity and efficacy of treatment, which has been shown in retrospective and prospective trials and meta-analyses. Patient characteristics, lifestyle and comedication also influence irinotecan pharmacokinetics. Other factors, including dietary restriction, are currently being studied. Meanwhile, a more tailored approach to prevent excessive toxicity and optimize efficacy is warranted. This review provides an updated overview on today’s literature on irinotecan pharmacokinetics, pharmacodynamics, and pharmacogenetics.

A randomized controlled, open-label early phase II trial comparing incidence of FOLFIRI.3-induced diarrhoea between Hangeshashinto and oral alkalization in Japanese patients with colorectal cancer

WHAT IS KNOWN AND OBJECTIVE

We conducted a pilot clinical trial to investigate whether Hangeshashinto (TJ-14) could be substituted for oral alkalization in patients scheduled to undergo chemotherapy by FOLFIRI.3 regimen for colorectal cancer (CRC).

METHODS

Patients with CRC were randomized 1:1 to a TJ-14 (7.5 g/day) group or an oral alkalization (sodium bicarbonate, 1.8 g/day; ursodeoxycholic acid, 300 mg/day) group. The primary endpoint was incident of late-onset diarrhoea. A total of 30 patients were randomized to either the TJ-14 group or the alkalization group.

RESULTS AND DISCUSSION

There was no statistical difference in age, concomitantly used drugs or UGT1A1 genotypes between the groups. In the alkalization group (n = 15), the frequency of grade 0/1/2 and grade 3 diarrhoea was 73% and 27%, respectively. In the TJ-14 group (n = 14), the frequency of grade 0/1/2 and grade 3 diarrhoea was 79% and 21%, respectively. Grade 4 diarrhoea was not observed in either group. There was no statistically significant difference in other adverse events or in response to FOLFIRI.3 between the groups.

WHAT IS NEW AND CONCLUSION

This pilot trial suggests that TJ-14 is a promising alternative treatment option to reduce FOLFIRI.3-induced late-onset diarrhoea, although additional clinical study with a larger number of patients is necessary to confirm these results.

Effects of activated charcoal-herb extractum complex on the growth performance, immunological indices, intestinal morphology and microflora in weaning piglets

This study was conducted to evaluate the effects of activated charcoal-herb extractum complex (CHC) on the growth performance, immunological indices, intestinal morphology and microflora in weaning piglets to determine the optimal supplemental dose. A total of 216 weaned piglets (Duroc × Landrace × Large White) with an initial body weight of 8.55 ± 1.18 kg were randomly assigned to six treatment groups; each treatment group had six pens, with six pigs per pen. The study period was 28 d. Pigs were fed a corn-soybean meal-based diet supplemented with 500, 1000, 1500 or 2000 mg kg-1 of CHC over two 14-d periods. Two additional diets containing 0 and 1000 mg kg-1 of montmorillonite were set as the negative and positive controls, respectively. Supplementation with 500 mg kg-1 of CHC significantly increased average daily gain compared with the positive and negative controls during phase I and the entire experimental period (P < 0.05). During phase I, 500 and 1000 mg kg-1 of CHC significantly decreased diarrhea incidence compared with the negative control, and increased serum IGF-1 and serum IgM levels compared with the controls (P < 0.05). CHC at 500 mg kg-1 significantly decreased the diarrhea score during the entire experimental period compared with the negative control (P < 0.05). On day 28, supplementation with 500 and 1000 mg kg-1 of CHC increased serum IgG, IL-1β, and duodenum and jejunum secretory IgA compared with the negative control and decreased duodenum and jejunum MDA levels compared with the controls (P < 0.05). Increased duodenum and jejunum villus height and an increased ratio of villus height to crypt depth were observed compared with the negative control and decreased viable counts of E. coli in the cecum were detected compared with the controls (P < 0.05). Collectively, the optimal dose of CHC was found to be 500 to 1000 mg kg-1 in this study.

Irinotecan toxicity during treatment of metastatic colorectal cancer: focus on pharmacogenomics and personalized medicine

Colorectal cancer, one of the most frequent types of cancer worldwide, has a high mortality rate. Irinotecan (CPT-11) has been approved for the treatment of advanced or metastatic disease either as a single agent or, more commonly, as part of combined chemotherapeutic regimens. Treatment with irinotecan is often accompanied by severe toxicity (e.g. neutropenia and diarrhea) that can result in treatment interruption or cessation, thus jeopardizing the patient's prognosis and quality of life. Irinotecan is bioactivated into its metabolite SN-38, which is subsequently detoxified by uridine diphosphate-glucuronosyl transferases (mainly UGT1A1). Further, ABC transporters (i.e. ABCB1, ABCC1-ABCC6, and ABCG2) are responsible for drug efflux into bile and urine whereas OATP transporters (SLCO1B1) enable its influx from blood into hepatocytes. Genetic polymorphisms in these enzymes/pumps may result in increased systemic SN-38 level, directly correlating with toxicity. Contemporary research is focused on the clinical implementation of genetic screenings for validated gene variations prior to treatment onset, allowing tailored individual doses or treatment regimens.

Adjunctive Treatments for the Prevention of Chemotherapy- and Radiotherapy-Induced Mucositis

Background: Chemoradiotherapy-associated mucositis can manifest as pain, inflammation, dysphagia, diarrhea, weight loss, rectal bleeding, and infection. Mucositis is a major dose-limiting side effect of chemotherapy, affecting nutritional intake and oral and intestinal function. Despite several interventions being available, there is a need for safe and effective preventative and treatment options for treatment-induced mucositis. The goals of this review are to discuss interventions based on foods and natural products and present the research to date. Methods: A narrative literature review identified 60 clinical studies examining various nutritional compounds and 20 examining probiotics. 9 studies on probiotics for the prevention of diarrhea were also assessed on methodological quality and limitations identified. Results: Several compounds have been posited as useful adjuvants for cancer treatment–related mucositis. Probiotics demonstrate efficacy for the prevention and treatment of chemoradiotherapy-induced gastrointestinal toxicity without significant side effects. Glutamine and activated charcoal were reported to reduce chemotherapy-induced diarrhea but not radiation-induced intestinal mucositis. Honey has been reported to decrease treatment interruptions, weight loss, and delays the onset of oral mucositis. Zinc, glutamine, and topical vitamin E were demonstrated efficacy for oral mucositis. Conclusion: There is plausible clinical evidence for the administration of several adjunctive treatments for the prevention and treatment of mucositis. Probiotics were reported to reduce the burden of intestinal mucositis and treatment-induced diarrhea. Activated charcoal and glutamine are beneficial for chemotherapy-induced diarrhea, whereas the administration of honey, zinc, and glutamine reduce the risk of developing oral mucositis during chemotherapy or radiotherapy.

Is there a role for charcoal in palliative diarrhea management?

OBJECTIVE

Symptomatic therapy is an intervention centered entirely on symptom management and pain relief. The utilization of charcoal in diarrhea management is a pertinent example of this type of medical care. Diarrhea is an ailment defined as an escalation in the frequency of bowel movements, unformed stool, abdominal discomfort, and pain. These symptoms can be extremely debilitating for patients, and effectuate frustration as well as severely dampening mood and overall well-being. This narrative review aims to explore the use of charcoal in diarrhea management and its possible benefits in alleviating discomfort associated with these symptoms.

METHODS

The authors used PubMed, MEDLINE, and Google Scholar searches on recent literature available on the role of activated charcoal in diarrhea management.

RESULTS

It was found that the main precursors of diarrhea include drugs and bacterial infection. Activated charcoal has a firm history in its ability to attract and expel ingested toxins from the gastrointestinal tract. It acts to prevent system absorption of these adverse entities, adsorbing them on the surface of its particles, making it a suitable diarrheal treatment.

CONCLUSIONS

Diarrhea can present itself alongside a multitude of treatments and conditions, such as chemotherapy, primary malignancy, intestinal, colorectal and pancreatic cancer, bacterial infection, and irritable bowel syndrome, making activated charcoal a potential therapy in these conditions. In comparison, with other common anti-diarrheal treatments, activated charcoal has exceptionally few side-effects. Overall, further research is necessary in order to wholly determine the effectiveness of charcoal in the management of diarrhea.

CPT-11-Induced Delayed Diarrhea Develops via Reduced Aquaporin-3 Expression in the Colon

While irinotecan (CPT-11) has a potent anti-cancer effect, it also causes serious diarrhea as an adverse reaction. In this study, we analyzed the pathogenic mechanism of CPT-11-induced delayed diarrhea by focusing on water channel aquaporin-3 (AQP3) in the colon. When rats received CPT-11, the expression level of AQP3 was reduced during severe diarrhea. It was found that the expression levels of inflammatory cytokines and the loss of crypt cells were increased in the colon when CPT-11 was administered. When celecoxib, an anti-inflammatory drug, was concomitantly administered, both the diarrhea and the reduced expression of AQP3 induced by CPT-11 were suppressed. The inflammation in the rat colon during diarrhea was caused via activated macrophage by CPT-11. These results showed that when CPT-11 is administered, the expression level of AQP3 in the colon is reduced, resulting in delayed diarrhea by preventing water transport from the intestinal tract. It was also suggested that the reduced expression of AQP3 might be due to the inflammation that occurs following the loss of colonic crypt cells and to the damage caused by the direct activation of macrophages by CPT-11. Therefore, it was considered that anti-inflammatory drugs that suppress the reduction of AQP3 expression could prevent CPT-11-induced delayed diarrhea.

Self-assembled polypeptide nanoparticles for intracellular irinotecan delivery

In this research poly(l-lysine)-b-poly(l-leucine) (PLys-b-PLeu) polymersomes were developed. It was shown that the size of nanoparticles depended on pH of self-assembly process and varied from 180 to 650nm. The biodegradation of PLys-b-PLeu nanoparticles was evaluated using in vitro polypeptide hydrolysis in two model enzymatic systems, as well as in human blood plasma. The experiments on the visualization of cellular uptake of rhodamine 6g-loaded and fluorescein-labeled nanoparticles were carried out and the possibility of their penetration into the cells was approved. The cytotoxicity of polymersomes obtained was tested using three cell lines, namely, HEK, NIH-3T3 and A549. It was shown that tested nanoparticles did not demonstrate any cytotoxicity in the concentrations up to 2mg/mL. The encapsulation of specific to colorectal cancer anti-tumor drug irinotecan into developed nanocontainers was performed by means of pH gradient method. The dispersion of drug-loaded polymersomes in PBS was stable at 4°C for a long time (at least 1month) without considerable drug leakage. The kinetics of drug release was thoroughly studied using two model enzymatic systems, human blood serum and PBS solution. The approximation of irinotecan release profiles with different mathematical drug release models was carried out and allowed identification of the release mechanism, as well as the morphological peculiarities of developed particles. The dependence of encapsulation efficiency, as well as maximal loading capacity, on initial drug concentration was studied. The maximal drug loading was found as 320±55μg/mg of polymersomes. In vitro anti-tumoral activity of irinotecan-loaded polymersomes on a colon cancer cell line (Caco-2) was measured and compared to that for free drug.

Efficacy of long-acting release octreotide for preventing chemotherapy-induced diarrhoea: protocol for a systematic review

INTRODUCTION

Diarrhoea is a common adverse effect induced by chemotherapy that can reduce the dose of chemotherapeutic drugs or interrupt the chemotherapy schedule. The current treatment strategies have various limitations. It has been shown that long-acting release octreotide (octreotide LAR) can decrease the occurrence and severity of diarrhoea, yet the efficacy of octreotide LAR in preventing chemotherapy-induced diarrhoea (CID) remains to be assessed. The main objective of this paper was to draw up a protocol for systematic review to evaluate the protective effects of octreotide LAR on CID.

METHODS AND ANALYSIS

We searched Medline, EMBASE, the Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang Data and the VIP Database without language restrictions from inception until 1 September 2016. The references of relevant studies were also manually searched. Two investigators independently accessed the selected studies, extracted data and assessed the reliability of the studies. Any discrepancies were resolved by a third investigator. The effect size of the selected studies was assessed by different measures based on the type of data. The selected studies were descriptively analysed. We then chose a fixed-effect model or a random-effect model based on statistical homogeneity, and pooled data from the studies for meta-analysis, if possible. The primary outcome was the incidence of diarrhoea. The secondary outcomes were the duration of diarrhoea, incidence of diarrhoea-associated symptoms, physical function and quality of life. All statistical analyses were performed by Review Manager V.5.3.

ETHICS AND DISSEMINATION

This systematic review did not require ethics approval, because it included aggregated published data, and not individual patient data. The review was published in a peer-reviewed journal.

TRIAL REGISTRATION

This systematic review protocol was registered with PROSPERO (registration number: CRD 42016048573).

Preventive Effects of a Chinese Herbal Formula, Shengjiang Xiexin Decoction, on Irinotecan-Induced Delayed-Onset Diarrhea in Rats

Irinotecan is a well-known chemotherapy drug for the treatment of various cancers. However, delayed-onset diarrhea is a common adverse reaction, limiting the application of the drug. The study presented was designed to evaluate the preventive effects of Shengjiang Xiexin decoction (SXD) on irinotecan-induced diarrhea and to explore the possible mechanisms of this action. We established a diarrhea rat model. The condition of the rats was observed. The proliferation and apoptosis of intestinal cells were measured using immunohistochemical assays and a caspase-3 activity assay, respectively. The expression of Lgr5 and CD44 staining were used to observe intestinal stem cells (ISCs). In addition, the activity of β-glucuronidase in the rats' feces was measured. Our results showed that the number of proliferating intestinal cells in the SXD groups was obviously higher, while the activity of caspase-3 was lower. The expression of Lgr5 and the integrated option density (IOD) of CD44 stain were increased significantly by SXD. Additionally, SXD decreased the activity of β-glucuronidase after irinotecan administration. In conclusion, SXD exhibited preventive effects on irinotecan-induced diarrhea, and this action was associated with an inhibitory effect on intestinal apoptosis and β-glucuronidase and a promotive effect on intestinal cell proliferation due to increased maintenance of ISCs.

Chemotherapy induced diarrhea

Purpose: To provide a current review of the literature related to chemotherapy induced diarrhea (CID), including clinical assessment, recommended management guidelines and investigational pharmacological approaches for the prevention and treatment of CID.

Data sources: A search of MEDLINE, PubMed, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, and Web of Science (1996—2006) databases was conducted using terms such as: chemotherapy, diarrhea, diarrhoea, and irinotecan. Appropriate references from selected articles were also used. The search engine, Google, provided further access to information.

Data extraction: The retrieved literature was reviewed to include all articles pertaining to the pathophysiology, assessment and management of CID.

Data synthesis: Diarrhea is a debilitating and potentially life-threatening side effect associated with many chemotherapeutic agents. Despite the high incidence and severity of CID, it is often under recognized and poorly managed. A multidisciplinary panel recently updated recommended practice guidelines for the assessment and management of CID. Prompt and aggressive intervention is important in order to minimize the negative consequences of CID, such as dehydration, which may cause interruptions in optimal clinical outcomes or may lead to life-threatening sequelae. Further investigation into the pathophysiology of CID may allow for more directed approaches in the prophylaxis and treatment of CID. J Oncol Pharm Practice (2007) 13: 181—198.

Prevention of irinotecan induced diarrhea by probiotics: A randomized double blind, placebo controlled pilot study

PURPOSE

Diarrhea is one of the dose limiting toxicity of irinotecan. SN-38 is main irinotecan metabolite responsible for diarrhea development, which is excreted in glucuronidated form into the intestine. This study aimed to determine the effectiveness of the probiotics in the prevention of irinotecan induced diarrhea due to reduction of intestinal beta-d-glucuronidase activity.

METHODS

Between January 2011 and December 2013, 46 patients with colorectal cancer starting a new line of irinotecan based therapy were included. Patients were randomized 1:1 to probiotics (PRO) or placebo (PLA). Probiotic formula Colon Dophilus™, was administered at a dose of 10×10(9)CFU of bacteria tid, orally for 12 weeks of chemotherapy. The study was prematurely terminated due to slow accrual, when 46 of 220 planned patients were accrued.

RESULTS

Twenty-three patients were randomized to PRO and 23 patients to PLA. Administration of probiotics compared to placebo led to a reduction in the incidence of severe diarrhea of grade 3 or 4 (0% for PRO vs. 17.4% for PLA, p=0.11), as well as reduction of the overall incidence of diarrhea (39.1% for PRO vs. 60.9% for PLA, p=0.24) and incidence of enterocolitis (0% for PRO vs. 8.7% for PLA). Patients on PRO used less antidiarrheal drugs compared to PLA. There was no infection caused by probiotic strains recorded.

CONCLUSIONS

Administration of probiotics in patients with colorectal cancer treated with irinotecan-based chemotherapy is safe and could lead to a reduction in the incidence and severity of gastrointestinal toxicity.

The number of intestinal bacteria is not critical for the enhancement of antitumor activity and reduction of intestinal toxicity of irinotecan by the Chinese herbal medicine PHY906 (KD018)

Background

The four-herb Chinese medicine PHY906(KD018) has been shown to both enhance the in vivo antitumor activity of irinotecan (CPT-11) against colon cancer tumor allografts and alleviate intestinal toxicity caused by CPT-11.

Methods

Since intestinal bacteria can metabolize CPT-11 and PHY906, we investigated whether intestinal bacteria play a critical role in the in vivo activity of PHY906 in murine Colon-38 tumor-bearing mice. Intestinal bacteria were depleted using streptomycin/neomycin for 10 days before and during treatment with PHY906 and/or CPT-11. qPCR using 16S DNA group-specific primers was used to quantify the levels of the major intestinal bacteria.

Results

Both PHY906 and antibiotic treatment changed the profile of intestinal bacteria species: Lactobacillus/Enterococcus, Bacteroides, Clostridium leptum, and E. rectale/C. coccoides. Antibiotic treatment did not alter the ability of PHY906 to enhance the antitumor activity of CPT-11. Antibiotic treatment alone partially reduced animal body weight loss in CPT-11-treated mice. However, PHY906 treatment was able to protect against the body weight loss in the CPT-11/antibiotic treatment group. H&E and PCNA staining of intestine showed that antibiotic treatment partially reduced the intestinal damage caused by CPT-11 but not as effectively as PHY906 treatment. Antibiotic treatment plus PHY906 conferred the most effective protection of intestine histological structure against damage by CPT-11. Both PHY906 and antibiotic treatment inhibited CPT-11-associated inflammatory processes, including infiltration of the intestine by neutrophils, MCP1 and TNF-alpha mRNA expression in the intestine, and expression of pro-inflammatory cytokines G-CSF and MCP1 proteins in the plasma. However, whereas antibiotic treatment suppressed the mRNA expression of two important intestinal progenitor/stem cell markers, Olfm4 and Lgr5, PHY906 treatment resulted in enhanced expression of these two stem cell markers.

Conclusions

Alterations in the population of intestinal bacteria did not affect the abilities of PHY906 to enhance CPT-11 antitumor activity or reduce the intestinal toxicity associated with CPT-11 treatment. The major species of intestinal bacteria do not appear to play a role in PHY906’s enhancement of the therapeutic index of CPT-11 in tumor-bearing mice. Thus, patients with different intestinal bacterial profiles may still benefit from PHY906 treatment alongside CPT-11.

A phase II, randomized, double blind trial of calcium aluminosilicate clay versus placebo for the prevention of diarrhea in patients with metastatic colorectal cancer treated with irinotecan

PURPOSE

Calcium aluminosilicate clay (CASAD) is a naturally occurring clay that serves as a cation exchange absorbent. We hypothesized that oral administration of CASAD would reduce the rate of grade 3/4 diarrhea associated with irinotecan use for metastatic colorectal cancer (CRC) by adsorbing the SN-38 metabolite.

METHODS

Patients receiving irinotecan-based chemotherapy were randomized equally between CASAD and placebo arms in this multicenter trial in order to assess differences in the proportions of patients with grade 3/4 diarrhea within 6 weeks. Additionally, we compared symptom severity between the two arms using the M.D. Anderson Symptom Inventory.

RESULTS

Between May 2009 and May 2012, 100 patients were enrolled. In evaluable patients, 7 of 43 (16 %) on the CASAD arm compared to 3 of 32 (9 %) on the placebo arm experienced grade 3/4 diarrhea (P = 0.70). The rate of any diarrhea among all patients was similar (CASAD arm, 64 % vs. placebo arm, 70 %). The rate of study dropout was 14 % in the CASAD arm and 38 % in the placebo arm (P = 0.01). No differences were found in symptom severity, individual symptom items, and in serious adverse events between the two arms.

CONCLUSION

Compared to placebo, CASAD use was safe but ineffective in preventing diarrhea in metastatic CRC patients treated with irinotecan-containing chemotherapy regimens. There were no distinct signals in terms of patient symptoms between arms, but there was significantly more patient dropout in the placebo arm. Future CASAD trials will focus on the active treatment of diarrhea.

Therapeutic targeting of CPT-11 induced diarrhea: a case for prophylaxis

CPT-11 (irinotecan), a DNA topoisomerase I inhibitor is one of the main treatments for colorectal cancer. The main dose limiting toxicities are neutropenia and late onset diarrhea. Though neutropenia is manageable, CPT-11 induced diarrhea is frequently severe, resulting in hospitalizations, dose reductions or omissions leading to ineffective treatment administration. Many potential agents have been tested in preclinical and clinical studies to prevent or ameliorate CPT-11 induced late onset diarrhea. It is predicted that prophylaxis of CPT-11 induced diarrhea will reduce sub-therapeutic dosing as well as hospitalizations and will eventually lead to dose escalations resulting in better response rates. This article reviews various experimental agents and strategies employed to prevent this debilitating toxicity. Covered topics include schedule/dose modification, intestinal alkalization, structural/chemical modification, genetic testing, anti-diarrheal therapies, transporter (ABCB1, ABCC2, BCRP2) inhibitors, enzyme (β-glucuronidase, UGT1A1, CYP3A4, carboxylesterase, COX-2) inducers and inhibitors, probiotics, antibiotics, adsorbing agents, cytokine and growth factor activators and inhibitors and other miscellaneous agents.

Predictors of irinotecan toxicity and efficacy in treatment of metastatic colorectal cancer

The colorectal cancer ranks high among the malignant tumours in incidence and mortality and irinotecan is standardly used in palliative treatment of metastatic disease in every therapeutic line. Unfortunately, the treatment with irinotecan is often associated with severe toxicities, especially neutropenia and diarrhea. The majority of the toxic manifestation is caused by the insufficient deactivation (glucuronidation) of irinotecan active metabolite SN-38 by UGT1A enzyme. The elevated SN-38 plasma concentration is responsible for the hematological and gastrointestinal toxicity that can become life-threatening. The patients carrying the mutation of the gene encoding UGT1A enzyme lack the ability of bilirubin glucuronidation, and suffer from the inherited un-conjugated hyperbilirubinemia (Gilbert syndrome, Crigler-Najjar type 1 and 2 syndrome). The mutations in other enzyme systems also play role in the etiopathogenesis of the irinotecan toxicity: CYP3A (cytochrome P-450), ABC family of transmembrane transporters (adenosine-triphosphate binding cassette). The goal of the contemporary research is to determine the predictive factors that will enable the individual adjustment of the individual drug dosage while minimising the adverse effects and maintaining the treatment benefit.

Probiotic bacteria in cancer patients undergoing chemotherapy and radiation therapy

BACKGROUND

Probiotics are live microorganisms, which as drugs or food supplements help to maintain health beneficial microbial balance in the digestive tract of a human or other host. Probiotics by their properties may help strengthen homeostasis and thus reduce side effects associated with cancer treatment. Experimental evidence suggests that probiotics might have beneficial effect on the toxicity of anticancer therapy.

METHODS

A computer-based literature search was carried out using PubMed (keywords: "probiotic" and "lactic acid bacteria" in association with the search terms "cancer" or "oncology" or "chemotherapy" or "radiation"); data reported at international meetings were included.

RESULTS

Probiotics might have beneficial effects on some aspects of toxicity related to anticancer treatment especially radiation therapy. However, reported trials vary in utilized probiotic strains, dose of probiotics and vast majority of them are small trials with substantial risk of bias. Despite limited data, it seems that probiotic bacteria as live microorganisms could be safely administered even in the setting of neutropenia.

CONCLUSIONS

Current evidence supporting probiotic use as adjunctive therapy to anticancer treatment is limited, especially in cancer patients treated with chemotherapy. Well designed clinical trials are needed to find true role of probiotics in oncology.

Pulmonary metabolism of resveratrol: in vitro and in vivo evidence

The role of pulmonary metabolism in trans-resveratrol (RES) pharmacokinetics was studied in a mouse model. Plasma concentrations of RES and its major metabolites trans-resveratrol-3-sulfate (R3S) and trans-resveratrol-3-glucuronide (R3G) were compared after administration of RES by intravenous (IV) and intra-arterial (IA) routes. Total area under the curve (AUC) of RES decreased by approximately 50% when RES was administered by the IV route compared with the IA route. The AUC of R3G was also significantly higher in mice administered RES by the IV route compared with the IA route. In vitro studies performed with mouse and human lung fractions confirmed pulmonary metabolism of RES. Interestingly, mouse-lung fractions gave rise to both R3S and R3G, whereas human lung fractions yielded R3S. This indicates marked interspecies variation in RES conjugation, especially in the context of extrapolating rodent data to humans. Taken together, the results presented here underline, for the first time, the impact of pulmonary metabolism on resveratrol pharmacokinetics and interspecies differences in RES pulmonary metabolism.

A randomised double-blind placebo-controlled phase II study of AGI004 for control of chemotherapy-induced diarrhoea

Background:

AGI004 is a controlled-release transdermal patch preparation of mecamylamine. We conducted a randomised placebo-controlled phase II study of two dose levels of AGI004 in chemotherapy-induced diarrhoea (CID).

Methods:

Adult patients receiving chemotherapy who had experienced diarrhoea (NCI grade 1–2) during previous cycles of chemotherapy were eligible. In all, 64 patients were randomised to receive AGI004 4 mg then 8 mg per 24 h transdermal patch or placebo for two sequential cycles of chemotherapy. Patients' severity of diarrhoea was physician-assessed using NCI grade of diarrhoea and patient-assessed using information recorded in daily diaries of bowel movements.

Results:

Overall AGI004 doubled the odds of a response to treatment on the first day of chemotherapy based on physician assessment of NCI grade of diarrhoea compared with placebo (odds ratio=2.0, 90% confidence interval: 0.9–4.5) and there was a trend to improved response rates for AGI004 for the full treatment cycle although these results were not statistically significant. There was also evidence of significantly improved response rates based on patient assessment of diarrhoea both overall (P=0.05) and at the 8-mg dose level (P=0.02) compared with placebo.

Conclusion:

AGI004 demonstrated effectiveness in reducing chemotherapy-associated diarrhoea, with results suggesting response across multiple measurements of diarrhoea. Treatment was well tolerated with no drug-related adverse events. Further evaluation of this agent in the management of CID is warranted.

Systematic review of agents for the management of gastrointestinal mucositis in cancer patients

PURPOSE

The aim of this study was to review the available literature and define clinical practice guidelines for the use of agents for the prevention and treatment of gastrointestinal mucositis.

METHODS

A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.

RESULTS

A total of 251 clinical studies across 29 interventions were examined. Panel members were able to make one new evidence-based negative recommendation; two new evidence-based suggestions, and one evidence-based change from previous guidelines. Firstly, the panel recommends against the use of misoprostol suppositories for the prevention of acute radiation-induced proctitis. Secondly, the panel suggests probiotic treatment containing Lactobacillus spp., may be beneficial for prevention of chemotherapy and radiotherapy-induced diarrhea in patients with malignancies of the pelvic region. Thirdly, the panel suggests the use of hyperbaric oxygen as an effective means in treating radiation-induced proctitis. Finally, new evidence has emerged which is in conflict with our previous guideline surrounding the use of systemic glutamine, meaning that the panel is unable to form a guideline. No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.

CONCLUSIONS

This updated review of the literature has allowed new recommendations and suggestions for clinical practice to be reached. This highlights the importance of regular updates.

A multicenter, phase I, dose-escalation study to assess the safety, tolerability, and pharmacokinetics of etirinotecan pegol in patients with refractory solid tumors

PURPOSE

This study was designed to establish the maximum tolerated dose (MTD) and to evaluate tolerability, pharmacokinetics, and antitumor activity of etirinotecan pegol.

EXPERIMENTAL DESIGN

Patients with refractory solid malignancies were enrolled and assigned to escalating-dose cohorts. Patients received 1 infusion of etirinotecan pegol weekly 3 times every 4 weeks (w × 3q4w), or every 14 days (q14d), or every 21 days (q21d), with MTD as the primary end point using a standard 3 + 3 design.

RESULTS

Seventy-six patients were entered onto 3 dosing schedules (58-245 mg/m(2)). The MTD was 115 mg/m(2) for the w × 3q4w schedule and 145 mg/m(2) for both the q14d and q21d schedules. Most adverse events related to study drug were gastrointestinal disorders and were more frequent at higher doses of etirinotecan pegol. Late onset diarrhea was observed in some patients, the frequency of which generally correlated with dose density. Cholinergic diarrhea commonly seen with irinotecan treatment did not occur in patients treated with etirinotecan pegol. Etirinotecan pegol administration resulted in sustained and controlled systemic exposure to SN-38, which had a mean half-life of approximately 50 days. Overall, the pharmacokinetics of etirinotecan pegol are predictable and do not require complex dosing adjustments. Confirmed partial responses were observed in 8 patients with breast, colon, lung (small and squamous cell), bladder, cervical, and neuroendocrine cancer.

CONCLUSION

Etirinotecan pegol showed substantial antitumor activity in patients with various solid tumors and a somewhat different safety profile compared with the irinotecan historical profile. The MTD recommended for phase II clinical trials is 145 mg/m(2) q14d or q21d.

Synergetic toxicity of DATR, a recombinant soluble human TRAIL mutant, in combination with traditional chemotherapeutics in rats

The recombinant soluble human TRAIL mutant (DATR), derived from tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), is a promising agent for cancer therapy. The present study evaluated the synergetic toxicity of DATR in combination with traditional chemotherapeutics, including irinotecan, polyene paclitaxel and oxaliplatin in rats. Rats treated with polyene paclitaxel alone or in combination with DATR showed severe diarrhea, appetite inhibition, increasing sodium (Na(+)), potassium (Cl(-)) and glucose (GLU) and serious disorders in the haematological system. Increasing total bilirubin (TBIL) and blood urea nitrogen (BUN) were detected in the rats treated with oxaliplatin alone or in combination with DATR. Furthermore, except that the BUN and Crea of male rats treated with irinotecan in combination with DATR were higher than those of treated with irinotecan, the addition of DATR does not increase the toxicity induced by irinotecan, polyene paclitaxel and oxaliplatin. In conclusion, DATR probably increases kidney lesions of rat with irinotecan, but does not increase the toxicity induced by polyene paclitaxel and oxaliplatin. This indicated that DATR has promising potential in clinical combination therapies. Furthermore, the toxicity induced by DATR on the liver, kidneys and haematological system should be considered carefully if DATR is used in combination with traditional chemotherapeutics.

Dose escalation of intravenous irinotecan using oral cefpodoxime: a phase I study in pediatric patients with refractory solid tumors

BACKGROUND

Administration of an oral cephalosporin allowed advancement of the dosage of oral irinotecan. This study investigates whether administration of an oral cephalosporin increases the maximum tolerated dose (MTD) of intravenous irinotecan.

PROCEDURE

Irinotecan was administered intravenously on Days 1-5 and Days 8-12 of a 21-day cycle with continuous oral cefpodoxime starting 2 days prior to irinotecan. Cohorts of 3-6 pediatric patients with refractory solid tumors were enrolled at 4 dosage levels, starting at the single-agent irinotecan MTD of 20 mg/m(2) /dose.

RESULTS

The 17 evaluable patients received 39 courses of therapy. None of the patients treated with 20 mg/m(2) /dose experienced dose-limiting toxicity (DLT). One of six patients treated at 30 mg/m(2) /dose experienced dose-limiting neutropenia. Two of three patients treated with 45 mg/m(2) /dose and two of five treated with 40 mg/m(2) /dose experienced dose-limiting diarrhea, with associated dehydration and anorexia. Two unconfirmed partial responses were observed after one course in a patient with Ewing sarcoma and one with paraganglioma. A child with refractory neuroblastoma had disease stabilization through 12 courses of therapy. Median (range) systemic exposure to SN-38 at the MTD (30 mg/m(2) /dose) was 67 ng-h/mL (36 to 111 ng-h/mL).

CONCLUSIONS

The MTD of intravenous irinotecan administered on a protracted schedule was increased by 50% from 20 to 30 mg/m(2) /dose with the addition of oral cefpodoxime. The most prominent DLT remained diarrhea. High interpatient variability in irinotecan pharmacokinetics was observed; however, SN-38 exposure at the MTD was greater than most reported exposures with the 20 mg/m(2) dosage.

Rapid deconjugation of SN-38 glucuronide and adsorption of released free SN-38 by intestinal microorganisms in rat

One of the dose-limiting toxicities of irinotecan hydrochloride (CPT-11) is delayed-onset diarrhea. CPT-11 is converted to its active metabolite, SN-38, which is conjugated to SN-38 glucuronide (SN-38G). SN-38G excreted in the intestinal lumen is extensively deconjugated by bacterial β-glucuronidase, resulting in the regeneration of SN-38, which causes diarrhea. However, the deconjugation of SN-38G by the intestinal microflora remains to be clarified. This study aimed to investigate the microbial transformation of SN-38G by an anaerobic mixed culture of rat cecal microorganisms. Concentrations of SN-38G and SN-38 were then determined using high-performance liquid chromatography. Complete deconjugation of SN-38G to SN-38 in the mixed cultures was observed within 1 h of incubation, with 62.7% of the added SN-38G being found in the supernatant. Approximately 80.4% of the SN-38 in the supernatant was bound to protein, and the remaining 19.6% was detected as active free SN-38. In total, only 12.3% (19.6 × 62.7%) of the SN-38G added to the test tube was found in the supernatant in the ultrafiltrable free form, indicating that approximately 90% of the SN-38G added to the growth medium either remained adsorbed onto the pelleted fraction or occurred in a protein-bound form in the supernatant. The remaining 10% of the SN-38G added to the growth medium existed in the unbound form, the form capable of causing damage to the intestinal membrane. In conclusion, these results indicated that the greater part of the SN-38 produced from SN-38G by the action of bacterial β-glucuronidase is rapidly adsorbed onto intestinal bacterial cell walls or dietary fibers in pelleted fraction, and only 10% remains in the ultrafiltrable unbound form in the intestinal luminal fluid.

Chemotherapy-induced diarrhea: pathophysiology, frequency and guideline-based management

Diarrhea is one of the main drawbacks for cancer patients. Possible etiologies could be radiotherapy, chemotherapeutic agents, decreased physical performance, graft versus host disease and infections. Chemotherapy-induced diarrhea (CID) is a common problem, especially in patients with advanced cancer. The incidence of CID has been reported to be as high as 50-80% of treated patients (≥30% CTC grade 3-5), especially with 5-fluorouracil bolus or some combination therapies of irinotecan and fluoropyrimidines (IFL, XELIRI). Regardless of the molecular targeted approach of tyrosine kinase inhibitors and antibodies, diarrhea is a common side effect in up to 60% of patients with up to 10% having severe diarrhea. Furthermore, the underlying pathophysiology is still under investigation. Despite the number of clinical trials evaluating therapeutic or prophylactic measures in CID, there are just three drugs recommended in current guidelines: loperamide, deodorized tincture of opium and octreotide. Newer strategies and more effective agents are being developed to reduce the morbidity and mortality associated with CID. Recent research focusing on the prophylactic use of antibiotics, budesonide, probiotics or activated charcoal still have to define the role of these drugs in the routine clinical setting. Whereas therapeutic management and clinical work-up of patients presenting with diarrhea after chemotherapy are rather well defined, prediction and prevention of CID is an evolving field. Current research focuses on establishing predictive factors for CID like uridine diphosphate glucuronosyltransferase-1A1 polymorphisms for irinotecan or dihydropyrimidine-dehydrogenase insufficiency for fluoropyrimidines.

Single nucleotide polymorphism in ABCG2 is associated with irinotecan-induced severe myelosuppression

Irinotecan is an anti-neoplastic agent that is widely used for treating colorectal and lung cancers, but often causes toxicities such as severe myelosuppression and diarrhea. In this study, we performed a two-stage case-control association study for irinotecan-induced severe myelosuppression (grades 3 and 4). In the first stage, 23 patients who developed severe myelosuppression and 58 patients who did not develop any toxicity were examined for 170 single nucleotide polymorphisms (SNPs) in 14 genes involved in the metabolism and transport of irinotecan. A total of five SNPs were identified to show the possible association with severe myelosuppression (P(Fisher)<0.01) and were further examined in 7 cases and 20 controls in the second stage of the study. An intronic SNP, rs2622604, in ABCG2 showed P(Fisher)=0.0419 in the second stage and indicated a significant association with severe myelosuppression in the combined study (P(Fisher)=0.000237; P(Corrected)=0.036). Although only limited subjects were investigated, our results suggested that a genetic polymorphism in ABCG2 might alter the transport activity for the drug and elevate the systemic circulation level of irinotecan, leading to severe myelosuppression.

Chemotherapy-induced diarrhoea

PURPOSE OF REVIEW

Diarrhoea is a major manifestation of chemotherapy-induced mucositis that until recently has received very little attention. To date, there is no detailed understanding of the underlying mechanisms of the condition. The purpose of this review is to examine the plethora of recent studies, both in the laboratory and in the clinic, which have attempted to elucidate effective treatment options.

RECENT FINDINGS

Over recent years, there have been many new treatment options trialled for ameliorating chemotherapy-induced diarrhoea. Some of these have shown great promise in small clinical studies and now need to be investigated in larger trials. Furthermore, there have been developments in the understanding of the underlying mechanisms of chemotherapy-induced diarrhoea. These developments may also lead to effective treatment options.

SUMMARY

Here, we describe the current thinking behind the mechanisms of chemotherapy-induced diarrhoea and present current and new treatment options. This opinion article highlights the shift towards more effective research into diarrhoea caused by chemotherapy.

Irinotecan toxicity

PURPOSE OF REVIEW

The toxicity of irinotecan is predictable, manageable and nonadditive in the majority of patients; however, with its increasing use alone and in combination with other agents and modalities, the recognition and control of these adverse effects remain a clinical challenge. Major efforts over the last several years have focused not only on adding fluoropyrimidines and epidermal growth factor receptor inhibitors to irinotecan, but also investigating factors that account for interindividual differences in toxicities.

RECENT FINDINGS

The association of uridine diphosphoglucuronosyl transferase 1A polymorphisms with increased irinotecan-induced diarrhea and neutropenia, the dose adjustment of irinotecan in the setting of hepatic dysfunction and the observation that 'chemo' liver can develop in the neoadjuvant colorectal cancer setting are recently reported. Also, data from the Sandostatin LAR Depot Trial for the Optimum Prevention of chemotherapy-induced diarrhea support the 30 mg dose of octreotide LAR to manage the condition.

SUMMARY

Recent evidence demonstrates that patients with hepatic insufficiency, uridine diphosphoglucuronosyl transferase 1A polymorphisms (e.g. 1A128 homozygotes and heterozygotes), are at greater risk for irinotecan-induced toxicity. Adjusting irinotecan's dose to the degree of hepatic insufficiency is now established. While 'chemo' liver is not specific to irinotecan, its occurrence influences strategies for treating advanced colorectal cancer. Finally, controlling chemotherapy-induced diarrhea with 30 mg of octreotide LAR is adequate for most patients.

Activated charcoal to prevent irinotecan-induced diarrhea in children

BACKGROUND

We performed a prospective study to evaluate the efficacy of activated charcoal (AC) to prevent irinotecan-induced diarrhea (IID).

PROCEDURE

We designed a prospective trial including all patients receiving irinotecan as part of their chemotherapy treatment. Patients were divided into two groups. The experimental group received AC at a dose of 250 mg three times daily during irinotecan administration. The number and severity of events were graded according to the gastrointestinal toxicity criteria of the NCI Common Toxicity Criteria. We used descriptive statistics, Mann-Whitney U test, and Fisher's exact test to evaluate our results.

RESULTS

Twenty-two evaluable patients were included for a total of 66 irinotecan chemotherapy cycles. Ten patients received AC and 12 did not. There were 45 cycles in the experimental group and 21 in the control group. A total of 28 events of diarrhea were registered, 13 in 45 cycles (28.88%) in the experimental group and 15 in 21 cycles (71.42%) in the control group (P = 0.002). Grade 3 and 4 diarrhea was present in 4.4% of patients receiving AC against 52.3% in the controls (P = 0.010). Chemotherapy was discontinued in 6.6% in the experimental group and 52.3% in the control group.

CONCLUSIONS

The use of AC decreased the frequency and severity of IID improving compliance with treatment. We consider AC and effective and safe prophylactic treatment to prevent IID.

Reducing irinotecan-associated diarrhea in children

Irinotecan is increasingly being used in pediatric oncology. Amelioration of diarrhea associated with protracted irinotecan administration may reduce morbidity and improve dose intensity. In this review, we discuss what is known about the pathogenesis of this toxicity as well as potential predisposing genetic factors. We comprehensively summarize the literature regarding available prevention and treatment strategies, and report data on the use of cephalosporin prophylaxis in 51 patients treated on various pediatric trials. This approach is feasible in children and allows for tolerance of higher doses of protracted irinotecan.

Camptothecin and podophyllotoxin derivatives: inhibitors of topoisomerase I and II - mechanisms of action, pharmacokinetics and toxicity profile

Camptothecins represent an established class of effective agents that selectively target topoisomerase I by trapping the catalytic intermediate of the topoisomerase I-DNA reaction, the cleavage complex. The water-soluble salt camptothecin-sodium - introduced in early trials in the 1960s - was highly toxic in animals, whereas the semisynthetic derivatives irinotecan and topotecan did not cause haemorrhagic cystitis because of their higher physicochemical stability and solubility at lower pH values. Myelosuppression, neutropenia and, to a lesser extent, thrombocytopenia are dose-limiting toxic effects of topotecan. In contrast to the structurally-related topotecan, irinotecan is a prodrug which has to be converted to SN-38, its active form. SN-38 is inactivated by conjugation, thus patients with Gilbert's syndrome and other forms of genetic glucuronidation deficiency are at an increased risk of irinotecan-induced adverse effects, such as neutropenia and diarrhoea. The cytotoxic mechanism of podophyllotoxin is the inhibition of topoisomerase II. Common adverse effects of etoposide include dose-limiting myelosuppression. Hypersensitivity reactions are more common with etoposide and teniposide than with etoposide phosphate because the formulations of the former contain sensitising solubilisers. Leukopenia and thrombocytopenia occur in 65% and 80%, respectively, of patients after administration of conventional doses of teniposide. Anorexia, vomiting and diarrhoea are generally of mild severity after administration of conventional doses of topoisomerase II inhibitors. Clinical pharmacokinetic studies have revealed substantial interindividual variabilities regarding the area under the concentration-time curve values and steady-state concentrations for all drugs reviewed in this article. Irinotecan, etoposide and teniposide are degraded via complex metabolic pathways. In contrast, topotecan primarily undergoes renal excretion. Regarding etoposide and teniposide, the extent of catechol formation over time during drug metabolism may be associated with a higher risk for secondary malignancies.

Irinotecan-induced diarrhea: functional significance of the polymorphic ABCC2 transporter protein

Interindividual pharmacokinetic variability of the anticancer agent irinotecan is high. Life-threatening diarrhea is observed in up to 25% of patients receiving irinotecan and has been related with irinotecan pharmacokinetics and UGT1A1 genotype status. Here, we explore the association of ABCC2 (MRP2) polymorphisms and haplotypes with irinotecan disposition and diarrhea. A cohort of 167 Caucasian cancer patients who were previously assessed for irinotecan pharmacokinetics (90-min infusion given every 21 days), toxicity, and UGT1A1*28 genotype were genotyped for polymorphisms in ABCC2 using Pyrosequencing. Fifteen ABCC2 haplotypes were identified in the studied patients. The haplotype ABCC2*2 was associated with lower irinotecan clearance (28.3 versus 31.6 l/h; P=0.020). In patients who did not carry a UGT1A1*28 allele, a significant reduction of severe diarrhea was noted in patients with the ABCC2*2 haplotype (10 versus 44%; odds ratio, 0.15; 95% confidence interval, 0.04-0.61; P=0.005). This effect was not observed in patients with at least one UGT1A1*28 allele (32 versus 20%; odds ratio, 1.87; 95% confidence interval, 0.49-7.05; P=0.354). This study suggests that the presence of the ABCC2*2 haplotype is associated with less irinotecan-related diarrhea, maybe as a consequence of reduced hepatobiliary secretion of irinotecan. As the association was seen in patients not genetically predisposed at risk for diarrhea due to UGT1A1*28, confirmatory studies of the relationships of ABCC2 genotypes and irinotecan disposition and toxicity are warranted.

Intestinal tract injury by drugs: Importance of metabolite delivery by yellow bile road

Drug secretion into bile is typically considered a safe route of clearance. However, biliary delivery of some drugs or their reactive metabolites to the intestinal tract evokes adverse consequences due to direct toxic actions or indirect disruption of intestinal homeostasis. Biliary concentration of the chemotherapy agent 5-fluorodeoxyuridine (FUDR) and other compounds is associated with bile duct damage while enterohepatic cycling of antibiotics contributes to the disruptions of gut flora that produce diarrhea. The goal of this review is to describe key evidence that biliary delivery is an important factor in the intestinal injury caused by representative drugs. Emphasis will be given to 3 widely used drugs whose reactive metabolites are plausible causes of small intestinal injury, namely the nonsteroidal anti-inflammatory drug (NSAID) diclofenac, the immunosuppressant mycophenolic acid (MPA), and the chemotherapy agent irinotecan. Capsule endoscopy and other sensitive diagnostic techniques have documented a previously unappreciated, high prevalence of small intestinal injury among NSAID users. Clinical use of MPA and irinotecan is frequently associated such severe intestinal injury that dosage must be reduced. Observations from clinical and experimental studies have defined key events in the pathogenesis of these drugs, including roles for multidrug resistance-associated protein 2 (MRP2) and other transporters in biliary secretion and adduction of enterocyte proteins by reactive acyl glucuronide metabolites as a likely mechanism for intestinal injury. New strategies for minimizing the adverse intestinal consequences of irinotecan chemotherapy illustrate how basic information about key events in the biliary secretion of drugs and the nature of their proximate toxicants can lead to safer protocols for drugs.