Mepham has been a key figure for Sunderland, starting 25 games since his loan move in August, contributing significantly to their promotion push.
The Welsh defender has helped Sunderland secure a spot in the play-offs, with the team currently sitting fourth.
Sunderland’s sporting director, Kristjaan Speakman compared this situation to that of Wilson Isidor, who did make the same loan move permanent.
“I think Chris's situation is slightly different to Wilson's,” he said.
“Chris has had an unbelievable impact; I was going to say to the team but it would be better to say to the football club.
“Because of the way he carries himself around the training ground, how he is as part of our leadership team even as a loan player.
“It just echoes how important he is and has been. I think that's just a conversation we will pick up at the end of the season.
“From Chris's perspective and from our perspective, and from Bournemouth's perspective - that was always the plan.”