Cidofovir dehydrate is an injectable antiviral medication for the treatment of cytomegalovirus (CMV) retinitis, which suppresses virus replication by selective inhibition of viral DNA synthesis.
Target: CMV DNA polymerase
Cidofovir is an injectable antiviral medication for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. It suppresses CMV replication by selective inhibition of viral DNA polymerase and therefore prevention of viral replication and transcription. It is an acyclic nucleoside phosphonate, and is therefore independent of phosphorylation by viral enzymes, unlike acyclovir.
Cidofovir was discovered at the Institute of Organic Chemistry and Biochemistry, Prague, by Antonín Hol?, and developed by Gilead Sciences and is marketed with the brand name Vistide by Gilead in the USA, and by Pfizer elsewhere. Maintenance therapy with cidofovir involves an infusion only once every two weeks, making it a convenient treatment option. Because dosing is relatively infrequent, a permanent catheter is not necessary for infusions.

Cidofovir

Cidofovir is an anti-CMV drug which can suppress CMV replication by selective inhibition of viral DNA polymerase and therefore prevention of viral replication and transcription.
IC50 Value:
Target: CMV DNA polymerase
in vitro: The minimum concentrations of (S)-HPMPC required to inhibit CMV plaque formation by 50% was microgram/ml. The selectivity indices of (S)-HPMPC, as determined by the ratio of the 50% inhibitory concentration for cell growth to the 50% inhibitory concentration for plaque formation for CMV (AD-169 strain), was 1,500 [1]. The time course of uptake of HPMPC into Vero cells was linear between 10 and 75 min and proportional to the concentration in the medium from 10(-6) to 10(-2) M. HPMPC uptake was temperature sensitive and the rate of uptake was considerably lower at 27 degrees than at 37 degrees and almost totally inhibited at 4 degrees [2].
in vivo: Levels of cidofovirin serum following intravenous infusion were dose proportional over the dose range of 1.0 to 10.0 mg/kg of body weight and declined biexponentially with an overall mean +/- standard deviation terminal half-life of 2.6 +/- 1.2 h (n = 25). Approximately 90% of the intravenous dose was recovered unchanged in the urine in 24 h. The overall mean +/- standard deviation total clearance of the drug from serum (148 +/- 25 ml/h/kg; n = 25) approximated renal clearance (129 +/- 42 ml/h/kg; n = 25), which was significantly higher (P < 0.001) than the baseline creatinine clearance in the same patients (83 +/- 21 ml/h/kg; n = 12) [3].  Positive CMV urine cultures reverted to negative in 2 of 8 patients receiving doses of < or = 1.5 mg/kg twice weekly and 11 of 13 patients receiving higher doses. Cidofovir has in vivo anti-CMV activity demonstrated by prolonged clearing of CMV viruria, although this observation is tempered by the fact that clearance of viremia could not be demonstrated [4].
Toxicity: Patients receiving 0.5 or 1.5 mg/kg twice weekly experienced no serious toxicity. The first two patients who received 5 mg/kg twice weekly developed glycosuria and 2+ proteinuria. Subsequent patients received concomitant probenecid to attempt to ameliorate renal toxicity [4].
Clinical trial: FDA approved drug