It’s not clear to me what sort of justification you’re looking for but the pharma company didn’t make the rules of this game.
Approved drugs which very few people use need to be very expensive if their development is to become profitable. The fewer patients, the more revenue is needed from each patient in order to recoup costs.
Again, malic acid clearly doesn’t do what pegloticase does. It is not an alternative.
Pegloticase treatment typically causes SUA to fall to a very low level. You took malic acid and your SUA increased from 6.9 to 7.6 which is consistent with a placebo and isn’t consistent with an intervention that does much to liquefy large tophi.
It is at this stage not a fact that malic acid has been instrumental in anything during your trial, just speculation.