Ted Cruz also dropped out of the race after finishing behind Trump in Indiana
Donald Trump looks to be the last remaining candidate in the Republican presidential pool as John Kasich is set to suspend his campaign.
Kasich had been scheduled to hold an event at Dulles Airport in Virginia, but canceled it to instead remain to Ohio, where where it is expected he will announce that he is suspending his campaign in a press conference on Wednesday evening.
On Tuesday evening, Texas senator Ted Cruz also announced that he was suspending his campaign "with a heavy heart, but with boundless optimism for the long term future of our nation."
Kasich had been dubbed the "only adult" at the GOP debates, which were characterised by name-calling and in-fighting among the candidates as they looked to avoid coming into the cross hairs of Donald Trump.
Kasich's only significant moment in the campaign to date was coming first in his home state of Ohio, but across the entire process he has only managed to pick up around 150 delegates.
By contrast, Trump now has over 1,000 and no competition remaining in the field as he heads towards the Republican National Convention in the summer. Kasich had been holding out hope that he, along with Cruz and others, would be able to stay in the race and hold out for a brokered convention, where delegates would not vote for Trump.
However, as the last man standing, the New York businessman is now on his way to being the GOP candidate for the general election in November.