Wow, there is a lot of differing information on this plant!
No where did it say it was toxic, so I think you are safe there. And I found this:

A fact sheet published by the University of Florida's Cooperative Extension Service explains the differences between this plant, S. ovigerum, (grown as an inedible ornamental plant) and white fruit varieties of S. melongena, which are edible:

Fruit color:
S. ovigerum fruit is white when immature but turn yellow as they mature.

S. melongena fruit remains white at maturity, some with a hint of green.

Fruit size:
S. ovigerum fruit typically remains small, resembling their namesake hen's eggs in size and shape.

S. melongena white varieties grow to typical eggplant size at maturity, significantly larger than the ornamental fruit.

No is not poisonous at all. Is edible you can use it to make lots of different dishes. Love it. In North America we call it Easter eggplant or the wonder plan. In West Africa we call it garden eggs.
Afua