The last letter to the editor in the September 5th edition of The New England Journal of Medicine, written from the Karolinska Institutet in Stockholm, just about knocked my socks off. I didn’t know that cytomegalovirus is expressed in several types of human cancers, but that in itself wouldn’t have startled me. But these investigators looked at patients with glioblastoma, a disease with a 2-year percent survival in the teens, and found that out of 250 such patients, only one was CMV-negative. CMV positivity is pretty common (80-90% in older people), but 249 out of 250 sounded significant enough to get my attention.
The Karolinska people found a significantly increased rate of 2-year survival in patients who received antiviral treatment: 50% vs. 21% in contemporary controls. So then they started treating all their glioblastoma patients with valganciclovir. Among patients who received at least 6 months of the drug, the 2-year rate of survival was 70%. Among patients who continued to receive valganciclovir after 6 months, the 2-year survival rate was 90%. They ended their letter modestly by saying that their results highlight the need for a randomized trial targeting CMV in patients with glioblastomas.
According to our most recent article on Antiviral Drugs, published in the March, 2013 issue of Treatment Guidelines from The Medical Letter, valganciclovir (Valcyte), an oral prodrug of ganciclovir, achieves plasma concentrations similar to those with IV administration of ganciclovir. It is FDA-approved for prevention of CMV disease in high-risk solid organ (kidney, heart, kidney-pancreas) transplant patients. The drug is also used in bone marrow transplant recipients for preemptive treatment of CMV disease (treating after detection of viremia or antigenemia). It has the same side effects as IV ganciclovir. Granulocytopenia, anemia and thrombocytopenia, which are usually reversible, are common and often dose-limiting. Other adverse effects include fever, rash, phlebitis, confusion, abnormal liver function, renal dysfunction, headache, GI toxicity and, rarely, psychiatric disturbances and seizures. Not a day in the country, but still…. I look forward to hearing much more about all this.