Oral Valganciclovir Versus Valacyclovir

Researchers will study the effectiveness of valganciclovir to help prevent cytomegalovirus infections in patients receiving alemtuzumab. Since alemtuzumab eliminates T-cells, which are the body's usual defense against viruses, patients taking alemtuzumab have an increased risk of developing CMV. Before treatment, you will have a physical exam. You will also have around 3-4 tablespoons of blood drawn for routine tests and for tests to see if you have ever been exposed to CMV. You will be randomly assigned (as in the toss of a coin) to one of two treatment groups. Participants in one group will be given treatment with valganciclovir. Participants in the other group will be given treatment with valacyclovir. This drug protects against herpes infections but not CMV. If you are assigned to the group that will receive valganciclovir, you will take valganciclovir by mouth once a day starting of your first day of alemtuzumab therapy. You will continue to take valganciclovir for 2 months after the end of alemtuzumab therapy. If you are assigned to the group that will receive valacyclovir, you will take valacyclovir by mouth once a day starting of your first day of alemtuzumab therapy. You will continue to take valacyclovir for 2 months after the end of alemtuzumab therapy. Every 2 weeks while you are receiving alemtuzumab (usually 4-12 weeks)you will have a repeat blood test to look for CMV. Your participation in this study will last for a maximum of 5 months. This is an investigational study. Both valganciclovir and valacyclovir are FDA approved and commercially available. However, the use of valganciclovir for this study is experimental. valganciclovir will be provided free of charge during the study.