FDA Grants Fast Track Designation to PRGN-3006 UltraCAR-T in R/R Acute Myeloid Leukemia

Based on results from a phase 1 trial, the FDA has granted fast track designation to PRGN-3006 UltraCAR-Tin relapsed/refractory acute myeloid leukemia.

The FDA has granted fast track designation to PRGN-3006 UltraCAR-T for patients with relapsed/ refractory acute myeloid leukemia (AML), according to a press release from Precigen.1

PRGN-3006 is part of Precigen’s non-viral Sleeping Beauty system that simultaneously expresses a CAR targeting CD33. The UltraCAR-T platform was designed to overcome the limitations of current CAR-T therapies.

“We are very pleased to receive the FDA’s Fast Track designation, which facilitates development and expedites the review process of drugs that address serious conditions and high unmet medical needs,” Helen Sabzevari, PhD, president and CEO at Precigen, said in the press release.

The fast track designation is based off results from a phase 1 trial (NCT03927261) that assessed that use of PRGN-3006 in patients with relapsed/ refractory AML and myelodysplastic syndrome with. Results from the study were presented during the 2021 American Society of Hematology Annual Meeting were presented of 15 patients with relapsed/refractory AML and 6 patients with lymphodepletion.2

Patients in this trial were heavily pretreated with a median of 4 lines of therapy in the non-lymphodepletion group and 3 in the lymphodepletion group. In the non-lymphodepletion and lymphodepletion cohorts, respectively, 33% and 55% of patients progressed following prior allogeneic hematopoietic stem cell transplant (allo-HSCT). In both groups, all patients received 1 single infusion of PRGN-3006.

Following a single infusion of PRGN-3006, UltraCAR-T cells were observed in the blood for over 7 months after treatment.

Three patients in the non-lymphodepletion cohort had stable disease for more than 3 months, with 1 patient achieving durable stable disease for more than 7 months with concomitant reduction in peripheral blast levels.

In the lymphodepletion cohort, UltraCAR-T cells were observed 3 months post-infusion in ther peripheral blood and bone marrow. Moreover, peak espansion was noted on days 14 and 21 with an expansion over 10-fold. Patients had an objective response rate (ORR) of 50%. The ORR at dose level 1 where patients receiving 8.7x106 of PRGN-3006 was 33% and 67% at dose level 2, which was 28x106 . Additionally, 1 patient who received allo-HSCT during PRGN-3006 treatment had ongoing survival greater than 1 year.

Investigators reported that there were no dose limiting toxicities and no neurotoxicity at any dose level. In total, 70% of patients had grade 1 or 2 treatment-emergent adverse effects. Onr patient reported grade 3 cytokine release syndrome (CRS) that resolved within 24 hours following treatment. Other patients also experienced grade 1 and 2 CRS but did not require any intervention.

In June 2020, PRGN-3006 received orphan drug designation for patients with relapsed/refractory AML.3


  1. Precigen Received fast track designation for PRGN-3006 UltraCAR-T in patients with relapsed or refractory acute myeloid leukemia. News Release. Precigen. April 4, 2022. Accessed April 4, 2022. https://bit.ly/3u7fyXX
  2. Precigen announces positive interim phase 1 data for PRGN-3006 UltraCAR-T in relapsed or refractory acute myeloid leukemia. News Release. Precigen. December 13, 2021. Accessed April 4, 2022. https://bit.ly/3j57SiK
  3. Precigen Received FDA orphan drug designation for PRGN-3006 UltraCAR-T in patients with acute myeloid leukemia (AML). News Release. Precigen. June 6, 2021. Accessed April 4, 2022. https://bit.ly/3DHXTcz