Tsuyoshi Ito has already answered this question, but I'd like to add one detail:
I think I see
目指すは〜 a lot more than other verbs followed by は. Although I can't find it in any dictionaries, from personal experience I think it might be common enough to be considered something like a set phrase, or possibly a holdover from when this grammar was more common.
Searching The Balanced Corpus of Contemporary Written Japanese (BCCWJ) for 目指すは, I find 73 results, of which 4 look like false positives (they matched はず rather than the particle は). So that's 69 results, and given the size of the corpus, I think that's a fairly large number. For comparison, the corpus has 194 results for カタツムリ.
A lot of the corpus results for 目指すは look something like this:
And that's more or less how I'm used to seeing this phrase used. Searching for the same phrase on Google gives a lot of similar results.
In any case, I think it's worth learning as a pattern of its own.