Dear Editor,
The authors indicate no conflict of interest and report no funding for this study.
The quest to find effective treatments in glioblastoma, with the exception of one agent in 20 years, continues to fail. One reason is the parading of ineffective treatments as “promising” based on flawed studies.
An underpowered randomized phase II study of valganciclovir demonstrated lack of efficacy,1 and yet a biased retrospective analysis subselecting favorable patients gets unwarranted publicity in the New England Journal of Medicine.2 Improved survival is claimed for 50 newly assembled valganciclovir patients, consisting of 22 from the experimental arm,1 8 crossover patients from the control arm1 (those who did well enough to make the crossover), and 20-odd patients treated outside a trial at the same institution.2 In all patients, valganciclovir was given only “when there was no evidence of progression” (ie, good prognosis patients). These were compared with a poorly characterized “contemporary control” group.
Looking at cytomegalovirus as a target may be reasonable, but to demonstrate efficacy of anti-cytomegalovirus strategies in glioblastoma needs well-designed prospective studies avoiding claims that are potentially misleading. On current evidence there is no justification to expose glioblastoma patients to valganciclovir outside a clinical trial.
References
- 1.Stragliotto G, Rahbar A, Solberg NW, et al. Effects of valganciclovir as an add-on therapy in patients with cytomegalovirus-positive glioblastoma: a randomized, double-blind, hypothesis-generating study. Int J Cancer. 2013;133:1204–1213. doi: 10.1002/ijc.28111. [DOI] [PubMed] [Google Scholar]
- 2.Söderberg-Naucler C, Rahbar A, Stragliotto G. Survival in patients with glioblastoma receiving valganciclovir. N Engl J Med. 2013;369:985–986. doi: 10.1056/NEJMc1302145. [DOI] [PubMed] [Google Scholar]