plumvj, your questions are like asking for the meaning of life...

plumvj, your questions are like asking for the meaning of life and yet in the world of biotech research, we actually do many tests to determine cause and effect. Before I go on, just remember that investing in this space is often compared to binary outcomes. In other words it either works and gets approved or it doesn’t get approved and you lose your stake. Try not to worry about the daily share price movements if you are a long term investor as worrying is about as useful in life as chewing bubblegum to solve algebra problems.
The data is coming in spades over the next 12 months across many trials and this will either result in a commercial outcome or it won’t. My guess is the stars are beginning to align on all fronts and a deal will get done in 2025 all going to plan.
Back to your question about outcomes being chance versus a result of our treatments:
Evidence-based medicine attempts to express clinical research using mathematical methods. Tools used by researchers include: the likelihood ratios, various (univariate or multivariate) statistical tests, the area under the receiver operator characteristic curve (ROC) and many others. Most Biotech companies use the p-value as it is one of the most widely used statistical terms in decision making in biomedical research, and it assists the investigators to conclude about the significance of a research consideration. Most researchers base their decision on the value of the probability p.In statistical theory, the p-value is a random variable defined over the sample space (i.e. the set of all possible outcomes) of the experiment, such that its distribution under the null hypothesis is uniform on the interval (0, 1).
For example, the p value for Her Vaxx was especially good indicating that the observed results were absolutely due to the treatment and not some other random outside influences. From memory it was a p value of 0.001 - exceptional.
Hope this helps.