A statement released by the freedom of expression advocates said Behairy tried to commit suicide on Sept. 9, adding that the incident took place "four days after resuming his hunger strike in protest against his prolonged arbitrary detention."
"We are deeply concerned about his health and well-being and hold the Egyptian authorities fully responsible for his suicide attempt," added the statement.
PEN gave no details on how Behairy tried to commit suicide.
PEN's president Burhan Sonmez expressed devastation towards the news of Behairy's suicide attempt while condemning his arrest.
"We are devastated to hear that such a prominent young poet nearly lost his life in prison and are relieved to learn that he survived his suicide attempt," Sonmez said.
Behairy "has done nothing but write poetry. He should be living his life as a free man ... not languishing in prison," he added.
The Egyptian poet was sentenced to three years in prison in 2018 for "insulting the military establishment" after publishing a collection of satirical poetry and writing song lyrics critical of the government.
Behairy was set for release in 2021 but the public prosecutor levelled a new charges against him for "joining a terrorist group and spreading false news."
The Egyptian Commission for Rights and Freedom said Behairy launched a hunger strike in March which lasted three months after refusing pen and paper and was subjected to round-the-clock cell lighting with visitation rights slashed to 20 minutes.
Behairy renewed his hunger strike on Sept. 5 as "he began his sixth year in jail," the commission added.
In 2020, Shady Habash, the director of the music video for the satirical song written by Behairy died in jail after more than two years in pre-trial detention.
Human rights groups have repeatedly criticized what they called a "revolving door" justice system in Egypt, in which prisoners are kept in jail to face new charges instead of being released.
In recent weeks, Egyptian authorities doled out presidential pardons and releases, in what many analysts deemed a bid to curry public and international favor ahead of next year's election.
Despite the release of nearly 1,000 political prisoners in the past year, non-governmental organizations argue almost three times as many have been detained over the same period.