In most healthy adults, the immune system wages a winning battle against a virus that infects up to 80 percent of the population by age 40. Most never even know they have cytomegalovirus, or CMV.
However, the virus is a leading cause of complications and serious illness in patients who have compromised immune systems, including those receiving hematopoietic cell transplants to treat leukemia or lymphoma.
CMV is life-threatening to these patients, and treatments can be expensive. For decades, City of Hope has been studying the best way to prevent the virus from becoming a complication for transplant patients.
A new CMV vaccine developed and manufactured at City of Hope could ultimately do that. The vaccine has just started its first safety trial, funded by the National Cancer Institute.
“About a third of patients get CMV infection after transplant,” said the trial's leader, John Zaia, M.D., chair of the Department of Virology and the Aaron D. Miller and Edith Miller chair in Gene Therapy at City of Hope. “Of those, you can control it in most patients, but it’s a difficult thing to do. It’s costly. It requires a toxic anti-viral medication. There could be great savings in terms of patient care – and also in the cost of care.”
Healthy patients will receive two doses of the CMV vaccine, and then their immune response will be measured. This data will be used to determine safety and efficacy of the vaccine, and to devise the most efficient dose. The safety trial will include about 30 patients and is expected to last about 18 months.
“A large part of our immune system – in healthy people – is devoted to suppressing this virus,” said Don Diamond, Ph.D., associate chair in City of Hope's Department of Virology and director of the Division of Translational Vaccine Research. “Evolutionarily, we have developed a very sophisticated immune assault on this virus. In transplant patients, this virus is a complication that can come up very early and begins to get out of control almost immediately.”
The new vaccine is a “next generation” vaccine, building on previous work by Diamond, who has been studying CMV and developing vaccines to fight it. Currently, a different vaccine to treat CMV is being used on an investigational basis in bone marrow transplant patients and has been successful so far.
The new vaccine has the potential to be more effective with fewer doses. Investigators on the trial hope that the vaccine will prevent infection not only in hematopoietic transplant patients, but in any immunocompromised patients, including those who receive organ transplants.
Jasson Duran is the first to volunteer for the study. Duran said he has family members who have had cancer, and that inspired him to want to help.
“Anything I can do to help out with patient care – or add to improving the treatment of cancer, I want to do,” Duran said.
For nearly three decades City of Hope has been studying CMV and seeking the best ways to control it, not just for cancer patients but for all who are adversely affected by the virus. In addition to conducting ongoing vaccine trials to limit its effect on transplant patients, Diamond and Zaia also are studying how to combat the virus for another patient population that is seriously affected: The virus is a major cause of birth defects, and affects as many as 5,000 babies each year.