This news release summarizes a study in which researchers deployed a Zika virus vaccine to target and kill human glioblastoma brain cancer stem cells, which had been transplanted into mice.
Some of the weaknesses of a Newsweek story on this research which we also reviewed can be found in the news release. Namely, it lacks a discussion of potential harms in humans; fails to include a description of the evidence along with study limitations; and doesn’t provide strong cautions that outcomes in mice are seldom replicated in human studies.
The idea of using the “bad side” of viruses for good purposes is intriguing. What’s not so great about this release is that it’s a report of findings from a clinical trial in mice. This potential treatment hasn’t even begun testing in humans yet so there’s strong reason for caution. One systematic review of animal intervention studies found that only one-third of the most promising studies translated to successful interventions in people. And those took an average of 14 years to make it to humans.
Communications officials should set a high bar for releasing information to the general public about preliminary cancer research. Most animal studies belong within academic journals where they can inform the efforts of the scientific community toward cancer treatment — not in news releases where they may convey the inaccurate impression that we’re on the cusp of a breakthrough.
This release reports results of a clinical trial in mice. It’s too early to estimate costs for human treatment.
We learn from the release that mice with the attenuated zika virus lived 50 days, in comparison to mice in the control group that lived 30 days.
We’ll award a marginal satisfactory grade for this description, but we emphasize that it’s a huge leap from mice to humans. We’ll address that issue in more detail below under the evidence criterion.
The release reports that the treatment had “no health effects on the mice, no weight loss, and no behavioral abnormalities such as loss of appetite, depression, lethargy, or self-injury. The mice also functioned normally in tests for anxiety and motor function.”
However, we interpret “harms” to mean harms to humans. The release doesn’t describe any potential harms to humans.
There is minimal description of the evidence or how good it might be. The release suggests that based on the results of this research, an attenuated version of the Zika virus could “form the basis of a new treatment option for fatal brain cancer.” It could, but we won’t know that for years because this is the report of the results of a mouse trial. Medical research often starts with animal models, but very, very few such results pan out for use as treatments among humans. A cautionary comment about the tentative nature of mouse studies should have been included.
There is no disease mongering in this release. Incurable cancer is clearly a serious concern.
The funding source for the study is not mentioned.
The release states that normal cancer treatments such as radiation, surgery, and chemotherapy are not successful in the long run against human glioblastoma brain cancer.
It’s clear this treatment isn’t yet available for use in humans. The release could have put the findings into clearer perspective if it noted that availability for human use is years in the future, if ever.
The release does not mention that multiple versions of oncolytic viruses have been explored for virotherapy against human Glioblastoma, with promising results. Thus, although the use of Zika virus may be new, research into using viruses to treat this cancer is well under way.
It is too early for the release headline to suggest to that this therapy will be of benefit in human populations and unreasonable to suggest that humans would live longer based on this research.