A Surprising Recovery

Thalidomide: dermatological indications, mechanisms of action and side-effects

Thalidomide was first introduced in the 1950s as a sedative but was quickly removed from the market after it was linked to cases of severe birth defects. However, it has since made a remarkable comeback for the U.S. Food and Drug Administration-approved use in the treatment of erythema nodosum leprosum. Further, it has shown its effectiveness in unresponsive dermatological conditions such as actinic prurigo, adult Langerhans cell histiocytosis, aphthous stomatitis, Behçet's 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 uraemic pruritus. This article reviews the history, pharmacology, mechanism of action, clinical uses and adverse effects of thalidomide.

Evolving new therapies of autoimmune hepatitis

Refinements in the understanding of the mechanisms of immunocyte activation and the emergence of new immunosuppressive agents with highly selective actions has created opportunities for improving the treatment of autoimmune hepatitis. Drugs, such as budesonide and deflazacort, may inhibit immunocyte activation and limit corticosteroid-related side effects. Agents, such as cyclosporine and tacrolimus, can impair calcineurin activity and restrict the generation of transcription factors necessary for T cell responses. Intravenous immunoglobulin can bind anti-idiotype antibodies and reduce interleukin-2 secretion, and monoclonal antibodies directed against critical components of the T cell activation cascade can dampen the immune reaction. Drugs, such as mycophenolate mofetil, cyclophosphamide, methotrexate, and KF20444, can inhibit T cell proliferation, and other interventions promise to deplete activated T cells, impair effector mechanisms, and induce self-tolerance.

Thalidomide

Thalidomide has been successful in the treatment of several dermatologic conditions unresponsive to other agents. Further experience may lead to a better understanding of its mechanism of action in these various diseases. Thalidomide should be considered an extremely valuable therapeutic option in selected patients when the benefits clearly outweigh the risks of teratogenicity and peripheral neuropathy.

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.

Thalidomide and metabolites: indications of the absence of 'genotoxic' carcinogenic potentials

Because of the reintroduction into human therapeutics of thalidomide, a recognized developmental toxicant in humans, there has been concern about its potential for inducing other health effects as well. The present study is concerned with the possible mutagenicity and carcinogenicity of this chemical. Using the expert system, META, a series of putative metabolites of thalidomide was generated. In addition to the known or hypothesized metabolites of thalidomide (N=12), a number of additional putative metabolites (N=131) were identified by META. The structures of these chemicals were subjected to structure-activity analyses using predictive CASE/MULTICASE models of developmental toxicity, rodent carcinogenicity and mutagenicity in Salmonella. While thalidomide and some of its putative metabolites were predicted to be developmental toxicants, none of them were predicted to be rodent carcinogens. Putative metabolites containing the hydroxamic acid or hydroxylamine moieties were predicted to be mutagens. None of the 'known' metabolites of thalidomide contained these reactive moieties. Whether such intermediates are indeed generated or whether they are generated and are either unstable in the presence of oxygen or react rapidly with nucleophiles is unknown.

Tumour necrosis factor alpha and mucocutaneous leishmaniasis

Allelic associations between polymorphisms at the tumour necrosis factor (TNF) locus within the major histocompatibility complex (MHC) and susceptibility to a range of autoimmune and infectious diseases have been established in humans. Among these is the severe and debilitating mucocutaneous form of leishmaniasis (MCL) caused by Leishmania braziliensis. This was preempted by the demonstration of high levels of circulating TNF-alpha in the sera of patients presenting with clinical mucocutaneous disease. Here, Jennie Blackwell looks at the implications this might have for the diagnosis and treatment of mucocutaneous disease, and the broader implications that the positive and negative immunomodulatory roles of TNF-alpha have in maintaining apparently detrimental alleles in the population.

Thalidomide and its impact in dermatology

Thalidomide, originally marketed as a sedative, was introduced in West Germany in 1956 and in numerous other countries soon thereafter. In part because it did not impair coordination or respiratory function, the drug rapidly became extremely popular. By 1961, however, there were mounting reports of phocomelia and other severe congenital abnormalities associated with maternal use of thalidomide, and the drug was withdrawn from the market and its availability highly restricted. A few years later, thalidomide would find use in dermatology after it was reported that leprosy patients with erythema nodosum leprosum (ENL) experienced rapid and dramatic improvement after taking the drug as a sedative. Additional data quickly confirmed thalidomide's efficacy in ENL, and today it is the drug of choice in the condition. In subsequent decades, the drug has been successfully tried in treatment of a variety of apparently unrelated dermatologic disorders. Meanwhile, thalidomide has been shown to possess a range of biologic actions, including inhibition of tumor necrosis factor alpha, possibly relevant to its clinical efficacy. Dermatologic disorders in addition to ENL in which thalidomide's effectiveness is well documented include aphthous stomatitis, discoid lupus erythematosus, actinic prurigo, Behçet's disease, and prurigo nodularis. More recently, the drug has been employed in dermatologic conditions associated with HIV infection. When used with safeguards to prevent teratogenicity and the drug's other major adverse effect, peripheral neuropathy, thalidomide may offer a good therapeutic option for many patients in whom other drug therapies have proven inadequate.