Once P gets approved for psoriasis, will following

Once P gets approved for psoriasis, will following trials by other companies for other pill form psoriasis treatments have to better the results of P as to efficacy and safety to keep moving forward as it seems they would be bringing nothing new to the table unless some improvement in efficacy/safety were to be realized?

Does a drug ever lose their FDA approval if a better/safer drug comes down the pike? Thinking of Otezla since it would be behind P in both these areas.