The companies Moderna and Merck revealed headline data late last month which suggested that when coupled with infusions of the immunotherapy Keytruda the mRNA vaccine, intismeran, reduced the odds that melanoma (skin cancer) that had been surgically removed would return or spread in patients. The personalized mRNA cancer vaccine has become the first of its kind to produce results like this in a Phase 3 trial, potentially opening the door to the first FDA-approved mRNA cancer treatment. Intismeran is tailored specifically to the unique genetic mutations of an individual patient’s tumor. This trains the immune system to recognize and attack the cancer cells.

However, while the press release calls the interim results a “statistically significant and clinically meaningful improvement” over the use of Keytruda alone, the drug makers have yet to release detailed data. Until the full dataset is presented in an independent, peer-reviewed setting, it may behoove the public to reserve judgement. This extends to all such press releases that precede complete data disclosure.

The Securities and Exchange Commission mandates prompt disclosure of “material” news, such as that pertaining to intismeran, that could affect the stock price and market valuation of a publicly traded company, including Phase 3 trial success. This can be in the form of topline data that confirms primary endpoints were met without giving the detailed datasets. This doesn’t just apply when there are positive data. Negative findings must also be made public. To illustrate, just last week Novartis announced a Phase 3 clinical trial failure for its cardiovascular drug, pelacarsen. The medication didn’t meet its primary endpoint of reducing major adverse cardiovascular events.

The SEC’s main mission is to protect investors from untoward actions such as insider trading. The agency’s job is not to evaluate medical science.

If results with respect to intismeran hold up , this could pave the way for novel approach to attack tumors. However, this remains an open scientific question. The public doesn’t yet know the clinical trial’s actual hazard ratio. This is the number that compares how often an event happens (recurrence or spread of melanoma in this case) in a treatment versus a control group. Nor are overall survival percentages provided in the press release. Delaying recurrence doesn’t necessarily translate into better overall survival. Neither are toxicity and safety data given, other than a claim that “no new safety signals have emerged.” In this context, it would seem that the public would benefit from knowing the exact rate of severe adverse events, treatment discontinuations or the specific side effects caused by adding intismeran to Keytruda.

This highlights an ongoing tension between financial regulation, as stipulated in SEC laws, and communication of scientific findings. Some observers argue that fuller data would offer a more complete and nuanced picture. Nevertheless, full data disclosure requires weeks or months of cleaning data, running statistical models and preparing formal manuscripts for peer review.

STAT News suggests that topline results from large pharmaceutical firms are rarely reversed once full datasets are published. While this appears to be true on the whole, there have been high-profile examples in which there’s a mismatch between initial and final results. Moreover, company communication teams may deploy spin tactics that exaggerate a treatment’s positive effects compared to the final, peer-reviewed data, or downplay risks.

Cases of the diabetes medicine Avandia, painkiller Vioxx and Alzheimer’s disease drugs simufilam and Aduhelm, come to mind. In the instance of Aduhelm , the full dataset revealed inconsistencies in the biologic’s ability to lessen cognitive decline and a relatively high rate of amyloid-related imaging abnormalities that showed brain bleeding and swelling. While Aduhelm cleared amyloid beta plaques, the data didn’t demonstrate a correlation between removal of the biomarker and a reduction in cognitive deterioration. This contradicted the sponsor’s claim that the drug worked. Two Phase 3 trials were halted in 2019 after a futility analysis suggested they would fail. The sponsor then re-examined data from both trials and claimed a subset of patients did derive positive effect in one of them while the other still showed no benefit. The sponsor’s assertion that safety risks were “manageable” flew in the face of the experience of more than 40% of patients taking high-dose Aduhelm who suffered brain swelling or bleeding.

Research published in PLOS Medicine found that nearly half of medical press releases and news stories spin data, leading readers to possibly overestimate a drug’s benefit in over 25% of cases.

In sum, while posting press releases containing headline data is standard industry practice and follows SEC laws, it can be problematic. It could, for example, buoy investor enthusiasm but not be grounded in peer-reviewed science. Until the full data packages are presented in settings in which independent review is a prerequisite, press releases should be judged with caution.