The two viruses are not the same. SARS-COV2 is only 80% similar to SARS-COV. To put that in perspective, the difference between a human and a chimpanzee is ~6 million years and 1-1.5%. Obviously, there are major differences between humans and chimpanzees. Those differences matter. What works for SARS-COV may not work for SARS-COV2 and vice versa. This should not surprise anyone. Why? Because even the shift in as few as 30 nucleotides meant the difference between drugs working on the original wild type of SARS-COV2 and not working on Omicron.

The fact that a drug worked on SARS-COV is totally meaningless beyond that very initial phase of searching for potential drugs to test. We tested HCQ against the new virus. It failed. The viruses are not the same.