Pilot study of sandostatin (octreotide) therapy of refractory HIV-associated diarrhea

Lanreotide Autogel in the Treatment of Idiopathic Refractory Diarrhea: Results of an Exploratory, Controlled, Before and After, Open-label, Multicenter, Prospective Clinical Trial

PURPOSE

Chronic idiopathic diarrhea is the passage of loose stools >3 times daily, or a stool weight >200 g/d, persisting for >4 weeks without clear clinical cause. Patients refractory to standard anti-diarrhetics have limited treatment options. Somatostatin analogues have the ability to reduce gastrointestinal secretions and motility. This study evaluated the efficacy and safety of lanreotide Autogel(*) 120 mg in chronic idiopathic diarrhea.

METHODS

Other anti-diarrhetics were not allowed during the study and were stopped at screening. Patients received lanreotide Autogel 120 mg at baseline and day 28. Stool frequency and consistency (Bristol Stool Scale) were recorded; quality of life (QoL) was assessed using the 36-item Short Form Health Survey and irritable bowel syndrome QoL questionnaires; adverse events were monitored. The primary outcome was the proportion of patients with a reduction of ≥50% or normalization to a mean of ≤3 stools/d at day 28.

FINDINGS

Thirty-three patients with >3 stools/d at baseline were included; mean (SD) age was 55.2 (16.4) years. Fourteen patients (42.4%) had a response to lanreotide Autogel at day 28 and 17 (51.5%) at day 56. Mean (SD) number of stools decreased significantly from 5.7 (2.2) at baseline to 3.7 (2.2) at day 56 overall (n = 32; P < 0.001). Significant and clinically meaningful improvements in disease-specific QoL were found in the overall populations. No new safety signals emerged.

IMPLICATIONS

Lanreotide Autogel 120 mg decreased symptoms in these patients with chronic idiopathic refractory diarrhea, and meaningfully improved QoL. These finding have to be confirmed in further clinical trials. ClinicalTrials.gov

IDENTIFICATION

NCT00891371; Eudract CT 2009-009356-20.

Systematic review: the use of somatostatin or octreotide in refractory diarrhoea

BACKGROUND

Somatostatin and octreotide have multiple effects which make them ideal for treating diarrhoea of different aetiologies. Their use in a variety of conditions with refractory diarrhoea, however, is based on a limited number of studies.

AIM

We undertook a systematic review of the available English literature to maximize an evidence-based approach to the treatment of refractory diarrhoea. We tested the hypothesis that efficacy is independent of aetiology.

METHODS AND RESULTS

A Medline and individual article search from 1965 to 2000 was undertaken on the use of somatostatin and octreotide in diarrhoea. All reports containing at least five subjects were included. The percentage response in case series and randomized controlled trials was compared, and a meta-analysis of randomized controlled trials where patient level data were provided was carried out. There were 30 publications found (18 case series, 12 randomized controlled trials). The response percentage was 73% overall in case series and 64% in randomized controlled trials (not significant). A meta-analysis of nine randomized controlled trials revealed significant heterogeneity despite an overall relative risk of 0.5 (95% confidence interval, 0.27-0.91). Subgroup analysis of the largest aetiological groups showed that acquired immunodeficiency syndrome studies were homogeneous, but somatostatin and octreotide were less effective. Post-chemotherapy studies remained heterogeneous and somatostatin and octreotide were highly effective.

CONCLUSIONS

While this review strengthens the consensus guidelines on the use of somatostatin and octreotide for refractory diarrhoea, evidence-based support requires additional studies.

Infectious diarrhea in human immunodeficiency virus

Chronic HIV-associated diarrhea is currently a field in flux. Improved noninvasive diagnostic tests, improved pathogen-specific regimens, and better empiric therapies may change some of the assumptions used to select algorithms for diagnostic evaluation and management. Any shift in the cause of diarrhea from pathogen-associated to idiopathic or a reduction in the overall incidence of diarrhea would have considerable impact. It is unclear how significant the problem of pathogen relapse in previous responders will become. Existing studies reviewed in this article show that the high diagnostic yield of endoscopy when stool tests are negative, coupled with significantly better outcomes when pathogens are identified, support the current practice of routine endoscopic evaluation. There currently are scant data on the economic impact of HIV-associated diarrhea as it relates to pathogen-specific and empiric therapy in the era of protease inhibitors. Such data would be integral to future evaluation of the impact of diagnostic and therapeutic strategies.

Lanreotide inhibits human jejunal secretion induced by prostaglandin E1 in healthy volunteers

1. Somatostatin inhibits hormonal secretions in the gastrointestinal tract. Somatostatin analogues are used in the treatment of VIPome-related watery diarrhoea. In addition, more than 10% of patients with AIDS suffer from diarrhoea likely due to the increased intestinal secretion of water and ions. However, the direct effect of somatostatin on the flux of water and ions in the intestine has not been, so far, analyzed in vivo. The aim of the present study was to evaluate the effect of lanreotide, a somatostatin analogue, on the movements of water and ions in the jejunum in man. 2. Accordingly, 10 healthy volunteers (age 18-35 years, mean 27) and two patients with AIDS (26 and 33 years) suffering from water diarrhoea (> 800 ml day-1) underwent intestinal perfusion using a four lumen tube with proximal occluding balloon. The segment tested was 25 cm long. The jejunum was infused by an isotonic control saline solution containing polyethylene glycol (PEG) as nonabsorbable marker. Basal jejunal secretions were measured in all subjects. Prostaglandin E1 (PGE1) was administered intraluminally to stimulate jejunal secretion in healthy volunteers. The effect of intravenous lanreotide on the jejunal PGE1-induced secretions of water and electrolytes was analysed in healthy subjects and on the basal secretions in AIDS patients. Each period was analyzed on the basis of three (10 min) successive intestinal juice collections after 20-30 min equilibration time. The antisecretory effect of lanreotide was evaluated in each subject as the difference between fluxes compared to the control period. 3. In healthy volunteers, PGE1 induced secretion of H2O, Na+, K+ and Cl- in the jejunum and lanreotide reduced significantly PGE1-induced response. In both AIDS patients basal fluxes of water and ions were reduced by lanreotide in a dose-dependent manner. 4. Somatostatin can reduce stimulated-jejunal secretion of ions and water in normal subjects and may improve water diarrhoea in AIDS patients.

Randomized trial of loperamide versus dose escalation of octreotide acetate for chemotherapy-induced diarrhea in bone marrow transplant and leukemia patients

This study compares maximal daily doses of loperamide to escalating doses of continuous intravenous (CI) octreotide acetate in bone marrow transplant (BMT) and leukemia patients. Following chemotherapy, BMT and leukemia patients who developed > or = 600 ml of stool volume in a 24-hr period were randomized to receive loperamide 4 mg po q6h or octreotide 150 micrograms mixed in hyperalimentation solution or normal saline and administered CI. Patients were assessed at 48 hr intervals for decrease in stool volume from baseline. Complete response (CR) was defined as > or = 50% from baseline stool volume (BSV). Patients receiving octreotide who did not achieve a CR at 48 hr were dose escalated by doubling the dose to a maximum of 2,400 micrograms with evaluations at 48 hr intervals. Patients receiving loperamide who did not achieve a CR at 48 hr had treatment discontinued. A total of 36 patients were enrolled in the study. Of these, all were evaluable for intention to treat, and 31 were evaluable for initial response. Based on intent to treat at the initial 48 hr, patients receiving loperamide had a higher complete response rate (86% vs. 45%, P = 0.033) than did those who received octreotide. By treatment analysis (patients who actually received the drug), patients receiving loperamide had a higher complete response rate (92% vs. 56%, P = 0.0448) than did those who received octreotide at the 150 micrograms dosage level. Additional octreotide patients eventually achieved a CR at a higher dosage level (78%). Loperamide at maximal doses of 4 mg po q6h is more effective than octreotide 150 micrograms CI in treating diarrhea following chemotherapy in BMT and leukemia patients. Higher doses of octreotide may be required in a significant number of patients not responding to lower doses.

Multicenter trial of octreotide in patients with refractory acquired immunodeficiency syndrome-associated diarrhea

BACKGROUND/AIMS

Diarrhea is a significant problem in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine octreotide effectiveness in refractory AIDS-associated diarrhea.

METHODS

In a 3-week protocol, 129 patients with a stool weight of > 500 g/day despite standard antidiarrheal therapy were randomized to receive octreotide or placebo (3:2 ratio). Octreotide dose was increased 100 micrograms weekly to a maximum of 300 micrograms three times a day based on weekly 72-hour stool collections. Subsequently, patients received open-label octreotide at doses of up to 500 micrograms three times a day.

RESULTS

A 30% decrease in stool weight defined response. After 3 weeks, 48% of octreotide- and 39% of placebo-treated patients had responded (P = 0.43). At 300 micrograms three times a day, 50% of octreotide- and 30.1% of placebo-treated patients responded (P = 0.12). At a baseline stool weight of 1000-2000 g/day, 57% of octreotide- and 25% of placebo-treated patients responded (P = 0.06). Response rates based on CD4 counts, diarrhea duration, body weight, human immunodeficiency virus risk factor, and presence or absence of pathogens showed no benefit of octreotide. Adverse events were more frequent in the octreotide-treated group.

CONCLUSION

In the doses studied, octreotide was not more effective than placebo in patients with refractory AIDS-associated diarrhea. This lack of effectiveness may be attributable to inadequate sample size, doses, and duration of study treatment.

Update on the management of intestinal cryptosporidiosis in AIDS

OBJECTIVE

To update readers on the pharmacotherapeutic management of cryptosporidiosis in patients with AIDS.

DATA SOURCES

A MEDLINE search was used to identify pertinent literature. Additionally, programs and abstracts from the 33rd Interscience Conference on Antimicrobial Agents and Chemotherapy; the 1st International Conference on Macrolides, Azalides, and Streptogramins; the 93rd American Society for Microbiology Meeting; and the 6th and 7th International Conferences on AIDS were used.

DATA EXTRACTION

Available data from in vitro, animal, and human experiments were reviewed.

DATA SYNTHESIS

Intestinal cryptosporidiosis in patients with AIDS can be a life-threatening opportunistic infection. However, there can be significant variability in disease expression, including spontaneous remission. Supportive care with hydration and nutritional supplementation remains a hallmark of therapy. Unfortunately, there is no proven specific pharmacotherapy of cryptosporidiosis in patients with AIDS. Numerous agents have been analyzed for in vitro activity and efficacy in experimental animal models and actual human cases of the infection, including paromomycin, azithromycin, clarithromycin, octreotide, hyperimmune bovine colostrum, bovine transfer factor, and many others. Because limited numbers of controlled trials have been conducted with potential therapeutic agents, the majority of the information to date is preliminary in nature.

CONCLUSIONS

Despite the availability of some evolving and potentially promising treatment modalities, further controlled clinical trials are necessary to evaluate the role of pharmacotherapy for intestinal cryptosporidiosis in patients with AIDS.

Expanding uses of octreotide

This chapter reviews the therapeutic use of octreotide in a variety of pancreatic disorders, including acute pancreatitis, in the prevention of postoperative and post-ERCP pancreatitis, in the control of postoperative pancreatic fistulae, and in chronic pancreatitis for the control of pain and of pseudocysts and ascites. The review also discusses the use of octreotide in intestinal disorders of motility, gastrointestinal bleeding, intestinal fistulae and refractory diarrhoea, including the diarrhoeas of AIDS, diabetes, short gut, chemotherapy, ileostomy and gastric surgery. The use of octreotide in neuroendocrine tumours, both for therapy and diagnostic imaging, is reviewed briefly. The paucity of adequately controlled studies in many of these situations is indicated and the potential usefulness of octreotide estimated.

Vasoactive intestinal polypeptide (VIP) secretion and refractory diarrhea in patients with AIDS or AIDS-related complex (ARC)

Elevated plasma levels of vasoactive intestinal polypeptide (VIP) (as assessed by a radio-immunoassay), were found in 7/11 patients with AIDS or AIDS-related Complex (ARC), evaluated because of prolonged intractable diarrhea with either an infectious (6 cases) or a non-infectious (5 cases) etiology. Six subjects have been treated with the somatostatin analogue octreotide, which gave both a favourable clinical response and a significant reduction in plasma VIP concentrations. Evaluation of plasma VIP levels may provide a pathophysiological basis for explaining the efficacy of octreotide therapy in HIV-infected patients suffering from both infectious and non-infectious refractory diarrhea.

Acute infectious diarrhea

Diarrhea continues to be a major cause of mortality and morbidity in third world countries as well as a major symptomatic complaint in the primary care setting in the United States. The etiologic pathogen depends on an exposure history to include recent travel to foreign countries, consuming fecally contaminated water or food, prior use of antibiotics, or homosexual behavior. A careful history from patients directed at attempting to identify particular risk factors may help in making a diagnosis. Not all patients require a diagnostic workup. A large number of patients may only require oral rehydration, careful observation over time with or without use of antimotility agents. In toxic appearing patients or patients with fever, however, bloody stools, abdominal pain or tenesmus, a selective diagnostic workup is indicated. Antimicrobial treatments are not always required, some pathogens clearly call for treatment while some have less clear indications and other pathogens are not responsive to antimicrobial agents at all. Finally, one needs to remember that the differential diagnosis of acute diarrhea includes many noninfectious origins.

Peptides in the gastrointestinal tract in human immunodeficiency virus infection. The GI/HIV Study Group of the University of Calgary

The presence of immunoreactivity to the neuronal phosphoprotein B-50 and the peptides bombesin, calcitonin gene-related peptide, galanin, neurotensin, neuropeptide Y, somatostatin, substance P, and vasoactive intestinal polypeptide was examined in biopsy specimens from the duodenum and rectum of human immunodeficiency virus (HIV)-seropositive and HIV-seronegative male homosexual patients. The distribution of B-50 and the peptides was correlated with HIV serology, number of CD4+ lymphocytes, and the presence of HIV in biopsy culture. There was a very low incidence of enteric pathogens in both groups of patients. It was found that HIV-seropositive patients had a greater incidence of abnormal patterns of immunoreactivity (reduced intensity and/or density of innervation) in enteric nerves and enteroendocrine cells than HIV-seronegative patients. A reduction of substance P immunoreactivity was significantly correlated with reduced CD4+ lymphocyte count and HIV status; a similar trend was also seen for somatostatin and vasoactive intestinal polypeptide. Using B-50 as a marker, it was found that both groups of patients had altered patterns of immunoreactivity in rectal nerves. The findings of this study suggest that some of the clinical symptoms associated with HIV infection may be caused by a specific HIV enteropathy that influences enteric nerve and/or enteroendocrine cell function by altering the density of peptide immunoreactivity.