Thalidomide: an old drug with new clinical applications

The efficacy and safety of thalidomide in the treatment of refractory Crohn's disease in adults: a double-center, double-blind, randomized-controlled trial

Background

Thalidomide is applied in therapy for refractory Crohn's disease (CD) in adults, but systematic and rigorous clinical evidence is scant. The aim was to provide theoretical references for the efficacy of thalidomide in the therapy for refractory CD in adults.

Methods

A double-center, double-blind, placebo-controlled, randomized clinical trial of refractory CD in adults in two inflammatory bowel disease centers in China. In the double-blind trial, patients were randomly assigned to 100 mg of thalidomide or placebo daily for 8 weeks. The primary outcome was considered as the clinical remission rate calculated based on the Crohn's disease activity index at the eighth week following thalidomide or placebo treatment. In open label, non-response to placebo was additionally treated with 8 weeks of thalidomide; all responders were continuously treated with thalidomide until the 48th week.

Results

Twenty-five patients were randomly assigned to each group. At the eighth week, the clinical remission rate in the thalidomide group was significantly higher than that in the placebo group (68.0% [17/25] vs 16.0% [4/25]; relative risk, 4.2; 95% confidence interval, 1.8-10.9, P < 0.001). After a 48-week follow-up, the continuous treatment rate of thalidomide was 46.3% (19/41). Adverse events during the whole process were reported in 58.5% of patients, mainly involving drowsiness, rash, and peripheral neuropathy that were mild and tolerable.

Conclusion

Thalidomide can be used in the induction and maintenance therapy of refractory CD in adults. And it could be one of the treatment options for refractory CD.

Drug repurposing of dermatologic medications to treat coronavirus disease 2019: Science or fiction?

No pharmaceutical products have been demonstrated to be safe and effective to specifically treat coronavirus disease 2019 (COVID-19); therefore, the therapy administered to infected patients remains symptomatic and empiric. Alongside the development of new, often high-cost drugs, a different tactic is being applied in parallel, investigating long-established, inexpensive medications originally designed for a variety of diseases to study their potential in treating COVID-19. The skin is the largest organ of the human body. With more than 3,000 skin conditions identified, the specialty of dermatology offers a rich armamentarium of systemic therapeutic agents aimed to treat the various chronic immunologically mediated, metabolic, infectious, occupational, inherited, or paraneoplastic dermatoses. Dermatologists have extensive experience with many drugs that have demonstrated promising in vitro antiviral action (directly targeting the viral replication). Many of these drugs have been used as nonspecific immunosuppressive strategies, such as glucocorticoids, synthetic antimalarials, colchicine, or other immunomodulators, and a number of targeted therapeutics have been directed at controlling hyperinflammatory processes similar to the "cytokine storm" associated with COVID-19 infection. We discuss several dermatologic drugs that have already been used or may have a promising role in the treatment of COVID-19.

Thalidomide for de novo Crohn's disease after ileal pouch anal anastomosis for ulcerative colitis

WHAT IS KNOWN AND THE OBJECTIVE

De novo Crohn's disease (CD) is an increasingly reported diagnosis after ileal pouch anal anastomosis (IPAA). Currently, no consensus exists on the best treatment strategy.

CASE SUMMARY

This report details the case of a 5-year-old child with early-onset ulcerative colitis (UC) who developed findings compatible with CD 12 months after IPAA. Thalidomide therapy led to clinical and endoscopic remission without side effects at 6 months.

WHAT IS NEW AND CONCLUSION

To our knowledge, this is the first report of thalidomide for treatment of de novo CD. Thalidomide therapy could be considered in patients with de novo CD, with similar indications of CD.

Fenoprofen-An Old Drug Rediscovered as a Biased Allosteric Enhancer for Melanocortin Receptors

It is time-consuming and costly to bring new drugs to market, making it necessary and urgent to exploit existing drugs for new uses. Recently, fenoprofen was demonstrated as an allosteric modulator at melanocortin receptors (MCRs), although the exact mode of action has not been clarified. MCRs regulate multiple functions, including pigmentation, adrenal steroidogenesis, inflammation, energy homeostasis, and exocrine gland secretion. In this study, we showed that fenoprofen failed to displace the orthosteric agonist Nle⁴-d-Phe⁷-α-melanocyte stimulating hormone from binding to MC3-5R while possessing positive allosteric modulator activities at these receptors. In addition, fenoprofen induced biased signaling at MC3-5R, as it selectively activated ERK1/2 cascade but not the canonical cAMP signaling. Notably, fenoprofen stimulated biased signaling at MC3-5R, but not at MC1R, hence acting selectively among this highly conserved family of receptors. Moreover, PAM activity and biased signaling induced by fenoprofen were observed not only at wild-type but also at naturally occurring mutant MC3Rs, suggesting that this biased allosteric enhancer action might constitute as novel therapeutic opportunity for obese patients harboring these mutations. Our study might guide novel therapeutic applications for repurposing current drugs or designing new drugs combining allosteric and biased properties.

Endoscopic and Histologic Healing in Children With Inflammatory Bowel Diseases Treated With Thalidomide

BACKGROUND & AIMS

Mucosal healing, determined by endoscopic evaluation, is one of the most important prognostic markers for patients with inflammatory bowel diseases. Findings from histologic evaluation, however, could complement findings from endoscopy in assessing mucosal responses to treatment. We analyzed long-term results of children treated with thalidomide to determine the association between clinical response and histology and endoscopy findings.

METHODS

We collected data from 2 multicenter trials of 70 children with refractory Crohn's disease (CD) or ulcerative colitis (UC) (2-18 years old; ileocolonic or colonic disease) given thalidomide or placebo (NCT00720538). Clinical remission and clinical response at 8 weeks were defined as a pediatric CD activity index scores 10 points or lower and a decrease of at least 50% from baseline, respectively, for patients with CD; and as a pediatric UC activity index score below 10 and a decrease of at least 20 points from baseline, respectively, for patients with UC. Patients with a clinical response to 8 weeks' treatment with thalidomide underwent endoscopic examination with biopsy collection at study weeks 12 and 52. Severity of inflammation in patients with UC was assessed by Mayo score and in patients with CD by 4-grade system. Biopsies were assessed for signs of active inflammation, erosion or ulceration, and crypt abscesses and assigned a histologic score.

RESULTS

Clinical remission was observed in 42 patients (60.0%) and clinical response in 45 patients (64.2%) at Week 8. At Week 52, a total of 38 patients (54.3%) were still in clinical remission or still had a clinical response; 29 patients (41.4%) had mucosal healing, defined as complete healing of erosions or ulcerations, and 20 patients (27.7%) had histologic healing, defined as complete absence of markers of inflammation. Of patients with clinical remission or clinical response, 75.3% also had mucosal healing and 52.6% also had histologic healing. The probability of achieving mucosal healing decreased significantly with increasing values of erythrocyte sedimentation rate (adjusted odds ratio, 0.96; 95% CI, 0.93-0.98; P = .006).

CONCLUSIONS

In a long-term analysis of data from 2 clinical trials of pediatric patients with CD or UC, 52 weeks' treatment with thalidomide led to clinical remission in 54.3% of patients with ileocolonic or colonic disease; of these patients, 75.3% had mucosal healing and 52.6% also had histologic healing. Further studies are needed to determine how thalidomide therapy affects long-term progression of inflammatory bowel diseases. (ClinicalTrials.gov number NCT00720538).

Longitudinal Patterns of Thalidomide Neuropathy in Children and Adolescents

OBJECTIVE

To characterize the longitudinal clinical and electrophysiological patterns of thalidomide neuropathy in children and adolescents.

STUDY DESIGN

Retrospective analysis of clinical records at a tertiary care children's hospital, including serial electrophysiological studies.

RESULTS

Sixteen patients aged 6-24 years received thalidomide to treat Crohn's disease from 2002 to 2012. Nine subjects had electrophysiological evidence of sensorimotor axonal polyneuropathy, 8 of whom had sensory and/or motor symptoms. The patients with polyneuropathy received thalidomide for 5 weeks to 52 months, with cumulative doses ranging from 1.4 to 207.7 g. All subjects with cumulative doses greater than 60 g developed polyneuropathy, and 4 of the 5 subjects who received thalidomide for more than 20 months developed polyneuropathy. The 7 subjects who had normal neurophysiological studies received therapy for 1 week to 25 months, with cumulative doses ranging from 0.7 to 47 g. In contrast to some previous reports, several patients had sensorimotor polyneuropathies, rather than pure sensory neuropathies. In patients with neuropathy who received therapy for more than 24 months and had 3 or more electromyography studies, the severity of the neuropathy plateaued.

CONCLUSIONS

Factors in addition to the total dose may contribute to the risk profile for thalidomide neuropathy, including pharmacogenetic susceptibilities. The severity of the neuropathy does not worsen relentlessly. Children, adolescents, and young adults receiving thalidomide should undergo regular neurophysiological studies to monitor for neuropathy.

Long-term Outcomes of Thalidomide Therapy for Adults With Refractory Crohn's Disease

BACKGROUND & AIMS

Little is known about the efficacy and safety of thalidomide therapy for patients with refractory Crohn's disease (CD), particularly in respect to long-term outcomes of patients.

METHODS

We conducted a retrospective multicenter observational study to evaluate thalidomide efficacy and the probability of its withdrawal because of either toxicity or lack/loss of efficacy. We analyzed data from 77 patients with active intestinal and/or perineal CD, refractory to conventional immunosuppressive therapies, treated with thalidomide at 5 tertiary referral inflammatory bowel disease centers in France. We also analyzed the long-term efficacy of thalidomide.

RESULTS

Fifty-four percent of the patients were in clinical remission after thalidomide treatment within the first year. The proportions of patients from whom thalidomide was withdrawn because of lack/loss of efficacy and/or toxicity were 35% at 3 months of treatment, 69% at 12 months, and 88% at 24 months. The proportions of patients from whom thalidomide was withdrawn because of toxicity alone were 22% at 3 months, 34% at 12 months, and 46% at 24 months. Overall, neuropathy occurred in 30 patients and was the main reason for thalidomide withdrawal.

CONCLUSIONS

On the basis of a retrospective multicenter observational study, thalidomide therapy is effective in most patients with refractory active intestinal and/or perineal CD. However, its toxicity limits its use as a maintenance therapy.

Treatment of refractory ulcerative necrobiosis lipoidica diabeticorum with oral thalidomide

Ulcerative necrobiosis lipoidica (NL) in diabetic patients is a rare, painful condition. It is a difficult-to-treat condition, impairing quality of life of patients. Although various drugs have been tried, none of them is consistently effective. Biologics in the form of TNF-alpha inhibitors show promising results in the treatment. But because of their high cost we chose thalidomide, which also has TNF-alpha inhibiting properties to successfully treat a long-standing case of ulcerative NL, which was refractory to various treatment modalities.

Effect of Thalidomide on Clinical Remission in Children and Adolescents with Ulcerative Colitis Refractory to Other Immunosuppressives: Pilot Randomized Clinical Trial

BACKGROUND

In a randomized controlled trial, thalidomide has shown to be effective in refractory Crohn's disease in children. This pilot study aimed at evaluating thalidomide in refractory pediatric ulcerative colitis (UC).

METHODS

Double-blind, placebo-controlled randomized clinical trial on thalidomide 1.5 to 2.5 mg/kg/day in children with active UC despite multiple immunosuppressive treatments. In an open-label extension, nonresponders to placebo received thalidomide for an additional 8 weeks; all responders were followed up for a minimum of 52 weeks.

RESULTS

Twenty-six children with refractory UC were randomized to thalidomide or placebo. Clinical remission at week 8 was achieved by significantly more children treated with thalidomide {10/12 (83.3%) versus 2/11 (18.8%); risk ratio, 4.5 (95% confidence interval [CI], 1.2-16.4); P = 0.005; number needed to treat, 1.5}. Of the nonresponders to placebo who were switched to thalidomide, 8 of 11 (72.7%) subsequently reached remission at week 8 (risk ratio, 4.0 [95% CI, 1.1-14.7]; number needed to treat, 2.45; P = 0.01). Clinical remission in the thalidomide group was 135.0 weeks (95% CI, 32-238), compared with 8.0 weeks (95% CI, 2.4-13.6) in the placebo group (P < 0.0001). Cumulative incidence of severe adverse events was 3.1 per 1000 patient-weeks. Peripheral neuropathy and amenorrhea were the most frequent adverse events.

CONCLUSIONS

In this pilot randomized controlled trial on cases of UC refractory to immunosuppressive therapy, thalidomide compared with placebo resulted in improved clinical remission at 8 weeks of treatment and in longer term maintenance of remission. These findings require replication in larger clinical studies evaluating both thalidomide efficacy and safety.

The clinical implications of thalidomide in inflammatory bowel diseases

Thalidomide has anti-inflammatory and anti-angiogenetic activity that makes it suitable for treating inflammatory bowel diseases (IBD). The recent guidelines from the European Crohn's and Colitis Organization/European Society for Pediatric Gastroenterology Hepatology and Nutrition conclude that thalidomide cannot be recommended in refractory pediatric Crohn's disease but that it may be considered in selected cohorts of patients who are not anti-TNFα agent responders. The main adverse effect is the potential teratogenicity that renders the long-term use of thalidomide problematic in young adults due to the strict need for contraceptive use. In short-term use it is relatively safe; the most likely adverse effect is the neuropathy, which is highly reversible in children. So far the use of thalidomide is reported in 223 adult and pediatric IBD patients (206 with Crohn's disease). In the following sections, the authors will discuss efficacy and safety of thalidomide, in the short-term treatment of IBD.

3,6'-dithiothalidomide improves experimental stroke outcome by suppressing neuroinflammation

Tumor necrosis factor-α (TNF) plays a prominent role in the brain damage and functional deficits that result from ischemic stroke. It was recently reported that the thalidomide analog 3,6'-dithiothalidomide (3,6'-DT) can selectively inhibit the synthesis of TNF in cultured cells. We therefore tested the therapeutic potential of 3,6'-DT in a mouse model of focal ischemic stroke. Administration of 3,6'-DT immediately prior to a stroke or within 3 hr after the stroke reduced infarct volume, neuronal death, and neurological deficits, whereas thalidomide was effective only when administered prior to stroke. Neuroprotection was accompanied by decreased inflammation; 3,6'-DT-treated mice exhibited reduced expression of TNF, interleukin-1β, and inducible nitric oxide synthase; reduced numbers of activated microglia/macrophages, astrocytes, and neutrophils; and reduced expression of intercellular adhesion molecule-1 in the ischemic brain tissue. 3,6'-DT treatment attenuated stroke-induced disruption of the blood-brain barrier by a mechanism that appears to involve suppression of matrix metalloproteinase-9 and preservation of occludin. Treatment with 3,6'-DT did not reduce ischemic brain damage in mice lacking TNF receptors, consistent with a critical role for suppression of TNF production and TNF signaling in the therapeutic action of 3,6'-DT. These findings suggest that anti-inflammatory mechanisms underlie the therapeutic actions of 3,6-DT in an animal model of stroke.

Determination of thalidomide concentration in human plasma by liquid chromatography-tandem mass spectrometry

A rapid, sensitive and specific analytical method based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of thalidomide concentration in human plasma. The analyte and internal standard were extracted by liquid-liquid extraction with ether-dichloromethane (3:2, v/v) and separated on a TC-C₁₈ column using methanol-10 mM ammonium acetate-formic acid (60:40:0.04, v/v/v) as the mobile phase at a flow rate of 0.9 ml/min. The detection was performed using an API 4000 triple quadrupole mass spectrometer in the positive electrospray ionization (ESI) mode and completed within 3.0 min. The multiple reaction monitoring (MRM) transitions were m/z 259.1→84.0 for the analyte and m/z 195.9→138.9 for temozolomide. The calibration curve exhibited a linear dynamic range of 2–1500 ng/ml (r>0.9991). The intra-and inter-day precisions (as relative standard deviation; RSD) were 6.8–13.5% and 4.3–5.0% respectively and the accuracy (as relative error; RE) was 2.0–3.5%. The recoveries and matrix effects were satisfactory in all the biological matrices examined. This method was successfully used in a pharmacokinetic study of thalidomide in healthy male volunteers receiving an oral administration of a 200-mg dose.

Venous thrombotic events are not increased in patients with rheumatoid arthritis treated with anti-TNF therapy: results from the British Society for Rheumatology Biologics Register

Objectives

Past studies have reported conflicting rates of venous thrombotic events (VTEs) in rheumatoid arthritis (RA). The current study aimed to compare (1) the rates of VTEs in patients with RA treated with anti-tumour necrosis factor (anti-TNF) therapy versus those treated with non-biological disease-modifying antirheumatic drugs (nbDMARDs) alone and (2) the rates between each individual anti-TNF agent and nbDMARDs.

Methods

Using data from the British Society for Rheumatology Biologics Register, a national prospective observational cohort study of biological safety in patients with RA, the authors compared the incidence of VTEs between 11 881 anti-TNF- and 3673 nbDMARD-treated patients. Analysis was limited to the first VTE per person. HRs were calculated using Cox modelling. Adjustment was made for potential confounders including surgery performed during follow-up.

Results

A total of 196 first VTEs were reported (151 anti-TNF, 45 nbDMARD). Overall there was no difference in the rates of VTEs between anti-TNF- and nbDMARD-treated patients (adjusted HR 0.8 (95% CI 0.5 to 1.5)). The risk was similar across all anti-TNF agents. Rates of postoperative VTEs did not significantly differ between groups.

Conclusions

These data suggest that anti-TNF therapy is not associated with an increased risk of VTEs in RA patients.

Antiallodynic Effect of Thalidomide and Morphine on Rat Spinal Nerve Ligation-induced Neuropathic Pain

Background

Tumor necrosis factor-alpha and other proinflammatory cytokines are becoming well recognized as key mediators in the pathogenesis of many types of neuropathic pain. Thalidomide has profound immunomodulatory actions in addition to their originally intended pharmacological actions. There has been debate on the analgesic efficacy of opioids in neuropathic pain. The aim of this study was to investigate the effect of thalidomide and morphine on a spinal nerve ligation model in rats.

Methods

Male Sprague-Dawley rats weighing 100-120 g were used. Lumbar (L) 5 and 6 spinal nerve ligations were performed to induce neuropathic pain. For assessment of mechanical allodynia, mechanical stimulus using von Frey filament was applied to the paw to measure withdrawal threshold. The effects of intraperitoneal thalidomide (6.25, 12.5, 25 and 50 mg/kg, respectively) and morphine (3 and 10 mg/kg, respectively) were examined on a withdrawal threshold evoked by spinal nerve ligation.

Results

After L5 and 6 spinal nerve ligation, paw withdrawal thresholds on the ipsilateral side were significantly decreased compared with pre-operative baseline and with those in the sham-operated group. Intraperitoneal thalidomide and morphine significantly increased the paw withdrawal threshold compared to controls and produced dose-responsiveness.

Conclusions

Systemic thalidomide and morphine have antiallodynic effect on neuropathic pain induced by spinal nerve ligation in rat. These results suggest that morphine and thalidomide may be alternative therapeutic approaches for neuropathic pain.

Acute rolipram/thalidomide treatment improves tissue sparing and locomotion after experimental spinal cord injury

Traumatic spinal cord injury (SCI) causes severe and permanent functional deficits due to the primary mechanical insult followed by secondary tissue degeneration. The cascade of secondary degenerative events constitutes a range of therapeutic targets which, if successfully treated, could significantly ameliorate functional loss after traumatic SCI. During the early hours after injury, potent pro-inflammatory cytokines, including tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) are synthesized and released, playing key roles in secondary tissue degeneration. In the present investigation, the ability of rolipram and thalidomide (FDA approved drugs) to reduce secondary tissue degeneration and improve motor function was assessed in an experimental model of spinal cord contusion injury. The combined acute single intraperitoneal administration of both drugs attenuated TNF-alpha and IL-1beta production and improved white matter sparing at the lesion epicenter. This was accompanied by a significant (2.6 point) improvement in the BBB locomotor score by 6 weeks. There is, at present, no widely accepted intervention strategy that is appropriate for the early treatment of human SCI. The present data suggest that clinical trials for the acute combined application of rolipram and thalidomide may be warranted. The use of such "established drugs" could facilitate the early initiation of trials.

Childhood thalidomide neuropathy: a clinical and neurophysiologic study

Thalidomide was recently reintroduced to treat several immune-mediated pathologies. Peripheral neuropathy is a significant side effect limiting its clinical use. Our aims include: (1) describing and identifying the incidence of clinical or electrophysiologic peripheral neuropathy in children, (2) determining whether peripheral neuropathy correlates with cumulative dose of thalidomide and with age, and (3) defining its reversibility rate. We studied 13 children manifesting immune-mediated pathologies treated with thalidomide at doses ranging from 25-100 mg/day. Clinical and neurophysiologic evaluation was performed before and after starting treatment. Seven children (53.8%) showed neurophysiologic signs of sensory peripheral axonal polyneuropathy. Five presented associated clinical symptoms, while the other two only presented subclinical, neurophysiologic signs of peripheral neuropathy. We found a significant correlation between the incidence of peripheral neuropathy and thalidomide cumulative dose (P = 0.02). We observed a lower incidence of peripheral neuropathy at a cumulative dose <20 gm, and a correlation with age (P < 0.01). The clinical and electrophysiologic recovery rate was 40%, and clinical improvement alone was observed in another 40%. Thalidomide induces dose-dependent and age-dependent peripheral neuropathy at a significant frequency in childhood (53.8%). In our experience a cumulative dosage at >20 gm and long-term administration for >10 months seem to increase the risk of peripheral neuropathy. We propose clinical and neurophysiologic follow-up every 3 months to identify and monitor possible side effects.

Effects of thalidomide in a mouse model of cerulein-induced acute pancreatitis

Current knowledge shows that pathophysiology of acute pancreatitis is characterized by intraacinar enzyme activation and subsequent dysregulation in immune response. Interactions between leukocytes, soluble mediators such as cytokines and vascular endothelium contribute to the systemic progression of the inflammatory response, whose entity may--in the end--determine disease severity and outcome. Recently, it has been shown that TNF-[alpha] may be a novel target for the treatment of acute pancreatitis; but the role of thalidomide, an immunomodulatory agent that inhibits TNF-(alpha) and angiogenesis, has not been investigated so far. The aim of the present study was to assess the effects of thalidomide in a murine model of necrotizing acute pancreatitis. Necrotizing acute pancreatitis was induced in mice by intraperitoneal injection of cerulein (hourly, x5, 50 microg/kg); in another group of animals, thalidomide was administered (200 mg/kg orally) at 1 h after first cerulein injection. After 24 h, biochemical, histological, and immunohistochemical evidences of acute pancreatitis developed in all cerulein-treated mice. On the contrary, pancreatitis histological features, amylase, lipase, TNF-alpha and IL-1beta levels, pancreas edema, and myeloperoxidase activity as well as immunohistochemical staining for inflammatory cytokines, leukocyte adhesion molecules, transforming growth factor [beta], vascular endothelial growth factor, and apoptosis-related proteins were found reduced in thalidomide-treated mice. Therefore, thalidomide treatment attenuates the development of acute pancreatitis caused by cerulein in mice. We propose that this evidence may help to clarify the role of anti-TNF-alpha and immunomodulatory agents in patients with acute pancreatitis.

Evaluation of interferon alpha-2B and thalidomide in patients with disseminated malignant melanoma, phase 2, SWOG 0026

BACKGROUND

Southwest Oncology Group protocol 0026 evaluated interferon alpha-2b plus thalidomide in patients with disseminated melanoma. Endpoints were 6-month progression-free survival rate, response rate, and toxicity.

METHODS

Twenty-six patients with Stage IV melanoma, measurable or nonmeasurable disease, performance status of 0-2, and adequate renal and hepatic functions were registered. One prior systemic therapy for Stage IV disease was required. Interferon was administered subcutaneously (1 million U) twice daily; thalidomide was orally administered (200-400 mg) each evening in a dose-escalating manner. Response evaluations using Response Evaluation Criteria in Solid Tumors were performed every 8 weeks.

RESULTS

After 2 sudden deaths and 1 grade 4 treatment-related pulmonary embolism, this study was temporarily closed. One patient with deep-vein thrombosis and 2 with grade 3 cardiac arrhythmias were reported. The relationship of these events to the treatment was worrisome but not definitive. Grade 3 treatment-related adverse events occurred in 14 of 26 patients. Because of concern for patient safety the study was permanently closed. No treatment responses were seen in the 22 evaluable patients. Estimated 6-month progression-free survival rate was 15% (95% confidence interval [CI], 2%-29%), estimated 6-month overall survival was 58% (95% CI, 39%-77%), and estimated response probability was 0 of 22 (95% CI, 0%-15%).

CONCLUSIONS

This regimen demonstrated a lack of response and was associated with multiple severe toxicities. Further investigation of interferon alpha-2b and thalidomide in this dose and schedule is not warranted.

Medical therapy for refractory pediatric Crohn's disease

Crohn's disease is a common indication for referral to pediatric gastroenterology. While most patients with Crohn's disease respond to standard induction therapy, steroid-refractory or steroid-dependent disease is a frequently encountered problem. This review discusses the data existing in both the adult and pediatric literature for medical therapy of refractory pediatric Crohn's disease.

Mitochondrial electron transport in models of neuropathic and inflammatory pain

Although peripheral nerve function is strongly dependent on energy stores, the role of the mitochondrial electron transport chain, which drives ATP synthesis, in peripheral pain mechanisms, has not been examined. In models of HIV/AIDS therapy (dideoxycytidine), cancer chemotherapy (vincristine), and diabetes (streptozotocin)-induced neuropathy, inhibitors of mitochondrial electron transport chain complexes I, II, III, IV, and V significantly attenuated neuropathic pain-related behavior in rats. While inhibitors of all five complexes also attenuated tumor necrosis factor alpha-induced hyperalgesia, they had no effect on hyperalgesia induced by prostaglandin E2 and epinephrine. Two competitive inhibitors of ATP-dependent mechanisms, adenosine 5'-(beta,gamma-imido) triphosphate and P1,P4-di(adenosine-5') tetraphosphate, attenuated dideoxycytidine, vincristine, and streptozotocin-induced hyperalgesia. Neither of these inhibitors, however, affected tumor necrosis factor alpha, prostaglandin E2 or epinephrine hyperalgesia. These experiments demonstrate a role of the mitochondrial electron transport chain in neuropathic and some forms of inflammatory pain. The contribution of the mitochondrial electron transport chain in neuropathic pain is ATP dependent.

Minimising the potential for metabolic activation in drug discovery

Investigations into the role of bioactivation in the pathogenesis of xenobiotic-induced toxicity have been a major area of research since the link between reactive metabolites and carcinogenesis was first reported in the 1930s. Circumstantial evidence suggests that bioactivation of relatively inert functional groups to reactive metabolites may contribute towards certain drug-induced adverse reactions. Reactive metabolites, if not detoxified, can covalently modify essential cellular targets. The identity of the susceptible biomacromolecule(s), and the physiological consequence of its covalent modification, will dictate the resulting toxicological response (e.g., covalent modification of DNA by reactive intermediates derived from procarcinogens that potentially leads to carcinogenesis). The formation of drug-protein adducts often carries a potential risk of clinical toxicities that may not be predicted from preclinical safety studies. Animal models used to reliably predict idiosyncratic drug toxicity are unavailable at present. Furthermore, considering that the frequency of occurrence of idiosyncratic adverse drug reactions (IADRs) is fairly rare (1 in 1000 to 1 in 10,000), it is impossible to detect such phenomena in early clinical trials. Thus, the occurrence of IADRs during late clinical trials or after a drug has been released can lead to an unanticipated restriction in its use and even in its withdrawal. Major themes explored in this review include a comprehensive cataloguing of bioactivation pathways of functional groups commonly utilised in drug design efforts with appropriate strategies towards detection of corresponding reactive intermediates. Several instances wherein replacement of putative structural alerts in drugs associated with IADRs with a latent functionality eliminates the underlying liability are also presented. Examples of where bioactivation phenomenon in drug candidates can be successfully abrogated via iterative chemical interventions are also discussed. Finally, appropriate strategies that aid in potentially mitigating the risk of IADRs are explored, especially in circumstances in which the structural alert is also responsible for the primary pharmacology of the drug candidate and cannot be replaced.

Tumour necrosis factor-α mediates neutrophil migration to the knee synovial cavity during immune inflammation

Tumour necrosis factor (TNF)-alpha, interleukin-1beta, interleukin-8 and leukotriene B4 have an important role on neutrophil recruitment during immune-inflammation. Here we evaluated the participation of several inflammatory mediators on ovalbumin-induced neutrophil recruitment in the knee articular space of immunized rats. Ovalbumin administration in immunized, but not in control, rats induced a dose- and time-dependent neutrophil accumulation, which was inhibited by dexamethasone, pentoxifylline or thalidomide, but not by selective inhibitors of nitric oxide (nitro-L-arginine), platelet-activating factor (BN50730 or UK74505), prostaglandins (indomethacin), histamine (meclisine) or leukotriene B4 (MK 886 and CP105,696). Anti-TNF-alpha antiserum, but not anti-interleukin-1beta or anti-CINC-1 (cytokine-induced neutrophil chemoattractant 1) antisera, impaired ovalbumin-induced neutrophil accumulation. High amounts of TNF-alpha were detected in the exudates, which was inhibited by dexamethasone, pentoxifylline and thalidomide. These results suggest a specific role for TNF-alpha in this model, and the ability of pentoxifylline and thalidomide to inhibit both neutrophil influx and TNF-alpha release may have therapeutic implications in arthritis.