Prime Minister John Key has just attended a dinner hosted by President Barack Obama in the East Room of the White House.
It was for leaders in Washington attending Mr Obama's Nuclear Security Summit.
Mr Key said he sat between leaders of Hungary and Poland.
He had a brief chat to Mr Obama and was due to have a longer talk to him tomorrow where one of the subjects would be TPP, he told the Herald after the dinner.
Mr Key had dinner last night at the residence of ambassador Tim Groser, the former Trade Minister, along with United States Trade Representative Mike Froman and several sector group leaders.
He said no one had raised the issue of patents on biologic medicines with him, an issue in the TPP which irked so many in Congress that there has been talk that the US might try to get changes to the TPP agreement through side letters with countries.
"No one has raised biologics," Mr Key said.
"We thought that they might but ...the sort of general feedback from everybody is once you start trying to play around with re-negotiating then everybody has got something on their wish list."
"You'd just be effectively re-opening Atlanta and that is not a winning strategy."
Atlanta was where the final round of TPP negotiations was concluded in October last year among 12 countries: New Zealand, Singapore, Brunei, Chile, United States, Australia, Peru, Vietnam, Malaysia, Canada, Mexico and Japan.
Mr Key said the view in Washington was that the TPP was more likely to go through Congress during the lame-duck period between the November presidential election and January 20 when the new president would be sworn in.
"They are basically saying it is not guaranteed but that's what they think."
He said he had had a long conversation about TPP with Japan's Prime Minister, Shinzo Abe.
"They are pushing TPP legislation through their parliament at the moment and he was actually pushing Obama pretty hard to be sure he was going to pass it."