935U83 is an experimental nucleoside analogue anti-HIV drug developed by GlaxoSmithKline. It is also known by its chemical name 23-dideoxy-3-fluoro-5-chlorouridine, or by the abbreviation FCU.

Tests in animals found that side-effects only occurred at doses 90 times higher than those needed to inhibit HIV in the test-tube. Laboratory tests are reported to have indicated that bone marrow suppression is likely to be less common than that seen at the 500 mg dose of AZT. Initial small safety studies using standard doses in humans showed no side-effects.

In 1996, the development of 935U83 was abandoned after phase I trials found no evidence of any anti-HIV effects.

Key research

Riddler conducted a multi-centre dose-escalating pharmacokinetics and safety study. No adverse effects to single doses of 935U83 (up to 1600mg) were noted. A high-fat meal prior to dosing decreased the rate of absorption but did not affect oral bioavailability.

References

Riddler SA et al. A phase I single-dose trial to evaluate the safety and pharmacokinetics of 5-chloro-2'3'-dideoxy-3'fluorouridine (935U83). First National Conference on Human Retroviruses, Washington, abstract 576, 1993.