Patients with multiple myeloma who were treated with lenalidomide are susceptible to new-onset or reactivated varicella zoster infection, according to a new report.
Prophylactic acyclovir appears to minimize this risk, said Dr. C. König of the department of hematology and oncology, University of Freiburg (Germany) Medical Center, and associates.
Patients with multiple myeloma are known to be susceptible to infections from the myeloma itself; underlying immunodeficiency; the intensive therapies they receive; age-related conditions such as frailty and immobility; and disease-related conditions such as renal dysfunction, pulmonary impairment, or damage to the alimentary mucosa. In addition, specific antimyeloma agents such as bortezomib are known to raise the risk of varicella zoster virus reactivation or infection.
However, the risk of varicella zoster infection after treatment with lenalidomide is unknown.
Dr. König and colleagues reviewed the medical records of 132 consecutive multiple myeloma patients treated with lenalidomide at their center during a 4-year period and found that 10 (7.6%) had varicella zoster infections. Six patients were infected during treatment with lenalidomide or shortly afterward, and the other four were infected months later.
Of the 10 patients, 7 were men and 3 were women. Their ages ranged from 46 to 81 years
Seven of these cases were typical varicella zoster infections. In addition, one patient had varicella zoster encephalitis, one had disseminated varicella zoster, and one had varicella zoster with conus-cauda syndrome (Ann. Hematol. 2013 [doi:10.1007/s00277-013-1951-6]).
In two patients, the infection was a reactivation of latent varicella zoster.
Given that varicella is a known complication of other antimyeloma agents and acyclovir prophylaxis usually prevents it, Dr. König and associates then introduced routine acyclovir prophylaxis for their multiple myeloma patients slated to receive lenalidomide.
During the next 18 months, they treated 40 more multiple myeloma patients with lenalidomide, but only 37 of these patients adhered to the recommended daily acyclovir prophylaxis. None of those 37 developed varicella zoster infection. However, extensive varicella zoster developed in all three who didn’t take prophylactic acyclovir.
If these findings are confirmed in other, prospective studies, acyclovir prophylaxis may become routine for patients with multiple myeloma who are treated with lenalidomide, the investigators said.
It will be important to monitor renal function in such patients, given that antivirals are known to raise the risk of nephrotoxicity, they noted.
This study was supported by German Cancer Aid (Deutsche Krebshilfe). No financial conflicts of interest were reported.