"a spin-off from" is correct and usable in written English.
You can use it to describe something that is derived from something else. For example, "The popular TV show was a spin-off from the original movie."
KSI's app is a spin-off from his book.
It's a spin-off from Thomas' existing fitness DVD.
EnOcean GmbH was founded as a spin-off from Siemens.
"Hell in the Pacific" is a spin-off from a grim series made for British television.
The firm is a spin-off from Enel, Italy's partially privatised electricity utility.
Liquavista, a spin-off from Philips, a big Dutch electronics company, is trying something called "electrowetting".
However, there could be a spin-off from United's latest deal.
The bi-annual mag is a spin-off from Northern & Shell's OK! magazine.
This bloated website, a spin-off from the TV channel, is simply a hoot.
The original incorrectly described ArborGen as a spin-off from Monsanto.
There's a whole Slow City movement, too, a spin-off from Italy's Slow Food concept.
