Optimizing anti-tumor necrosis factor strategies in inflammatory bowel disease

The extended understanding of chronic granulomatous disease

PURPOSE OF REVIEW

We briefly address the advances in genetics, pathophysiology, and phenotypes of chronic granulomatous disease (CGD). This is one of the most studied primary immunodeficiencies, which comprise mutations in genes encoding the different subunits of the NADPH oxidase system. Those mutations lead to defective reactive oxygen species production, and consequently a failure to eliminate pathogens.

RECENT FINDINGS

Patients with CGD are susceptible to fungal, bacterial, and parasitic infections. Other symptoms, as systemic adverse effects to BCG vaccine and hyperinflammation, are also important clinical conditions in this disease. This wide-ranging clinical spectrum of CGD comes from heterogeneity of mutations, X-linked-CGD or autosomal recessive inheritance, and diverse environmental pressure factors. Early accurate diagnosis and prompt treatment are necessary to diminish the consequences of the disease. The most used diagnostic tests are dihydrorhodamine, cytochrome c reduction, and luminol-enhanced chemiluminescence assay.

SUMMARY

The determination of mutations is essential for diagnosis confirmation and genetic counseling. CGD treatment usually includes prophylactic antibiotics and antifungals. Prophylactic recombinant human interferon-γ, immunosuppressors or immune modulators may be, respectively, indicated for preventing infections or inflammatory manifestations. Hematopoietic stem cell transplantation and gene therapy are currently the available options for curative treatment of CGD.

Treatment of Sarcoidosis

Treatment of sarcoidosis is not required in all patients with the diagnosis. The decision to treat and the strategy for how to treat usually require input and shared decision making by the patient. Some common consequences of sarcoidosis are not caused by granulomatous inflammation, but may be the dominant disease manifestation and should be actively considered when formulating a treatment plan. The medication regimen should be tailored to each patient. Steroid-sparing medications should be prescribed early as part of a long-term strategy.

High Doses of Infliximab in the Management of Juvenile Idiopathic Arthritis

Objective.

To review our experiences with high-dose infliximab (IFX) to treat juvenile idiopathic arthritis (JIA). We routinely use high doses of IFX (10–20 mg/kg) in children with recalcitrant or highly active JIA. Although biologics have revolutionized treatment of JIA, many patients have active disease despite therapy. Studies have shown benefits of high-dose IFX in several conditions, including inflammatory bowel disease, psoriasis, and idiopathic uveitis. The safety and effectiveness of high-dose IFX have not been evaluated in JIA.

Methods.

We performed a retrospective review of children with JIA who received IFX ≥ 10 mg/kg. We recorded all serious adverse events (SAE), medically important infections, and infusion reactions. We also recorded the physician global assessment of disease activity (MD global) and active joint count (AJC) at initiation of high-dose IFX and 3, 6, and 12 months thereafter.

Results.

Fifty-eight subjects received a total of 1064 infusions over 95 person-years. There were a total of 9 SAE (9.5/100 person-yrs), 7 of which were potentially related to therapy, and 6 infusion reactions (0.5%), none constituting anaphylaxis. Statistically significant improvements were observed in the AJC (median 0, range 0–31, vs 2, 0–39) and MD global (12, 2–31, vs 22, 5–80) over the first year.

Conclusion.

High-dose IFX appears safe in the management of JIA. Future prospective controlled studies are necessary to evaluate its safety and efficacy.

The Role of Biological and Small Molecule Therapy in the Management of Psoriatic Arthritis

The therapy of psoriatic arthritis (PsA) has blossomed in the past decade. Inhibition of tumor necrosis factor (TNF) has been at the fore of this approach and has paved the way for the investigation of many other potential pro-inflammatory and signaling pathways. Most of the initial studies of TNF inhibitors in PsA have been conducted in specific populations, largely focusing on those with established, peripheral joint disease. That said, in excess of 10 years’ worth of real world clinical experience has led to increased confidence in the wider use of these agents. We are now faced with an exciting time of discovery of many new molecules; these not only include new, large protein biological agents, but also smaller synthetic chemical molecules, many of which can be administered orally. Those currently under development are discussed within this article. Whilst there is scarce data about their real world efficacy and safety profile, it is evident that the therapeutic armamentarium for treating PsA will greatly increase in the foreseeable future and this is anticipated to improve patient outcomes.

Anti-TNF-α biotherapies: perspectives for evidence-based personalized medicine

This article discusses the rationale behind recommending immunopharmacological guidance of long-term therapies with genetically engineered anti-TNF-α immunoglobulin constructs. Arguments why therapeutic decision-making should not rely on clinical outcome alone are presented. Central to this is that the use of theranostics (i.e., monitoring circulating levels of functional anti-TNF-α drugs and antidrug antibodies) would markedly improve treatment because therapies can be tailored to individual patients and provide more effective and economical long-term therapies with minimal risk of side effects. Large-scale immunopharmacological knowledge of how patients ‘handle’ TNF-α biopharmaceuticals would also help industry develop more effective and safer TNF-α inhibitors.

Monitoring functional serum antitumor necrosis factor antibody level in Crohn's disease patients who maintained and those who lost response to anti-TNF

BACKGROUND

Infliximab (IFX) is an antitumor necrosis factor (TNF)-α antibody used to treat Crohn's disease (CD). However, antibodies to IFX (ATI) emerge, which can impair its efficacy. A fluid-phase enzyme immunoassay (FP-EIA) was established for measuring serum functional IFX (f-IFX) in CD patients receiving maintenance IFX.

METHODS

In 31 patients, 16 had maintained response (GI) and 15 had lost response to IFX despite good initial response (GII) were selected. Serum f-IFX was measured just before and immediately after IFX infusion and the values together with CD activity index (CDAI) and C-reactive protein (CRP) were compared.

RESULTS

IFX therapy in GI and GII were 1.8 ± 1.2 years and 2.7 ± 1.5 years, respectively, while the median dose frequency was 56 days in GI and 29 days in GII. Our FP-EIA for f-IFX showed TNF-α binding increasing with the IFX dose, which was suppressed by antibodies to IFX. On the infusion day, CRP and CDAI in GII were significantly higher than in GI, while median trough f-IFX for GI and GII were 4.7 μg/mL and 6.3 μg/mL, respectively. The median f-IFX immediately after IFX infusion for GI and GII were 149.5 μg/mL and 126.3 μg/mL, respectively (P = 0.0488), and binary logistic regression showed conditional maximum likelihood estimate to be -0.0258 (P = 0.0395), supporting association of low postinfusion f-IFX to the loss of response.

CONCLUSIONS

FP-EIA could accurately measure f-IFX. High serum ATI strongly impacted f-IFX levels immediately after an infusion. The postinfusion f-IFX level was associated with clinical response. f-IFX level should be valuable in decision-making to optimize treatment efficacy.

[Markers of the course of inflammatory bowel disease treated with immunomodulators or biological agents]

Immunosuppressive or biological treatment in patients with inflammatory bowel disease can modify the natural history of their disease, although these treatments are not universally effective and can have severe adverse effects. Attempts have been made to identify predictive factors of response to the various therapeutic options in order to aid the choice of the most appropriate therapeutic alternative in each patient. The possibility of modifying any one of these predictive factors would be of great interest since it would provide the opportunity to alter the course of the disease. Epidemiological, biological, clinical, endoscopic, radiological, genetic and even proteomic markers have been studied, in addition to others related to the disease itself or to specific treatments. The present article briefly discusses the real use of each of these markers and the evidence supporting their utility.

Management of Crohn's disease in adults

Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of published literature. When data that will withstand objective scrutiny are not available, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health-care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. Expert opinion is solicited from the outset for the document. The quality of evidence upon which a specific recommendation is based is as follows: Grade A: Homogeneous evidence from multiple well-designed randomized (therapeutic) or cohort (descriptive) controlled trials, each involving a number of participants to be of sufficient statistical power. Grade B: Evidence from at least one large well-designed clinical trial with or without randomization, from cohort or case-control analytic studies, or well-designed meta-analysis. Grade C: Evidence based on clinical experience, descriptive studies, or reports of expert committees. The Committee reviews guidelines in depth, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time.

Analysis of the tensile strength on the healing of the abdominal wall of rats treated with infliximab

PURPOSE: To evaluate the effects of infliximab, a murine/human chimeric monoclonal antibody, on the tensile strength of abdominal wall surgical wounds. METHODS: Sixty Wistar healthy male rats with initial body weight between 215 and 390 g and 60 and 90 days of age were randomly assigned into two groups, E (Experimental) and C (Control) with 30 animals each. Group E animals received a single subcutaneous dose of 5mg/Kg of infliximab, and Group C animals received equivalent subcutaneous volume of a solution of 0.9% NaCl. After 48h, animals from both groups were submitted to a 4 cm median incision in the abdominal wall, including all layers that had been reconstituted with continuous suture of the aponeurotic muscle and skin, with 5.0 nylon thread. Then, Group E animals were separated by simple allotment into three subgroups named E3, E7 and E14 with ten animals each, and those from group C into C3, C7, C14 and were submitted, respectively, the reoperation and euthanasia at the third, seventh and fourteenth postoperative day. The anterior abdominal wall, which was resected during reoperation, was cut with No 15 scalpel lamina perpendicularly to the surgical wound. Each specimen, in the form of a 6 cm x 2 cm strip, was fixed by the extremity so that the suture line was equidistant from the fixation points of the dynamometer, in order to undergo the tensile strength test. The dynamometer, which was gauged for each series of measures, was calibrated to apply velocity to the 25 mm/min rupture test; the rupture value was expressed in N (Newton). Prior to euthanasia, the abdominal vena cava was identified and punctured in order to collect blood for TNF-α dosage. RESULTS: The mean tensile strength found for animals from subgroups E3, E7, E14, C3, C7, C14 were, respectively, 16.03, 18.69, 27.01, 28.40, 27.22, 29.15 and 24.30 N. In the results of the multiple comparisons tests, significant differences (p<0.05) was found between subgroups E3 and E7 compared with C3, C7 and C14. CONCLUSION: The infliximab interfered in the healing of the abdominal wall wound decreasing the rupture strength in the inflammatory and proliferative phases.

Efficacy and safety of TNF-blocker therapy in systemic lupus erythematosus

BACKGROUND

There is still unmet medical need in the therapy of severe organ manifestations of patients with systemic lupus erythematosus (SLE). Therapeutic agents targeting pro-inflammatory cytokines may be an interesting option.

OBJECTIVE

To review available data on the efficacy and safety of tumour necrosis factor (TNF) blockade in SLE.

METHODS

A review of the literature was conducted.

RESULTS/CONCLUSIONS

Open-label experience suggests that TNF blockade is effective in SLE patients with arthritis, nephritis and skin disease. In particular, nephritis may remain in long-term remission after just four infusions of infliximab administered. Despite the induction of lupus-specific autoantibodies, short-term therapy with infliximab in combination with azathioprine appears feasible and relatively safe. The data call for controlled clinical trials, at least one of which has been initiated.

Modern management of chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder of phagocytic cells resulting in failure to kill a characteristic spectrum of bacteria and fungi and in defective degradation of inflammatory mediators with concomitant granuloma formation. Current prophylaxis with trimethoprim-sulfamethoxazole, itraconazole and in selected cases additional interferon gamma is efficient, but imperfect. A significant recent progress towards new antibiotic (e.g. linezolid) and antifungal (e.g. voriconazole and posaconazole) therapy will allow survival of most patients into adulthood. Adolescent and adult CGD is increasingly characterized by inflammatory complications, such as granulomatous lung and inflammatory bowel disease, requiring immunosupressive therapy. Allogeneic haematopoietic stem cell transplantation from a human leucocyte antigen identical donor is currently the only proven curative treatment for CGD and can be offered to the selected patients. Gene-replacement therapy for patients lacking a suitable stem cell donor is still experimental and faces major obstacles and risks. However, it may offer some transitory benefits and has helped in a few cases to overcome life-threatening infections.

Tumor necrosis factor-alpha binding capacity and anti-infliximab antibodies measured by fluid-phase radioimmunoassays as predictors of clinical efficacy of infliximab in Crohn's disease

OBJECTIVES

To investigate if the combined assessment of anti-infliximab antibodies (Ab) and the degree of TNF-alpha binding capacity (TNF-alpha-BC) afforded by infliximab may predict the response to infliximab treatment in patients with Crohn's disease (CD).

METHODS

Three groups of CD patients, in total 33 patients, treated with infliximab were retrospectively selected: (a) patients with a maintained response throughout treatment; (b) patients with good initial response, but subsequent loss of response; and (c) patients with inadequate response to the first two or three doses. Blood samples were analyzed for TNF-alpha-BC and Ab using fluid-phase radioimmunoassay (RIA).

RESULTS

At 8 wk after last infliximab infusion, TNF-alpha-BC was significantly higher (P = 0.002) in patients maintaining response (median [interquartile range] 2.9 [0.9-4.3] microg/mL), as compared to patients losing response (0.0 [0-0.1] microg/mL). Conversely, Ab levels were significantly lower (P < 0.0001) in patients maintaining response (1.3 [0-6]% bound tracer/total tracer), as compared to patients losing response (19 [14-27]%). Ab were not present and TNF-alpha-BC was high (30 [20-32]) in patients with no primary response.

CONCLUSIONS

While secondary loss of response to infliximab is associated with high levels of Ab and low levels of TNF-alpha-BC, primary response failure may be seen in the presence of high effective levels of TNF-alpha-BC afforded by infliximab. The results suggest that combined assessment of anti-infliximab Ab and serum TNF-alpha-BC may pave the way for a more rational use of infliximab in patients with CD.

Safety of biologic therapy in rheumatoid arthritis and other autoimmune diseases: focus on rituximab

OBJECTIVES

To review the safety of biologic agents used to treat rheumatoid arthritis (RA) and other autoimmune diseases, with a focus on rituximab.

METHODS

Information was gathered from a search of the PubMed database and from major congress abstract listings through June 2007.

RESULTS

Rituximab is approved for treating RA in patients with an inadequate response to TNF inhibitors and is under study in other indications for RA and other autoimmune disorders. The current safety profile of rituximab in RA is known from Phase II and III studies conducted preapproval, treating approximately 750 patients, as well as from long-term extension studies with repeated therapy. Clinical trials have established that the most common adverse events are infusion-associated reactions, seen in 29 to 40% of patients, most of which are mild to moderate and occur following the first rituximab infusion, with incidence and severity decreasing with subsequent infusions. Rates of infections and serious infections to date are within the range expected for RA patients treated with other biologic agents, but the longer term effects of B-cell depletion and the effects of repeated treatment on the risk of infections are uncertain. Information is limited for rituximab safety in other autoimmune disorders but current data do not suggest that there is a significant difference in adverse events from that previously reported.

CONCLUSIONS

Rituximab is an important addition to the rheumatologist's armamentarium for the treatment of difficult RA and ongoing trials will determine its utility in other indications for RA and other autoimmune conditions. The true safety profile of rituximab will emerge as larger numbers of patients are treated in routine clinical practice.

Switching anti-TNF-α agents: What is the evidence?

The availability of biologic agents targeting tumor necrosis factor (TNF)-alpha represents a significant advance in the management of rheumatoid arthritis. Anti-TNF-alpha therapy has been associated with dramatic improvements in the clinical signs and symptoms of rheumatoid arthritis and has been shown to greatly retard the destructive process that too often characterizes this condition. Although effective and well-tolerated in a substantial proportion of patients, primary and secondary failures of anti-TNF-alpha strategies have been well described, affecting up to one-third to one-half of subjects treated with these agents. Switching from one anti-TNF-alpha agent to a second (or even third) anti-TNF-alpha therapy has emerged as a means of addressing treatment failures with this drug class. This review examines data addressing the practice of switching anti-TNF-alpha agents in the context of initial treatment failure, with a focus on data from peer-reviewed reports.

[Role of biological markers in inflammatory bowel disease]

The role played by the distinct biological markers in chronic inflammatory bowel disease (IBD) remains insufficiently characterized. C-reactive protein (CRP) has a short half-life and consequently it is elevated early after the onset of the inflammatory process and rapidly decreases after its resolution, making it an attractive marker of disease activity. Moreover, this test is inexpensive and easy to perform and is unaffected by medication. While Crohn's disease is associated with a marked CRP response, there is little or no elevation in the synthesis of this protein in ulcerative colitis. Erythrocyte sedimentation rate provides some advantages such as its ease of determination, availability, and reduced cost. Nevertheless, it also has several disadvantages, notably the fact that its concentration depends on age, the presence of anemia, smoking, and the use of certain drugs. Moreover, its utility is limited by its long half life and consequent prolonged latency period after changes in chronic IBD activity. In theory, fecal markers have the advantages of showing greater specificity in the diagnosis of chronic IBD. Several gastrointestinal diseases, including chronic IBD, show greater leukocyte elimination in feces and a close correlation has been described between fecal calprotectin concentration and leukocyte excretion quantified by 111indium. Advantages of this fecal marker are that it can be detected through a simple and inexpensive technique and also shows excellent stability in feces for prolonged periods. Like calprotectin, fecal lactoferrin is also quantified by a simple and inexpensive ELISA method, although there is considerably less experience with this latter marker.

ANCA-associated vasculitis: new options beyond steroids and cytotoxic drugs

Small vessel vasculitic syndromes--Wegener's granulomatosis, microscopic polyangiitis and renal limited vasculitis (which are associated with circulating antineutrophil cytoplasmic autoantibodies)--are an important cause of renal failure. Present immunosuppressive regimens that are based on cyclophosphamide have significantly increased survival rates. However, these treatments are toxic, increase the risk of infection and do not cure disease. Therefore, newer approaches are required. Understanding disease pathogenesis has allowed rational use for newer therapies such as rituximab, which depletes B cells. Unfortunately, blockade of promising targets such as TNF-alpha, which was thought to be a pivotal cytokine in inflammation, has not shown benefit in a randomised controlled trial. Better understanding of the pathogenesis of the disease is the key to the development of novel targeted therapies, which are urgently required to improve patient prognosis. Gene therapy with targeted delivery of specific proteins is an exciting future prospect.

Individualized monitoring of drug bioavailability and immunogenicity in rheumatoid arthritis patients treated with the tumor necrosis factor alpha inhibitor infliximab

OBJECTIVE

Infliximab, an anti-tumor necrosis factor alpha (anti-TNFalpha) antibody, is effective in the treatment of several immunoinflammatory diseases. However, many patients experience primary or secondary response failure, suggesting that individualization of treatment regimens may be beneficial. This study was undertaken to investigate whether serologic monitoring of infliximab bioavailability and immunogenicity in individual patients would be useful in optimizing treatment regimens to improve efficacy and tolerability.

METHODS

To avoid the use of solid-phase assays, two radioimmunoassays were developed: one for measurement of levels of anti-infliximab antibody, and a functional one for measurement of TNFalpha binding due to infliximab. Sera from 106 randomly selected rheumatoid arthritis patients were tested within 6 months of therapy initiation, and associations between findings of serum assays and disease activity, infusion reactions, and treatment failure occurring within 18 months were assessed.

RESULTS

Trough serum infliximab levels after the first 2 intravenous infusions of infliximab at 3 mg/kg varied considerably between patients (range 0-22 microg/ml). At this stage, only 13% of the patients were anti-infliximab antibody positive. With subsequent infusions, the frequency of antibody positivity rose to 30% and 44% (at 3 months and 6 months, respectively), accompanied by diminished trough levels of infliximab. Indeed, low infliximab levels at 1.5 months predicted antibody development and later treatment failure. There were highly significant correlations between high levels of antibodies and later dose increases, side effects, and cessation of therapy. High baseline disease activity, judged by C-reactive protein level and Disease Activity Score, was associated with low levels of infliximab at the early stage of treatment and later development of anti-infliximab antibodies. Cotreatment with methotrexate resulted in slightly reduced antibody levels after 6 months; other disease-modifying antirheumatic drugs and prednisolone had no effect.

CONCLUSION

Development of anti-infliximab antibodies, heralded by low preinfusion serum infliximab levels, is associated with increased risk of infusion reaction and treatment failure. Early monitoring may help optimize dosing regimens for individual patients, diminish side effects, and prevent prolonged use of inadequate infliximab therapy.

Targeting nanomedicines in the treatment of Crohn's disease: focus on certolizumab pegol (CDP870)

A variety of targets for therapeutic intervention are based upon advances in understanding of the immunopathogenesis of Crohn's disease. Crohn's disease is initiated by an innate immune response, which eventuates in a T-cell driven process, characterized by a T-helper cell 1 type cytokine profile. Several new treatments now focus on suppressing T-cell differentiation or T-cell inflammation. Since inflammatory bowel disease (IBD) represents a state of dysregulated inflammation, drugs that augment the anti-inflammatory response have the potential to downregulate inflammation and thereby hopefully modify the disease. Tumour necrosis factor (TNF) is a major target of research and clinical investigation. TNF has proinflammatory effects in the intestinal mucosa and is a pivotal cytokine in the inflammatory cascade. Certolizumab pegol (CDP870) is a PEGylated, Fab' fragment of a humanized anti-TNF-alpha monoclonal antibody. PEGylation increases the half-life, reduces the requirement for frequent dosing, and possibly reduces antigenicity as well. Certolizumab has been shown in Phase III trials to achieve and maintain clinical response and remission in Crohn's disease patients. It improves the quality of life. Certolizumab pegol will be indicated for moderately to severely active Crohn's disease, but it is not yet licensed in Europe or the US. It is not possible to construct an algorithm for treatment, but when compared with infliximab the two principal advantages are likely to be lower immunogenicity (as shown by anti-drug antibodies, absence of infusion reactions, and low rate of antinuclear antibodies), and a subcutaneous route of administration. These two factors may be sufficient to promote it up the pecking order of anti-TNF agents.

Adalimumab: a review of side effects

Adalimumab (Humira) is a human monoclonal TNF-alpha antibody that blocks the effects of TNF-alpha. It is administered by subcutaneous injection. It has been approved alone or in combination with methotrexate for the treatment of rheumatoid arthritis in the EU and US. Approval for its use for the treatment of psoriasis, psoriatic arthritis and ankylosing spondylitis is expected in the near future. Its side effect profile is favourable when compared with traditional systemic treatments for these diseases. It does not require laboratory monitoring. The most common side effects of adalimumab are injection site reactions. Adalimumab increases the risk of rare serious infections. There is a two-fold risk of serious infections with the use of adalimumab, as reported in the Premier trial. This risk should not be minimised in this way. It should not be used during periods of active infection. Its most notable infectious complication is the reactivation of tuberculosis. Tuberculosis screening should be according to country standards and may or may not include purified protein derivative test or chest X-ray. Deep fungal and other serious and atypical infection can also be promoted by adalimumab. It has been associated infrequently with skin rashes. Rare side effects include: worsening or initiation of congestive heart failure, a lupus-like syndrome, a promotion of lymphoma, medically significant cytopenias, and worsening or initiation of a multiple sclerosis/neurological disease. There has been reported pancytopenia and elevated transamines with the use of adalimumab, which suggest that laboratory monitoring blood counts and liver functions, at least intermittently, are useful. In patients with any of the foregoing problems, its use should be extremely carefully considered. Adalimumab is a useful medication which can be safely used if its side effects are recognised.

Pulmonary infectious complications associated with anti-TNFalpha therapy (infliximab) for rheumatoid arthritis

Two patients with rheumatoid arthritis (RA) that developed serious infectious complications following anti-TNFalpha therapy (infliximab) are reported. Patient 1 developed tuberculosis with high fever, refractory diarrhea and mediastinal lymphadenopathy. Trans-bronchial needle biopsy was useful to confirm the diagnosis. Patient 2 showed sudden onset of dyspnea with diffuse bilateral lung infiltration caused by pneumocystis jiroveci pneumonia and the diagnosis was confirmed by broncho-alveolar lavage. Physicians should be alerted to infectious complications with atypical presentation and rapid progression in infliximab-treated patients. Invasive diagnostic procedures including fiber-optic bronchoscopy may be necessary early in the course for such cases.

Demonstration of specific antibodies against infliximab induced during treatment of a patient with ankylosing spondylitis

Therapeutic proteins, such as infliximab, have revolutionized the treatment of many diseases during the last decade and more than 80 therapeutic proteins are currently approved for clinical use. However, all exogenous proteins have the potential to cause antibody formation. In order to ensure patient safety and the efficacy of therapeutic proteins, careful monitoring of the immunogenicity of therapeutic proteins is therefore necessary not only during preclinical trials, but also during the treatment of patients. Here, we report a clear-cut demonstration of the induction of anti-infliximab antibodies during the treatment of a patient with ankylosing spondylitis (AS). Assessment of anti-infliximab antibodies in sera obtained at various time periods were performed using a highly specific double antigen assay system developed in our laboratory. Immunoreactivity was found to be solely specific for infliximab. Because all sera obtained from the patient were found to be negative for the presence of human anti-mouse antibody (HAMA) and anti-human antibodies. The loss of effect of infliximab, as judged by observing the relapse of signs and symptoms of disease in the patient, seemed to be related with the appearance of antibodies. This study clearly demonstrates that monitoring for the induction of specific antibodies during clinical trials is an important issue for therapeutic proteins.

The risk of lymphoma in the treatment of inflammatory bowel disease with immunosuppressive agents

Immunosuppressive agents have become an established part of the therapeutic armamentarium for inflammatory bowel disease (IBD). However, when used in transplant recipients or for other indications, agents that suppress or modulate the immune system (immunomodulators) have been associated with an increased risk of lymphoma. Fortunately, in part because of the lower doses used in IBD patients, the risk of lymphoma in IBD patients appears to be significantly less than that associated with renal and hepatic transplant-related immunosuppression. Whether the risk of azathioprine or 6-mercaptopurine associated lymphoma in IBD is real or relates to the underlying disease remains unclear. The results of several recent large well designed population-based studies suggest that the lymphoma risk associated with azathioprine and 6-mercaptopurine therapy is likely to be of minimal clinical significance compared to the established and more frequent risks of myelosuppression and infection, and is far outweighed by the clinical benefit of immunomodulator therapy in IBD. While the issue of lymphoma risk is likely to become more relevant with the growing number of biologic and immunomodulators being tested in clinical trials for IBD, early post-marketing surveillance data on infliximab suggests that the lymphoma risk may not be any greater than that associated with azathioprine and 6-mercaptopurine.

Novel drug delivery strategies for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses two idiopathic inflammatory diseases of the intestinal tract: Crohn's disease and ulcerative colitis. Existing therapy for IBD consists mainly of orally or rectally administered small drug molecules, such as 5-aminosalicylates and corticosteroids, or potent systemic immune suppressants. IBD presents a challenging target for drug delivery, particularly by the oral route, as, contrary to most therapeutic regimens, minimal systemic absorption and maximal intestinal wall drug levels are desired. Several delivery strategies are employed to achieve this goal, including the chemical modification of the drug molecules, the use of controlled- and delayed-release formulations and the use of bioadhesive particles. The goal of this review is to summarise existing IBD therapy and examine novel approaches in intestinal drug delivery.

C-reactive protein as a marker for inflammatory bowel disease

The production of CRP occurs almost exclusively in the liver by the hepatocytes as part of the acute phase response upon stimulation by IL-6, TNF-alphaand IL-1-betaoriginating at the site of inflammation. Its short half-life makes CRP a valuable marker to detect and follow up disease activity in Crohn's disease (CD). In contrast, ulcerative colitis has only a modest to absent CRP response despite active inflammation, and the reason for this is unknown. In CD, serum levels of CRP correlate well with disease activity and with other markers of inflammation as the CDAI, serum amyloid, IL-6 and faecal calprotectin. CRP is a valuable marker for predicting the outcome of certain diseases as coronary heart disease and haematological malignancies. An increased CRP (>45 mg/L) in patients with IBD predicts with a high certainty the need for colectomy and this by reflecting severe ongoing and uncontrollable inflammation in the gut. Finally, trials with anti-TNF and anti-adhesion molecules have shown that a high CRP predicts better response to these drugs. However, whether we need to include CRP as an inclusion criterion for future trials with biologicals is still a matter of debate.