Embryo-fetal exposure and developmental outcome of lenalidomide following oral administration to pregnant cynomolgus monkeys.

Lenalidomide is an immunomodulatory drug and is very effective in the management of a number of malignancies, including multiple myeloma. Like thalidomide, lenalidomide interacts with the cereblon E3 ligase complex, which results in targeted destruction of proteins. This study was conducted to study the teratogenic potential of lenalidomide when administered to pregnant cynomolgus monkeys. Lenalidomide was administered orally on gestation days 20-50 at dosages of 0 (vehicle control), 0.5, 1, 2 and 4 mg/kg/day. Thalidomide was used as a positive control and was administered orally at 15 mg/kg/day on gestation days 26-28. Each group consisted of 5 pregnant monkeys. Pregnancy was terminated on gestation day 100 ± 1 by cesarean section and fetuses examined for external, internal and skeletal changes. Intrauterine loss was 40% in the thalidomide group and 20 % in each of the lenalidomide 2 and 4 mg/kg/day groups. Treatment with lenalidomide and thalidomide resulted in no effects on placental weights, fetal body weights and body measurements. External fetal examination revealed malformations in fetuses of all lenalidomide-treated groups, including malformations of upper and lower extremities. These external malformations had correlated skeletal findings and were similar to those seen in the thalidomide-treated group, where two of three fetuses showed the classic thalidomide syndrome of malformed upper and lower extremities. A no-observed-adverse-effect level was not identified in this study, and the mean maternal exposures at the lowest dosage, where fetal malformations were observed, were 5-folder lower than the exposures observed in the MM patients treated with 25 mg of lenalidomide.

Nonclinical genotoxicity and carcinogenicity profile of apremilast, an oral selective inhibitor of PDE4.

Apremilast is an oral, selective small molecule inhibitor of phosphodiesterase-4 (PDE4) that has been approved for the treatment of active psoriatic arthritis, moderate to severe plaque psoriasis, and for patients with oral ulcers associated with Behçet's disease. Apremilast modulates the inflammatory cascade in cells by inhibiting PDE4, thus preventing the degradation of cyclic adenosine monophosphate, resulting in the upregulation of interleukin (IL)-10 and the downregulation of proinflammatory cytokines, including IL-23, interferon gamma (IFNγ), and tumor necrosis factor alpha (TNFα). Here, we evaluated the genotoxic and carcinogenic potential of apremilast using Good Laboratory Practice (GLP)-compliant in vitro and in vivo studies. Apremilast was not genotoxic in the genetic toxicology battery, as evaluated for mutagenicity in the Ames test up to concentrations of 5000 µg/plate, clastogenicity in cultured human peripheral blood lymphocytes up to concentrations of 700 ug/mL was in excess of the solubility limit in culture medium and not able to assess; and negative for the induction of micronuclei in the bone marrow micronucleus test in mice up to doses of 2000 mg/kg/day. Furthermore, apremilast did not increase the incidence of tumors in lifetime rat or mouse carcinogenicity studies up to the maximum tolerated dose. In summary, in non-clinical studies, apremilast is not genotoxic and is not carcinogenic.

[Reproductive and Developmental Toxicity of Drugs-Background of the Birth of Thalidomide].

INTRODUCTION: Thalidomide was a terrible drug‒induced suffering that should not have occurred, but it was revived in the market after more than 40 years. When we understand the historical background that caused the tragedy, safety measures for drugs have been established based on the lessons learned. We learn the background of the birth of this world from"The God and the Devil's Drug Thalidomide"and make use of it to the present.

R-MACLO-IVAM regimen followed by maintenance therapy induces durable remissions in untreated mantle cell lymphoma - Long term follow up results.

We present long-term combined results of two clinical trials implementing R-MACLO-IVAM induction followed by thalidomide or rituximab maintenance in 44 patients with untreated mantle cell lymphoma (MCL). The first 22 patients (UM-MCL1 ClinicalTrials.gov identifier NCT00450801) received maintenance with thalidomide (200 mg daily until relapse/intolerable toxicity) and a subsequent cohort of 22 patients (UM-MCL2 ClinicalTrials.gov identifier NCT00878254) received rituximab (375 mg/m2 IV weekly × 4, repeated every 6 months for 3 years). Considering all 44 patients, 41 (93.2%) achieved complete response (CR), two (4.5%) partial response (PR), and one (2.3%) was not evaluated for response. With a median follow up of 7.2 years (range < 1 month to 16 years), the 5-year progression-free survival (PFS) was 55.6% (95% CI: 38.9%-69.4%) and median PFS 7.9 years (95% CI: 3.7-11 years). The 5-year OS was 83.3% (95% CI: 68.1%-91.7%) and median OS was not reached. Patients with blastic variant (n = 6) had a 5-year PFS and OS of 20.8% and 60%, respectively. Myelosuppression was the most common adverse event during immunochemotherapy. Long-term treatment-related mortality was 6.8%. Note, R-MACLO-IVAM followed by maintenance therapy is an effective regimen to induce long-term remission in MCL without need for consolidation with ASCT.

Thalidomide and its metabolite 5-hydroxythalidomide induce teratogenicity via the cereblon neosubstrate PLZF.

Thalidomide causes teratogenic effects by inducing protein degradation via cereblon (CRBN)-containing ubiquitin ligase and modification of its substrate specificity. Human P450 cytochromes convert thalidomide into two monohydroxylated metabolites that are considered to contribute to thalidomide effects, through mechanisms that remain unclear. Here, we report that promyelocytic leukaemia zinc finger (PLZF)/ZBTB16 is a CRBN target protein whose degradation is involved in thalidomide- and 5-hydroxythalidomide-induced teratogenicity. Using a human transcription factor protein array produced in a wheat cell-free protein synthesis system, PLZF was identified as a thalidomide-dependent CRBN substrate. PLZF is degraded by the ubiquitin ligase CRL4CRBN in complex with thalidomide, its derivatives or 5-hydroxythalidomide in a manner dependent on the conserved first and third zinc finger domains of PLZF. Surprisingly, thalidomide and 5-hydroxythalidomide confer distinctly different substrate specificities to mouse and chicken CRBN, and both compounds cause teratogenic phenotypes in chicken embryos. Consistently, knockdown of Plzf induces short bone formation in chicken limbs. Most importantly, degradation of PLZF protein, but not of the known thalidomide-dependent CRBN substrate SALL4, was induced by thalidomide or 5-hydroxythalidomide treatment in chicken embryos. Furthermore, PLZF overexpression partially rescued the thalidomide-induced phenotypes. Our findings implicate PLZF as an important thalidomide-induced CRBN neosubstrate involved in thalidomide teratogenicity.

PYR-41 and Thalidomide Impair Dendritic Cell Cross-Presentation by Inhibiting Myddosome Formation and Attenuating the Endosomal Recruitments of p97 and Sec61 via NF-κB Inactivation.

PYR-41 and thalidomide have therapeutic effects on inflammation-associated diseases with side effects such as tumorigenesis. Cross-presentation allows dendritic cells (DC) to present endogenous antigen and induce protective immunity against microbe infection and tumors. But, up to now, the effects of PYR-41 and thalidomide on cross-presentation are still uncertain. In this study, we investigated the effect and mechanism of PYR-41 and thalidomide on DC cross-presentation by observing Myddosome formation, endosomal recruitment of p97 and Sec61, NF-κB activation, and cross-priming ability. We demonstrated that the inhibition of endosomal recruitment of p97 and Sec61, together with attenuated NF-κB activation and Myddosome formation, contributes to PYR-41- and thalidomide-impaired cross-presentation and thereby reverses cross-activation of T cells. These observations suggest that NF-κB signaling and p97 and Sec61 molecules are candidates for dealing with the side effects of PYR-41 and thalidomide.

Thalidomide remodels developing heart in chick embryo: discovery of a thalidomide mediated hematoma in heart muscle.

Despite of medical disaster caused by thalidomide in 1960s, the drug came to clinical use again for the treatment of erythema nodosum leprosum (ENL) and multiple myeloma. Recently, a new generation of children affected by thalidomide intake by their mothers during pregnancy has been identified in Brazil. In the past few years, there is the great enhancement in our understanding of the molecular mechanisms and targets of thalidomide with the help of modern OMICS technologies. However, understanding of cardiac-specific anomalies in fetus due to thalidomide intake by the respective mother has not been explored fully. At organ level, thalidomide causes congenital heart diseases, limb deformities in addition to ocular, and neural and ear abnormalities. The period of morning sickness and cardiogenesis is synchronized in pregnant women. Therefore, thalidomide intake during the first trimester could affect cardiogenesis severely. Thalidomide intake in pregnant women either causes miscarriage or heart abnormalities such as patent ductus arteriosus, ventricular septal defect (VSD), atrial septal defect (ASD), and pulmonary stenosis in survivors. In the present study, we identified a novel morphological defect (lump) in the heart of thalidomide-treated chick embryos. We characterized the lump at morphological, histo-pathological, oxidative stress, electro-physiological, and gene expression level. To our knowledge, here, we report the very first electrophysiological characterization of embryonic heart affected by thalidomide treatment.

Association of pharmacokinetic profiles of lenalidomide in human plasma simulated using pharmacokinetic data in humanized-liver mice with liver toxicity detected by human serum albumin RNA.

Lenalidomide has been shown to be potentially teratogenic in thalidomide-sensitive animal species. Screening for thalidomide analogs devoid of teratogenicity/toxicity-attributable to drug metabolism and disposition, but having immunomodulatory properties-is a strategic pathway towards development of new anticancer drugs. Plasma concentrations of lenalidomide were investigated in immunodeficient control and humanized-liver mice following oral administration of lenalidomide (50 mg/kg). Plasma concentrations of lenalidomide (1-2 hr after administration) were slightly but significantly higher in humanized-liver mice than in control mice (p < 0.05). Human albumin mRNA, a liver-specific toxicity marker, was found in the blood of humanized-liver mice 24 hr after lenalidomide administration. Simulations of human plasma concentrations of lenalidomide were achieved with simplified physiologically-based pharmacokinetic models in control and humanized-liver mice or by the direct fitting analysis of reported human data, in accordance with reported lenalidomide concentrations after low dose administration in humans. The results indicate that pharmacokinetic profiles of lenalidomide, a compound resulting from introducing one aromatic amino group into thalidomide and removing one keto group, resulted in less species variation in in vivo pharmacokinetics in control and humanized-liver mice and that immunodeficient humanized-liver mice can serve as experimental model animals for human liver injury in drug development at high doses, with human albumin RNA analysis in plasma.

CPS49-induced neurotoxicity does not cause limb patterning anomalies in developing chicken embryos.

Thalidomide notoriously caused severe birth defects, particularly to the limbs, in those exposed in utero following maternal use of the drug to treat morning sickness. How the drug caused these birth defects remains unclear. Many theories have been proposed including actions on the forming blood vessels. However, thalidomide survivors also have altered nerve patterns and the drug is known for its neurotoxic actions in adults following prolonged use. We have previously shown that CPS49, an anti-angiogenic analog of thalidomide, causes a range of limb malformations in a time-sensitive manner in chicken embryos. Here we investigated whether CPS49 also is neurotoxic and whether effects on nerve development impact upon limb development. We found that CPS49 is neurotoxic, just like thalidomide, and can cause some neuronal loss late developing chicken limbs, but only when the limb is already innervated. However, CPS49 exposure does not cause defects in limb size when added to late developing chicken limbs. In contrast, in early limb buds which are not innervated, CPS49 exposure affects limb area significantly. To investigate in more detail the role of neurotoxicity and its impact on chicken limb development we inhibited nerve innervation at a range of developmental timepoints through using ß-bungarotoxin. We found that neuronal inhibition or ablation before, during or after limb outgrowth and innervation does not result in obvious limb cartilage patterning or number changes. We conclude that while CPS49 is neurotoxic, given the late innervation of the developing limb, and that neuronal inhibition/ablation throughout limb development does not cause similar limb patterning anomalies to those seen in thalidomide survivors, nerve defects are not the primary underlying cause of the severe limb patterning defects induced by CPS49/thalidomide.

Middle-aged individuals with thalidomide embryopathy have undergone few surgical limb procedures and demonstrate a high degree of physical independence.

BACKGROUND: Thalidomide is known to have induced thalidomide embryopathy (TE) in more than 10,000 live-born children worldwide between 1957-1962. AIM: The aim of this study was to investigate the need for orthopaedic surgery and limb orthosis in relation to function and physical independence in middle-aged individuals with TE. METHODS: 13 women/18 men with a mean age of 45.8 (SD 1.1) years were included. Information about limb surgery, the use of orthotic devices, jobs, accommodation, disability adjustments and personal assistants was collected. Physical function was measured by a modified general function score. The time needed for activities of daily living (ADL) was collected. Individuals with proximal focal femoral deficiency, PFFD, and participants in need of home or work adaptations were compared with the rest of the group. RESULT: 31 surgical procedures had been performed in the extremities. Three individuals were in need of personal assistance and seven had disability-adjusted homes. 28 individuals were working and 24 reported participation in exercises. Those with PFFD had significantly lower function score and needed a significantly longer time for ADL in the morning (p = 0.001 and p = 0.032). The group in need of home or work adjustments had significantly lower function score and needed longer time for morning ADL (p = 0.012 and p = 0.009). DISCUSSION: Few orthopaedic procedures had been performed. The TE individuals except the ones with PFFD and those in the need of disability adjustments, were mostly active workers, reported good physical function and participated in exercises, despite limb malformations.

The Dihydroxy Metabolite of the Teratogen Thalidomide Causes Oxidative DNA Damage.

Thalidomide [α-(N-phthalimido)glutarimide] (1) is a sedative and antiemetic drug originally introduced into the clinic in the 1950s for the treatment of morning sickness. Although marketed as entirely safe, more than 10 000 babies were born with severe birth defects. Thalidomide was banned and subsequently approved for the treatment of multiple myeloma and complications associated with leprosy. Although known for more than 5 decades, the mechanism of teratogenicity remains to be conclusively understood. Various theories have been proposed in the literature including DNA damage and ROS and inhibition of angiogenesis and cereblon. All of the theories have their merits and limitations. Although the recently proposed cereblon theory has gained wide acceptance, it fails to explain the metabolism and low-dose requirement reported by a number of groups. Recently, we have provided convincing structural evidence in support of the presence of arene oxide and the quinone-reactive intermediates. However, the ability of these reactive intermediates to impart toxicity/teratogenicity needs investigation. Herein we report that the oxidative metabolite of thalidomide, dihydroxythalidomide, is responsible for generating ROS and causing DNA damage. We show, using cell lines, the formation of comet (DNA damage) and ROS. Using DNA-cleavage assays, we also show that catalase, radical scavengers, and desferal are capable of inhibiting DNA damage. A mechanism of teratogenicity is proposed that not only explains the DNA-damaging property but also the metabolism, low concentration, and species-specificity requirements of thalidomide.

Angiogenesis-related genes and thalidomide teratogenesis in humans: an approach on genetic variation and review of past in vitro studies.

Thalidomide embryopathy (TE) has affected more than 10,000 babies worldwide. The hypothesis of antiangiogenesis as the teratogenic mechanism of thalidomide has been investigated in several experimental models; but, in humans, it has only been accessed by in vitro studies. Here, we hypothesized the effect of thalidomide upon angiogenesis-related molecules or proteins, previously identified in human embryonic cells, through the in silico STRING-tool. We also investigated ten polymorphisms in angiogenesis-related genes in 38 Brazilian TE individuals and 136 non-affected Brazilians. NOS2, PTGS2, and VEGFA polymorphisms were chosen for genotyping. The STRING-tool suggested nitric oxide and ß-catenin as the central angiogenesis-related molecules affected by thalidomide's antiangiogenic property. We did not identify a significant difference of allelic, genotypic or haplotypic frequencies between the groups. We could not predict a risk allele or a protective one for TE in NOS2, PTGS2, or VEGFA, although other genes should be analyzed in larger samples. The role of nitric oxide and ß-catenin must be further evaluated, regarding thalidomide teratogenesis complex etiology.

Old Drug Scaffold, New Activity: Thalidomide-Correlated Compounds Exert Different Effects on Breast Cancer Cell Growth and Progression.

Thalidomide was first used for relief of morning sickness in pregnant women and then withdrawn from the market because of its dramatic effects on normal fetal development. Over the last decades, it has been used successfully for the treatment of several pathologies, including cancer. Many analogues with improved activity have been synthesized and tested. Herein we report some effects on the growth and progression of MCF-7 and MDA-MB-231 breast cancer cells by a small series of thalidomide-correlated compounds, which are very effective at inducing cancer cell death by triggering TNFα-mediated apoptosis. The most active compounds are able to drastically reduce the migration of breast cancer cells by regulation of the two major proteins involved in epithelial-mesenchymal transition (EMT): vimentin and E-cadherin. Moreover, these compounds diminish the intracellular biosynthesis of vascular endothelial growth factor (VEGF), which is primarily involved in the promotion of angiogenesis, sustaining tumor progression. The multiple features of these compounds that act on various key points of the tumorigenesis process make them good candidates for preclinical studies.

In vivo screening and discovery of novel candidate thalidomide analogs in the zebrafish embryo and chicken embryo model systems.

Thalidomide, a drug known for its teratogenic side-effects, is used successfully to treat a variety of clinical conditions including leprosy and multiple myeloma. Intense efforts are underway to synthesize and identify safer, clinically relevant analogs. Here, we conduct a preliminary in vivo screen of a library of new thalidomide analogs to determine which agents demonstrate activity, and describe a cohort of compounds with anti-angiogenic properties, anti-inflammatory properties and some compounds which exhibited both. The combination of the in vivo zebrafish and chicken embryo model systems allows for the accelerated discovery of new, potential therapies for cancerous and inflammatory conditions.

Clarithromycin Synergistically Enhances Thalidomide Cytotoxicity in Myeloma Cells.

Clarithromycin (CAM) is a macrolide antibiotic that is widely used in the treatment of respiratory tract infections, sexually transmitted diseases and infections caused by the Helicobacter pylori and Mycobacterium avium complex. Recent studies showed that CAM was highly effective against multiple myeloma (MM) when used in combination with immunomodulatory drugs and dexamethasone. However, the related mechanism is still unknown. As 3 immunomodulatory agents are all effective in the respective regimen, we postulated that CAM might enhance the effect of immunomodulatory drugs. We evaluated the interaction effects of CAM and thalidomide on myeloma cells. Taking into consideration that thalidomide did not affect the proliferation of myeloma cells in vitro, we cocultured myeloma cells with peripheral blood monocytes and evaluated the effects of CAM and thalidomide on the cocultured cell model. Data showed that thalidomide and CAM synergistically inhibited the proliferation of the cells. On this same model, we also found that thalidomide and CAM synergistically decreased the secretion of tumor necrosis factor-α and interleukin-6. This might be caused by the effect of the 2 drugs on inhibiting the activation of ERK1/2 and AKT. These data suggest that the efficacy of CAM against MM was partly due to its synergistic action with the immunomodulatory agents.

Thalidomide (5HPP-33) suppresses microtubule dynamics and depolymerizes the microtubule network by binding at the vinblastine binding site on tubulin.

Thalidomides were initially thought to be broad-range drugs specifically for curing insomnia and relieving morning sickness in pregnant women. However, its use was discontinued because of a major drawback of causing teratogenicity. In this study, we found that a thalidomide derivative, 5-hydroxy-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (5HPP-33), inhibited the proliferation of MCF-7 with a half-maximal inhibitory concentration of 4.5 ± 0.4 µM. 5HPP-33 depolymerized microtubules and inhibited the reassembly of cold-depolymerized microtubules in MCF-7 cells. Using time-lapse imaging, the effect of 5HPP-33 on the dynamics of individual microtubules in live MCF-7 cells was analyzed. 5HPP-33 (5 µM) decreased the rates of growth and shortening excursions by 34 and 33%, respectively, and increased the time microtubules spent in the pause state by 92% as compared to that of the vehicle-treated MCF-7 cells. 5HPP-33 (5 µM) reduced the dynamicity of microtubules by 62% compared to the control. 5HPP-33 treatment reduced the distance between the two poles of a bipolar spindle, induced multipolarity in some of the treated cells, and blocked cells at mitosis. In vitro, 5HPP-33 bound to tubulin with a weak affinity. Vinblastine inhibited the binding of 5HPP-33 to tubulin, and 5HPP-33 inhibited the binding of BODIPY FL-vinblastine to tubulin. Further, a molecular docking analysis suggested that 5HPP-33 shares its binding site on tubulin with vinblastine. The results provided significant insight into the antimitotic mechanism of action of 5HPP-33 and also suggest a possible mechanism for the teratogenicity of thalidomides.

Thalidomide combined with irradiation alters the activity of two proteases.

The aim of the present study was to investigate the effects of thalidomide, a drug known for its anti­angiogenic and antitumor properties, at its cytotoxic dose previously determined as 40 µg/ml (according to four cytotoxic test results). The effect of the drug alone and in combination with radiotherapy using Cobalt 60 (60Co) at 45 Gy on the enzymatic activity of substance­P degrading A disintegrin and metalloproteinase (ADAM)10 and neprilysin (NEP) was investigated in the mouse breast cancer cell lines 4T1 and 4T1 heart metastases post­capsaicin (4THMpc). Thalidomide (40 µg/ml) exerted differing effects on the activities of ADAM10 and NEP enzymes. In 4T1 cells, 40 µg/ml thalidomide alone did not alter ADAM10 enzyme activity. 60Co irradiation at 45 Gy alone caused a 42% inhibition in ADAM10 activity, however, the inhibition increased to 89% when combined therapy was used. By contrast, in the 4THMpc cell line, 40 µg/ml thalidomide alone induced a 66.6% increase in ADAM10 enzyme activity. Radiotherapy alone and thalidomide with 60Co combined therapy caused a 33.3 and 40% inhibition of ADAM10 activity, respectively. In 4T1 cells, thalidomide alone caused a 40.9% increase in NEP activity. Radiation therapy alone or in combination with the drug caused a 40.7% increase in NEP activity. In more aggressive 4THMpc cells, thalidomide alone caused a 26.6% increase in NEP activity. Radiotherapy alone and combined therapy caused a 33.3 and 37% increase in enzyme activity, respectively. To the best of our knowledge, the present study is the first to demonstrate that thalidomide alone or in combination with radiotherapy exhibits significant cytotoxic effects on 4T1 and 4THMpc mouse breast cancer cell lines indicating that this drug affects the enzymatic activity of ADAM10 and NEP in vitro.

Modulation of natural killer cell effector functions through lenalidomide/dasatinib and their combined effects against multiple myeloma cells.

The multikinase inhibitor dasatinib blocks the constitutive activation of oncogenic Src kinases in multiple myeloma (MM) cells and potentially enhances natural killer (NK) cell activity. Therefore, we tested combination effects of dasatinib and lenalidomide regarding MM cell viability and NK cell effector functions. The drug combination mostly had little influence on the viability of MM cell lines, and produced mixed results on primary MM cells. Prolonged lenalidomide treatment enhanced NK cell effector functions, and dasatinib addition at late stages of NK cell expansion increased levels of CD107a/b and interferon-γ (IFNγ), but not of tumor necrosis factor-α (TNFα). Additive effects were observed for the enhancement of cytokine production and degranulation, but only lenalidomide increased NK cell cytotoxicity against MM cells. This effect correlated with increased TNF-related apoptosis-inducing ligand (TRAIL) expression and was attenuated by dasatinib, or suppressors of TRAIL or TNFα. Our data thus indicate a functional role for the TRAIL/TRAIL-R system in lenalidomide-mediated NK-cell activity against MM cells, but also show that dasatinib is unsuitable to support or boost this effect.

Identification of phototransformation products of thalidomide and mixture toxicity assessment: an experimental and quantitative structural activity relationships (QSAR) approach.

The fate of thalidomide (TD) was investigated after irradiation with a medium-pressure Hg-lamp. The primary elimination of TD was monitored and structures of phototransformation products (PTPs) were assessed by LC-UV-FL-MS/MS. Environmentally relevant properties of TD and its PTPs as well as hydrolysis products (HTPs) were predicted using in silico QSAR models. Mutagenicity of TD and its PTPs was investigated in the Ames microplate format (MPF) aqua assay (Xenometrix, AG). Furthermore, a modified luminescent bacteria test (kinetic luminescent bacteria test (kinetic LBT)), using the luminescent bacteria species Vibrio fischeri, was applied for the initial screening of environmental toxicity. Additionally, toxicity of phthalimide, one of the identified PTPs, was investigated separately in the kinetic LBT. The UV irradiation eliminated TD itself without complete mineralization and led to the formation of several PTPs. TD and its PTPs did not exhibit mutagenic response in the Salmonella typhimurium strains TA 98, and TA 100 with and without metabolic activation. In contrast, QSAR analysis of PTPs and HTPs provided evidence for mutagenicity, genotoxicity and carcinogenicity using additional endpoints in silico software. QSAR analysis of different ecotoxicological endpoints, such as acute toxicity towards V. fischeri, provided positive alerts for several identified PTPs and HTPs. This was partially confirmed by the results of the kinetic LBT, in which a steady increase of acute and chronic toxicity during the UV-treatment procedure was observed for the photolytic mixtures at the highest tested concentration. Moreover, the number of PTPs within the reaction mixture that might be responsible for the toxification of TD during UV-treatment was successfully narrowed down by correlating the formation kinetics of PTPs with QSAR predictions and experimental toxicity data. Beyond that, further analysis of the commercially available PTP phthalimide indicated that transformation of TD into phthalimide was not the cause for the toxification of TD during UV-treatment. These results provide a path for toxicological assessment of complex chemical mixtures and in detail show the toxic potential of TD and its PTPs as well as its HTPs. This deserves further attention as UV irradiation might not always be a green technology, because it might pose a toxicological risk for the environment in general and specifically for water compartments.

[Chemotherapy-free treatment of chronic lymphocytic leukemia?]. / Chemotherapie-freie Behandlung der chronischen lymphatischen Leukämie?

Treatment of CLL patients with conventional cytotoxic agents is often combined with significant toxicity that prevents broad application especially in elderly patients. In addition, relapse frequently occurs after application of conventional chemotherapy in CLL. Recently several new chemo-free treatment options have been introduced within clinical trials. Among them are monoclonal antibodies, most of them targeting the CD20 molecule: besides the licensed drugs rituximab and ofatumumab obinutuzumab, although in combination with chemotherapy, has recently shown high clinical efficacy in front-line treatment of elderly patients with CLL. Lenalidomide as monotherapy has demonstrated clinical efficacy in patients with relapsed disease and first data within clinical trials have been generated in the front-line setting. A promising class of novel agents has been designed to block aberrant signaling from the B-cell receptor. Ibrutinib acts by inhibiting the Bruton's tyrosine kinase (BTK) while idelalisib represents a first-in-class specific inhibitor of the phosphoinositol-3 kinase (PI3K) delta isoform. Another class of drugs with potential impact for chemo-free treatment strategies in CLL are the BH3-mimetic inhibitors of the Bcl-2 family of pro-survival proteins. Other interesting candidate drugs that are currently explored for CLL patients include small modular immunopharmaceutical (SMIP) proteins (e. g. TRU-016), CDK inhibitors (e. g. dinaciclib), HDAC inhibitors and others. Given all these novel agents and targets, chemo-free or at least chemo-reduced concepts may become reality in the near future for our patients suffering from CLL.