A drug once considered for cancer chemotherapy is advancing in clinical trials to test its effectiveness in fighting a virus from the herpes family that threatens transplant patients.
University of Michigan professors Leroy Townsend and John Drach developed the compound maribavir. It is licensed by ViroPharma, which announced today that maribavir is headed for phase 2 clinical trials for the treatment of cytomegalovirus infection in stem cell transplant patients. New drugs go through three phases of clinical trials before the Food and Drug Administration decides on their approval.
Cytomegalovirus (CMV) is part of the herpes virus family, which also includes the viruses that causes chicken pox, mononucleosis and herpes simplexes 1 and 2. Like other herpes viruses, CMV can remain dormant in the body for long periods of time.
In most people with intact immune systems, CMV causes little to no apparent illness. However, in people with weakened immune systems, CMV can lead to serious complications or death.
Patients who are immunosuppressed following transplant of hematopoietic stem cells, such as a bone marrow transplant or solid organ transplantation, are at high risk of CMV infection, as are AIDS patients, fetuses and newborns. In these patients, CMV can lead to conditions such as pneumonitis or hepatitis, or to complications such as acute or chronic rejection of a transplanted organ. When contracted in utero or at birth, CMV can cause babies to be born with birth defects or impairment such as hearing loss.
ViroPharma Inc. (Nasdaq:VPHM) is looking at the potential effectiveness and safety of the oral antiviral drug for transplant patients in the phase 2 trial. The study will be conducted at up to 15 transplant centers across the United States.
Drach, a biochemist and virologist who is a professor in the schools of dentistry and pharmacy, and Townsend, emeritus professor in chemistry and Pharmacy's medicinal chemistry, began researching cytomegalovirus in the 1980s, prompted by a National Institutes of Health call for proposals to find drugs to treat CMV infections.
The U-M researchers collaborated with scientists at what is now GlaxoSmithKline, leading to prompt clinical evaluation of maribavir. But advances in treatment of HIV and AIDS patients temporarily slowed interest in the compound and development work ceased. CMV was a common cause of blindness and ultimately death in HIV patients, and as the medical community invented drugs to treat the HIV infection directly, there was less urgency by large pharmaceutical firms to develop a CMV drug.
"We had mixed feelings—naturally we were pleased to see the remarkable progress in treating HIV and the dramatic decrease in death from AIDS-related complications, but we also wanted to see our compound get to market for other people with CMV," Drach said.