Evaluation of Loco-Regional Skin Toxicity Induced by an In Situ Forming Depot after a Single Subcutaneous Injection at Different Volumes and Flow Rates in Göttingen Minipigs.

The present study aims to investigate the loco-regional tolerability and injection parameters (i.e., flow rate and administration volume) of an in situ forming depot (ISFD) in Göttingen minipigs, to secure both the therapeutic procedure and compliance in chronic medical prescriptions. The ISFD BEPO® technology (MedinCell S.A.) is investigated over 10 days, after a single subcutaneous injection of test item based on a DMSO solution of diblock and triblock polyethylene glycol-polylactic acid copolymers. Injection sites are systematically observed for macroscopic loco-regional skin reactions as well as ultrasound scanning, enabling longitudinal in vivo imaging of the depot. Observations are complemented by histopathological examinations at 72 h and 240 h post-injection. Overall, no treatment-emergent adverse effects are macroscopically or microscopically observed at the subcutaneous injection sites, for the tested injection flow rates of 1 and 8 mL/min and volumes of 0.2 and 1 mL. The histopathology examination confirms an expected foreign body reaction, with an intensity depending on the injected volume. The depot morphology is similar irrespective of the administration flow rates. These results indicate that the ISFD BEPO® technology can be considered safe when administered subcutaneously in Göttingen minipigs, a human-relevant animal model for subcutaneous administrations, in the tested ranges.

Nonclinical evaluation of immunological safety in Göttingen Minipigs: The CONFIRM initiative.

There is a growing need to consider non-rodent species for the immunological safety evaluation of drug candidates. The EU Framework-6 RETHINK Project demonstrated that the Göttingen Minipig is a relevant animal model for regulatory toxicology studies. Extensive knowledge on the immune system of domestic pigs is available and fewer differences from humans have been identified as compared to other species, such as mice or non-human primates. Minipig data are too scarce to allow for claiming full immunological comparability with domestic pigs. Another gap limiting minipig use for immunological safety evaluation is the lack of a qualified and validated database. However, available data lend support to the use of minipigs. The need for a COllaborative Network For Immunological safety Research in Minipigs (the CONFIRM Initiative) was obvious. It is intended to trigger immunological safety research in Göttingen Minipigs, to assist and synergize fundamental, translational and regulatory investigative efforts relevant to the immunological safety evaluation of pharmaceuticals and biologics, and to spread current knowledge and new findings to the scientific and regulatory toxicology community.

Safety evaluation of a whey protein fraction containing a concentrated amount of naturally occurring TGF-ß2.

TM0601p is a whey protein isolate derived from cow milk, containing a concentrated amount of transforming growth factor ß2 (TGF-ß2), and is intended for nutritional use in infants and adults. In vivo and in vitro studies have been performed to evaluate the safety of this product. In a 13-week toxicity study, treatment of adult Sprague-Dawley rats by gavage at up to 2000mg/kg/day did not result in any significant findings other than minor non-adverse changes in urinary parameters in females. The no-observed-adverse-effect level (NOAEL) was established as 2000mg/kg/day. In a juvenile toxicity study, rat pups received 600mg/kg/day by gavage from postnatal day (PND) 7 to PND 49. Transient lower bodyweight gain in the pre-weaning period was attributed to gastrointestinal effects of the viscous test material; following weaning, bodyweight gain was comparable to the vehicle controls. Reduced eosinophil counts and changes in urinary parameters (females) were recorded in treated pups at PND 49, and higher thymus weights were recorded in males only at the end of the recovery period (Day 77). None of the findings were considered adverse. There were no other significant findings and the NOAEL was established as 600mg/kg/day. No evidence of genotoxicity was seen in the bacterial reverse mutation test or the in vitro micronucleus test. Overall the results obtained present a reassuring safety profile for TM0601p.

Imiquimod and pulmonary embolism: a case report.

Bilateral pulmonary embolism possibly related due to topically applied imiquimod is reported in a 47-year-old male patient with no evidence of risk factors.

Tramadol and hypoglycaemia: comparison with other step 2 analgesic drugs.

AIMS: The risk of hypoglycaemia with tramadol (TRM) is not well described. Our aim was to analyze spontaneous reports of hypoglycaemia registered in the French Pharmacovigilance database and to compare these data with two other step-2 analgesic drugs. METHODS: Cases of hypoglycaemia associated with TRM, dextropropoxyphene (DXP) and codeine (COD) recorded between 1997 and November 2010 in the French pharmacovigilance database were compared. RESULTS: Seventy-two cases of hypoglycaemia associated with DXP and 43 with TRM were retained for evaluation (the single case reported with COD was not further considered). Most patients were elderly people with no significant difference in age between DXP- and TRM-treated patients (71.2 ± 21 vs. 69.4 ± 22.5 years). Hypoglycaemia occurred after a median of 4 and 5 days with DXP and TRM treatment, respectively. The mean lowest serum glucose concentration was 2.1 ± 0.9 mmol l(-1) in the DXP group compared with 2.5 ± 1 mmol l(-1) in the TRM group (P = 0.072). At least, one risk factor of hypoglycaemia was found in most patients, with no significant difference between groups (58.3% in the DXP group and 58.1% in the TRM group). In particular, 31.9% patients from the DXP group had diabetes compared with 41.8 % from the TRM group (P = 0.28) and 18% of DXP patients had renal insufficiency compared with 16.3% of TRM patients (P = 0.8). CONCLUSIONS: Our study confirms that TRM is associated with the occurrence of hypoglycaemia in elderly or predisposed patients, with characteristics similar to those previously reported with DXP.

Critical review of preclinical approaches to evaluate the potential of immunosuppressive drugs to influence human neoplasia.

Many immunosuppressive drugs are associated with an increased risk of B-cell lymphoma, squamous cell carcinoma, and Kaposi sarcoma. Thirteen immunosuppressive drugs have been tested in 2-year carcinogenicity studies (abatacept; azathioprine; busulfan; cyclophosphamide; cyclosporine; dexamethasone; everolimus; leflunomide; methotrexate; mycophenolate mofetil; prednisone; sirolimus; and tacrolimus) and in additional models including neonatal and genetically modified mice; chemical, viral, ultraviolet, and ionizing radiation co-carcinogenesis, and in models with transplanted tumor cells. The purpose of this review is to outline the mechanisms by which immunosuppressive drugs can influence neoplasia, to summarize the available preclinical data on the 13 drugs, and to critically review the performance of the models. A combination of primary tumor and metastasis assays conducted with transplanted cells may provide the highest value for hazard identification and can be applied on a case-by-case basis. However, for both small molecules and therapeutic proteins, determining the relative risk to patients from preclinical data remains problematic. Classifying immunosuppressive drugs based on their mechanism of action and hazard identification from preclinical studies and a prospective pharmacovigilance program to monitor carcinogenic risk may be a feasible way to manage patient safety during the clinical development program and postmarketing.

Proton pump inhibitor-induced neutropenia: possible cross-reactivity between omeprazole and pantoprazole.

Proton pump inhibitors (PPIs) are widely used drugs in the treatment or prophylaxis of peptic ulcer and gastro-oesophageal reflux disease. In addition to their well documented efficacy, these drugs are generally well tolerated with only rare serious adverse effects having been reported. Neutropenia and agranulocytosis are rare adverse events associated with PPI treatment. All previously published cases of isolated neutropenia have involved omeprazole, but leukopenia is labelled as a possible adverse effect in the summary of product characteristics of the other PPIs. In this report, we describe a case of omeprazole-induced neutropenia with further recurrence upon pantoprazole treatment. A 60-year-old man with chronic alcoholism and a medical history of pulmonary tuberculosis, untreated chronic C hepatitis, peripheral artery disease, chronic obstructive pulmonary disease and stable stage 3 chronic kidney disease was admitted with dehydration and malnutrition. Omeprazole 20 mg/day and sucralfate 3 g/day were started for diffuse gastritis on gastric endoscopy. While the patient's blood cell count had been within the normal range before this treatment, routine laboratory examination revealed moderate neutropenia (0.9 x 109/L) after 9 days of treatment. His blood cell count returned to the normal range after discontinuation of omeprazole and no further episodes of neutropenia were noted in the following months. One year later, oesophago-gastroscopy revealed a hiatal hernia with an extensive zone of Barrett's oesophagus. As the lesions did not improve with ranitidine and sucralfate therapy, the patient was started on pantoprazole 40 mg/day. His initial white blood cell count was normal, but moderate neutropenia (0.8 x 109/L) was again noted after only 2 days of pantoprazole treatment. Complete and further stable normalization was obtained within 3 days after replacement of pantoprazole with ranitidine. Toxic and immune-mediated mechanisms are the two commonly proposed mechanisms to explain the pathogenesis of drug-induced neutropenia. This report suggests that PPI-induced neutropenia is immune mediated and argues for a possible cross-reactivity between the two PPIs, as has already been described for PPI-induced hypersensitivity reactions. The report also indicates that patients with a history of neutropenia induced by one PPI may be at risk of recurrence of neutropenia if given another member of this drug class. In these patients, close haematological monitoring is proposed.

Second meeting of the French CEIP (Centres d'Evaluation et d'Information sur la Pharmacodépendance). Part II: benzodiazepine withdrawal.

The aim of this meeting was to describe the news trends about abuse and addiction of anxiolytics and hypnotics. The part II of this meeting reviewed several aspects of the withdrawing benzodiazepines focusing in particular on clinical symptoms, biological patterns, and strategies for discontinuation. The discontinuation is usually beneficial due to the importance of adverse effects induced by long-term use of benzodiazepines. Several clinicals options have been described including gradual tapering of the current benzodiazepine, substitution with a long acting benzodiazepines or treating the symptoms of withdrawal. Psychological interventions range from a simple support through counselling to expert cognitive-behavioural therapy. However more controlled clinical trials are needed to promote adequate and optimal patient care in management of benzodiazepine withdrawing.

Ivabradine induces an increase in ventricular fibrillation threshold during acute myocardial ischemia: an experimental study.

BACKGROUND: Tachycardia often facilitates ischemic ventricular fibrillation (VF). OBJECTIVE: This study assessed the impact of ivabradine (IVA), a selective inhibitor of the cardiac pacemaker If current, on ventricular fibrillation threshold (VFT) during acute myocardial ischemia. METHODS: The experiments were conducted on a total of 54 domestic pigs. Myocardial ischemia was induced in anesthetized pigs by total 1-minute coronary occlusion at baseline and then on 2 occasions after intravenous administration of saline or 0.5 mg/kg of IVA. VF was triggered by electrical stimuli of increasing intensity at a fixed rate. Heart rate (HR), VFT, monophasic action potential duration, and peak of the time derivative of left ventricular pressure (LV dP/dt max) were monitored on each occasion. The activity of mitochondrial succinodehydrogenase was measured on heart sections. RESULTS: Compared with controls, IVA induced a 31% reduction in HR, a 2.9-fold increase in VFT, and prevented ischemia-induced monophasic action potential duration shortening (+1 +/- 12 vs. -14 +/- 11 milliseconds) without affecting peak LV dP/dt. This beneficial effect on VFT was mainly due to HR reduction and was accompanied by a significant reduction in the hypoxic area (26% +/- 1% vs. 38% +/- 1%, P < 0.0001). CONCLUSION: HR reduction and the decrease in myocardial damage induced by IVA protected against primary ischemic VF without altering myocardial contractility.

Trimetazidine protective effect against ischemia-induced susceptibility to ventricular fibrillation in pigs.

PURPOSE: Ventricular fibrillation (VF) is a possible consequence of brief myocardial ischemia. Such a short ischemia does not provoke cell damage, but induces changes in intracellular cardiac metabolism due to diminished oxygen supply to the heart. Trimetazidine (TMZ) is a drug able to restore the metabolic balance between fatty acid and glucose oxidation in ischemic myocardial cells. The aim of this double-blind study was to investigate TMZ effect on VF in pigs during short-term ischemia. METHODS: Ischemia was induced after thoracotomy by complete, but brief (1 min) occlusion of the left anterior descending coronary artery under electrical stimulation. The ventricular fibrillation threshold (VFT), heart rate (HR), various hemodynamic parameters and malondialdehyde (MDA) blood levels were measured before and during ischemia in two groups of eight anesthetized pigs. The mass of ischemic myocardial tissue was also evaluated. RESULTS: No effects on either the HR or the hemodynamic parameters were observed during myocardial ischemia, whereas TMZ increased the VFT and decreased both MDA blood levels (an index of lipid peroxidation) and the ischemic area. CONCLUSIONS: TMZ limited ischemia-induced electrical dysfunction leading to cardiac susceptibility to VF by decreasing lipid peroxidation and maintaining ionic homeostasis. TMZ could therefore provide protection against ischemia-induced VF.

Clinical immunotoxicity of therapeutic proteins.

Therapeutic proteins are proteins engineered in the laboratory for pharmaceutical use. Although they tend to offer a better safety margin than most synthetic small molecules because they are processed by the same pathways as natural proteins in the human body, or mimic or replace natural proteins that are missing or defective, they can induce a variety of adverse effects in human patients among which immunotoxic effects deserve particular attention. Infectious complications and virus-induced neoplasias are the main consequences of intended or unexpected immunosuppression. They have been primarily described with anti-TNF-alpha drugs and anticancer monoclonal antibodies (mAbs) whose immunosuppressive effects can be largely anticipated from their mechanism of action. Cytokine release-associated adverse reactions ranging from mild-to-moderate flu-like reactions to severe cytokine release syndromes, or exceptionally cytokine storm, are now an issue of chief concern. They have been observed with most of the therapeutic proteins in current use. Acute infusion reactions whose clinical features are somewhat similar have been variably described with many mAbs. Immunostimulatory properties are suspected to account for the occurrence of more frequent autoimmune diseases as seen in patients treated with recombinant cytokines such as the IFNs-alpha and rIL-2. The risk of more frequent hypersensitivity reactions to unrelated allergens is also suspected to be a potential consequence of immunostimulation but compelling evidence is limited to radiocontrast media-induced hypersensitivity reactions in IL-2 treated cancer patients. In addition, recombinant cytokines can inhibit cytochrome P450 dependent biotransformation pathways with resulting alterations in the pharmacokinetics of the combined drugs at therapeutic dose. Because of their structure and origin, therapeutic proteins are intrinsically immunogenic. Despite extensive laboratory and clinical studies that were instrumental in delineating general concepts about key factors involved in immunogenicity, it is impossible nowadays to anticipate to what extent a novel therapeutic protein will be immunogenic in human patients. Specific antibodies are frequently detected in the sera of treated patients. They are often inconsequential but can also be neutralizing and result in decreased efficacy. Anaphylactic reactions induced by human therapeutic proteins have been rarely reported and true serum sickness extremely rarely. Because the immunotoxic effects of therapeutic proteins are frequent, sometimes severe and even potentially life-threatening, there is an urgent need to improve our capacity to anticipate the immunotoxic risks of novel therapeutic proteins and this could be achieved by the development of clinical immunotoxicology.

Lead poisoning following ingestion of pieces of lead roofing plates: pica-like behavior in an adult.

A 37-year-old man was admitted to hospital after complaining of abdominal pain for the past two weeks. On admission the abdominal radiograph showed multiple radio-opaque flecks dispersed throughout the gastrointestinal tract. Blood testing showed hemoglobin level 8.7 g/dL and a blood lead level of 112.4 microg/dL. The family interview revealed that the patient had pica-like behavior since childhood. He was a site foreman and had been ingesting pieces of roofing plates for a few weeks. The patient was treated with laxatives and CaNa(2)EDTA therapy was initiated. The blood lead level then dropped to 69.9 microg/dL. The patient received two subsequent courses of oral succimer and the blood lead level decreased to 59 microg/dL 21 days after the first course. The follow-up abdominal X-ray 20 days after the first examination was normal. Four months later, an outpatient follow-up visit showed a blood lead level within normal limits (14.5 microg/dL) and a psychiatric follow-up was initiated. Lead poisoning following the ingestion of lead-containing foreign bodies is particularly rare in adults, while it is sometimes observed in children. Pica behavior is a well-identified risk factor of lead intoxication in children but is quite exceptional in adults, where it is usually considered to be a psychiatric condition. Other unusual sources of lead poisoning include the ingestion of lead bullets, ceramic lead glaze or glazed earthenware, lead-contaminated candies, ethnic or herbal remedies.

[Digital ischemia following injection of a crushed tablet of zolpidem: tardive improvement with iloprost]. / Ischémie digitale après injection d'un comprimé pilé de zolpidem, amélioration tardive par l'iloprost.

The intra-arterial injection of crushed tablets can lead to severe vascular disorders including necrosis. A 35-year-old patient was hospitalized after the involuntary intra-radial injection of a crushed tablet of zolpidem. As the initial treatment with heparin and vasodilators was inefficient, iloprost injections were proposed. A recovery of most lesions was obtained, but the middle finger distal phalange had to be amputated. Iloprost has already been used successfully in the treatment of lesions caused by the intra-arterial injections of drugs of abuse. It can limit ischemia and even lead to necrosis healing, thus being an alternative to conventional treatments when they are ineffective.

Evaluation of a surgical procedure to measure drug biliary excretion of rats in regulatory safety studies.

A surgical procedure was evaluated to allow bile collection from the freely moving male Sprague-Dawley rats for the assessment of drug biliary excretion during regulatory safety studies. A catheter was implanted into the bile duct to divert the bile flow via an exteriorized loop. Following recovery from the surgery and verification of normal hepatic function, the exteriorized catheter was sectioned to allow collection of the bile and replacement with a commercial bile salt solution. Approximately 80% of the catheterized animals (10 females and 10 males) had normal serum liver enzyme levels 2 days after surgery. Then, the effect of acute or repeated administrations of the immunosuppressant tacrolimus on the biliary excretion of 14C diazepam was studied to validate the technique. A first group of 12 rats received an intravenous injection of 10 mg/kg 14C-diazepam and the total and sequential amounts of diazepam excreted in the bile were measured over 72 h. Biliary excretion accounted for 80% of diazepam elimination. These rats were then given an oral administration of 3 mg/kg tacrolimus on days 7 and 8 followed by the same intravenous dose of 14C-diazepam. Another group of 10 catheterized rats was given 21 daily oral doses of 3 mg/kg tacrolimus followed by a single intravenous administration of 14C-diazepam. No significant changes in diazepam biliary excretion were observed following either acute or repeated administration of tacrolimus. This study demonstrates the feasibility of drug biliary excretion investigations under Good Laboratory Practices conditions as a complement to regulatory acute or repeated dose safety studies.

Methods of evaluating immunotoxicity.

Immunotoxicology is an important aspect of the safety evaluation of drugs and chemicals. Immunosuppression, (unspecific) immunostimulation, hypersensitivity and autoimmunity are the four types of immune-mediated adverse effects. However, the nonclinical assessment of immunotoxicity is at present often restricted to animal models and assays to predict unexpected immunosuppression. There is, however, no general consensus that a variety of assays can be considered depending on the compound to be tested. A major issue is whether histological examination of the thymus, spleen, lymphoid organs and Peyer's patches is a reliable predictor of immunosuppression or whether immune function should also be assessed. A T-dependent antibody response assay, either the plaque-forming cell assay or anti-keyhole limpet haemocyanin enzyme-linked immunosorbant assay, is recommended as a first-line assay. A variety of assays, including lymphocyte subset analysis, natural killer-cell activity, lymphocyte proliferation, delayed-type hypersensitivity, cytotoxic T-lymphocyte activity and macrophage/neutrophil function assays, can also be used. In certain circumstances, host resistance assays can be considered. With the exception of contact sensitisation, very few animal models and assays can reliably predict the potential for (unspecific) immunostimulation, hypersensitivity or autoimmunity. A major limitation of immunotoxicity risk assessment is the lack of human data. Immunological end points and clinical criteria to be included in clinical trials and epidemiological studies have to be carefully standardised and validated.

Acute occupational poisoning by octogen: first case report.

BACKGROUND: Octogen (HMX) is a polynitramine explosive closely related to hexogen, a known occupational toxin in military munitions plants. No acute human poisoning with octogen has ever been reported. CASE REPORT: A 28-year-old man with no history of epilepsy was admitted to the Emergency Department for seizures that had developed during the night after a full working day when he manually sieved large amounts of dry octogen. On admission, the clinical examination was normal and all other examinations could not substantiate the development of essential or secondary epilepsy. Elevated octogen concentrations were measured in his plasma, which confirmed occupational exposure to the explosive. CONCLUSION: The rarity of acute human poisonings by octogen is due to the infrequent use of this explosive and, more importantly, its very low oral bioavailability. However, acute poisoning can occur, but should be easily avoided by implementing adequate preventive measures.

Safety profile of etifoxine: A French pharmacovigilance survey.

Etifoxine chlorhydrate is a benzoxazine derivative approved for the treatment of psychosomatic manifestations of anxiety since 1979. Previously labeled adverse drug reactions (ADRs) only include drowsiness, benign cutaneous reactions, and acute hypersensitivity reactions. The objectives were to examine recent data on etifoxine-related ADR by reviewing Individual Case Safety Reports (ICSRs) recorded in France especially unexpected ADRs. Etifoxine-related ICSRs were extracted from the French Pharmacovigilance database from 1 January 2000 to 30 April 2012 and data from the marketing authorization holder up to 31 December 2011 were also obtained. Of the 350 cases retained for analysis, 123 (35%) were considered serious. Dermatological or acute hypersensitivity reactions were the most frequent ADRs (59%) mainly isolated cutaneous eruptions. However, there were 24 cases of severe toxidermia (DRESS in 5, erythema multiforme in 10 and Stevens-Johnson syndrome in 5) with etifoxine as the most suspected drug in 11 patients, and seven cases of vasculitis or serum sickness-like reaction. Liver disorders were reported in 34 patients of whom 25 developed acute hepatitis with a cytolytic biological pattern in 16. Other unexpected ADRs included 16 reversible cases of metrorrhagia with positive rechallenge in 5, and three cases of biopsy-proven microscopic colitis of which one recurred after etifoxine re-administration. Although etifoxine has been marketed for more than 30 years, this survey identified a number of unexpected and sometimes serious ADRs, in particularly severe toxidermia and acute cytolytic hepatitis. A recent update of the French etifoxine summary of the product characteristics (SPC) was based on these findings.

Toxicovigilance: a new approach for the hazard identification and risk assessment of toxicants in human beings.

The concept of toxicovigilance encompasses the active detection, validation and follow-up of clinical adverse events related to toxic exposures in human beings. Poison centers are key players in this function as poisoning statistics are essential to define the cause, incidence and severity of poisonings occurring in the general population. In addition, the systematic search for unexpected shifts in the recorded causes of poisonings, e.g., following the introduction of a new product, or change in the formulation or recommended use of an old product, allows for a rapid detection of potential adverse health consequences and the implementation of preventive or corrective measures. However, toxicovigilance is genuinely a medical and not only a statistical approach of human toxicity issues. In contrast to epidemiology, toxicovigilance is based on the in-depth medical assessment of acute or chronic intoxications on an individual basis, which requires detailed information that poison centers can rarely obtain via emergency telephone calls and that epidemiologists cannot collect or process. Validation of this medical information must primarily be based on toxicological expertise to help identify causal links between otherwise unexplained pathological conditions and documented toxic exposures. Thus, toxicovigilance can contribute to hazard identification and risk assessment by providing medically validated data which are often overlooked in the process of risk assessment. So far, very few structured toxicovigilance systems have been set up and hopefully national and international initiatives will bridge this gap in our knowledge of the toxicity of many chemicals and commercial products in human beings.

Immunotoxicology: role in the safety assessment of drugs.

The immunotoxic effects of drugs are divided into immunosuppression, immunostimulation, hypersensitivity and autoimmunity. The major adverse consequences of immunosuppression are infectious complications and virus-induced malignancies. Flu-like reactions, more frequent autoimmune diseases and hypersensitivity reactions to unrelated allergens, and inhibition of drug-metabolising enzymes are the adverse effects related to immunostimulation. Hypersensitivity reactions are the most frequent immunotoxic effects of drugs. They include immune-mediated ('allergic') and non immune-mediated ('pseudoallergic') reactions. Drug-induced autoimmune reactions, either systemic or organ-specific, are seemingly rare. A review of drug-induced immunotoxic effects demonstrates that immunotoxicity is a significant cause of morbidity and even mortality. As immunotoxicologists have long focused on immunosuppression, the nonclinical immunotoxicity safety assessment of unexpected immunosuppression is based on a number of relatively well standardised and validated animal models and assays. However, there is no general consensus regarding the minimal requirement for this assessment. Many different assays can be used to extend the assessment case by case. Few animal models and assays have been validated for use in the nonclinical safety assessment of unexpected immunostimulation. The situation is worse regarding the prediction of hypersensitivity and autoimmune reactions. Our limited understanding of the molecular and cellular mechanisms of immunotoxicity accounts, at least partly, for this situation. Recent guidelines for the immunotoxicity safety assessment of drugs, even though conflicting on several points, will serve as an impetus not only to refine current animal models and assays, but also to search for better alternatives. The new data generated will have to be interpreted and extended to animal species other than just rodents. Likewise, animal results will have to be compared with findings in humans. The search for immunological endpoints that can be used in several animal species and in humans will therefore become essential. Specific endpoints and clinical criteria that can be included in clinical trials to further investigate the potential for immunotoxicity of new drugs will have to be defined. Because immunotoxicity plays a key role in drug-induced adverse effects, the role of immunotoxicology in drug safety assessment is indisputable and the systematic nonclinical as well as clinical immunotoxicity assessment of every new drug is deemed essential.