That's something we won't know till they are able

That's something we won't know till they are able to try it in humans. People with psoriasis have a high rate of progressing to psoriatic arthritis, so maybe if we can stop the psoriasis, presumably it stops the progression to arthritis too. But, if someone already has it, who knows? It could be that P will help, but it could also be that once the arthritic disease is set in motion, it continues.

Only clinical trials will give us the answer.