mRNA vaccines benefited from the statistical power of having a widespread pandemic. Trials could simply do a double blind test and check how often the treatment subjects got covid vs. control. With thousands of study participants and a fast moving virus statistical power is reached quickly.
For cancers, the disease is slow moving and there are fewer patients seeking experimental treatment. Fewer still are willing to chance that they are part of a control group. The patients who do participate are likely taking multiple other treatments, limiting the statistical power of the trial.
For cancers, the disease is slow moving and there are fewer patients seeking experimental treatment. Fewer still are willing to chance that they are part of a control group. The patients who do participate are likely taking multiple other treatments, limiting the statistical power of the trial.