Really more of an unnecessary clarification than a correction. A "billion dollar drug" would encompass any one that earns or is valued between $1B and $999B, no?
I routinely see drugs like Lipitor, Humira, and Keytruda referred to as billion dollar drugs. Obviously their annual sales peaked well above $1B.
Given Remdesivir had quarterly sales over $800M last year I would hope for Brilacidin to at least match that yielding over $3B in sales and a value quite a bit higher than that.