IRBs do not evaluate the value of a research endeavour. They are in fact unable to do this due to lack of knowledge and expertise. They approve trials which fit the mold of trials they have seen before. Why does a clinical trial get done? The main reason is that someone, usually a pharmaceutical or device company, is willing to pay for it.

Some recent examples of problems with clinical trials:

1. Using a harmful or deliberately inadequate placebo. https://academic.oup.com/jnci/article/104/4/273/979399 https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.122.0... https://pubmed.ncbi.nlm.nih.gov/34688044/

2. Starting a bunch of clinical trials using a biomarker which turned out to be invalid. https://www.nejm.org/doi/10.1056/NEJMoa1214271

3. Endless 'me-too' trials driven by pharma, with a low chance of success. https://www.statnews.com/2019/09/04/me-too-drugs-cancer-clin...