1. Don't play D&D alone.
No one character can be proof against everything. Even without digging in the whole ruleset, I think it's fairly likely that there are various attacks which hit the Int-based casters particularly hard too. If you're playing with a balanced party, they'll have your back. Specifically,
The spell can also be ended by greater restoration, heal, or wish.
None of these are low-level (and greater restoration does have a token cost), but if you're at the level where this is a threat, the party should have these available. Greater restoration is a 5th level spell available to bards, clerics, and druids; heal a 6th level spell for clerics and druids; and wish, of course, a 9th level spell for sorcerers and wizards.
And, if you have none of those in your party, having a scroll of heal or greater restoration seems useful anyways (although the rules there don't seem to be in final form yet).
2. If your DM keeps doing it, ask them to stop
If you are playing a solo game, or for other reasons the above doesn't apply, talk to your DM about it.
Spells which shut you down with little opportunity to do anything to prepare or respond aren't fun. Nothing wrong with it being a real threat sometimes... it's an 8th-level spell, and it should be serious. But if your DM is casting this at you all the time... have a talk about that not really being a fun way to spend your time.
3. Talk to your DM (different approach)
The basic rules include a Ring of Evasion, which gives advantage on Dexterity saving throws and some other benefits. I don't see a strong reason why your character couldn't have (find, commission, create, etc...) a Ring of Mental Protection which does something similar for Intelligence saves. Again, this is all work-in-progress in the rules — presumably the DMG will have guidelines for creation of custom magic items. But this doesn't seem like it would be particularly controversial.
You might even ask for a ring which gives protection from this spell in specific. Since it is so situational, I really don't see why not. It'd probably take up one of your three "attuned" items, and were it my game that'd seem perfectly reasonable.