Thalidomide therapy for patients with refractory Crohn's disease: an open-label trial

Inflammatory bowel disease. Medical therapy of specific clinical presentations

Ulcerative colitis and Crohn's disease are chronic relapsing inflammatory disorders of the gastrointestinal tracts. The inflammatory process is restricted to the mucosa and submucosa of the colon in ulcerative colitis and is transmural and may occur anywhere in the gastrointestinal tract in Crohn's disease. Clinical presentation of these inflammatory disorders depends on the segments of digestive tract affected and on the extent and aggressiveness of the disease process. The treatment of specific clinical presentations of these disorders is discussed in this article.

Medical treatment of Crohn's disease

Crohn's disease is not medically (and is rarely surgically) curable. Patients do, however, live a normal life span. The goal of therapy is to optimize the quality of life, minimize disease activity and disease-related complications, and avoid therapeutic toxicity.

New developments in the treatment of inflammatory bowel disease

Therapy of inflammatory bowel disease (IBD) is rapidly changing with the advent of new discoveries in disease pathogenesis. The need for targeted therapies against the uncontrolled immuno-inflammatory reaction in IBD together with a prerequisite for minimal side effects is driving improvement in old medicines and is leading to the development of new drugs. This review introduces emerging changes in IBD treatment, such as improvements in conventional IBD medications or their use. Balsalazide, budesonide and changes in the use of 5-aminosalicylate (5-ASA) products and purine analogues, such as azathioprine, are discussed. Additionally, studies examining the role of drugs newly introduced into IBD therapy, such as mycophenolate mofetil (MMF), thalidomide and heparin, are stated. Emerging biological therapies, such as therapies against TNF, therapies to enhance anti-inflammatory cytokines, therapeutic manoeuvres to disrupt immune cell trafficking, anti-oxidant therapies, as well as non-conventional treatments, such as diet therapies, prebiotics and probiotics, and helminth therapies are discussed.

Early studies on the safety and efficacy of thalidomide for symptomatic inflammatory bowel disease

BACKGROUND AND AIM

Thalidomide is clinically effective in the treatment of graft versus host disease in bone marrow transplantation and aphthous ulceration in HIV infection. It appears to exert a selective effect on tumor necrosis factor-alpha (TNF-alpha) production. Tumor necrosis factor-alpha is implicated in the pathogenesis of inflammatory bowel disease (IBD). The aim of this study was to assess the efficacy and safety of thalidomide in symptomatic IBD.

METHODS

Eleven patients (nine males, mean age 33 years, range 20-77 years) with chronic inflammatory bowel disease (six Crohn's disease (CD), four ulcerative colitis (UC), one indeterminate colitis (IC)) who were symptomatic despite standard medical therapy were administered a daily dose of thalidomide for 12 weeks in an open-labeled protocol. Their response was assessed by using clinical, colonoscopic, histological, and immunological methods.

RESULTS

Two patients withdrew at 3 weeks because of mood disturbances. Of the remaining nine patients, eight (five CD, two UC and one IC) had a marked clinical response, while one patient with CD had no response. The mean stool frequency decreased from 4.3 to 2.3 per day (P = 0.0012), and the stool consistency increased from 2.1 to 1.2 (P = 0.02). The mean Crohn's Disease Activity Index decreased from 117 to 48 (P = 0.0008). Endoscopic inflammatory and histological grade, C-reactive protein and erythrocyte sedimentation rate (ESR) all decreased significantly (P = 0.011, P = 0.03, P = 0.023 and P = 0.044, respectively). However, the serum TNF-alpha levels did not change. Side-effects included mild sedation, xerostomia and skin dryness in all, constipation in three, and minor abnormalities in nerve conduction in one patient.

CONCLUSION

These data strongly suggest that thalidomide is an effective short-term treatment for symptomatic IBD.

A critical assessment of new therapies in inflammatory bowel disease

The only therapy in inflammatory bowel disease (IBD), which up to the mid-1990s was disease modifying, was immunosuppression with azathioprine. Other 'standard' therapies in IBD were merely symptomatic. With the advent of biological therapies, especially the chimeric monoclonal anti-TNF antibody infliximab, we start to target specific pathogenic disease mechanisms, which allow thorough suppression of the disease process and healing of the bowel in the long term. Moreover, infliximab is the only drug up to the present that allows short-term healing of fistulizing Crohn's disease. This therapy is, however, associated with problems of immunogenicity. The formation of antibodies to infliximab jeopardizes the efficacy and is associated with infusion reactions. Optimization of anti-TNF strategies will occur in the coming years. Another promising therapy is antagonization of alpha4 integrins and hence, of migration of inflammatory cells to the intestine. It can be expected that more simple therapies using small molecules that inhibit the key cytokines or pro-inflammatory processes will take over in the next decade. In the current and future approach to IBD therapy immunosuppression with azathioprine or 6-MP and methotrexate play a central role. At the present time, the combination of infliximab with azathioprine or methotrexate can be regarded as the new standard for the therapy of refractory Crohn's disease. In ulcerative colitis (UC) much less progress has been made and the value of biological therapy as well as of long-term management with immunosuppression remains controversial. Probiotics are an attractive treatment option for IBD but studies so far are small and data are not yet convincing.

Biological and novel therapies for inflammatory bowel disease in children

During the past decade, a tremendous wealth of information regarding the pathogenesis, genetics, and therapy of IBD has been discovered. Judging by the number of new publications published every month in scientific journals and the great enthusiasm at scientific meetings, this outstanding pace surely will continue. In the near future, clinicians may be able to classify IBD into several subtypes depending on patients' cytokine and gene profiles. For example, two groups of researchers recently have identified mutation in the NOD2 gene, which is associated with susceptibility to CD. This identification may allow the clinician to better predict outcome and response to medical therapy. At the same time, several promising new therapies are being investigated. Technologic advances will continue to result in the development of potent and specific agents that will control and possibly correct the abnormal inflammatory processes responsible for pediatric IBD.

Theoretical basis for the activity of thalidomide

The revival of thalidomide began shortly after the drug was withdrawn from the market because of its teratogenic properties. Therapeutic effects of thalidomide were found accidentally in leprosy patients with erythema nodosum leprosum (ENL). Subsequent research widened the understanding of the activity of thalidomide, and with improved methodology and the augmented background knowledge of immunology it was possible to interpret the properties of thalidomide more coherently. Effects on tumour necrosis factor-alpha (TNFalpha) release play an important role in the ability of thalidomide to affect the immune system. Alteration of synthesis and release of cytokines such as interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12 and interferon-gamma is involved in the complex mechanisms of thalidomide. Thalidomide targets leucocytes, endothelial cells and keratinocytes, affecting them in a different manner and at different cellular levels. Changes in the density of adhesion molecules alter leucocyte extravasation and the inflammatory response in the tissue involved. Several mechanisms for the teratogenic action of thalidomide are currently under review, but this mode of action of the drug still remains unclear and we review evidence-based hypotheses for the teratogenicity of thalidomide. Thalidomide shows significant clinical impact in several diseases such as ENL in lepromatous leprosy, chronic graft-versus-host disease, systemic lupus erythematosus, sarcoidosis, aphthous lesions in HIV infection, wasting syndrome in chronic illness, inflammatory bowel disease, multiple myeloma and some solid tumours. In 1998 the US Food and Drug Administration approved thalidomide exclusively for the treatment of ENL, and strict conditions were stipulated for its use in order to prevent teratogenic adverse effects. However, despite the promising findings of thalidomide at the molecular level, namely its anti-TNFalpha properties and its intercalation with DNA, and activity in clinical trials, there is still a great need for more intensive research.

Thalidomide therapy for recalcitrant systemic onset juvenile rheumatoid arthritis

Systemic onset juvenile rheumatoid arthritis unresponsive to nonsteroidal anti-inflammatory drugs may be controlled with corticosteroids, but these drugs have significant side effects. We report 2 steroid-dependent children with systemic onset juvenile rheumatoid arthritis who did not respond to multiple nonsteroidal anti-inflammatory drugs, methotrexate, azathioprine, cyclosporine, and etanercept. Both children had significant improvement with thalidomide therapy.

Clinical aspects and pathophysiology of inflammatory bowel disease

The chronic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are recognized as important causes of gastrointestinal disease in children and adults. In this review we delineate the clinical manifestations and diagnostic features of IBD. In addition, we summarize important recent advances in our understanding of the immune mediators of intestinal inflammation. This information has led to new therapeutic approaches in IBD. Further, we discuss the considerable data that point to the significance of genetic factors in the development of IBD and the genetic loci which have been implicated through genome-wide searches. The commensal bacterial flora also appears to be a critical element, particularly in regards to Crohn's disease, although the precise role of the bacteria in the disease manifestations remains unclear. Current investigations promise to yield fresh insights in these areas.

Immune therapy in inflammatory bowel disease and models of colitis

BACKGROUND

A proliferation of animal models has not only improved our understanding of inflammatory bowel disease, it has also formed the basis of new treatment strategies.

METHODS

A search was conducted using the National Library of Medicine for articles discussing immune therapies for inflammatory bowel disease. This was supplemented by findings from the authors' own laboratory.

RESULTS

An overview of the different animal models is presented. These models are used to highlight the recent human trials of immune therapies. Potential future therapies are also discussed.

CONCLUSION

Immune therapies have altered the management of patients with inflammatory bowel disease. In future they will influence not only the indications for surgery but also its timing and outcome.

Thalidomide: new indications?

Thalidomide, which was developed as a nonbarbiturate sedative agent, was taken off the market in 1961 after it was linked to a spate of major birth defects. Gradually, thalidomide was reintroduced for the treatment of a few skin diseases including leprous erythema nodosum, severe mucosal ulcers (e.g., associated with HIV infection or Behçet's disease), lymphocytic skin infiltrations, cutaneous lupus erythematosus, and chronic graft-versus-host disease. Recent reports of original pharmacological properties including modulation of cytokine production (mainly reduced TNF-alpha production) and inhibition of angiogenesis have led to the suggestion that thalidomide may be useful in some inflammatory and neoplastic conditions. Several open-label studies and case reports have described the effects of thalidomide in Crohn's disease, rheumatoid arthritis, ankylosing spondylarthritis, systemic sclerosis, and a few other systemic disorders. In these indications, minor but dose-limiting side effects were apparently common. Thalidomide analogs with better acceptability profiles are under evaluation. The anti-angiogenic effects of thalidomide may make this compound valuable as single-drug therapy or as an adjunct to chemotherapy in patients with cancer, particularly those with metastases or multiple myeloma. This possibility requires further evaluation.

Thalidomide treatment for refractory Crohn's disease: a review of the history, pharmacological mechanisms and clinical literature

Several recent case reports and clinical trials have demonstrated that thalidomide is emerging as an efficacious alternative in the treatment of selected patients with refractory Crohn's disease. The effects of thalidomide are at least partly mediated by down-regulation of tumour necrosis factor (TNF)-alpha, a potent proinflammatory cytokine. However, thalidomide is also known to inhibit angiogenesis, and it has several other well-described immunomodulatory properties. Clinical studies have confirmed that previously refractory Crohn's disease patients respond to thalidomide, and many enter clinical remission. Efficacy usually occurs within 4 weeks. Thalidomide also has steroid-sparing properties, and it is particularly useful in treating oral and fistulous complications of Crohn's disease. Although it is usually tolerable, careful monitoring is recommended to prevent toxicities, such as birth defects and peripheral neuropathy. This review provides a detailed summary of the literature to date on the use of thalidomide treatment for Crohn's disease. Special attention is directed towards its history, mechanisms, and proposed role. The recent development of thalidomide analogues is also discussed briefly.

Thalidomide in gastrointestinal disorders

Thalidomide was originally marketed as a sedative, but was removed from the market in 1961 after it was associated with an epidemic of severe birth defects. Subsequently, it has been shown to have therapeutic efficacy in a number of the gastrointestinal tract conditions characterised by immune dysregulation. The exact mechanism of the immunosuppressive effects of thalidomide is unknown; proposed mechanisms include inhibition of tumour necrosis factor alpha release and inhibition of angiogenesis. In chronic graft versus host disease, use of high dose thalidomide (1200 mg/day) may bring about a response in 20% of patients with refractory disease. Thalidomide 200 mg/day helps eradicate ulcers in 50% of patients with HIV-associated oral aphthous ulceration. In Behçet's disease, thalidomide 100 to 300 mg/day can decrease the number of mucocutaneous ulcers, although full remission occurs in less than 20% of patients. In Crohn's disease, thalidomide 50 to 300 mg/day may decrease the severity of mucosal disease and prompt closure of fistulae. Patients to be placed on thalidomide therapy must practice either abstinence or strict birth control; women must undergo regular pregnancy testing and utilise 2 forms of contraception. Other adverse effects include sedation (present in nearly all patients), symptomatic neuropathy (present in approximately 20%), and skin rashes. Given the potential toxicity, thalidomide use should generally be limited to clinical protocols with institutional review board oversight.

Targeting tumor necrosis factor alpha. New drugs used to modulate inflammatory diseases

Since its discovery, the understanding of the roles for TNF-alpha in human biology and disease has grown. Receptors for TNF are found on virtually all cell types, and many physiologic processes seem to be altered by TNF-alpha. The understanding of how TNF-alpha is involved in the pathophysiology of diseases, such as inflammatory diseases, has allowed the development of new drugs that can interfere with excess TNF-alpha and thus has allowed novel therapies for rheumatoid arthritis and Crohn's disease. As the role of TNF-alpha in other diseases becomes better understood, such TNF-alpha-modulating drugs may find further applications. In the skin, TNF-alpha is prominent cytokine that seems to be important in allergic and irritant contact dermatitis and inflammatory skin conditions. Modulating TNF-alpha activity in the skin may provide therapeutic benefits for a variety of skin conditions (Table 4). Tumor necrosis factor-alpha levels are elevated in skin lesions of psoriasis. A few reports have already suggested that etanercept and infliximab may offer a therapeutic effect in patients with psoriasis. Clinical studies evaluating the true efficacy of these drugs in psoriasis are under way. Specifically, the authors and others are involved in a double-blind, placebo-controlled study to assess the efficacy of etanercept for psoriasis. Thalidomide has been used off-label with some success to treat a number of dermatologic diseases, including several inflammatory skin conditions. Etanercept and infliximab might perhaps prove efficacious for inflammatory skin conditions as well. Finally, it is possible that drugs targeting TNF-alpha may have yet-unrecognized serious side effects. Because TNF-alpha seems to be a central cytokine in UVR-induced apoptosis, the chronic use of TNF-alpha-altering drugs might increase the risk for skin cancers. Tumor necrosis factor-alpha also plays some role in cutaneous wound healing; the effect these drugs might have on this process is also unknown at this time. Certainly, much is already [table: see text] known about TNF-alpha and how it plays many central roles. This understanding has allowed the development of useful new drugs for intractable disease. As the understanding of TNF-alpha and other cytokine biology increases, so will the number of potential therapeutic agents.

Potent inhibition of cytokine production from intestinal lamina propria T cells by phosphodiesterase-4 inhibitory thalidomide analogues

In Crohn's disease, intestinal lamina propria (LP) T cells overproduce TNF-alpha and IFN-gamma, and clinical and animal studies indicate that this is pathogenic. Thalidomide influences cytokine production by leukocytes, inhibiting macrophage TNF-alpha, and is beneficial in treating Crohn's disease. Chemical analogues have been synthesized that may lack teratogenic and other side effects of thalidomide. We tested three analogues [selective cytokine inhibitory drugs (SelCIDs) A, B, and C, all potent PDE4 inhibitors] for effect on TNF-alpha, IFN-gamma, and IL-10 production by and on proliferation of intestinal LP mononuclear cells after T-cell stimulation and results were compared with those for peripheral blood leukocytes (PBL). While thalidomide itself had little effect, the SelCIDs were potent inhibitors, with relative inhibitory potencies: A> or =B>>C. The LP T cells were less sensitive to inhibition by the SelCIDs than were PBL. Since highly pre-activated PBL were even less sensitive, activation state alone can account for the responsiveness of intestinal LP T cells. Thalidomide analogues could play a role in treating Crohn's disease and other inflammatory disorders.

Thalidomide impairment of trinitrobenzene sulphonic acid-induced colitis in the rat - role of endothelial cell-leukocyte interaction

1. Immune response-modulating drugs such as thalidomide may be of therapeutic value in the treatment of chronic inflammatory bowel diseases including Crohn's disease (CD). In the present study, we have investigated whether thalidomide exerts this effect by impairing endothelial cell-leukocyte interaction through down-regulation of the expression of pro-inflammatory gene products in these cells. 2. Transient CD-like colitis was induced in male Wistar rats by single enema with trinitrobenzene sulphonic acid (TNBS) in ethanol followed by macroscopic scoring, histology, intravital microscopy, RT - PCR and immunohistochemistry (IHC) analyses. Thalidomide or its analogue supidimide were administered in olive oil by intragastric instillation 6 h prior to the induction of colitis and then daily for one week. 3. Both thalidomide and supidimide (200 mg kg(-1) d(-1)) significantly attenuated TNBS-induced colitis as compared to vehicle-treated control animals (44 and 37% inhibition, respectively), and this effect persisted for 7 days post cessation of thalidomide treatment (46% inhibition). 4. Moreover, thalidomide significantly reduced leukocyte sticking to postcapillary venular endothelial cells in the submucosa (by 45%), improved functional capillary density and perfusion, and attenuated endothelial interleukin-8 expression, as judged by IHC analysis. According to RT - PCR analysis, both thalidomide and supidimide also significantly reduced vascular cell adhesion molecule-1 mRNA expression in the affected part of the descending colon. 5. These findings suggest that thalidomide and one of its derivatives impairs CD-like TNBS-induced colitis in the rat by down-regulating endothelial adhesion molecule and chemokine expression and, as a consequence, the interaction of these cells with circulating leukocytes.

Novel therapies in the treatment of ulcerative colitis

Ulcerative colitis is a chronic inflammatory disease of unknown cause. Its course is one of relapse and remission and requires therapy for both the induction and maintenance of remission. The progress in the fields of genetics and immunology has afforded important advances in our understanding of the inflammatory process. Traditional therapy with non-specific anti-inflammatories for ulcerative colitis remains our gold standard as newer targeted therapies have failed to provide any improved efficacy. This review examines the most recent compounds in development for the treatment of ulcerative colitis, including data from early clinical trials and the potential clinical impact of future entities.

Integrating anti-tumor necrosis factor therapy in inflammatory bowel disease: current and future perspectives

Crohn's disease and ulcerative colitis are two idiopathic inflammatory disorders of the GI tract. Manifestations of disease can be severe and lead to long term therapy with a variety of medications and/or surgery. Standard medical therapy consists of agents that either treat suppurative complications or modulate the inflammatory cascade in a nonspecific manner. Many specific chemokine and cytokine effectors that promote intestinal inflammation have been identified. Such work has led to experimental clinical trials with a variety of cytokine antagonists. Compounds directed against one such cytokine, tumor necrosis factor alpha (TNF), have demonstrated the greatest clinical efficacy to date. This is consistent with scientific observations that suggest a central role for TNF in the inflammatory cascade. Infliximab is a chimeric monoclonal antibody against TNF that has been demonstrated to be effective for the treatment of Crohn's disease. Infliximab is Food and Drug Administration approved for the treatment of Crohn's disease. There exist several other TNF antagonists in various phases of investigation, including the monoclonal antibody CDP 571, the fusion peptide etanercept, the phosphodiesterase inhibitor oxpentifylline, and thalidomide. The clinical efficacy of these agents and the role of TNF in the pathogenesis of inflammatory bowel disease is reviewed.

Refractory Inflammatory Bowel Disease

Therapeutic options for refractory colonic inflammation in patients with ulcerative colitis or Crohn's disease have recently been augmented by the introduction of biologic therapies. Intravenous corticosteroids and cyclosporin A remain the standard therapies for severe ulcerative colitis. Monoclonal antibodies directed at tumor necrosis factor alfa (TNF-alpha) have proven to be most efficacious in patients with severe or refractory Crohn's disease. Immunomodulatory therapy with azathioprine, 6-mercaptopurine, or methotrexate has demonstrated efficacy for maintenance of remission in patients with refractory ulcerative colitis or Crohn's disease. The use of experimental biologic agents may be considered for those patients who fail to respond to or remain dependent on corticosteroids. Surgical intervention is indicated for patients with severe colitis who fail to respond to medical therapy or develop life-threatening complications such as perforation or toxic megacolon.

Transcending conventional therapies: the role of biologic and other novel therapies

Biologic and other novel therapies targeted to specific pathogenic processes offer the potential for improved treatment outcomes in patients with Crohn's disease and alteration of the course of the disease. Therapies targeted to tumor necrosis factor alpha (TNF-alpha) include anti-TNF-alpha monoclonal antibodies (infliximab and CDP-571), TNF-binding neutralizing fusion proteins (etanercept), and TNF-alpha production inhibitors (thalidomide). In placebo-controlled trials, infliximab has rapidly induced clinical response and remission in patients with moderately to severely active Crohn's disease refractory to conventional therapy and patients with fistulizing Crohn's disease, with minimal toxicity; retreatment with infliximab in patients who experienced an initial response maintained their clinical improvement. Clinical experience suggests that infliximab may also be effective when administered as corticosteroid-sparing therapy. Infliximab is the only anti-TNF-alpha therapy currently available in clinical practice for the treatment of active Crohn's disease. Controlled trials of the investigational anti-TNF-alpha agent CDP-571 show benefit for induction of clinical improvement and steroid-sparing, but further investigation is needed. A pilot study of etanercept suggested a beneficial effect, but its efficacy was not confirmed in a controlled trial. In open-label trials, thalidomide has demonstrated efficacy in patients with refractory Crohn's disease; however, the therapeutic potential of thalidomide may be severely limited by the high incidence of drug-induced side effects. Other novel agents, including anti-alpha4 integrin antibodies, interleukin (IL)-10 and IL-11, and the immunomodulators tacrolimus and mycophenolate mofetil have been evaluated as treatment in patients with severely active or fistulizing Crohn's disease in open-label and controlled trials, with varied results reported to date. The development of these new therapies is an exciting advance that promises to improve the management of Crohn's disease and expand current knowledge of underlying pathophysiologic mechanisms.

Evolving treatment strategies for inflammatory bowel disease

Crohn's disease and ulcerative colitis are idiopathic inflammatory bowel diseases characterized by dysregulated intestinal immune responses in genetically susceptible hosts. Conventional approaches to the medical therapy of ulcerative colitis and Crohn's disease can now be directed at either induction or maintenance of remission to improve therapeutic efficacy while minimizing complications. Newer approaches have expanded the utility of conventional therapies by improving both safety and efficacy and highlight the importance of specific targets along the immunoinflammatory pathways. The combination of conventional and novel approaches now offers the potential of modifying the natural history of these diseases.

Inflammatory bowel disease and pregnancy

Most women with inflammatory bowel disease who desire to become pregnant can expect to conceive successfully, carry to term, and deliver a healthy infant. However, the management of inflammatory bowel disease during pregnancy remains challenging, and some women with ulcerative colitis or Crohn's disease will have difficulty becoming pregnant or have increased disease symptoms while pregnant. Control of disease activity before conception and during pregnancy is critical to optimize both maternal and fetal health. The natural history of inflammatory bowel disease during pregnancy will be reviewed and the medical and surgical therapy discussed.

Approach to corticosteroid-dependent and corticosteroid-refractory Crohn's disease

Corticosteroids are considered a drug of choice for the treatment of patients with moderately to severely active Crohn's disease (CD), an inflammatory bowel disease characterized by chronic recurrent flares of disease activity. However, among patients receiving corticosteroid therapy for induction of remission, 20% have corticosteroid-refractory disease and 36% of those with an initial response develop corticosteroid dependency within 1 year. Chronic corticosteroid exposure in patients who are corticosteroid dependent increases the risk for serious drug-related adverse effects. Withdrawal or reduction of corticosteroid therapy without exacerbation of symptoms is therefore recognized as an important goal of treatment. Therapies that have been shown to facilitate "steroid sparing' include the immunomodulators azathioprine/6-mercaptopurine and methotrexate and the antitumor necrosis factor-alpha monoclonal antibody infliximab. In corticosteroid-dependent patients, budesonide may be substituted for conventional corticosteroid therapy without loss of response and with less risk for toxicity, but its long-term efficacy requires further evaluation. A preliminary controlled study suggests that the investigational anti-TNF monoclonal antibody CDP-571 may also be clinically beneficial as a corticosteroid-sparing agent. This review summarizes the clinical evidence that supports consideration of these agents as alternatives in patients with CD who are dependent on, refractory to, or intolerant of conventional corticosteroid therapy.

Immunotherapeutic approaches to inflammatory bowel diseases

For a long time corticosteroids, aminosalicylic acid preparations and antibiotics have represented the principal approaches in evidence-based drug therapy for chronic inflammatory bowel diseases (IBD), e.g., Crohn's disease (CD) and ulcerative colitis (UC), and are able to suppress disease activity in most cases. However, there are cases that do not respond to conventional drug therapy or remain dependent on high doses of steroids associated with severe side effects in the long run. It is generally accepted now that IBD has an immunological basis and results from a hyperresponsive state of the intestinal immune system. Although the primary etiological defect respectively immunogenic agent still remains to be identified, substantial progress has been made in our understanding to regulatory mechanisms of the intestinal immune system and their alterations in IBD at the molecular level. Due to the concurrent advent of biotechnological processes it has been possible to utilise these insights for the development of novel immunomodulatory therapeutic strategies ranging from recombinant cytokines and blocking antibodies to oligonucleotide antisense strategies and gene therapeutic approaches. This review will present the current status of the development of these novel immunomodulatory therapeutic strategies in IBD and the status of their use in clinical practice. For a better understanding, it will be necessary to address the recent advances in the elucidation of pathogenetic mechanisms of IBD from studies in human specimen and experimental colitis models that have provided the basis for these novel therapeutic approaches.

Pathophysiology of otosclerosis

OBJECTIVE

To review current knowledge of the pathophysiology of otosclerosis and to review hypotheses for the amelioration of this disease.

DATA SOURCES

Review of the literature and experimental observations by the authors.

CONCLUSIONS

Otosclerosis is a localized disease of bone remodeling within the otic capsule of the human temporal bone. Unlike other similar bone diseases, it does not occur outside of the temporal bone. These lesions seem to begin by resorption of stable otic capsule bone in adults, followed by a reparative phase with bone deposition. There are clearly genetic factors that lead to this disease, but measles virus infection and autoimmunity also may play contributing roles. Surgical correction of the conductive hearing loss is highly effective, but nonsurgical intervention has not yet been shown to prevent or slow the disease. Of the factors that may inhibit this process, fluorides, cytokine inhibitors, and bisphosphonates, third-generation bisphosphonates appear to hold the most promise.

Efficacy of long-term treatment with thalidomide in children and young adults with Crohn disease: preliminary results

BACKGROUND

Several proinflammatory cytokines are involved in the pathogenesis of inflammatory bowel diseases. A significant role has been given to tumor necrosis factor alpha (TNF-alpha) as a guide proinflammatory cytokine. Thalidomide selectively reduces TNF-alpha production by inflammatory cells. The aim of the study was to assess the efficacy of thalidomide to induce and maintain remission in refractory Crohn disease.

METHODS

The decision to administer thalidomide was made on the basis of patient intolerance or resistance to conventional medical treatment or as the last medical resort before surgical intervention. Only 5 of 96 patients with inflammatory bowel disease satisfied these criteria. All five patients had Crohn disease (male: mean age, 17 years). Thalidomide was administered at night at a dose of 1.5-2 mg/kg/day. The Pediatric Crohn Disease Activity Index, modified Harvey-Bradshaw scores, and steroids reduction were used to assess clinical response.

RESULTS

Disease activity decreased consistently in four patients with a reduction of mean Pediatric Crohn Disease Activity Index from 36,9 to 2,5 and the mean Harvey-Bradshaw from 8.5 to 0.75 after 3 months of treatment. Steroid treatment (mean dose, 35 mg/day before treatment) was tapered and then discontinued, in four patients, within 1-3 months. Four patients are in remission after 19-24 months of treatment. The fifth patient discontinued thalidomide after 1 week because of distal paresthesia.

CONCLUSION

Thalidomide seems to be an effective and safe treatment in patients with refractory Crohn disease. This is the first report of long-term use of thalidomide in refractory Crohn disease in pediatric patients.

Recent advances in inflammatory bowel disease

The last decade has seen tremendous advances in our knowledge, which has led to genuine improvements in our understanding of the pathogenesis and management of inflammatory bowel disease (IBD). The combined power of cellular and molecular biology has begun to unveil the enigmas of IBD, and, consequently, substantial gains have been made in the treatment of IBD. Refinements in drug formulation have provided the ability to target distinct sites of delivery, while enhancing the safety and efficacy of older agents. Simultaneous progress in biotechnology has fostered the development of new agents that strategically target pivotal processes in disease pathogenesis. This article addresses our current understanding of the pathogenesis of IBD, including the latest developments in animal models and covers agents currently used in the treatment of IBD as well as emerging therapies.

Medical therapy for Crohn's disease: the state of the art

Various medications are used to control the symptoms of Crohn's disease. This article reviews the traditional medical therapies of Crohn's disease, including aminosalicylates and corticosteroids, and the broad armamentarium of immune modulators and biologic agents that are becoming increasingly important in the management of Crohn's disease.

Inflammatory bowel disease: immunodiagnostics, immunotherapeutics, and ecotherapeutics

Treatment options for inflammatory bowel disease (IBD) reflect a continuing shift from empiricism to strategies based on improved understanding of the pathophysiology of disease. In susceptible individuals, IBD appears to be the result of defective regulation of mucosal immune interactions with the enteric microflora. This has prompted research directed at the interface of the traditional disciplines of immunology, microbiology, and epithelial cell biology. Whereas immunodiagnostics have been of limited clinical value in IBD, assessments of mucosal rather than systemic immune function are promising. Therapeutically, there is an increasing trend toward more aggressive and earlier use of immunomodulatory agents, particularly for prevention of relapse, with cytokine manipulation as a bridge therapy to achieve remission in patients with acute severe disease. Although most drug treatments are directed toward altering the host response, the rationale for manipulating the enteric flora appears sound and will be the basis of additional future therapeutic strategies. Notwithstanding the widening range of options for drug therapy in IBD, other outcome modifiers and well-established principles of managing chronic disease are as important as ever.

Drugs, inflammation and cell adhesion receptors

The cell adhesion receptors that participate in the extravasation and migration of leucocytes towards inflammatory foci mainly include the selectins and different members of the integrin and immunoglobulin superfamilies. These adhesion receptors mediate the sequential steps of leucocyte-endothelial cell interaction and, together with chemoattractant molecules (e.g., chemokines), direct the influx of inflammatory cells and define the characteristics of the cell infiltrate. Many different drugs, including non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, rheumatoid arthritis disease-modifying agents and phosphodiesterase inhibitors, interfere with the expression and/or function of cell adhesion receptors and this effect accounts for, at least in part, their anti-inflammatory activity. In recent years, novel approaches for the modulation of the cell membrane receptors involved in inflammation have been active areas in pharmaceutical research. Upgraded synthetic blocking compounds, chimeric monoclonal antibodies or improved antisense oligonucleotides represent important advances in this field. The proper development of these novel approaches, as well as other alternative strategies, will allow a better and more specific pharmacological modulation of the inflammatory phenomenon.

COX-2 inhibitors vs. NSAIDs in gastrointestinal damage and prevention

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit production of protective gastric mucosal prostaglandins and also have a direct topical irritant effect. In some patients this results in dyspepsia and development of gastroduodenal erosions and ulceration. The risk of ulcer complications, such as bleeding, perforation and death is increased approximately 4-fold in NSAID users. Patients at high risk of ulcer complications include the elderly, those taking anticoagulants, steroids and aspirin, those with a previous history of peptic ulceration and patients with concomitant serious medical problems. The interaction of NSAIDs with Helicobacter pylori (the major cause of peptic ulceration in non-NSAID users) is controversial and some studies suggest that H. pylori infection may even protect against NSAID-induced ulceration. Selective inhibitors of the inducible cyclooxygenase-2 (COX-2) enzyme spare COX-1 in the gastric mucosa and, hence, do not inhibit production of mucosal prostaglandins. COX-2-selective inhibitors are associated with a significant reduction in gastroduodenal damage compared with traditional NSAIDs. Proton pump inhibitors (PPI) are probably the best agents for healing and prevention of NSAID-induced ulcers. Preliminary studies suggest that COX-2 selective inhibitors, like traditional NSAIDs, may prevent lower gastrointestinal cancer. Further studies are needed but they may be useful in individuals at high risk of certain types of lower gastrointestinal malignancy with increased gastrointestinal tolerability and safety.

Update in medical treatment of Crohn's disease

Crohn's disease is an inflammatory bowel disorder that has no known cause. The goal of medical treatment is to control active disease, induce and maintain clinical remission, and treat complications. Anti-inflammatory medications and immunomodulatory therapies are the primary treatment modalities for Crohn's disease. The categories of standard treatment include the 5-aminosalicylic acid compounds, corticosteroids, antibiotics, and immunomodulators. New biologic therapy has been developed to better target the immune mediators that are active in Crohn's disease. Infliximab is the first of the biologic agents approved for the treatment of fistulizing and active Crohn's disease. Despite medical advances in treatment, there is still no cure for Crohn's disease.

The re-emergence of thalidomide: results of a scientific conference

BACKGROUND

The use of thalidomide during the 1950s resulted in teratogenic effects in thousands of infants. Although thalidomide is currently approved for the treatment of a complication of leprosy, it is commercially available to treat other diseases through a controlled distribution system. This article presents a summary of a scientific conference organized to assess clinical research on thalidomide, its new clinical applications, and the social and ethical implications for its use.

METHODS

Summaries of 10 presentations and two panel discussions were developed from the authors's, oral presentations, conference slides, responses to questions, and supporting literature.

RESULTS

Thalidomide shows promise in treating several diseases, including HIV/AIDS, rheumatoid arthritis, Crohn's disease, and multiple myeloma. The STEPStrade mark (System for Thalidomide Education and Prescribing Safety) Program has been developed by Celgene, the commercial manufacturer of thalidomide, to ensure compliance with prescription and usage protocols. A surveillance system is also in place to monitor and report compliance patterns.

CONCLUSIONS

Despite the tragic past associated with thalidomide, the drug shows promise as a treatment for many clinical disorders. The challenge is to answer lingering questions of risks and benefits through clinical trials and discovery, to monitor participation and compliance with protocols developed to avoid use of the drug during pregnancy, and to continue to search for safer and more effective treatment options.

Medical therapies for ulcerative colitis and Crohn's disease

This review focuses on data reported in the last year on medical treatment of Crohn's disease and ulcerative colitis. In Crohn's disease, a broad range of cytokine-based therapies are currently being tested. Although all are very exciting, the anti-tumor-necrosis-factor (TNF) approach remains the most effective, with infliximab (a chimeric monoclonal antibody directed against TNF) being the most active agent. With repeated infusions every 8 weeks, remission is induced and can be maintained even in refractory patients with no major apparent side effects. Thalidomide, an oral agent with anti-TNF effects, shows promise in non-controlled experience. Important new data on azathioprine/6-mercaptopurine (6-MP) and its metabolites are also helpful. Methotrexate can induce remissions in 6-MP-allergic or refractory Crohn's patients and has now shown efficacy as a maintenance agent. Beneficial effects are also reported for a variety of new agents: mycophenolate mofetil, tacrolimus (FK506), growth hormone, and granulocyte colony-stimulating factor (G-CSF). Important observations in ulcerative colitis (UC) over the past year include evidence of a protective effect of 5-aminosalicylic acid (5-ASA) with respect to colorectal cancer, negative results from a study for heparin monotherapy, and results from a comparison of mycophenolate mofetil versus azathioprine as maintenance therapy. Epidemiologically, the negative association between appendectomy and UC was corroborated in a meta-analysis, suggesting an immunologic role for this organ. Finally, in chronic pouchitis, probiotic therapy was found to maintain remissions very significantly.

Comparative tolerability of treatments for inflammatory bowel disease

Despite limited understanding of therapeutic aetiopathogenesis of ulcerative colitis and Crohn's disease, there is a strong evidence base for the efficacy of pharmacological and biological therapies. It is equally important to recognise toxicity of the medical armamentarium for inflammatory bowel disease (IBD). Sulfasalazine consists of sulfapyridine linked to 5-aminosalicylic acid (5-ASA) via an azo bond. Common adverse effects related to sulfapyridine 'intolerance' include headache, nausea, anorexia, and malaise. Other allergic or toxic adverse effects include fever, rash, haemolytic anaemia, hepatitis, pancreatitis, paradoxical worsening of colitis, and reversible sperm abnormalities. The newer 5-ASA agents were developed to deliver the active ingredient of sulfasalazine while minimising adverse effects. Adverse effects are infrequent but may include nausea, dyspepsia and headache. Olsalazine may cause a secretory diarrhoea. Uncommon hypersensitivity reactions, including worsening of colitis, pancreatitis, pericarditis and nephritis, have also been reported. Corticosteroids are commonly prescribed for treatment of moderate to severe IBD. Despite short term efficacy, corticosteroids have numerous adverse effects that preclude their long term use. Adverse effects include acne, fluid retention, fat redistribution, hypertension, hyperglycaemia, psycho-neurological disturbances, cataracts, adrenal suppression, growth failure in children, and osteonecrosis. Newer corticosteroid preparations offer potential for targeted therapy and less corticosteroid-related adverse effects. Azathioprine and mercaptopurine are associated with pancreatitis in 3 to 15% of patients that resolves upon drug cessation. Bone marrow suppression is dose related and may be delayed. The adverse effects of methotrexate include nausea, leucopenia and, rarely, hypersensitivity pneumonia or hepatic fibrosis. Common adverse effects of cyclosporin include nephrotoxicity, hypertension, headache, gingival hyperplasia, hyperkalaemia, paresthesias, and tremors. These adverse effects usually abate with dose reduction or cessation of therapy. Seizures and opportunistic infections have also been reported. Antibacterials are commonly employed as primary therapy for Crohn's disease. Common adverse effects of metronidazole include nausea and a metallic taste. Peripheral neuropathy can occur with prolonged administration. Ciprofloxacin and other antibacterials may be beneficial in those intolerant to metronidazole. Newer immunosuppressive agents previously reserved for transplant recipients are under investigation for IBD. Tacrolimus has an adverse effect profile similar to cyclosporin, and may cause renal insufficiency. Mycophenolate mofetil, a purine synthesis inhibitor, has primarily gastrointestinal adverse effects. Biological agents targeting specific sites in the immunoinflammatory cascade are now available to treat IBD. Infliximab, a chimeric antibody targeting tumour necrosis factor-or has been well tolerated in clinical trials and early postmarketing experience. Additional trials are needed to assess long term adverse effects.

Manipulation of cytokines in the management of patients with inflammatory bowel disease

In recent years, new concepts have been formulated for the therapeutic management of the intractable forms of Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease. These advances are based largely on new insights into the immune-inflammatory events occurring in the gut of these patients. Analysis of the types of immune response ongoing in the inflamed intestine has revealed that in Crohn's disease there is predominantly a T-helper cell type 1 response, with exaggerated production of interleukin (IL)-12 and interferon (IFN)-gamma, whereas in ulcerative colitis the lesion seems more of an antibody-mediated hypersensitivity reaction. Despite these differences, downstream inflammatory events are the same in both conditions. In both Crohn's disease and ulcerative colitis mucosa, IL-1gamma, IL-6, IL-8 and tumour necrosis factor (TNF)-alpha are produced in excess, and the production of free radicals accompanying the influx of nonspecific inflammatory cells into the mucosa is above the normal range. Strategies aimed at inhibiting T-cell responses are therefore more relevant in Crohn's disease, whereas, in theory at least, inhibition of downstream inflammatory processes should be therapeutic in both Crohn's disease and ulcerative colitis. This review seeks to summarize studies in which anticytokine antibodies, cytokines or cytokine-modifying agents have been used in the treatment of either Crohn's disease or ulcerative colitis.

New immunologic treatments for inflammatory bowel disease

After many years with little progress in new treatments for patients with inflammatory bowel disease, there is now rapid expansion of a new class of immunologic agents. These agents are designed to disrupt proinflammatory pathways at specific sites. Monoclonal antibodies to tumor necrosis factor-alpha (TNF-alpha) are already transforming the lives of some patients with previously intractable Crohn disease, and further TNF-alpha directed therapies are being developed. Clinical trials are now underway on agents that inhibit adhesion molecules and antiinflammatory cytokines, while attempts are being made to actively immunize against TNF-alpha. Promising data continue to be reported, although long-term safety data are still mostly unavailable. Although these agents are proving to be very effective in the treatment of patients with Crohn disease, their use should continue to be restricted while indications and dose regimens are defined.

Mechanisms in failure of infliximab for Crohn's disease

BACKGROUND

Expression of tumour necrosis factor-alpha (TNF-alpha) is increased in patients with Crohn's disease. Nuclear factor kappa B (NFkappaB) controls transcription of inflammation genes. Treatment with monoclonal antibodies to TNF (infliximab) in refractory Crohn's disease results in a remission rate of 30-50% after 4 weeks. We aimed to assess the clinical and immunological mechanism of failure to respond to infliximab.

METHODS

24 patients with steroid refractory, chronic active Crohn's disease (Crohn's disease activity index [CDAI]>200), who showed an inflammatory manifestation in the sigmoid colon, had a single infusion of infliximab (5 mg/kg bodyweight) and were followed up for 16 weeks. Secretion capacity for TNF-alpha was assessed in whole-blood cytokine assays and nuclear concentrations of NFkappaB p65 were determined in colonic mucosal biopsy samples.

FINDINGS

21 (88%) of 24 patients were in remission (CDAI<150) after 1 week, ten (42%) at 4 weeks, five (21%) at 8 weeks, and two (8%) of 24 at 12 and 16 weeks. Six (29%) of 21 patients who reached remission in week 1 relapsed at week 4, 13 (62%) at week 8, 17 (81%) at week 12, and 19 (90%) at week 16. Infliximab downregulated secretion of TNF-alpha in all patients to undetectable concentrations (day 1 after infusion). Relapsers were characterised by a rise in TNF-alpha secretion capacity and by increase of mucosal nuclear NFkappaB p65 before reactivation of clinical symptoms.

INTERPRETATION

Infliximab greatly improved clinical symptoms in 88% of patients with Crohn's disease after 1 week. Response in some patients was of short duration. Reactivation of the mucosal and the systemic immune system preceded clinical relapse.

Pediatric Inflammatory Bowel Disease

The combination of an unprecedented number of new therapeutic options (Fig. 1), along with new insights in how to optimize currently available therapies and advances in our understanding of disease pathogenesis, present many exciting new aspects to the management of patients with inflammatory bowel disease (IBD). Clinical management paradigms must evolve in parallel to keep pace with these advances. Traditional pediatric IBD regimens have underutilized combination therapies (Fig. 2) and immunomodulatory agents. Increased appreciation for steroid side effects is leading to a shift away from their inclusion in maintenance regimens. Immunomodulators are being introduced earlier in the course of disease for maintenance of remission and growth promotion. Recognition that the sole signs of active disease in children and adolescents may be growth and maturational delay, despite a relative lack of gastrointestinal symptoms, should prompt earlier, more aggressive interventions. When more potent, rapidly acting interventions such as infliximab, cyclosporine (CSA), or tacrolimus are considered, they should generally be co-administered with agents such as 6-mercaptopurine (6-MP) or azathioprine (AZA) for longer-term disease suppression.