Valganciclovir, the L-valyl ester of ganciclovir, is actually a prodrug for ganciclovir. Valganciclovir is an antiviral medication used to treat cytomegalovirus infections.IC50 Value: Target: CMVin vitro: In cell culture model systems using Caco-2 cells for PEPT1 and SKPT cells for PEPT2, valganciclovir inhibited glycylsarcosine transport mediated by PEPT1 and PEPT2 with K(i) values (inhibition constant) of 1.68+/-0.30 and 0.043+/- 0.005 mM, respectively. The inhibition by valganciclovir was competitive in both cases [1].in vivo: 37 patients were enrolled; 19 patients received treatment with VGV and 18 patients received treatment with GCV. The VGV was not inferior in efficacy to GCV as pre-emptive therapy, with rates of viral clearance at 28 days of 89.5% and 83%, respectively (P-value for non-inferiority = 0.030). Toxicities were similar between the 2 arms. No patients developed CMV disease [2]. Patients being treated with an alemtuzumab-containing regimen received prophylaxis with either valaciclovir 500 mg orally daily orvalganciclovir 450 mg orally twice daily. None of the 20 patients randomized to valganciclovir experienced CMV reactivation (P = .004) [3].

[1]. Sugawara M, et al. Transport of valganciclovir, a ganciclovir prodrug, via peptide transporters PEPT1 and PEPT2. J Pharm Sci. 2000 Jun;89(6):781-9. [2]. Chawla JS, et al. Oral valganciclovir versus ganciclovir as delayed pre-emptive therapy for patients after allogeneic hematopoietic stem cell transplant: a pilot trial (04-0274) and review of the literature. Transpl Infect Dis. 2012 Jun;14(3):259-67. [3]. O'Brien S, et al. Valganciclovir prevents cytomegalovirus reactivation in patients receiving alemtuzumab-based therapy. Blood. 2008 Feb 15;111(4):1816-9.