Recent studies on the antiviral and biochemical properties of 5-halo-5'-amino-deoxyribonucleosides

Carbocyclic thymidine analogues for use as potential therapeutic agents

The discovery of azidothymidine's (AZT) activity against human immunodeficiency virus (HIV) provided strong rationale for the design of additional thymidine analogues. One drawback of many nucleoside analogues is the toxicity that often arises due to phosphorylation by cellular kinases. In order to overcome this problem, a number of truncated nucleosides lacking the 4'-hydroxymethyl group have been synthesized. In that regard, the synthesis and preliminary biological results for two truncated carbocyclic thymidine analogues are presented herein.

Trifluridine: a review of its antiviral activity and therapeutic use in the topical treatment of viral eye infections

Trifluridine (trifluorothymidine) is an antiviral agent for topical use in the eye, and is structurally related to idoxuridine. In vitro studies have shown that it effectively inhibits the replication of herpes simplex virus type 1, which causes primary keratoconjunctivitis and recurrent epithelial keratitis in man. In masked comparative studies, predominantly in patients with dendritic ulcers, trifluridine 1% solution was effective in over 90% of patients; in such studies it was comparable with vidarabine in treating dendritic ulcers, and was at least as effective as, and in some studies more effective than, idoxuridine. The drug was also effective in treating a small number of patients with geographic ulcers (sometimes associated with the usage of topical corticosteroids), and this could be an important advantage if confirmed in further well-designed studies. However, experience at present is too limited to reliably determine the usual response rate in this difficult therapeutic area. In open studies the drug proved to be particularly useful in treating ulcers previously unresponsive to idoxuridine or vidarabine, and in treating patients intolerant of idoxuridine, with a high success rate and minimal side effects being reported. The role of trifluridine in treating deep stromal disease, uveitis, or adenovirus kerato-conjunctivitis has not been established. The drug is well tolerated and cross-hypersensitivity and cross-toxicity between trifluridine, idoxuridine and vidarabine are rare. Thus, trifluridine is an effective alternative to the drugs available for treating herpetic keratitis, and seems especially useful in 'difficult' cases.