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Baclofen is a γ-aminobutyric acid-B receptor agonist used for control of spastic muscle activity and as a treatment for alcohol abuse. The review of the nonclinical database suggested a data gap for potential carcinogenicity following long-term use. Regulatory requirements for pharmaceutical safety testing of cancer-causing potential have historically included 2-year rodent studies in rats and mice. The availability of transgenic models with greater specificity and sensitivity to carcinogens provides safety testing alternatives that align with the 3Rs. The carcinogenicity of baclofen was evaluated in CB6F1-TgrasH2 transgenic mice following daily oral administration at 45, 90, and 180 mg/kg/d for 26 weeks, preceded by a 2-week drug-conditioning period. There were no treatment-related palpable masses or neoplastic findings, and survival rates were not affected by the baclofen treatment. In conclusion, baclofen was considered as noncarcinogenic in CB6F1-TgrasH2 mice, which is consistent with results previously obtained in a 2-year rat study.

Background The Médecins Sans Frontières Clinic in Mumbai, India, has been providing concomitant bedaquiline (BDQ) and delamanid (DLM) in treatment regimen for patients with drug-resistant tuberculosis (DR-TB) and limited therapeutic options, referred from other healthcare institutions, since 2016. The study documents the end-of-treatment outcomes, culture-conversion rates, and serious adverse events (SAEs) during treatment. Methods This was a retrospective cohort study based on routinely collected program data. In clinic, treatment regimens are designed based on culture drug sensitivity test patterns and previous drug exposures, and are provided for 20–22 months. BDQ and DLM are extended beyond 24 weeks as off-label use. Patients who initiated DR-TB treatment including BDQ and DLM (concomitantly for at least 4 weeks) during February 2016–February 2018 were included. Results Of the 70 patients included, the median age was 25 (interquartile range [IQR], 22–32) years and 56% were females. All except 1 were fluoroquinolone resistant. The median duration of exposure to BDQ and DLM was 77 (IQR, 43–96) weeks. Thirty-nine episodes of SAEs were reported among 30 (43%) patients, including 5 instances of QTc prolongation, assessed as possibly related to BDQ and/or DLM. The majority (69%) had culture conversion before 24 weeks of treatment. In 61 (87%), use of BDQ and DLM was extended beyond 24 weeks. Successful end-of-treatment outcomes were reported in 49 (70%) patients. Conclusions The successful treatment outcomes of this cohort show that regimens including concomitant BDQ and DLM for longer than 24 weeks are effective and can be safely administered on an ambulatory basis. National TB programs globally should scale up access to life-saving DR-TB regimens with new drugs.

Lenadogene nolparvovec (Lumevoq) gene therapy was developed to treat Leber hereditary optic neuropathy (LHON) caused by the m.11778G > A in MT-ND4 that affects complex I of the mitochondrial respiratory chain. Lenadogene nolparvovec is a replication-defective, single-stranded DNA recombinant adeno-associated virus vector 2 serotype 2, containing a codon-optimized complementary DNA encoding the human wild-type MT-ND4 subunit protein. Lenadogene nolparvovec was administered by unilateral intravitreal injection in MT-ND4 LHON patients in two randomized, double-masked, and sham-controlled phase III clinical trials (REVERSE and RESCUE), resulting in bilateral improvement of visual acuity. These and other earlier results suggest that lenadogene nolparvovec may travel from the treated to the untreated eye. To investigate this possibility further, lenadogene nolparvovec was unilaterally injected into the vitreous body of the right eye of healthy, nonhuman primates. Viral vector DNA was quantifiable in all eye and optic nerve tissues of the injected eye and was detected at lower levels in some tissues of the contralateral, noninjected eye, and optic projections, at 3 and 6 months after injection. The results suggest that lenadogene nolparvovec transfers from the injected to the noninjected eye, thus providing a potential explanation for the bilateral improvement of visual function observed in the LHON patients., Graphical abstract, Lenadogene nolparvovec is a gene therapy for LHON, and bilateral improvement of visual acuity was observed after unilateral intravitreal injection in clinical trials. NHPs were therefore treated by unilateral injection, and viral vector DNA was detected in the contralateral eye, thus providing a potential explanation for the observed bilateral improvement.

Species-dependent differences in relative incidence of spontaneous variations and malformations should be considered in the assessment of the translational value of reproductive and developmental safety assessments. The objective of this evaluation was to compare litter parameters and the frequency of external, visceral, and skeletal malformations and variations across species in the Sprague-Dawley rat, New Zealand White rabbit, and Göttingen minipig and to determine whether notable differences exist. Pregnant female rats (n = 824), rabbits (n = 540), and minipigs (n = 70) from vehicle control groups were included in the analysis, equating to 10,749 rat, 5,073 rabbit, and 378 pig fetuses collected at term by cesarean delivery. Preimplantation loss was more frequent than postimplantation loss in the rat and rabbit, whereas the opposite was observed in the minipig. Several external and visceral malformations and variations such as domed head, bent tail, abdominal edema, and anal atresia were observed in all 3 species. Visceral malformations of the heart and major blood vessels were remarkably more frequent in the minipig and rabbit, respectively; ventricular and atrium septum defects were observed in 1.9% and 2.1%, respectively, for the minipig fetuses, whereas they were observed in equal or less than 0.02% among the rat and rabbit fetuses evaluated in this study. Understanding species-dependent differences in spontaneous variations and malformations can be useful for the interpretation of embryo–fetal development study results. The current analysis identified relevant differences between commonly used species in reproductive toxicology with potential implications for data assessment.

SETTING: Médecins Sans Frontières (MSF) clinic in Mumbai, India.OBJECTIVE: To determine the final treatment outcomes, culture conversion and adverse events (AEs) during treatment among children and adolescents (0–19 years) with rifampicin-resistant tuberculosis (RR-TB) who received ambulatory injectable-free treatment, including bedaquiline (BDQ) and/or delamanid (DLM) during September 2014–January 2020.DESIGN: This was a retrospective cohort study based on review of routinely collected programme data.RESULTS: Twenty-four patients were included; the median age was 15.5 years (min-max 3–19) and 15 (63%) were females. None were HIV-coinfected. All had fluoroquinolone resistance. Twelve received treatment, including BDQ and DLM, 11 received DLM and one BDQ. The median exposure to BDQ (n = 13) and DLM (n = 23) was 82 (IQR 80–93) and 82 (IQR 77–96) weeks, respectively. Seventeen (94%) patients with positive culture at baseline (n = 18) had negative culture during treatment; median time for culture-conversion was 7 weeks (IQR 5–11). Twenty-three (96%) had successful treatment outcomes: cured (n = 16) or completed treatment (n = 7); one died. Eleven (46%) had 17 episodes of AEs. Two of 12 serious AEs were associated with new drugs (QTcF >500 ms).CONCLUSION: Based on one of the largest global cohorts of children and adolescents to receive new TB drugs, this study has shown that injectable-free regimens containing BDQ and/or DLM on ambulatory basis were effective and well-tolerated among children and adolescents and should be made routinely accessible to these vulnerable groups.

BackgroundImipenem, an intravenous antibiotic is recommended for use in drug resistant tuberculosis (DR-TB) when an effective regimen with combination of other second line drugs is not possible. Though the treatment success rates with carbapenems are promising, the twice daily injection of Imipenem usually requires patients to be hospitalized. The Médecins Sans Frontières independent clinic in Mumbai, India implemented ambulatory and home based management of patients receiving Imipenem through the use of port-a-cath.ObjectiveWe aimed to describe the adverse events and treatment outcomes of ambulatory pre- and XDR-TB patients initiated on imipenem through port-a-cath between January 2015 and June 2018 and to explore the challenges with this regimen as perceived by healthcare providers and patients.MethodsA convergent mixed methods study with quantitative (longitudinal descriptive study using the routine data) and qualitative (descriptive study) part conducted concurrently. For the quantitative component, all XDR-TB and pre-XDR-TB initiated on imipenem containing regimen during January 2015-June 2018 were included. For qualitative component, interviews were carried out including patients who initiated on imipenem (n = 5) and healthcare providers (n = 7) involved in providing treatment. Treatment outcomes, culture conversion and adverse events during treatment were described. Thematic analysis was carried out for qualitative component.ResultsOf the 70 patients included, the mean age was 28.1 (standard deviation: 11.2) years and 36 (51.4%) were females. Fifty one (72.9%) had XDR-TB. All patients were resistant to fluoroquinilone, levofloxacin. Vomiting was reported by 55 (78.6%) patients and at least one episode of QTC prolongation (more than 500 msec by Fredrecia method) was detected in 25 (35.7%). Port-a-cath block and infection was seen in 11 (15.7%) and 20 (28.6%) patients respectively. Favourable outcomes were seen in 43 (61.4%) patients. Mortality was seen in 22 (31.4%) patients, 2 (2.9%) were lost-to-follow-up and 3 (4.3%) were declared as treatment failure. The overarching theme of the qualitative analysis was: Challenges in delivering Imipenem via port-a-cath device in ambulatory care. Major challenges identified were difficulties in adhering to drug dose timelines, vomiting, restricted mobility due to port-a-cath, paucity of infection control and space constraints at patients' home for optimal care.ConclusionAdministration of imipenem was feasible through port-a-cath. Though outcomes with ambulatory based imipenem containing regimens were promising, there were several challenges in providing care. The feasibility of infusion at day care facilities needs to explored to overcome challenges in infusion at patients home.

While risk of tuberculosis (TB) is high among household contacts (HHCs) of pre-extensively drug resistant (pre-XDR) TB and XDR-TB, data on yield of systematic longitudinal screening are lacking. We aim to describe the yield of systematic longitudinal TB contact tracing among HHCs of patients with pre-XDR-TB and XDR-TB. At the Médecins Sans Frontières (MSF) clinic, Mumbai, India a cohort comprising 518 HHCs of 109 pre-XDR and XDR index cases was enrolled between January 2016 and June 2018. Regular HHC follow-ups were done till one year post treatment of index cases. Of 518 HHCs, 23 had TB (21 on TB treatment and two newly diagnosed) at the time of first visit. Of the rest, 19% HHCs had no follow-ups. Fourteen (3.5%) TB cases were identified among 400 HHCs; incidence rate: 2072/100,000 person-years (95% CI: 1227–3499). The overall yield of household contact tracing was 3% (16/518). Of 14 who were diagnosed with TB during follow-up, six had drug susceptible TB (DSTB); six had pre-XDR-TB and one had XDR-TB. Five of fourteen cases had resistance patterns concordant with their index case. In view of the high incidence of TB among HHCs of pre-XDR and XDR-TB cases, follow-up of HHCs for at least the duration of index cases’ treatment should be considered.

Introduction Cardiovascular safety assessment requires accurate evaluation of QT interval, which depends on the length of the cardiac cycle and also on core body temperature (BT). Increases in QT interval duration have been shown to be associated with decreases in BT in dogs. Methods An example of altered QT interval duration associated with changes in body temperature observed during a 4-week regulatory toxicology study in dogs is presented. Four groups of Beagle dogs received the vehicle or test item once on Day 1, followed by a 4-week observation period. Electrocardiogram (ECG) parameters were continuously recorded on Days 1 and 26 by jacketed external telemetry (JET). Core body temperature (BT) was measured with a conventional rectal thermometer at appropriate time-points during the Day 1 recording period. Results Decreased BT was observed approximately 2 h after treatment on Day 1, along with increased QT interval duration corrected according to the Van de Water formula (QTcV), but the effect was no longer observed after correction for changes in BT [QTcVcT = QTcV − 14(37.5 − BT)] according to the Van der Linde formula. No significant changes in QTcV were reported at the end of the observation period, on Day 26. Discussion The present study demonstrates that core body (rectal) temperature can easily be monitored at appropriate time-points during JET recording in regulatory toxicology studies in dogs, in order to correct QT interval duration values for treatment-related changes in BT. The successful application of the Van der Linde formula to correct QTc prolongation for changes in BT was demonstrated.

Benfluralin, an herbicide of the dinitroaniline class used in weed control, was first registered in the United States in 1970. Increased incidence of liver tumors was observed in the 2 year dietary carcinogenicity studies. A review of the toxicology database provides evidence that the mode of action (MOA) of benfluralin responsible for hepatocellular adenoma and carcinoma in rodents depends on activation of the constitutive androstane (CAR)/pregnane X (PXR) receptors, that triggers enzyme induction and altered gene expression leading to hepatocyte proliferation. After prolonged exposures at high dose levels, altered hepatic foci and liver tumors are observed. This hepatocarcinogenic MOA has been described in rodents following long-term dietary exposures to other CAR/PXR activator chemicals, such as phenobarbital, and is generally considered as non-relevant in humans due to differences between human and rodent responses. We analyzed the existing and newly acquired toxicology data to establish that the hepatocarcinogenic MOA of benfluralin in rodents includes the same key events previously described in the rodent MOA of phenobarbital. A weight of evidence approach was taken to establish temporal and dose-related concordance of the causal key events supporting the conclusion that rodent liver carcinogenicity of benfluralin is unlikely to be relevant for human cancer risk.

Propaquizafop is an herbicide with demonstrated hepatocarcinogenic activity in rodents. A rodent-specific mode of action (MOA) in the liver via activation of peroxisome proliferator-activated receptor α (PPARα) has been postulated based on existing data. Experience with PPARα-inducing pharmaceuticals indicates a lack of human relevance of this MOA. The objective of the present investigation was to evaluate the dependency of early key events leading to liver tumors on PPARα activation in wildtype (WT) compared to PPARα-knockout (KO) rats following 2 weeks exposure to 75, 500 and 1000 ppm propaquizafop in the diet. In WT rats, both WY-14643 (50 mg/kg bw/day) and propaquizafop (dose-dependently) induced marked increases in liver weights, correlating with liver enlargement and hepatocellular hypertrophy, along with increased CYP4A and acyl-CoA oxidase mRNA expression and enzyme activities versus controls, while in KO rats liver weight was mildly increased only at the high dose with minimal microscopic correlates and without any changes in liver peroxisomal or CYP4A activities. In addition, BrdU labeling resulted in higher numbers and density of positive hepatocytes versus controls in WT but not in KO rats, indicating increased mitotic activity and cell proliferation only in WT rats, thus confirming the PPARα-dependency of the biochemical and histological changes in the liver. Based on an assessment of the results of this investigation, together with existing propaquizafop data according to the MOA-Human Relevance Framework, we conclude that liver tumors observed in rodents after dietary administration of propaquizafop do not pose a relevant health risk to humans.

Two samples of diesel exhaust particles (DEPs) predominate in health effects research: an automobile-derived DEP (A-DEP) sample and the National Institute of Standards Technology standard reference material (SRM 2975) generated from a forklift engine. A-DEPs have been tested extensively for their effects on pulmonary inflammation and exacerbation of allergic asthmalike responses. In contrast, SRM 2975 has been tested thoroughly for its genotoxicity. In the present study, we combined physical and chemical analyses of both DEP samples with pulmonary toxicity testing in CD-1 mice to compare the two materials and to make associations between their physicochemical properties and their biologic effects. A-DEPs had more than 10 times the amount of extractable organic material and less than one-sixth the amount of elemental carbon compared with SRM 2975. Aspiration of 100 micro g of either DEP sample in saline produced mild acute lung injury; however, A-DEPs induced macrophage influx and activation, whereas SRM 2975 enhanced polymorphonuclear cell inflammation. A-DEPs stimulated an increase in interleukin-6 (IL-6), tumor necrosis factor alpha, macrophage inhibitory protein-2, and the TH2 cytokine IL-5, whereas SRM 2975 only induced significant levels of IL-6. Fractionated organic extracts of the same quantity of DEPs (100 micro g) did not have a discernable effect on lung responses and will require further study. The disparate results obtained highlight the need for chemical, physical, and source characterization of particle samples under investigation. Multidisciplinary toxicity testing of diesel emissions derived from a variety of generation and collection conditions is required to meaningfully assess the health hazards associated with exposures to DEPs. Key words: automobile, diesel exhaust particles, forklift, mice, pulmonary toxicity, SRM 2975.

Brown Norway (BN) rats develop a robust response to antigens in the lung, characterized by a large increase in allergen-specific immune function and pulmonary eosinophilia. The objective of this study was to investigate alternative models by determining whether other rat strains could be sensitized to house dust mite (HDM) antigen and whether the allergic disease process could be worsened with repeated allergen exposure. In general, BN rats sensitized by either subcutaneous or intratracheal routes exhibited increased pulmonary allergy compared with Sprague-Dawley (SD) and Lewis (L) rats. Multiple intratracheal allergen exposures incrementally increased HDM-specific immune function in BN rats but progressively decreased eosinophil recruitment and markers of lung injury. SD rats had more moderate responses, whereas L rats were relatively unresponsive. Because BN rats developed stronger clinical hallmarks of allergic asthma under various immunization regimes compared with SD and L rats, we conclude that the BN is the most appropriate strain for studying allergic asthma-like responses in rats. Phenotypic differences in response to HDM were associated with differences in the Th1/Th2 cytokine balance and antioxidant capacity.

Folpet, an agricultural fungicide, induces tumors in the mouse gastrointestinal tract, primarily in the duodenum. Bioassays show a threshold for tumors at ~1000 ppm dietary administration. We investigated the early histologic changes to the mouse duodenum in mice fed a diet containing 6000 ppm folpet for 28 days. Reversibility of folpet-induced changes was evaluated after treatment for 28 days and a recovery period of 17 days. Macroscopic changes in the cecum (dilatation) and duodenum (roughening) were evident by day 7, continued through day 28, then returned to normal by recovery day 17. The duodenal mucosa also appeared to be thickened. Macroscopic changes to the forestomach were also evident as a rough surface or depressions; they also decreased in incidence and severity in the recovery animals. Histologic changes of the duodenum (crypt cell hyperplasia, villous hypertrophy, numerous intraepithelial lymphocytes, and elongation of epithelial columnar cells) were evident in all treated mice by day 7 and continued and increased in severity through 28 days of administration. The incidence and severity of these findings was reduced on recovery day 17, indicating reversibility. Histologic changes (epithelial hyperplasia and hyperkeratosis) of the non-glandular squamous epithelium in the forestomach occurred later than the changes to the duodenum. The incidence and severity of these changes also lessened by recovery day 17. These early histologic changes support a non-DNA reactive mode of action for folpet carcinogenicity in mice involving the key events of mucosal cytotoxicity with consequent regenerative proliferation. Exposures that are not sufficient to produce cytotoxicity would also not lead to tumor formation.

Folpet and captan are fungicides whose genotoxicity depends on their chemical reaction with thiols. Multiple mutagenicity tests have been conducted on these compounds due to their positive activity in vitro and their association with gastrointestinal tumors in mice. A review of the collective data shows that these compounds have in vitro mutagenic activity but are not genotoxic in vivo. This dichotomy is primarily due to the rapid degradation of folpet and captan in the presence of thiol-rich matrices typically found in vivo. Genotoxicity has not been found in the duodenum, the mouse tumor target tissue. It is concluded that folpet like captan presents an unlikely risk of genotoxic effects in humans.

A framework has been evolving for evaluation of mode of action (MOA) of rodent toxicity and carcinogenicity findings and their relevance to humans. Folpet produces duodenal glandular tumors in mice, but is not carcinogenic in rats. A wealth of information is available regarding folpet's mode of action, providing an excellent example of how this tumor can be evaluated using this framework. Folpet reacts with thiol groups, and is rapidly hydrolyzed at pH 7. Both reactions produce thiophosgene that reacts with thiols and other functional groups. Folpet is not genotoxic in vivo. At sufficiently high, prolonged dietary doses, folpet irritates the mouse duodenum, resulting in cytotoxicity with consequent regenerative proliferation and ultimately tumor development. Forestomach lesions secondary to cytotoxicity are also induced. Dogs have stomachs similar to humans and show no evidence of gastrointestinal toxicity or tumor formation at exposure levels at least as high as rodents. The data support a MOA in mice involving cytotoxicity and regenerative proliferation. Based on MOA analysis and assessment of human relevance, folpet, like captan, another trichloromethylthio-related fungicide with similar toxic and carcinogenic effects, is not likely to be a human carcinogen at dose levels that do not cause cytotoxicity and regenerative proliferation.

The mechanisms for increased cardiopulmonary disease in individuals exposed to particulate air pollution are associated with fine and ultrafine particles that have a high oxidative potential. Particulate matter (PM) from Research Triangle Park (NC) was collected and separated into 3 different size fractions: coarse (CO;3.5 microm), fine (FI; 1.7-3.5 microm), and fine/ultrafine (FU;1.7 microm) using impaction and electrostatic precipitation. Particle chemistry indicated the presence of sulfates, zinc, iron, and copper in all fractions. CD1 mice were intratracheally instilled with 10, 50, or 100 microg of each fraction. After 18 h, the lungs were lavaged and assayed for signs of inflammation. All particles produced increases in neutrophil number, and this was highest in the high-dose FU group. Biochemical analysis revealed ni change in lactate dehydrogenase (LDH) activity, and increased albumin and tumor necrosis factor (TNF)-alpha levels were only seen with the high-dose FI particles. Interleukin 6 (IL-6) levels were increased over control levels after treatment with 100 microg of all 3 particle sizes. To determine whether oxidative stress may contribute to these effects, antioxidant levels in the ling were boosted by an intraperitoneal (ip) injection with dimethylthiourea (DMTU). This treatment resulted in a twofold increase in the total antioxidant capacity of the lung and decreased the PM-induced cytokine and neutrophil influx up to 50%. The data indicate that on the equal mass basis, ambient particles of these three size ranges produce pulmonary inflammation, and that increasing the antioxidant capacity of the lung reduces particle-induced cytokine and cellular responses.