The showrunners, Michael Green and Aïda Mashaka Croal, confirmed the news in a joint statement on Twitter.
"FX has decided not to move forward with our series in its current form," the pair wrote, before thanking the talent involved with the show. "We hoped to reward their talent and their trust not just with success but with a show that had something to say, in a time when things must be said. As Y fans ourselves, we hope the future allows just that."
Based on Y: The Last Man, the critically-acclaimed early 2000s Vertigo Comics series by Brian K. Vaughan and Pia Guerra, the series would've followed Yorick Brown and his pet Capuchin monkey Ampersand as they navigate a world where a plague has wiped out every other male mammal on Earth.
Up until this point, development on Y had apparently been going well. Last year, FX ordered a pilot and assembled an impressive cast for the series that included Diane Lane, Imogen Poots, Lashana Lynch, Juliana Canfield, Marin Ireland, Amber Tamblyn, Timothy Hutton and Barry Keoghan as Yorick. After the pilot was ordered to series in February, Keoghan even shared a photo from the series.
In a statement to Variety, a FX spokesperson said that the network planned to move forward on the series with the same cast and cited "creative differences" as the reason for the showrunners' exit.
While the show was expected to hit airwaves in 2020, it's currently unclear if the show is still on track for that premiere date.