No. While made of a toxic plant, after it is prepared and baked, it no longer is toxic.
Cassava bread is bread baked out of the Cassava or Yuca plant flour (not to be confused with the different Yucca shrub). In its raw form, the Yuca plant is indeed toxic.
Yuca in its raw -- and toxic -- form.
One kilogram of Yuca can produce 20 milligrams of cyanide, a poison used as a murder weapon, for suicide and during world war 2 as a chemical weapon and in the concentration camp gas chambers. It may be poetic justice that those involved in these genocidal killings -- Himmler, Göring among others -- later committed suicide using the same toxin.
There are several methods to process the Yucca in order to cancel out the toxins such as soaking, cooking and fermenting. While improper preparation may leave slightly toxic residues behind that can cause goiters, ataxia or pancreatitis, this is rare. In general Yuca is cooked or baked for a long time in addition to soaking to become edible, which kills all of its toxicity.
Cassava undergoes various processes before consumed, including soaking and baking, and this leaves virtually no toxicity behind. All it is is a delicious cracker-like bread that is a great Gluten-alternative and delicious with all sorts of meals.
I can recommend using it as a pizza base.