The Molecular Mechanisms of Thalidomide Teratogenicity and Implications for Modern Medicine.

Thalidomide is a teratogen that affects many organs but primarily induces limb truncations like phocomelia. Rodents are thalidomide resistant. In the 1950s, this has led to misinterpretations of animal tests and to the fatal assumption that the drug was safe for pregnant women to use against morning sickness. The result was one of the biggest scandals in medical history: 10.000 and more infants with birth defects in Europe. Nonetheless, thalidomide still has its place in modern medicine as it has strong therapeutic potential: it has been approved by the FDA for multiple myeloma and erythema nodosum leprosum, and its anti-inflammatory, immunomodulatory and antiangiogenic activities are considered in many other refractory diseases. The aim is to develop derivatives that are not teratogenic but maintain the therapeutic potential. This requires detailed knowledge about the underlying molecular mechanisms. Much progress has been made in deciphering the teratogenic mechanisms in the last decade. Here, we summarize these mechanisms, explain thalidomide resistance of rodents, and discuss possible mechanisms that could explain why the drug primarily targets the developing limb in the embryo. We also summarize the most important therapeutic mechanisms. Finally, we discuss which therapeutic and teratogenic mechanisms do and do not overlap, and if there is a chance for the development of non-teratogenic thalidomide derivatives with therapeutic potential.

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.

Thalidomide-induced teratogenesis: history and mechanisms.

Nearly 60 years ago thalidomide was prescribed to treat morning sickness in pregnant women. What followed was the biggest man-made medical disaster ever, where over 10,000 children were born with a range of severe and debilitating malformations. Despite this, the drug is now used successfully to treat a range of adult conditions, including multiple myeloma and complications of leprosy. Tragically, a new generation of thalidomide damaged children has been identified in Brazil. Yet, how thalidomide caused its devastating effects in the forming embryo remains unclear. However, studies in the past few years have greatly enhanced our understanding of the molecular mechanisms the drug. This review will look at the history of the drug, and the range and type of damage the drug caused, and outline the mechanisms of action the drug uses including recent molecular advances and new findings. Some of the remaining challenges facing thalidomide biologists are also discussed.

[Current therapeutic indications of thalidomide and lenalidomide]. / Indicaciones terapéuticas actuales de la talidomida y la lenalidomida.

Thalidomide is a synthetic glutamic acid derivative first introduced in 1956 in Germany as an over the counter medications. It was thought to be one of the safest sedatives ever produced as it was effective in small doses, was not addictive, and did not have acute side-effects such as motor impairment, but was quickly removed from market after it was linked to cases of severe birth defects. The Food and Drug Administration approved use in the treatment of erythema nodosum leprosum. Further, it was shown its effectiveness in unresponsive dermatological conditions such as actinic prurigo, adult Langerhans cell hystiocytosis, aphthous stomatitis, Behçet syndrome, graft-versus-host disease, cutaneous sarcoidosis, erythema multiforme, Jessner-Kanof lymphocytic infiltration of the skin, Kaposi sarcoma, lichen planus, lupus erythematosus, melanoma, prurigo nodularis, pyoderma gangrenosum and others. In May 2006, it was approved for the treating multiple myeloma. New thalidomide analogues have been developed but lack clinical experience. This paper is a review of the history, pharmacology, mechanism of action, clinical applications and side effects of thalidomide and its analogues.

Tumor necrosis factor-α antagonists: Side effects and their management.

As elevated levels of tumor necrosis factor-alpha (TNF-α) are associated with disease severity in psoriasis and psoriatic arthritis, TNF-α antagonists are being used to treat moderate to severe disease in patients who have contraindications, fail to respond or develop side effects to conventional systemic therapies. It is of utmost importance to be well versed with the possible adverse effects and contraindications of TNF-α antagonists so that they can be used effectively and safely. Many of their adverse effects have been well studied in patients of rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) and may not be completely applicable in psoriasis. This is because patients with RA and IBD are on multiple immunosuppressants while those with psoriasis are mostly receiving single systemic therapy and often have comorbidities that distinguish them from those with RA or IBD. Also, some of the side effects are still controversial and debated. Long-term prospective randomized controlled studies are needed to better understand the associated risk in patients of psoriasis. Baseline screening and periodic monitoring during treatment can reduce and help in early identification and appropriate management of the adverse outcomes. This article reviews the side effects known to be associated with TNF-α antagonists, their pathomechanisms and management guidelines. Some of the common side effects include infusion and injection site reactions, infections particularly reactivation of tuberculosis, autoantibody formation and drug induced lupus erythematosus, liver function abnormalities, hematological, and solid organ malignancies.

New cases of thalidomide embryopathy in Brazil.

Thalidomide is the best known human teratogen. Although withdrawn from the market in 1961, thalidomide was remarketed after 1965 in several countries, for the treatment of erythema nodosum leprosum. Thalidomide has a potent immunomodulatory property and has now a number of approved and off-label uses in dermatologic, oncologic, infectious and gastrointestinal conditions. In the U.S., FDA approved the use of thalidomide in 1998, but no cases of thalidomide embriophaty were registered after that. Since 1996 no new cases were reported in Latin America. However, the Teratogen Information Service (TIS) Porto Alegre, recorded three new cases of thalidomide embriophaty born in Brazil since 2005. Considering that these three cases were not registered through a systematic surveillance system, but that came to our attention through a series of coincidental random events, it can be assumed that the actual occurrence of affected babies by thalidomide continues being as frequent as denounced ten years ago.

Dapsone therapy for malaria during pregnancy: maternal and fetal outcomes.

The need to consider using dapsone in pregnant women for its antimalarial activity is becoming greater in areas where Plasmodium falciparum resistance to chloroquine and pyrimethamine-sulfadoxine is rapidly increasing. Dapsone in combination with other antimalarials might provide a valuable alternative for both treatment and prophylaxis. This review assesses the clinical pharmacology of dapsone and its adverse drug reactions in relation to haemolysis, glucose-6-phosphate dehydrogenase (G6PD) deficiency, blood dyscrasias and methaemoglobinaemia. Studies are summarised reporting its use in leprosy, dermatological and other conditions, and malaria, in relation to maternal and infant outcomes. A total of 924 pregnancies were identified during which dapsone therapy was taken. Only limited data are available and this precludes a meaningful quantitative benefit-risk analysis. Mild degrees of haemolysis consistently occur with continued therapy, although adverse effects may be less likely with intermittent treatment, as most reported adverse effects have occurred with long-term use of dapsone. There are a number of gaps in knowledge where more data are needed. These include no data on pharmacokinetics in pregnancy and whether these are altered with co-administration of chlorproguanil. Potential complications in women with severe anaemia are unknown and there is no information on haemolytic effects in women or the fetus with G6PD deficiency. The use of dapsone in HIV-infected women in malarious areas could carry increased risks because of the immunosuppressive actions of the drug. Trials of dapsone therapy in pregnancy should be considered in malarious areas where there is good reason for its deployment. Controlled trials have provided data on maternal tolerance, and dapsone in combination with other antimalarial drugs can offer clear benefit in terms of improved birthweight. The use of dapsone combinations should be considered when no good alternative is available and the threat of malaria is the greater risk.

Thalidomide: a review of approved and investigational uses.

BACKGROUND: Thalidomide is best known as a major teratogen that caused birth defects in up to 12,000 children in the 1960s. More recently, this agent has been approved by the US Food and Drug Administration for the treatment of erythema nodosum leprosum (ENL) through a restricted-use program. Its immunomodulatory, anti-inflammatory, and antiangiogenic properties are currently under study in a number of clinical conditions. OBJECTIVE: This article reviews the pharmacology of thalidomide; its approved and off-label uses in dermatologic, oncologic, and gastrointestinal conditions; and adverse events associated with its use. METHODS: Relevant articles were identified through searches of MEDLINE (1966-June 2002), International Pharmaceutical Abstracts (1970-June 2002), and EMBASE (1990-June 2002). Search terms included but were not limited to thalidomide, pharmacokinetics, pharmacology, therapeutic use, and teratogenicity, as well as terms for specific disease states and adverse events. Further publications were identified from the reference lists of the reviewed articles. Abstracts of recent symposia were obtained from the American Society of Clinical Oncology Web site. RESULTS: Thalidomide is thought to exert its therapeutic effect through the modulation of cytokines, particularly tumor necrosis factor-alpha. In addition to its approved indication for ENL, thalidomide has been studied in various other conditions, including graft-versus-host disease, discoid lupus erythematosus, sarcoidosis, relapsed/refractory multiple myeloma, Waldenstrom's macroglobulinemia, myelodysplastic syndromes, acute myeloid leukemia, myelofibrosis with myeloid metaplasia, renal cell carcinoma, malignant gliomas, prostate cancer, Kaposi's sarcoma, colorectal carcinoma, oral aphthous ulcers, Behçet's disease, Crohn's disease, and HIV/AIDS-associated wasting. Adverse events most frequently associated with its use include somnolence, constipation, rash, peripheral neuropathy, and thromboembolism. CONCLUSIONS: Use of thalidomide is limited by toxicity, limited efficacy data, and restricted access. Evidence of its efficacy in conditions other than ENL awaits the results of controlled clinical trials.

[Thalidomide--a dreaded drug with new indications]. / Thalidomid--fryktet medikament med nye bruksområder.

BACKGROUND: Thalidomide was introduced as a non-toxic sleeping pill in 1957 and was prescribed in more than 20 countries. In 1961 the link between congenital limb defects and thalidomide use in pregnancy was proven, resulting in withdrawal of the drug. MATERIAL AND METHODS: On the basis of literature searches and personal experience we review the effects and use of thalidomide today. RESULTS: In vitro, thalidomide has immunoregulatory properties. This has lead to the administration of thalidomide in many immunological diseases. In 1964 it was discovered that thalidomide was effective against erythema nodosum leprosum. Thalidomide also has effect on aphthous stomatitis and Behçet's disease. The effect is more uncertain in graft-versus-host-disease, rheumatoid arthritis and Crohn's disease. Thalidomide reduces angiogenesis in experimental animals, and this has led to several studies of thalidomide as a possible anticancer drug. Advanced or resistant multiple myeloma may be a new target for thalidomide; at least 30% of these patients obtain response during treatment. Results indicate that patients with breast cancer and glioma do not benefit from treatment with thalidomide. INTERPRETATION: Thalidomide has proven to be effective in the treatment of erythema nodosum leprosum and aphthous stomatitis. It is also effective in advanced multiple myeloma, but not in other cancers.

The re-emergence of thalidomide: results of a scientific conference.

BACKGROUND: The use of thalidomide during the 1950s resulted in teratogenic effects in thousands of infants. Although thalidomide is currently approved for the treatment of a complication of leprosy, it is commercially available to treat other diseases through a controlled distribution system. This article presents a summary of a scientific conference organized to assess clinical research on thalidomide, its new clinical applications, and the social and ethical implications for its use. METHODS: Summaries of 10 presentations and two panel discussions were developed from the authors's, oral presentations, conference slides, responses to questions, and supporting literature. RESULTS: Thalidomide shows promise in treating several diseases, including HIV/AIDS, rheumatoid arthritis, Crohn's disease, and multiple myeloma. The STEPStrade mark (System for Thalidomide Education and Prescribing Safety) Program has been developed by Celgene, the commercial manufacturer of thalidomide, to ensure compliance with prescription and usage protocols. A surveillance system is also in place to monitor and report compliance patterns. CONCLUSIONS: Despite the tragic past associated with thalidomide, the drug shows promise as a treatment for many clinical disorders. The challenge is to answer lingering questions of risks and benefits through clinical trials and discovery, to monitor participation and compliance with protocols developed to avoid use of the drug during pregnancy, and to continue to search for safer and more effective treatment options.