Key Highlights

  • Phase 1/2 dosing in the OTC-HOPE study has been completed.
  • Low-dose cohort data presented at SSIEM showed a 57% reduction in hyperammonemic events and a 74% reduction in hyperammonemic crises.
  • The FDA previously granted RMAT designation and aligned with the company on trial endpoints, noted January 7, 2026.
  • The update was disclosed on August 27, 2026.

A Gene Therapy Approach to a Rare Metabolic Disorder

Precision BioSciences Inc. (NASDAQ:DTIL) is developing ECUR-506 for Ornithine Transcarbamylase (OTC) Deficiency, a rare genetic condition in which the body cannot properly break down ammonia, leading to potentially dangerous ammonia buildup in the blood. On August 27, 2026, the company confirmed that dosing in its Phase 1/2 OTC-HOPE study has been completed, while sharing new preclinical-stage data from the low-dose cohort at the SSIEM Symposium, a conference focused on inherited metabolic disease.

What the Data Showed

The low-dose cohort data showed a 57% reduction in the annualized rate of hyperammonemic events (HAEs), a statistically significant result (p=0.02), alongside a 74% reduction in the annualized rate of hyperammonemic crises (HACs), also statistically significant (p=0.01). Hyperammonemic crises are acute, potentially life-threatening episodes in OTC deficiency patients, so a reduction of this magnitude — if confirmed in later data — would represent a meaningful change in disease management for the population studied.

Regulatory Foundation

The current data builds on regulatory groundwork laid earlier in the year: on January 7, 2026, Precision BioSciences (NASDAQ:DTIL) said it had reached alignment with the FDA on the trial's endpoints, and that the FDA had granted Regenerative Medicine Advanced Therapy (RMAT) designation to the program — a designation intended for regenerative therapies, including certain gene therapies, that show promise in treating serious conditions and can qualify for expedited development and review support.

Market Reaction

Precision BioSciences (NASDAQ:DTIL) shares traded at $8.40, down 1.06%, with a market Capitalization of approximately $231.85 million.

What is ECUR-506 being developed to treat?

ECUR-506, developed by Precision BioSciences (NASDAQ:DTIL), is being developed for Ornithine Transcarbamylase (OTC) Deficiency, a rare metabolic disorder.

What did the low-dose cohort data show?

It showed a 57% reduction in hyperammonemic events and a 74% reduction in hyperammonemic crises, both statistically significant.

Has the FDA granted any special designation to this program?

Yes, the FDA granted RMAT (Regenerative Medicine Advanced Therapy) designation and aligned with the company on trial endpoints, as noted on January 7, 2026.