EXTON, Pa., June 27, 2013 /PRNewswire/ -- ViroPharma Incorporated (Nasdaq: VPHM) today announced updated data from the two ongoing, Phase 2 dose ranging studies investigating maribavir for both first line treatment of cytomegalovirus (CMV) viremia and treatment of resistant/refractory CMV.
ViroPharma is currently conducting two Phase 2 dose ranging studies of oral maribavir at one of three doses (400mg, 800mg or 1200mg BID) in transplant recipients. The first is a randomized, active (valganciclovir) controlled maribavir dose blinded multicenter Phase 2 study in up to 160 European hematopoietic stem cell or solid organ transplant recipients who have demonstrated CMV viremia but do not have CMV organ disease. ViroPharma is also conducting a randomized, dose blinded multicenter Phase 2 study intended to enroll up to 120 hematopoietic stem cell or solid organ transplant recipients who have resistant or refractory CMV viremia with or without CMV organ disease. In both studies investigators have flexibility in determining duration of treatment depending on a subject's response. The resistant/refractory study has been conducted in the U.S. to date and is now being expanded to add additional EU sites.
Between the two studies, preliminary virology data are available from 83 subjects who have been followed for at least three weeks (52 in the "asymptomatic" CMV viremia treatment study and 31 in the U.S. resistant/refractory CMV treatment study).
In the asymptomatic CMV viremia study, among 39 subjects receiving maribavir (all doses combined), 36 (92 percent) achieved plasma CMV DNA levels below the quantification limit (BQL) during therapy, 1 subject failed to achieve BQL while on therapy, and 2 subjects had withdrawn for non-virologic reasons prior to achieving BQL. Two of the 36 subjects who achieved BQL subsequently experienced virologic breakthrough (detectable plasma CMV DNA at any level, even if levels returned to BQL at later visits) while on treatment. Among 13 subjects receiving valganciclovir, 9 (69 percent) achieved BQL during therapy, 1 subject failed to achieve BQL while on therapy, and 3 subjects had withdrawn for non-virologic reasons prior to achieving BQL. One of the 9 subjects receiving valganciclovir who achieved BQL subsequently experienced virologic breakthrough while on treatment.