Asia is full of countries America exploits, semi-exploits, isn't exploiting enough, or opposes entirely. The goal of that treaty would be to exploit those countries more, increase our power in future interactions, and reduce various risks they or their markets pose. Very different situation. However, methods elites in government and business use to achieve their objectives will be similar. Hence, the overlap in the two.
They just have more work to do and stronger competition on the Pacific side. ;)
Also, there's the practical reason - the Asian partners don't know the contents of TTIP because they're not parties to it. TTIP covers EU-US trade, and TPP covers Asia-US trade. I think these flows are larger than direct EU-Asia trade, but if not, it's up to the EU and the TPP partners to negotiate between themselves. Which is part of the untidiness of these trade deals happening outside of the WTO, but those global deals seem to be pretty dead; there are just too many parties involved with too many competing interests to come to a single deal that everyone's happy with.
The whole thing is a bit strange.
TPP allows new trade from China to the US, as automobile parts that will be counted as "Made in Japan/TPP" and qualify for reduced tariffs, http://www.ibtimes.com/trans-pacific-partnership-winners-toy...