PlayPenn, Philadelphia’s prestigious play-development organization, has postponed its annual summer workshop — essentially its season — amid accusations of institutional racism and calls for leadership to resign. PlayPenn also announced it will sever ties with one of its donors.

Board president Stephan Schifter confirmed Saturday the postponement of 2020′s New Play Development Conference, where eight playwrights were scheduled to present plays virtually July 20-26. New dates for the conference — which provided work for more than 80 artists — have not been set.

On Friday, PlayPenn’s artistic director, Paul Meshejian, posted a letter on the organization’s website that pledged “a commitment to do better.” The letter acknowledged as true various accusations of racism recently raised by Philadelphia’s theater community, as well as allegations of sexual misconduct by a PlayPenn donor. The letter did not identify the donor.

“In light of the allegations made against this individual of inappropriate behavior from a handful of former PlayPenn interns and staff,” the letter read, “we have made the decision to return the individual’s most recent leadership gift and to end ties going forward.”

In four places the letter reads: “We failed.”

“We allowed the comforts of familiarity to stall our progress toward making PlayPenn’s administration and board more welcome to different voices, to LGBTQ+ people, to people of color. Our shared culture, whiteness, history, and vernacular, comfortable to us all, lulled us into inaction,” the letter says.

Later on it says: “We allowed this year’s Conference playwright selection not to adequately represent the diversity of the field. We made bad judgements in equitable promotion, in reader diversity, in the curatorial selection of our playwrights.”

Among the transgressions Meshejian addressed was a recent Metro Philly article about this year’s conference that overwhelmingly featured pictures of Black actors and directors, even though only one Black playwright was expected to participate. (The online story has since been updated with different pictures.)

“We didn’t realize what impact it would have,” Meshejian wrote, “because we have been largely blind to those concerns.”

Meshejian went on to outline steps PlayPenn will take to diversify its staff and its selection process for future conference participants.

The letter, which was also posted to PlayPenn’s Facebook page, prompted angry responses and calls for the resignations of Meshejian and associate artistic director Michele Volansky. A change.org petition calling for the organization to “fire Paul Meshejian” had garnered more than 200 signatures by Saturday evening. “This lip service is not enough!” the petition read. “Public trust is broken.”

Meshejian and Volansky could not immediately be reached for comment Saturday night.

This year would have been the 16th edition of PlayPenn’s summer workshop. Since 2005, the organization has helped to develop over 140 new plays, about 60% of which have been produced nationally and internationally. In 2017, one of the plays it helped develop — J.T. Rogers’ Oslo — was performed on Broadway and won the Obie and Tony awards for best play.