Herpes drug suppresses HSV in people with HIV
Herpes drug suppresses HSV in people with HIV
Famvir is only drug approved for HIV patients
Clinicians now have a potent treatment for herpes simplex virus (HSV) infections in HIV patients. A recent study shows that Famvir (famciclovir), manufactured by SmithKline Beecham Pharmaceuticals in Collegeville, PA, suppresses recurrent HSV infections in people with HIV.
During a four-month period, 97% of patients treated with Famvir did not experienced any culture-confirmed HSV recurrences, according to Clarence Young, MD, director of antivirals, clinical research and development, and medical affairs at SmithKline Beecham.
In an open-label clinical trial, the researchers gave 500 mg of Famvir twice daily for four months to 65 patients (49 men and 16 women) co-infected with HSV and HIV. Each month, clinicians evaluated patients with a clinical exam. If lesions were present, they took a viral culture. Thirty-eight of the patients (58%) had AIDS or AIDS-defining illnesses. The median CD4 cell count at study entry was 168 cells/ milliliter, with a range of two to 969. Thirty-three of the patients (51%) had CD4 counts of less than 200.
Of the 65 patients, 48 (74%) had baseline HSV lesions. After treatment with Famvir, which cleared the initial lesions, 59 of the patients (91%) remained free from clinically diagnosed recurrences during the four-month observation period, and 63 (97%) remained free from culture-proven viral recurrences.
• Patients tolerated the drug well. The most commonly reported side effect was diarrhea, followed by headaches and nausea. However, Young notes that people who took placebos in other studies reported the same symptoms at similar incidence rates. "It’s fair to say that the adverse events we saw were comparable to what we saw in other controlled studies where the incidence was comparable to a placebo," he says.
Herpes/HIV co-infection high
Young says the findings could have a big impact on the quality of life experienced by HIV patients.
"Studies show that as many as 90% of HIV-infected people have concurrent infection with herpes simplex virus," Young says. "It’s possible people could have been exposed to herpes I as a child and then herpes II later in life before they acquired HIV."
Also, people who have herpes lesions are more susceptible to HIV infection, and they may be more likely to spread HIV, he adds. "Researchers have shown that you can culture HIV in these lesions."
While herpes outbreaks can be painful and uncomfortable for anyone, they can especially be a problem for HIV patients.
"Genital herpes impacts their sense of well-being," Young says. "Most studies that look at this have found that HIV-infected patients who have prior evidence of herpes have more outbreaks, and these last longer [than in non-HIV infected people]." Also, herpes outbreaks are more severe in HIV-infected people, sometimes spreading to their liver or lungs and causing potentially life-threatening complications.
An earlier Famvir study showed that treating HIV patients with the drug over an extended period of time reduced the amount of time the patients had any evidence of HSV shedding, Young notes.
"They were looking for herpes even on normal skin daily for the whole 16-week study," he explains. "Famvir was pretty effective at significantly reducing the finding of herpes virus in the genital region."
The Rockville, MD-based U.S. Food and Drug Administration (FDA) has approved Famvir for treatment of recurrent herpes simplex virus infections, including genital herpes and cold sores, in HIV-infected people.
SmithKline Beecham pursued the famciclovir study at physicians’ requests for information on the drug’s use in HIV-infected patients.
Famvir’s protocol calls for a dosage of 500 mg twice a day for seven days. The study followed patients who were taking the drug over a four-month period to observe the medication’s impact on preventing outbreaks of genital herpes. However, the FDA has given approval only for treatment of acute recurrences, Young says.
"It has not been approved in HIV-infected patients for prevention of outbreaks, and it’s likely that studies involving large numbers of patients would be required in order to obtain that approval," Young says.
Unlike other herpes medications, Famciclovir has excellent viability. The amount of the active drug that gets into a person’s bloodstream is very high, somewhere in the 70% to 80% range, Young says.
"What happens is, once you take the Famvir pill orally, the drug gets metabolized in the bloodstream to form penciclovir, and that’s the active form of the drug," he explains. "These drugs are called pro-drugs because you give a form of the drug that enhances the ability to absorb it, and then it’s quickly metabolized and releases an active form of the drug."
SmithKline Beecham also sells a herpes penciclovir cream that is used to treat herpes simplex cold sores. The company is studying an intravenous form of penciclovir for treatment of herpes simplex infections in immunocompromised patients, including patients who have been receiving chemotherapy for cancer.
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