ROCKVILLE, Maryland—The Food and Drug Administration has approved Viread (tenofovir disoproxil fumarate, Gilead Sciences, Inc.) for the treatment of HIV-1 infection in combination with other antiretroviral agents. Viread, a nucleotide analog, remains in cells longer than other antiretrovirals, which enables a dosage of 300 mg taken once a day in tablet form.
Viread’s approval marks the first entry of a nucleotide analog reverse transcriptase inhibitor into the HIV-medication market. Nucleotide analogs are similar to nucleoside analogs and inhibit HIV replication in the same way, by blocking the enzyme reverse transcriptase. The FDA action occurred 6 months after Gilead submitted its new drug application to the FDA.
The drug won marketing approval based on data the FDA reviewed from two clinical studies submitted by the sponsor that involved more than 700 patients. One was a 24-week, phase III, placebo-controlled trial; the other was a 48-week controlled dose-ranging trial.
"Patients who received Viread showed significant decreases in the quantities of HIV RNA in their blood, compared to patients who received a placebo with the standard antiretroviral regimen," the FDA said in announcing the approval.
Both clinical trials enrolled patients previously treated with antiretroviral drugs. As a result, the risk-benefit ratio for patients who have not had antiretroviral therapy remains unknown.
Gilead said that an ongoing clinical trial is evaluating Viread in 601 treatment-naïve HIV patients who will receive the drug for 96 weeks in combination with lamivudine(Drug information on lamivudine) (Epivir) and efavirenz(Drug information on efavirenz) (Sustiva). Controls will receive stavudine(Drug information on stavudine) (Zerit), lamivudine, and efavirenz. Safety and efficacy data for the first 48 weeks of the trial will become available in the first half of 2002.
The FDA noted that there are no Viread study results to show a long-term inhibition of HIV progression.
