Bigger numbers are always nice but if there is no statistical significance for 87 patients i don't think 870 patients will fare much better, assuming they all have the same disease. Bigger numbers won't make something that doesn't work, work
The way stats testing works is that you try to reject the null hypothesis (that two groups are the same) and in doing do try to show a difference between the groups. In doing this the sample size makes a difference. This is why in doing a trial a power calculation is normally done to workout the chance given an effect that the null hypothesis will be rejected. It uses the sample size, predicted effect size and the significance test level (including multitest corrections). This is used to give a minimum estimated sample size for a trial to lead to significance given the predicted effect size. Its normally required for ethical approval.
So having more patients could lead to a significant result. However, they will have done a power calculation so it would suggest that the effect is smaller than predicted (if any).
The intuition would be something like if you draw more samples from a population and see an effect you get more certainty than if you draw a smaller number. But to me significance testing is not intuitive.