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.

p63 is a cereblon substrate involved in thalidomide teratogenicity.

Cereblon (CRBN) is a primary target of thalidomide and mediates its multiple pharmacological activities, including teratogenic and antimyeloma activities. CRBN functions as a substrate receptor of the E3 ubiquitin ligase CRL4, whose substrate specificity is modulated by thalidomide and its analogs. Although a number of CRL4CRBN substrates have recently been identified, the substrate involved in thalidomide teratogenicity is unclear. Here we show that p63 isoforms are thalidomide-dependent CRL4CRBN neosubstrates that are responsible, at least in part, for its teratogenic effects. The p53 family member p63 is associated with multiple developmental processes. ∆Np63α is essential for limb development, while TAp63α is important for cochlea development and hearing. Using a zebrafish model, we demonstrate that thalidomide exerts its teratogenic effects on pectoral fins and otic vesicles by inducing the degradation of ∆Np63α and TAp63α, respectively. These results may contribute to the invention of new thalidomide analogs lacking teratogenic activity.

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.

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.

[Thalidomide and unilateral limb defects: the Italian chapter of a neverending story]. / Talidomide e difetti monolaterali degli arti: il capitolo italiano di una storia infinita.

Fifty years after the event, Italy introduced legislation to compensate malformations in children - now in their sixties - born to mothers who had been prescribed the antiemetic drug thalidomide for morning sickness. However, compensation has been denied to people 'only' damaged in one half of their body as opposed to those with bilateral malformations. The present study reviews the papers describing case series of children born with 'thalidomide embryopathy' in the UK, Germany, and other countries around 1960. Most clinical series were not organized on the basis of inclusion/exclusion criteria, thus allowing for probable selection and information biases on maternal use of thalidomide. In any case, they included a sizable number of children with a unilateral limb defect born from mothers certainly exposed to thalidomide during the relevant pregnancy. In many of these children, limb defects were associated with visceral malformations, as frequently observed following exposure to thalidomide in utero. Similarly, later literature reviews were not bias-free in their choice of articles, as is the case of a recently proposed 'diagnostic algorithm' for thalidomide-caused specific malformations and of the advice by the Italian National Institute of Health ruling out the possibility of thalidomide producing unilateral limb defects. Overall, the scientific evidence suggests that thalidomide can cause unilateral limb defects.

[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.

A novel human pluripotent stem cell-based assay to predict developmental toxicity.

There is a great need for novel in vitro methods to predict human developmental toxicity to comply with the 3R principles and to improve human safety. Human-induced pluripotent stem cells (hiPSC) are ideal for the development of such methods, because they are easy to retrieve by conversion of adult somatic cells and can differentiate into most cell types of the body. Advanced three-dimensional (3D) cultures of these cells, so-called embryoid bodies (EBs), moreover mimic the early developing embryo. We took advantage of this to develop a novel human toxicity assay to predict chemically induced developmental toxicity, which we termed the PluriBeat assay. We employed three different hiPSC lines from male and female donors and a robust microtiter plate-based method to produce EBs. We differentiated the cells into cardiomyocytes and introduced a scoring system for a quantitative readout of the assay-cardiomyocyte contractions in the EBs observed on day 7. Finally, we tested the three compounds thalidomide (2.3-36 µM), valproic acid (25-300 µM), and epoxiconazole (1.3-20 µM) on beating and size of the EBs. We were able to detect the human-specific teratogenicity of thalidomide and found the rodent toxicant epoxiconazole as more potent than thalidomide in our assay. We conclude that the PluriBeat assay is a novel method for predicting chemicals' adverse effects on embryonic development.

Early Transcriptomic Changes upon Thalidomide Exposure Influence the Later Neuronal Development in Human Embryonic Stem Cell-Derived Spheres.

Stress in early life has been linked with the development of late-life neurological disorders. Early developmental age is potentially sensitive to several environmental chemicals such as alcohol, drugs, food contaminants, or air pollutants. The recent advances using three-dimensional neural sphere cultures derived from pluripotent stem cells have provided insights into the etiology of neurological diseases and new therapeutic strategies for assessing chemical safety. In this study, we investigated the neurodevelopmental effects of exposure to thalidomide (TMD); 2,2',4,4'-tetrabromodiphenyl ether; bisphenol A; and 4-hydroxy-2,2',3,4',5,5',6-heptachlorobiphenyl using a human embryonic stem cell (hESC)-derived sphere model. We exposed each chemical to the spheres and conducted a combinational analysis of global gene expression profiling using microarray at the early stage and morphological examination of neural differentiation at the later stage to understand the molecular events underlying the development of hESC-derived spheres. Among the four chemicals, TMD exposure especially influenced the differentiation of spheres into neuronal cells. Transcriptomic analysis and functional annotation identified specific genes that are TMD-induced and associated with ERK and synaptic signaling pathways. Computational network analysis predicted that TMD induced the expression of DNA-binding protein inhibitor ID2, which plays an important role in neuronal development. These findings provide direct evidence that early transcriptomic changes during differentiation of hESCs upon exposure to TMD influence neuronal development in the later stages.

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.

Transcriptomic Analysis of Thalidomide Challenged Chick Embryo Suggests Possible Link between Impaired Vasculogenesis and Defective Organogenesis.

Since the conception of thalidomide as a teratogen, approximately 30 hypotheses have been put forward to explain the developmental toxicity of the molecule. However, no systems biology approach has been taken to understand the phenomena yet. The proposed work was aimed to explore the mechanism of thalidomide toxicity in developing chick embryo in the context of transcriptomics by using genome wide RNA sequencing data. In this study, we challenged the developing embryo at the stage of blood island formations (HH8), which is the most vulnerable stage for thalidomide-induced deformities. We observed that thalidomide affected the early vasculogenesis through interfering with the blood island formation extending the effect to organogenesis. The transcriptome analyses of the embryos collected on sixth day of incubation showed that liver, eye, and blood tissue associated genes were down regulated due to thalidomide treatment. The conserved gene coexpression module also indicated that the genes involved in lens development were heavily affected. Further, the Gene Ontology analysis explored that the pathways of eye development, retinol metabolism, and cartilage development were dampened, consistent with the observed deformities of various organs. The study concludes that thalidomide exerts its toxic teratogenic effects through interfering with early extra-embryonic vasculogenesis and ultimately gives an erroneous transcriptomic pattern to organogenesis.

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.

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.

[Not Available]. / Un médicament "monstrueux": débats publics et couverture médiatique de la tragédie de la thalidomide au Canada, 1961-1963.

This article focuses on the thalidomide tragedy that occurred in Canada in 1962. Through the study of various primary sources, including letters sent by citizens to the federal Minister of Health and newspaper coverage of the tragedy, we provide an analysis of the public debates provoked by babies born with phocomelia in order to better assess the conception Quebec and Canadian societies had of disabled persons at the beginning of the 1960s. Inspired by the French philosopher Marie-Claire Cagnolo's classification scheme of the "logics" that characterized the treatment of disabled persons through history, the study concludes that a "separatist logic of elimination" clearly arose, while a "paternalistic logic of reparation" also began to appear. A "societal logic of integration", however, did not emerge, as concern was limited to the fate of thalidomide babies, rather than that of all disabled children.

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 induced early gene expression perturbations indicative of human embryopathy in mouse embryonic stem cells.

Developmental toxicity testing has traditionally relied on animal models which are costly, time consuming, and require the sacrifice of large numbers of animals. In addition, there are significant disparities between human beings and animals in their responses to chemicals. Thalidomide is a species-specific developmental toxicant that causes severe limb malformations in humans but not in mice. Here, we used microarrays to study transcriptomic changes induced by thalidomide in an in vitro model based on differentiation of mouse embryonic stem cells (mESCs). C57BL/6 mESCs were allowed to differentiate spontaneously and RNA was collected at 24, 48, and 72h after exposure to 0.25mM thalidomide. Global gene expression analysis using microarrays revealed hundreds of differentially expressed genes upon thalidomide exposure that were enriched in gene ontology (GO) terms and canonical pathways associated with embryonic development and differentiation. In addition, many genes were found to be involved in small GTPases-mediated signal transduction, heart development, and inflammatory responses, which coincide with clinical evidences and may represent critical embryotoxicities of thalidomide. These results demonstrate that transcriptomics in combination with mouse embryonic stem cell differentiation is a promising alternative model for developmental toxicity assessment.

A phase 1/2 study of lenalidomide with low-dose oral cyclophosphamide and low-dose dexamethasone (RdC) in AL amyloidosis.

In this phase 1/2 study, we explored the feasibility and activity of an oral regimen of lenalidomide with low-dose dexamethasone and low-dose oral cyclophosphamide (RdC) in patients with primary systemic light chain amyloidosis. RdC was given for up to 12 cycles in prespecified cohorts at escalated doses: 13 patients were treated in phase 1 and 24 in phase 2; 65% were previously untreated, and most had renal and/or cardiac involvement and elevated cardiac biomarkers. Lenalidomide 15 mg/d and cyclophosphamide 100 mg/d were further evaluated in phase 2. On intention to treat, 20 (55%) patients achieved a hematologic response, including 3 (8%) complete remissions. Hematologic responses were seen at all dose levels and in 4 of 5 patients who had received bortezomib previously. An organ response was recorded in 22% of patients on intention-to-treat and in 40% of patients who survived at least 6 months. The median time to progression was 10 months and the 2-year survival was 41%. Fatigue, nonneutropenic infections, and rash were the most common toxicities. The results of the present study show that RdC is an oral regimen with activity in primary systemic light chain amyloidosis and may be an additional treatment option, especially for patients with preserved organ function or for patients who cannot receive or who relapse after bortezomib. This study is registered at www.clinicaltrials.gov as NCT00981708.

Superiority of bortezomib, thalidomide, and dexamethasone (VTD) as induction pretransplantation therapy in multiple myeloma: a randomized phase 3 PETHEMA/GEM study.

The Spanish Myeloma Group conducted a trial to compare bortezomib/thalidomide/dexamethasone (VTD) versus thalidomide/dexamethasone (TD) versus vincristine, BCNU, melphalan, cyclophosphamide, prednisone/vincristine, BCNU, doxorubicin, dexamethasone/bortezomib (VBMCP/VBAD/B) in patients aged 65 years or younger with multiple myeloma. The primary endpoint was complete response (CR) rate postinduction and post-autologous stem cell transplantation (ASCT). Three hundred eighty-six patients were allocated to VTD (130), TD (127), or VBMCP/VBAD/B (129). The CR rate was significantly higher with VTD than with TD (35% vs 14%, P = .001) or with VBMCP/VBAD/B (35% vs 21%, P = .01). The median progression-free survival (PFS) was significantly longer with VTD (56.2 vs 28.2 vs 35.5 months, P = .01). In an intention-to-treat analysis, the post-ASCT CR rate was higher with VTD than with TD (46% vs 24%, P = .004) or with VBMCP/VBAD/B (46% vs 38%, P = .1). Patients with high-risk cytogenetics had a shorter PFS and overall survival in the overall series and in all treatment groups. In conclusion, VTD resulted in a higher pre- and posttransplantation CR rate and in a significantly longer PFS although it was not able to overcome the poor prognosis of high-risk cytogenetics. Our results support the use of VTD as a highly effective induction regimen prior to ASCT. The study was registered with http://www.clinicaltrials.gov (NCT00461747) and Eudra CT (no. 2005-001110-41).

Detection of thalidomide embryotoxicity by in vitro embryotoxicity testing based on human iPS cells.

The mouse embryonic stem cell test (mEST) is used to assess the embryotoxicity of drug candidates by evaluating the effects on the cardiac differentiation of stem cells. However, thalidomide embryotoxicity has not yet been reported using the mEST. To detect the effects of thalidomide, we used human induced pluripotent stem cells (hiPSCs) instead of mouse embryonic stem cells, and assessed three endpoints: the inhibition of cardiac differentiation, the cytotoxicity to hiPSCs, and the cytotoxicity to human dermal fibroblasts, according to the mEST. From these data (IC50 values), the embryotoxicity was classified into one of three different classes based on the mEST and our criteria. Valproate was used as a positive control and ascorbic acid was used as a negative control, and their effects were assessed. Similar to valproate, thalidomide was classified as a Class 2 agent, with weak embryotoxicity, by the mEST criteria, and was classified as Category 3 embryotoxic based on our criteria. Ascorbic acid was classified as a Class 1 / Category 1, non-embryotoxic agent, based on both criteria. Thalidomide embryotoxicity was detected in the embryonic stem cell test based on hiPSCs. This test system is thus considered to have a much greater predictive ability than the mEST.

ESNATS conference - the use of human embryonic stem cells for novel toxicity testing approaches.

The main achievements and results of the ESNATS project (Embryonic Stem Cell-based Novel Alternative Testing Strategies) were presented at the final project conference that was held on 15 September 2013, the day before the traditional EUSAAT (European Society for Alternatives to Animal Testing) Congress in Linz, Austria. The ESNATS project was an FP7 European Integrated Project, running from 2008 to 2013, the aim of which was to develop a novel toxicity testing platform based on embryonic stem cells (ESCs), and in particular, human ESC (hESCs), to accelerate drug development, reduce related R&D costs, and propose a powerful alternative to animal tests in the spirit of the Three Rs principles. Altogether, ESNATS offered the first proof of concept that hESCs can be used to create robust, reproducible and ready-to-use test assays for predicting human toxicity. In the end, essentially five test systems were developed to an adequate level for entering possible pre-validation procedures. These methods are based on hESCs, and can be combined to study the possible effects, on the human embryo, of exposure to a chemical during the early stages of development. In addition to the presentations by the main project partners, external speakers were invited to give lectures on relevant topics, both in the field of neurotoxicity and, more generally, on the applicability of hESCs in the development of advanced in vitro tests.

Isosteric analogs of lenalidomide and pomalidomide: synthesis and biological activity.

A series of analogs of the immunomodulary drugs lenalidomide (1) and pomalidomide (2), in which the amino group is replaced with various isosteres, was prepared and assayed for immunomodulatory activity and activity against cancer cell lines. The 4-methyl and 4-chloro analogs 4 and 15, respectively, displayed potent inhibition of tumor necrosis factor-α (TNF-α) in LPS-stimulated hPBMC, potent stimulation of IL-2 in a human T cell co-stimulation assay, and anti-proliferative activity against the Namalwa lymphoma cell line. Both of these analogs displayed oral bioavailability in rat.