New drug ‘a potential game-changer’ for preventing CMV infection in transplant patients
By Deborah Bach
A new drug shows promise in preventing a common but sometimes serious virus in stem cell transplant recipients, according to a paper published today in The New England Journal of Medicine.
The Harvard University-led study, which involved researchers from Fred Hutchinson Cancer Research Center and other institutions, found that patients who took the antiviral drug CMX001 after undergoing stem-cell transplantation were significantly less likely than those who took a placebo to develop cytomegalovirus (CMV). A type of herpes virus, CMV can cause potentially life-threatening problems including pneumonia, gastrointestinal disease and encephalitis in patients who undergo transplantation to treat serious blood diseases such as leukemia.
The three antiviral drugs currently available to treat CMV can cause serious kidney disease and lower the body’s ability to produce blood cells, and have the potential for long-term toxicity in children. Researchers have long sought less-toxic treatments to combat the virus, said Dr. Michael Boeckh, head of the Hutch’s Infectious Disease Sciences Program of the Vaccine and Infectious Disease Division, and the senior author of the study.
“None of the [treatment] options that we have for CMV are good,” he said. “Innovations were needed. This is the first real potential advance in a long time.”
Part of a group of viruses including Epstein-Barr, which causes mononucleosis and is associated with Hodgkin lymphoma, and varicella-zoster virus, which causes chickenpox and shingles, CMV infects as much as 70 percent of the U.S. population aged 40 and older. Most healthy children and adults infected with the virus have no symptoms and may not even realize they have it. But in stem-cell transplant patients, whose immune systems are temporarily compromised following the procedure, the virus can take hold and, in the most severe cases, lead to fatal complications.
“With current agents, between 3 and 5 percent of allogeneic [donor] transplant patients develop CMV disease within six months of transplantation, and a small number of them may die of it,” said Dr. Francisco Marty of Dana-Farber Cancer Institute and Brigham and Women’s Hospital, the study’s lead author.
“There clearly is a need for better treatments with fewer adverse effects,” Marty said in a news release. “This clinical trial examined whether the disease can be prevented, rather than waiting for blood tests to show that treatment is needed.”
The study – sponsored by Chimerix Inc. the manufacturer of CMX001 – involved 230 hematopoietic stem-cell transplant patients at 27 centers nationwide, including Seattle Cancer Care Alliance. The patients were randomly assigned to take either CMX001 or a placebo for between nine and 11 weeks. Just 10 percent of patients who took 100 mg of the drug twice weekly developed CMV or had a detectable amount of CMV in their blood at the end of treatment, compared with 37 percent of patients who took the placebo. The most common adverse effect of the drug was diarrhea.
CMX001 is currently undergoing a Phase 3 trial focused on CMV, and has completed a Phase 2 trial to assess its efficacy in preventing adenovirus disease, a common cause of respiratory illness, in stem-cell transplant recipients.
The drug was originally developed as an oral treatment for smallpox, and Boeckh said other studies have suggested it is effective in treating a range of other viruses. For that reason, he said, CMX001 is stirring considerable interest among researchers and clinicians alike.
“There are a lot of viral infections that we don’t have good treatment for,” he said. “This drug could potentially be the answer. It’s a potential game-changer.”