Prelude Therapeutics Announces Acceptance of Preclinical Abstract for PRT13722, a First-in-Class Oral KAT6A Selective Degrader at the 2026 AACR Annual Meeting

WILMINGTON, Del., March 17, 2026 -- Prelude Therapeutics Incorporated (Nasdaq: PRLD), a precision oncology company, today announced that a poster with preclinical data on the Company’s oral KAT6A selective degrader (PRT13722) has been accepted for presentation at the American Association for Cancer Research (AACR) Annual Meeting 2026, taking place from April 17-22.

“We look forward to sharing additional preclinical data from our potent and selective first-in-class KAT6A degrader development candidate, PRT13722. We believe that our selective KAT6A degrader, with the potential for improved efficacy and tolerability in combination with other standard of care agents, has the potential to be a promising new therapy for patients with ER+ breast cancer. We expect to file an IND in the middle of this year and enter clinical trials in the second half of 2026,” stated Peggy Scherle, Ph.D., Chief Scientific Officer of Prelude.

Details on the poster presentation are as follows:

Poster Details:
Title: First-in-class potent and selective oral KAT6A degrader development candidate, PRT13722, drives complete tumor regressions as a monotherapy with an improved pre-clinical hematological safety profile.
Session Category: Experimental and Molecular Therapeutics
Session Title: Proximity-Induced Drug Discovery 2
Session Start: 4/21/2026 2:00 PM
Session End: 4/21/2026 5:00 PM
Location: Poster Section 15
Poster Board Number: 20
Poster Number: 5793

Highly selective KAT6A oral degrader program
KAT6 is an emerging and recently validated target in the treatment of ER+ breast cancer. Prelude discovered and is developing first-in-class, highly potent, highly selective and orally bioavailable KAT6A selective degraders. The Company has selected a development candidate and remains on track to file an IND in mid-2026 with phase 1 study initiation planned in the 2

half of 2026. Prelude believes that selectively degrading KAT6A has the potential for improved efficacy, tolerability and combinability with other agents relative to non-selective inhibitors of KAT6A/B and KAT7.

The Company presented initial preclinical data supporting this hypothesis at the AACR Annual Meeting 2025.

Additionally, on April 18, 2026, Prelude’s Director of Biology and Translational Research, Norman Fultang, Ph.D. will be providing a lecture during an educational session entitled: ED08 – Chemistry to the Clinic Part 1 of 4: Next-Level Conjugates: Transforming Targeted Therapies. The title of the presentation is: “Beyond Conventional Payloads: Unlocking New Therapeutic Landscapes with Targeted Protein Degrader-Antibody Conjugates (DACs).”

About Prelude Therapeutics 
Prelude Therapeutics is a leading precision oncology company developing innovative medicines in areas of high unmet need for cancer patients. Our pipeline features highly selective KAT6A degraders and JAK2V617F mutant selective inhibitors -- new approaches to clinically validated targets with transformative potential for patients. We are leveraging our expertise in targeted protein degradation to create and develop next generation degrader antibody conjugates (DACs) with novel degrader payloads. We are on a mission to extend the promise of precision medicine to every cancer patient in need. For more information, visit preludetx.com.