This case series involving 25 patients looked at the effect of pembrolizumab on patients with pleural mesothelioma (a cancer that develops on the lining of the lungs) and found what appears to be an improved level of tolerance. By omitting many important details of the study, it’s very hard to determine what sort of advantage this treatment has over other existing treatments. Because this was a phase 1b safety trial, testing different doses for safety and side effects, it should be viewed with a healthy dose of skepticism until more carefully done controlled trials on effectiveness are completed.
The release makes an effort to show some restraint in describing the study but it may not be enough to counteract the many references to “evidence” claimed here. The release also omits some significant financial conflicts of interests among the study co-authors.
If there is a new class of drugs, checkpoint inhibitors, that are more effective than what’s been available in the past for mesothelioma, it could be a major advance for these patients. Unfortunately, this small study of 25 patients misses many important details and fails to establish the value of this therapy.
No mention of costs here. Describing cost information in new cancer therapies is essential as it will have a significant impact on future patient access.
The benefits aren’t put into clear context. It is only partially useful to know that 14 of 25 patients had “reduced tumor size” with pembrolizumab every two weeks. How much reduction was there?
Without a control group we have no idea how long patients would survive in the absence of the therapy, even if we are told in the release that “Most patients survive less than a year” with chemotherapy as the first-line treatment. We’re told that patients given pembrolizumab “went about six months without their disease progressing” and that 14 patients passed away during the study, and that four were still undergoing therapy.
How significant is it that 14 patients died during the study?
The study states the median survival from pembrolizumab treatment to be 5.7 to 10.7 months, very similar to the 6-7 months of standard second-line therapy noted in the news release.
Moreover, the goal of the study is to show safety, so claiming it’s “effective” is premature.
The release mentions that “the most common side-effects reported were fatigue, nausea, loss of appetite, and dry mouth,” but we have no idea of magnitude of those effects or whether more serious, less common effects may have occurred.
The study reported that 64% of the patients had a treatment related adverse effect, but this wasn’t mentioned in the news release. Side effects directly relate to quality of life and could be a deal-breaker for many patients.
We’ve outlined some of the common challenges in writing about harms from immunotherapy drugs in this guide for journalists.
We need to see caveats around this type of research including the lack of a control group, and the many possibilities of bias that are involved in non-blinded studies. Sometimes blinding is not possible for ethical or other reasons and that may be the case here. Even so, the limitations of non-blinded research should be acknowledged.
To its credit, the release notes at the bottom that multiple other studies are being undertaken as “a necessary step before the drug can become a standard second-line therapy.” However, it then claims that the study “provides evidence that some patients can have long-term disease control with this drug” which seems to negate that wise caution.
There release doesn’t engage in disease mongering. It provides ample context on what malignant pleural mesothelioma is and how often it occurs, as well as current treatment strategies.
The release notes that the study was funded by the manufacturer (Merck) and that no financial relationship exists between the lead researcher and the manufacturer.
However, according to the study, four of the co-authors do have individual conflicts of interest and three of the seven authors are Merck employees, two of whom own Merck stock options. These relationships go beyond Merck’s funding of the study and should have been mentioned in the news release.
The release mentions that chemotherapy is a first-line treatment for these types of mesotheliomas and it alludes to other standard therapies without naming them. We are not told of the potential of other therapies to treat this disease and the prognosis of those patients, nor the effectiveness or safety of competing therapies. We’ll give the benefit of the doubt but that additional information would have been helpful.
Mesothelioma patients would want to know if the drug is available for them and that’s not the case here. As used in a phase 1b study the drug is considered experimental.
We are told that this treatment is used for other types of cancer so presumably it’s on the market. There may be a risk that some oncologists will see the release and use the drug “off label” for mesothelioma, since it is available for other conditions.
The release states that the study “is the first to show a positive impact from checkpoint inhibitor immunotherapy drugs on this disease.” We’ll give the benefit of the doubt here since the study may be the first of its kind, but the phase 1b trial set out to show safety, not effectiveness.
The lead author is quoted as saying: “we’ve found this new class of drugs, checkpoint inhibitors, seems to be more effective than what’s been available in the past.” It is unclear that the trial proved its effectiveness and it certainly wasn’t compared to another drug.
And as noted above, claiming effectiveness based on a phase1b safety trial is unjustified and potentially dangerous since the drug is available to physicians who treat other cancers, they could use the drug to treat mesothelioma off label.