ViroPharma Initiates Phase 3 Study Of CAMVIA In Liver Transplant Patients

Armen Hareyan's picture
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Recently initiated second Phase 3 clinical study of CAMVIA (maribavir) in transplant patients is now open to patient recruitment.

This study will evaluate the prophylactic use of CAMVIA in patients undergoing a liver transplant procedure, and will be conducted in up to 60 U.S. transplant centers. The first Phase 3 study of CAMVIA was initiated in September 2006 in patients undergoing a stem cell transplant.

ViroPharma's Phase 3 liver transplant study will compare the efficacy, safety and tolerability of prophylactic use of CAMVIA versus oral ganciclovir when administered for up to 14 weeks for the prevention of cytomegalovirus disease in recipients of orthotopic liver transplants at high risk of developing CMV disease. The study also will evaluate the pharmacokinetics of CAMVIA in this subject population.

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"We have made great progress with CAMVIA in the last 12 months; the initiation of this second Phase 3 study is our latest milestone as we work towards our goal of making this important drug available for the more than 120,000 transplant patients throughout the world who are at risk of deadly CMV disease," commented Colin Broom, M.D., ViroPharma's chief scientific officer. "The excellent CAMVIA Phase 2 data presented at the 2006 ASH meeting encourage us as we execute on our comprehensive Phase 3 program in transplant patients."

This Phase 3 study is a randomized, double-blind, multicenter study intended to enroll over 300 subjects who have undergone liver transplantation and are at high-risk of developing CMV disease (i.e., donor CMV seropositive / recipient CMV seronegative). Following transplantation, eligible subjects will be randomized to receive CAMVIA 100mg BID or oral ganciclovir 1,000mg TID in a 1:1 allocation ratio for up to 14 weeks. If CMV disease, defined as symptomatic CMV infection or CMV organ disease, occurs during the study drug administration period, study drug will be discontinued and the subject will be managed according to standard CMV treatment practices at the transplant center.

The primary efficacy endpoint is the incidence of CMV disease (either symptomatic CMV infection or CMV organ disease) within 6 months post transplantation, which is expected to be approximately 12 percent in the oral ganciclovir arm of the study, based on data from published literature. A number of key secondary endpoints have been identified and assessment of these endpoints will play an important part in assessing the clinical benefit of CAMVIA. These secondary endpoints include time to onset of CMV infection and disease; the incidence and time to onset of anti-CMV therapy; and survival without CMV infection or disease; in addition to the incidence of adverse effects that limit the use of current therapies, including suppression of bone marrow function.

CAMVIA's antiviral activity and tolerability were elucidated in a Phase 2 study designed to assess the rate of CMV reactivation in patients undergoing allogeneic stem cell transplantation.

CMV is a member of the herpes virus group, which includes the viruses that cause chicken pox, mononucleosis, herpes labialis (cold sores), and herpes genitalis (genital herpes). Like other herpes viruses, CMV has the ability to remain dormant in the body for long periods of time. Human CMV infection rates average between 50 percent and 85 percent of adults in the U.S. by 40 years of age, but in healthy adults causes little to no apparent illness. However, in immunocompromised individuals including cancer patients, HIV patients, and transplant patients, and in children born with primary CMV infection, CMV can lead to serious disease or death. Patients who are immunosuppressed following hematopoietic stem cell (bone marrow) or solid organ transplantation are at high risk of CMV infection. In these patients, CMV can lead to severe conditions such as pneumonitis or hepatitis, or to complications such as acute or chronic rejection of a transplanted organ. While currently available systemic anti-CMV agents are effective against the virus, their use is limited by toxicities, most notably bone marrow suppression and renal impairment.

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