According to a couple of posts on the LF photorec.group someone received an Email from Agfa in Australia that APX 100 in sheet film will be discontinued and no longer manufactured. Reason given was the steady decline in the demand for sheet film by professional photographers who had made up the vast majority of users.

I don't know if it is true or not, but it makes sense considering most pros are going digital and from LF to medium or 35mm formats. The response from AGFA did state that it would continue to make APX100 120 and 35mm.